Change search
Refine search result
12 1 - 50 of 75
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abdi, Amir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Numerical investigation of melting in a cavity with vertically oriented fins2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 1027-1040Article in journal (Refereed)
    Abstract [en]

    This paper investigates the effect of vertical fins, as an enhancement technique, on the heat transfer rate and energy density of a latent heat thermal energy storage system. This contributes with knowledge on the interaction of heat transfer surface with the storage material for optimizing storage capacity (energy) and power (heat transfer rate). For the assessment, numerical modeling is employed to study the melting process in a two-dimensional rectangular cavity. The cavity is considered heated isothermally from the bottom with surface temperatures of 55 degrees C, 60 degrees C or 70 degrees C, while the other surfaces are insulated from the surrounding. Aluminum and lauric acid are considered as fin/enclosure material and phase change material, respectively. Vertical fins attached to the bottom surface are employed to enhance the charging rate, and a parametric study is carried out by varying the fin length and number of fins. Thus, a broad range of data is provided to analyze the influence of fin configurations on contributing natural convection patterns, as well as the effects on melting time, enhanced heat transfer rate and accumulated energy. The results show that in addition to increasing the heat transfer surface area, the installation of vertically oriented fins does not suppress the natural convection mechanism. This is as opposed to horizontal fins which in previous studies have shown tendencies to reduce the impact of natural convection. This paper also highlights how using longer fins offers a higher rate of heat transfer and a better overall heat transfer coefficient rather than increasing the number of fins. Also, fins do not only enhance the heat transfer performance in the corresponding melting time, but also maintain similar total amount of stored energy as compared to the no-fin case. This paper discusses how this is the result of the enhanced heat transfer allowing a larger portion of sensible heat to be recovered. For example, in the case with long fins, the relative mean power enhancement is about 200% with merely 6% capacity reduction, even though the amount of PCM in the cavity has been reduced by 12% as compared to the no-fin case. Although the basis for these results stems from the principles of thermodynamics, this paper is bringing it forward with design consideration. This is because despite its importance for making appropriate comparisons among heat transfer enhancement techniques in latent heat thermal energy storage, it has not been previously discussed in the literature. In the end, the aim is to accomplish robust storage systems in terms of power and energy density.

  • 2. Cabeza, Luisa F.
    et al.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, School of Business, Västerås, Sweden .
    Advances in energy storage research and development: The 12th International Conference on Energy Storage Innostock 20122013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, p. 291-292Article in journal (Other academic)
  • 3. Cabeza, Luisa F.
    et al.
    Miro, Laia
    Oro, Eduard
    de Gracia, Alvaro
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Kroenauer, Andreas
    Rathgeber, Christoph
    Farid, Mohammed M.
    Paksoy, Halime O.
    Martinez, Monica
    Ines Fernandez, A.
    CO2 mitigation accounting for Thermal Energy Storage (TES) case studies2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 155, p. 365-377Article in journal (Refereed)
    Abstract [en]

    According to the IPCC, societies can respond to climate changes by adapting to its impacts and by mitigation, that is, by reducing GHG emissions. No single technology can provide all of the mitigation potential in any sector, but many technologies have been acknowledged in being able to contribute to such potential. Among the technologies that can contribute in such potential, Thermal Energy Storage (TES) is not included explicitly, but implicitly as part of technologies such as energy supply, buildings, and industry. To enable a more detailed assessment of the CO2 mitigation potential of TES across many sectors, the group Annex 25 "Surplus heat management using advanced TES for CO2 mitigation" of the Energy Conservation through Energy Storage Implementing Agreement (ECES IA) of the International Energy Agency (AEI) present in this article the CO2 mitigation potential of different case studies with integrated TES. This potential is shown using operational and embodied CO2 parameters. Results are difficult to compare since TES is always designed in relation to its application, and each technology impacts the energy system as a whole to different extents. The applications analyzed for operational CO2 are refrigeration, solar power plants, mobile heat storage in industrial waste heat recovery, passive systems in buildings, ATES for a supermarket, greenhouse applications, and dishwasher with zeolite in Germany. The paper shows that the reason for mitigation is different in each application, from energy savings to larger solar share or lowering energy consumption from appliances. The mitigation potential dues to integrated TES is quantified in kg/MW h energy produced or heat delivered. Embodied CO2 in two TES case studies is presented, buildings and solar power plants.

  • 4.
    Castro Flores, J. Castro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Chiu, Justin Ningwei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Le Corre, O.
    Lacarrière, B.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Energetic and exergetic analysis of a low- Temperature based district heating substation for low energy buildings2015In: ECOS 2015 - 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems , 2015Conference paper (Refereed)
    Abstract [en]

    District Heating (DH) technology contributes to the low GHG emissions energy system, facilitates a renewable energy usage, and increases the overall system efficiency, while providing the necessary heating services to the built environment. However, the existing DH technology may not be technically and economically effective to service buildings with low-energy demands. Here, low- Temperature based district heating (LTDH) provides a better match between supply and demand in terms of energy quality. This paper deals with the energy and exergy analyses of a LTDH substation supplying a secondary LTDH network as a subnet of the existing DH system. The substation is supplied with a mix of supply and return flows from the main DH network. An energy and exergy analysis was employed based on modelling and simulation to compare the performance of two proposed substation configurations to that of a conventional DH substation operating at low- Temperature. The study was performed for a year round outdoor temperatures scenario under steady-state conditions. The exergy destruction at the system components was identified and compared. The results of this analysis show that by using the low- Temperature flow from the DH return pipe, the final exergy efficiency of the overall system is increased. On the other hand, assuming an adiabatic system the energy performance stays the same. As compared with the conventional DH network, the integration of the proposed LTDH substation reduced the share of energy demand covered by the main DH supply by 20-25% and improved the overall exergy efficiency from 79% to 85-87% depending on the substation configuration. Based on the results, the solution presented is seen as an effective approach to reduce the system's losses, and to increase the quality match between the low-energy heating demands and the supply.

  • 5.
    Castro Flores, José Fiacro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Lacarrière, Bruno
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Le Corre, Olivier
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Conceptual study of a solar-assisted low-temperature district heating substation2015In: Book of abstracts: International Conference on Smart EnergySystems and 4th Generation District Heating: Low-temperature district heating and buildings / [ed] Lund, H. (Ed.), & Mathiesen, B. V., Copenhagen, DK: Aalborg Universitetsforlag, 2015Conference paper (Refereed)
    Abstract [en]

    At present, the viability of Low-Temperature District Heating (LTDH) systems has already been tested and demonstrated. Even so, for LTDH to be successfully implemented, further ideas are needed in order to improve the flexibility and effectiveness. In this study, we analyze the performance of a local LTDH network for a multi-dwelling low-energy building supplied by both a roof-mounted solar collector and the conventional DH network via a LTDH substation. The DH network serves as a short-term storage buffer, so no heat storages are required. The collector’s size is chosen based on the available roof area, independently from the building’s loads, and three possible connection configurations were simulated. A mix of both the existing DH forward and return flows are used as thermal energy sources. The results show that more than 15% of the summer heat demand in the LTDH network can be covered by the roof-mounted solar collector. With a feed-in contract, heat costs savings range 3-6% annually according to the Swedish system. System integration in LTDH from the design phase has the potential to enhance the recovery of solar thermal energy, increase its conversion efficiency, and in general, to improve the utilization of low-grade thermal energy sources.

  • 6.
    Castro Flores, José Fiacro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Le Corre, Olivier
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Lacarrière, Bruno
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Energetic and exergetic analysis of alternative low-temperature based district heating substation arrangements2016In: International Journal of Thermodynamics, ISSN 1301-9724, Vol. 19, no 2, p. 71-80Article in journal (Refereed)
    Abstract [en]

    District Heating (DH) technology is an efficient and cost-effective solution to provide heating services to the built environment. However, the existing DH technology may not be technically and economically effective to service buildings with low energy demands. Here, low-temperature based district heating (LTDH) can provide a better match between supply and demand in terms of energy quality and quantity. This paper deals with the energy and exergy analyses of a LTDH substation supplying a secondary LTDH network as a subnet of the existing DH system. In order to improve the temperature match, a mix of supply and return streams from the main DH network are used to supply the substation. Based on modelling and simulation, an energy and exergy analysis is employed to compare the performance of two proposed substation configurations to that of a conventional DH substation operating at low temperatures. The results of this analysis show that the proposed LTDH substation reduced the share of energy demand covered by the main DH supply by 20% to 25%. Likewise, by using the flow from the main DH return pipe, the final exergy efficiency of the overall system increased by 5% on average. The exergy destruction occurring at the system components was also identified and compared: during high heat demands the substation heat exchanger is responsible for the largest share of exergy destruction, whereas for low heat demands, it is due to the pumping effort. Based on these results, the proposed system is seen as an effective approach to increase the quality and quantity match between the low-temperature network and the conventional supply.

  • 7.
    Castro Flores, José Fiacro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Lacarrière, Bruno
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Assessing the techno-economic impact of low-temperature subnets in conventional district heating networks2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 116, no C, p. 260-272Article in journal (Refereed)
    Abstract [en]

    The 4th generation Low-Temperature District Heating (LTDH) is envisioned as a more efficient and environmentally friendly solution to provide heating services to the building stock. Specifically, in countries already with a large share of well-established DH systems, conventional DH and LTDH technologies will be operating simultaneously in the near future. Newly built or refurbished buildings have lower heat demands, which in combination with LTDH brings potential savings compared to conventional DH. This work explores the advantages in DH operation by connecting these loads via LTDH subnets to a conventional DH system, supplied by a Combined Heat and Power (CHP) plant. A techno-economic analysis was performed, through modelling and simulation, by estimating the annual DH operating costs and revenues achieved by the reduction in return temperatures that LTDH would bring. The savings are related to: (1) the reduction in distribution heat losses in the return pipe; and (2) lower pumping power demand. Likewise, additional revenues are assessed from: (3) improved Power-to-Heat ratio for electricity production; and (4) enhanced heat recovery through Flue Gas Condensation (FGC). The annual savings per kWh of delivered heat are estimated as a function of the penetration percentage of ‘energy efficient’ loads over the conventional DH network. Key outcomes show the trade-offs between the potential savings in operating costs and the reduction in heat demand: relative losses in this scenario are maintained at 13.1% compared to 15.3% expected with conventional DH; and relative pumping power demand decreased as well. In other words, the costs of supplying heat decrease, even though the total heat supplied is reduced.

  • 8.
    Castro Flores, José Fiacro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Lacarrière, Bruno
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Le Corre, Olivier
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Study of a district heating substation using the return water of the main system to service a low-temperature secondary network2014In: Proceedings of The 14th International Symposium on District Heating and Cooling: Low temperature district heating and key developments for future energy systems / [ed] Anna LAND, Stockholm, SE: Swedish District Heating Association , 2014Conference paper (Refereed)
    Abstract [en]

    The development of district heating (DH) systems is facing the challenge of servicing areas with lower energy demands whose connection might not be either effective or profitable if the conventional DH technology is used. The purpose of this paper is to propose a complementary approach on how to effectively service low-energy building (LEB) areas using the existing DH networks. The proposed solution consists in supplying a secondary low-temperature (LT) network by means of a ‘low temperature’ substation that uses the return water from the main DH network as a substitute for the primary energy source, together with a minor portion of the main DH supply. Two types of LT substations are proposed and compared to a reference substation: First, a one-stage heat exchanger that uses a mixture of the main DH network return and supply flows as thermal energy source. Second, a two-stage heat exchanger that is fed by both the main DH return and supply flows. The system subject to this study consists on the LT substation with supply/return temperatures at 55/25 °C average. The system energetic performance is analysed though thermodynamic simulation. Outdoor ambient temperatures variations throughout the year are considered for two specific locations, assuming full and partial load operation. The results show that it is possible to supply 20-50% of the total annual heat demand of a LTDH network using the return flow from the main DH network. The solution presented in this paper is seen as being of potential interest to deliver thermal energy services to LEB areas.

  • 9.
    Castro Flores, José Fiacro
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Rossi Espagnet, Alberto
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lacarrière, Bruno
    IMT Atlantique - Energy Systems and Environment - DSEE.
    Techno-Economic Assessment of Active Latent Heat Thermal Energy Storage Systems with Low-Temperature District Heating2017In: International Journal of Sustainable Energy Planning and Management, ISSN 2246-2929, E-ISSN 2246-2929, p. 5-17Article in journal (Refereed)
    Abstract [en]

    Thermal energy storage (TES) is a set of technologies with the potential to enhance the efficiency and flexibility of the 4th generation of district heating systems. This study presents a comparative techno-economic assessment of active TES systems suited to operate with low-temperature district heating (LTDH) for short-term heat storage applications. Latent heat systems (LH-TES) are compared qualitatively and quantitatively to water-based sensible heat systems (SH-TES). It is concluded that latent heat TES systems are still more expensive than water-based systems regarding energy storage cost (EUR/kWh) ranging from 1.5 to 4 times more, mainly due to the cost of the storage media. However, considering distributed TES systems integrated to LTDH, small-scale active LH-TES systems will become more cost-competitive as storage media costs are expected to decline in the future. This study represents a step forward in the development and improvement of the DH system through the integration of TES which will play a key role in the future smart energy system.

  • 10.
    Chiu, Justin N. W.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Castro Flores, José Fiacro
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lacarrière, B.
    Industrial surplus heat transportation for use in district heating2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 110, p. 139-147Article in journal (Refereed)
    Abstract [en]

    M-TES (Mobile Thermal Energy Storage) technology is explored in this paper for transportation of industrial surplus heat for use in LTDH (low temperature district heating network). LTDH has promising potential in utilizing low grade heat, on the other hand, 20%–50% of industry generated surplus heat is often released to the ambient environment. M-TES is used to match thermal energy supply and demand that occur at different locations and that are shifted in time. In this paper, design of M-TES is conducted, optimization in operating strategies is performed, sensitivity analysis on levelized cost is studied, and environmental impact of CO2 emissions due to transportation is evaluated. The results of the study show an array of transportation means and storage operating strategies under which M-TES is technically, economically and environmentally sound for transportation of industrial surplus heat for use in LTDH network. © 2016 Elsevier Ltd

  • 11.
    Chiu, Justin N. W.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Industrial surplus heat storage in smart cities2015In: ASME 2015 9th International Conference on Energy Sustainability, ES 2015, collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum, American Society of Mechanical Engineers , 2015Conference paper (Refereed)
    Abstract [en]

    Surplus heat generated from industrial sectors amounts to between 20% and 50% of the total industrial energy input. Smart reuse of surplus heat resulted from industrial sectors and power generation companies is an opportunity to improve the overall energy efficiency through more efficient use the primary energy sources. A potential solution to tackle this issue is through use of thermal energy storage (TES) to match user demand to that of the generated surplus heat. A mobile TES (MTES) concept of transportation of industrial surplus heat from production sites to end customers has shown promising results. One commissioned demonstration project using industrial heat for swimming pool water temperature regulation in Dortmund, Germany proved the interest and attention given to this concept. In this paper, a techno-economic case study in Sweden of transportation of surplus thermal energy to district heating in smart cities is presented. The application consists of heat storage at 110°C- 130°C through the use of phase change materials (PCM) based TES, notably with use of Erythritol (90 kWh/ton) for the considered temperature range, to remote district heating network located at 48 km from the thermal energy generation site. The advantages of using latent heat based PCM are the high enthalpy density per unit volume and per unit mass, as well as the quasi-constant temperature during charging and releasing of heat. The M-TES in this study has a total storage capacity of 2.1 MWh, the optimization of charge/discharge time to the amount of stored/released energy and to that of energy transportation rate is presented in this paper. Contrary to logical thinking, it is shown through this work that under certain conditions, it is more cost-effective to operate at partial load of storage units albeit the increased number of transport trips and charge/discharge cycles.

  • 12.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gravoille, Pauline
    Ecole Nationale Supérieure de l'Energie, l'Eau et l'Environnement.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Active Free Cooling Optimization with Thermal Energy Storage in Stockholm2012In: InnoStock The 12th International Conference on Energy Storage: Book of Abstract / [ed] Stock Conference, 2012, p. 106-107Conference paper (Refereed)
    Abstract [en]

    In the goal of reaching an environmental benign society, energy saving through green building design has gained increasing attention. Passive buildings may cut down the energy requirement in winter through use of solar based heating, increased insulation and smart design of energy management. However it has also been shown that over insulated structures also create excessive heat gain in summer generating thus an increased cooling demand [1,2].

    In countries where the ambient environment is at sufficiently low temperature at night to act as a heat sink, thermal energy displacement from period when cold is available to period when cooling is needed may alleviate fossil fuel based cooling produced with conventional means. The displacement of thermal energy may be reliably achieved with use of Thermal Energy Storage (TES), such systems in buildings have been shown to provide better indoor thermal comfort by a number of researchers [3,4,5]. Direct advantages of using TESs are reduction in size of cooling equipment, decrease in electricity consumption, and better utilization of renewable sources.

    Phase change materials (PCMs) that rely on use of latent heat for storage of thermal energy prove to lead to more compact design of energy system and a steadier source temperature [6]. An environmentally friendly active free cooling solution with use of Latent Heat Thermal Energy Storage (LHTES) is proposed in this work where an optimization between cost, comfort level and storage design is studied and compared against conventional chillers in Stockholm climate.

  • 13.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gravoille, Pauline
    National Institute of Energy, Hydraulic and Environmental Engineering, Grenoble, France.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Active free cooling optimization with thermal energy storage in Stockholm2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 523-529Article in journal (Refereed)
    Abstract [en]

    Latent heat thermal energy storage (LHTES) integrated active free cooling stores night time cold and serves as heat sink for cooling when demand rises. Passive buildings, albeit their advantages in limiting heat loss during winter time, are often paired with excessive internal overheating in summer, as shown in the first part of this study. Under the climate condition in Stockholm, LHTES systems may provide solutions for sustainable cooling with use of renewable cooling sources. This study presents a multi-objective optimization on system cost and cooling supply for various LHTES configurations followed with a sensitivity analysis on phase change material cost and energy price. Results indicate that optimized LHTES may meet cooling needs while retaining economic viability. However, LHTES based cooling systems may require substantially higher electricity demand than conventional air conditioning unit for applications where high cooling thermal power rate is to be met, a tradeoff to indoor comfort level needs to be considered to reach the concept of sustainable free cooling. We here provide a novel techno-economic feasibility study of active free cooling LHTES in Stockholm as well as new insights to cost, comfort level and energy requirement with use of multi-objective optimization algorithm.

  • 14.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    ­Multistage Latent Heat Cold Thermal Energy Storage Design Analysis2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 1438-1445Article in journal (Refereed)
    Abstract [en]

    Thermal energy storage in cooling applications contributes to improvements in overall system efficiency as well as to better energy quality management. Latent heat thermal energy storage (LHTES) is used to provide load shifted thermal energy at small temperature swing with high storage density, hence an overall more compact energy system. However, the low thermal conductivity of the majority of the phase change materials (PCMs) necessitates delicate design of the active storage unit to meet power demand (high enough energy extraction/storage per amount of time).

    A performance analysis of two LHTES configurations is carried out in this work. Thermal charge and discharge rate of single PCM is compared with multistage LHTES using a cascade design of multiple PCMs at various phase change temperatures in a submerged finned pipe heat exchanger design. The work is conducted with a validated finite element based numerical simulation for evaluation of both full charge/discharge cycle and continuous half charge/discharge cycles.

    The results show that in full charge/discharge mode, the thermal performance of a multi-PCM LHTES may be improved by 10% to 40% as compared to that of a homogeneous­­ single-PCM storage unit in terms of thermal charge/discharge rate. This is due to the capability of the multistage LHTES to maintain a higher driving temperature difference for the heat transfer process in the charging and discharging processes. In half charge/discharge cycling mode, however, the thermal power rating performance of multi-PCM storage converges towards that of the single-PCM storage in melting process, reducing thus the multi-PCM enhancement. This work provides preliminary insights to multistage latent heat cold thermal energy storage design with finned pipe heat exchanger.

  • 15.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Submerged finned heat exchanger latent heat storage design and its experimental verification2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 93, no SI, p. 507-516Article in journal (Refereed)
    Abstract [en]

    Thermal energy storage (TES) has shown potential in improving the overall performance in energy systems, through shifting of thermal load demand, and through matching of uneven energy availability in time and in space. Latent heat TESs demonstrate advantages over sensible heat TESs for their high storage density and small temperature swing; however, lack of accurate knowledge in novel material properties and lack in a holistic design protocol often lead to difficulties in reaching technically viable storage design. With the aim of proposing a sound latent heat based TES design-to-validation protocol, this paper covers material property characterization through Temperature-history (T-history) method, heat exchanger design through heat transfer modeling, and model validation through experimental verification. A model for submerged cylindrically finned heat exchanger latent heat storage unit with phase change material was built. The results show that performance of gelled salt-hydrate based TES can be assessed with a pure conduction based model. This material property characterization-to-model verification approach may serve as a standard in providing accurate storage design for performance evaluation.

  • 16.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal Energy Storage: Climate Change Mitigation Solution?2011In: International Conference for Sustainable Energy Storage, Belfast, UK: University of Ulster , 2011Conference paper (Refereed)
    Abstract [en]

    Environmental well being and technology development are on the verge of collapsing. It has been asserted by IPCC that 30% of fauna and flora will face extinction by mid 21st century in the pursuit of business as usual path with current economic development pace. In order to minimize the anthropogenic related damage to the environment, a maximum level of 450ppm CO2 emission has to be maintained at all cost. Technologies that provide climate change mitigation solution and economic growth are hence the highlight; thermal energy storage (TES) is one among them. Energy storage provides the possibility to shift load from on peak energy demand to off peak thermal and electricity production, this results in lower energy flux in the system and therefore cuts down the marginal thermal and electricity production. This reduction in peak power demand translates to a decrease in marginal power production which, in today’s fossil fuel based economy, often pars with auxiliary and high carbon emitting thermal and electric power plants. This study provides a scenario analysis which quantifies the environmental benefit of TES implementation for the Swedish energy system. In the studied scenario, thermal energy storage will be implemented to the existing energy grid to alleviate peak electric and thermal power demand. The rate of implementation is paired with decrease in technology cost, reproduced from typical Learning Curve Model. The study shows that for the Swedish energy system, the total amount of fossil fuel used in heating of residential and service sectors is 19TWh, while reduction that can be achieved cost effectively with implementation of TES amounts to 2.5TWh. This corresponds to a Green House Gas (GHG) emission reduction of 620kton/year or 13% of total fossil fuel based emissions from heating in residential and service sectors.

     

  • 17.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal energy storage for sustainable future: impact of power enhancement on storage performance2010In: International Conference on Sustainable Refrigeration and Heat Pump Technology, Stockholm, June 13-16, 2010., 2010Conference paper (Refereed)
    Abstract [en]

    Sustainable future may be reached by means of maximizing the use of renewable energies through energy storage solutions. Active thermal storage exploits the potential of storing low cost, off-peak thermal cooling and heating for use at later time. Many studies have been carried out for optimization of energy storage systems through proactive planning of storage capacity design, fine tuning of control systems, and realization of cost effective scenario modeling. In the field of latent heat based thermal energy storage with use of phase change materials (PCM), low material thermal conductivity has shown to be one of the main barriers for providing sufficient cooling and heating power to the system. Thus, despite the apparent benefit of PCM-technology when it comes to large storage energy density, practical implementation of the technology has been hampered in many cases. Although a large number of available power enhancing techniques have been reported, the influence of power enhancement to the energy storage capacity has so far not been thoroughly assessed. In this paper, we perform an evaluation of power enhancing solutions and their impact on thermal energy storage density through theoretical modeling of a set of enhancement techniques. The techniques considered are: extended surfaced heat exchangers with various fin geometries (e.g. radial fins around circular piping) as well as PCM enhanced through blending with high conductive materials. Results analyses show the importance of balancing usable power with storable energy in the design of power enhancement technology, so as to achieve the maximum storage capacity while maintaining required extraction power load.

  • 18.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Setterwall, Fredrik
    A Review of Thermal Energy Storage Systems with Salt Hydrate Phase Change Materials for Comfort Cooling2009In: 11th International Conference on Thermal Energy Storage, June 14-17 , 2009, Stockholm, Sweden., 2009Conference paper (Refereed)
    Abstract [en]

    This paper presents a review of cold thermal energy storage technologies. Latent heat thermal energy storage (LHTES) with phase change materials (PCMs) deserves attention as they provide high energy density and small temperature change interval upon melting/solidifying. Salt hydrates are especially interesting since they demonstrate high latent heat of fusion, high thermal conductivity, low flammability, and facilitate the use in buildings as compared to organic PCMs. A review of system performance obtained from experimental work, theoretical analyses and real case studies has however shown some material shortcomings. To reach cost effectiveness, future work in the field of LHTES with salt hydrates lies in finding suitable methods for limiting incongruent melting and subcooling without compromising the storage density. Also, system integration of LHTES in cold applications can be further developed in terms of innovative design for high power and storage capacity, load optimized sizing, controls, and elimination of PCM encapsulation.

  • 19.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Setterwall, Fredrik
    Next Generation Cost Effective Phase Change Materials: TUD Action COST-STSM-TU0802-052552009Report (Other academic)
  • 20.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Setterwall, Fredrik
    System Integration of Latent Heat Thermal Energy Storage Systems for Comfort Cooling Integrated in district cooling network2009In: 11th International Conference on Thermal Energy Storage, EFFSTOCK 2009, Stockholm, Sweden, June 14-17, 2009., 2009Conference paper (Refereed)
    Abstract [en]

    Latent heat thermal energy storage for comfort cooling with phase change materials (PCMs) has increasingly gained attention. For effective system integration, an optimized strategy for load shifting to cut down peak hour energy use is needed. With the focus on overall system performance, this paper addresses matching of a cold storage capacity and power to a demand while assessing the cost effectiveness of the PCM technology. A simulation model based on one office building cooling load in Stockholm Sweden was used. Storage capacity, power output and PCM cost were shown to be the predominant factors in a system design. It has been found that load leveling can cost effectively reduce the peak load by 5% to 9% in a fixed tariff system. However, with 50% reduction in today’s PCM price combined with removal of district cooling return temperature penalty, the peak power reduction rate may be increased to 30%.

  • 21.
    Chiu, NingWei Justin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Castro Flores, José Fiacro
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Le Corre, Olivier
    École des Mines de Nantes, Energy Systems and Environment.
    Lacarrière, Bruno
    École des Mines de Nantes, Energy Systems and Environment.
    Environomic Assessment of Industrial Surplus Heat Transportation2015In: Smart Energy Infrastructure and Storage Options, 2015Conference paper (Refereed)
    Abstract [en]

    The fourth generation low temperature district heating network (LTDH) has to meet challenges in supplying low temperature heat, achieving low grid losses, integrating renewable heat sources, assimilating smart energy system and ensuring suitable planning structure. The new generation LTDH has promising potential in utilizing low grade waste heat where heat at temperature of as low as 55°C can be injected into the system. Industry generated surplus heat is often released to the ambient environment due to their remote location from end users. A solution is presented here to exploit the potential of recycling low grade industrial surplus heat for use in LTDH network.

    Mobile Thermal Energy Storage (M-TES) is used for shifting thermal energy to meet supply and demands that occur in different locations and that are shifted in time. M-TES technology is explored in this paper for utilization of industrial surplus heat in LTDH. Technical feasibility has been previously established with finned pipe and tube & shell type heat exchangers, however the economic justification is not always demonstrated. In this paper, parametric study on operating conditions, operating strategies and component costs will be performed. Furthermore, environmental impact from CO2 emissions due to different transportation means production will be evaluated against other heat production possibilities, such as conventional natural gas boilers. The results of the study show the optimal transportation distance, transportation means, partial/full storage operating conditions, storage means and power to energy ratio (PER) under which M-TES are technically, economically and environmentally sound for transportation of industrial surplus heat for use in the 4th generation LTDH network.

  • 22.
    Chiu, NingWei Justin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Meany, Bechara Hage
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Industrial Surplus Heat Utilization through Mobile Thermal Energy Storage with Enhanced Operating Strategy2015In: Greenstock: Industrial Energy Storage Application/ Transportation Energy Storage/ Grid integration, Beijing, 2015Conference paper (Refereed)
    Abstract [en]

    In Europe, 40% of the total energy use originates from the building sector and amounts to 36% of Europe’s Greenhouse Gas (GHG) emission (European Commission, 2013). With the smart use of a Phase Change Material (PCM) integrated Mobile Thermal Energy Storage (M-TES), industrial surplus heat may be transported to a District Heating (DH) network for building space heating and domestic hot water supply. Here, 2D and 3D numerical models were constructed for the design analysis of a latent heat (LH) M-TES. Thermal power performance is shown to be a tradeoff to storage capacity and varies exponentially to the shell and tube’s pitch to diameter ratio (PDR). For a fixed PDR configuration, the performance curve varies nonlinearly. Operating strategy with partial charge is shown to provide high thermal power when the demand arises, reducing thus the additional capital expenditure for extra tailor designed M-TES units. Partial storage is an essential control strategy for reaching economic sound mobile energy storage solution.

  • 23. Eriksson, Marcus
    et al.
    Lindmark, Susanne
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Martin, Viktoria
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Systems Study Of Absorption And Compression Chillers In A Combined District Cooling And District Heating System2003In: in Proceedings of the International Congress of Refrigeration 2003, Washington D.C., August 2003, 2003Conference paper (Refereed)
  • 24. Fujii, S.
    et al.
    Kanematsu, Y.
    Kikuchi, Y.
    Nakagaki, T.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Techno economic analysis of thermochemical energy storage and transport system utilizing "zeolite Boiler": Case study in Sweden2018In: Energy Procedia, Elsevier, 2018, p. 102-111Conference paper (Refereed)
    Abstract [en]

    Thermochemical energy storage and transport system utilizing zeolite steam adsorption and desorption cycle is one of the methods to resolve the mismatch between industrial surplus heat and heat demands. To generate 60°C hot water utilizing zeolite 13X, zeolite boiler employing moving bed and indirect heat exchanger was developed. Pressurized water is heated up and flash steam is injected into the zeolite bed for adsorption. A quasi - 2D model solving heat and mass conservation equations was developed, leading to a performance characterization of this zeolite boiler. The developed simulation model was used to predict performance of a heat charging device employing moving bed as well. Based on this calculation, a case study, heat transporting between a local steel works and a hotel was examined and all corresponding cost were fixed. The Levelized Cost of Energy (LCOE) results in around 60 €/MWh which is comparable cost against conventional pellet boiler. Sensitivity analysis showed both of cheaper transportation cost and larger zeolite capacity on the one trailer give a comparable impact on the LCOE.

  • 25.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Design Optimization of a Complex Polygeneration System for a Hospital2018In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, no 5, article id 1071Article in journal (Refereed)
    Abstract [en]

    Small-scale decentralized polygeneration systems have several energetic, economic and environmental benefits. However, using multiple energy sources and providing multiple energy services can lead to complicated studies which require advanced optimization techniques for determining optimal solutions. Furthermore, several parameters can influence the design and performance of a polygeneration system. In this study, the effects of heat load, renewable generation and storage units on the optimal design and performance of a polygeneration system for a hypothetical hospital located in northern Italy are investigated. The polygeneration system shows higher performance compared to the reference system, which is based on the separate generation of heat and power. It reduces fuel consumption by 14-32%, CO2 emissions by 10-29% and annualized total cost by 7-19%, for various studied scenarios. The avoided fuel and electricity purchase of the polygeneration system has a positive impact on the economy. This, together with the environmental and energetic benefits if the renewable generation and use of storage devices, indicate the viability and competitiveness of the system.

  • 26.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Design optimization of a small-scale polygeneration energy system in different climate zones in Iran2018In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, no 5, article id 1115Article in journal (Refereed)
    Abstract [en]

    Design and performance of polygeneration energy systems are highly influenced by several variables, including the climate zone, which can affect the load profile as well as the availability of renewable energy sources. To investigate the effects, in this study, the design of a polygeneration system for identical residential buildings that are located in three different climate zones in Iran has been investigated. To perform the study, a model has previously developed by the author is used. The performance of the polygeneration system in terms of energy, economy and environment were compared to each other. The results show significant energetic and environmental benefits of the implementation of polygeneration systems in Iran, especially in the building that is located in a hot climate, with a high cooling demand and a low heating demand. Optimal polygeneration system for an identical building has achieved a 27% carbon dioxide emission reduction in the cold climate, while this value is around 41% in the hot climate. However, when considering the price of electricity and gas in the current energy market in Iran, none of the systems are feasible and financial support mechanisms or other incentives are required to promote the application of decentralized polygeneration energy systems.

  • 27.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimal planning and design method for complex polygeneration systems: A case study for a residential building in ItalyManuscript (preprint) (Other academic)
    Abstract [en]

    Polygeneration energy systems using multiple energy sources (e.g., wind, biomass, solar) and delivering multiple energy services (i.e., heating, cooling, and electricity) have potential economic and environmental benefits over traditional energy generation systems. However, for maximized benefits, such systems must be the correct size and have a suitable operating strategy implemented. In this study, an optimization model is proposed to identify the optimal design and operating strategy of a complex polygeneration system. The system includes photovoltaic modules, solar thermal units, wind turbines, combined heat and power units, energy storages (hot, cold, and electric), vapor compression and absorption chillers, and a boiler. The interactions between these units are managed based on the integrated operating strategies: following thermal load, following electric load and modified base load. A particle swarm optimization is used as an optimization algorithm and the objective function is defined to minimize the annualized total cost, fuel consumption, and carbon dioxide emissions using a weighting factor method. The careful incorporation of the realistic operation of the CHP is considered in the theoretical model. This includes the effects of the part-load operation and outdoor temperature on the efficiency and power output of the CHP. In addition, the size dependency of the unit cost of the chillers and CHP units over the search space is taken into account. With this approach, the achieved results would be as close to real conditions as possible. Six configuration scenarios are examined for a case study in a residential building complex located in northern Italy. It is concluded that implementation of the optimized polygeneration system has energetic, economic, and environmental conservation benefits in all these scenarios. The annualized cost and fuel consumption of the optimal solutions decreased by 3–19% and 10–37%, respectively, for the various scenarios compared to the separate generation system.

  • 28.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    The choice of operating strategy for a complex polygeneration system: A case study for a residential building in Italy2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 163, p. 278-291Article in journal (Refereed)
    Abstract [en]

    The operating strategy can affect the optimal solution and performance of a polygeneration energy system. In this study, the effect of operating strategies: following thermal load; following electric load; and modified base load on the optimal solution of a polygeneration system for a residential building complex in the northern part of Italy is investigated. For the optimal solutions, a comparative analysis is carried out considering the techno-economic and environmental performance of the system. The result elaborates on how the benefits achieved in a polygeneration system are influenced by the choice of operating strategy. In the building complex, implementation of the operating strategies shows considerable energetic, economic and environmental benefits compared to conventional separate heat and power generation. The ranges of annualized total cost reduction of 17-19%, carbon dioxide emission reduction of 35-43% and fuel consumption reduction of 30-38% are achieved for the various operating strategies. However, each of the operating strategies has its own advantages and drawbacks which emphasizes the importance of post-processing of the results in order to make the right choice. For example, the following thermal load shows the advantage of a higher carbon dioxide emission reduction. On the other hand, one drawback is its lower self-sustainability in terms of electric power compared to the other strategies.

  • 29.
    Ghaem Sigarchian, Sara
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Malmquist, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    The choice of operating strategy for a complex polygeneration system: A case study for a residential building in Italy2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 163, p. 278-291Article in journal (Refereed)
    Abstract [en]

    The operating strategy can affect the optimal solution and performance of a polygeneration energy system. In this study, the effect of operating strategies: following thermal load; following electric load; and modified baseload on the optimal solution of a polygeneration system for a residential building complex in the northern part of Italy is investigated. For the optimal solutions, a comparative analysis is carried out considering the techno-economic and environmental performance of the system. The result elaborates on how the benefits achieved in a polygeneration system are influenced by the choice of operating strategy. In the building complex, implementation of the operating strategies shows considerable energetic, economic and environmental benefits compared to conventional separate heat and power generation. The ranges of annualized total cost reduction of 17–19%, carbon dioxide emission reduction of 35–43% and fuel consumption reduction of 30–38% are achieved for the various operating strategies. However, each of the operating strategies has its own advantages and drawbacks which emphasizes the importance of post-processing of the results in order to make the right choice. For example, the following thermal load shows the advantage of a higher carbon dioxide emission reduction. On the other hand, one drawback is its lower self-sustainability in terms of electric power compared to the other strategies.

  • 30.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Binary Phase Equilibrium Study of the Polyols Blend Erythritol-Xylitol with the T-History Method for Phase Change Materials Design2015In: The 13th International Conference on Energy Storage- Greenstock 2015, 2015Conference paper (Refereed)
    Abstract [en]

    Polyols are emerging PCM with attractive melting temperatures and enthalpies. The binary phase diagram of the system Erythritol-Xylitol is constructed using the Temperature-history method, and evaluated for its PCM-suitability. With blending, lowering of the melting points was expected, also verified with a recent study presenting the system as a simple eutectic. Herein, the tests covered the full compositional range, with thermal cycling around the previously reported eutectic. Some compositions exhibited possible glass transition after the first melting. For these, by seeding the starting material to the supercooled liquid, a preceding melting with heating was achieved. The results show several PCM suitable points in the phase diagram: eutectics and congruent melting compounds. This appears to be a partially isomorphous type, but not simple eutectic type. Microstructural evaluations for phase and miscibility verifications can further clarify this. For some compositions secondary phase changes were observed, indicating probable polymorphs, of solid-solid PCM interest.

  • 31.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Bigdeli, Sedigheh
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Computational Thermodynamics.
    Chiu, Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Thermodynamic assessment of binary erythritol-xylitol phase diagram for phase change materials design2018In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 60, p. 29-36Article in journal (Refereed)
    Abstract [en]

    Here, the erythritol-xylitol binary system was thermodynamically optimized based on available experimental phase equilibrium data, to explore compositions suitable as phase change materials (PCMs) for thermal energy storage (TES). A previous experimental study revealed that erythritol-xylitol was a partially isomorphous system with a eutectic. In the thermodynamic evaluation, the CALPHAD method was employed coupling the phase diagram and thermodynamic property information. There, both unary and binary systems’ experimental data were taken into account, and all phases were described using the substitutional solution model. Finally, a self-consistent thermodynamic description for the erythritol-xylitol system was achieved. The calculated eutectic point is at 76.7 °C and 26.8 mol% erythritol, agreeing well with the experimental data. The calculated phase diagram better-verifies the systems’ solidus and the solvus, disclosing the stable phase relations. Based on the Gibbs energy minimization, phase diagrams can be predicted for the binary and higher order systems, provided the component subsystems are thermodynamically assessed beforehand. In conclusion, to move forward beyond e.g. non-isomorphous simple eutectic systems, methods using Gibbs free energy minimization from a fundamental point-of-view such as CALPHAD are essential.

  • 32.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Phase Diagrams as Effective Tools in Thermal Energy Storage (TES) Design using Phase Change Materials (PCM)2013In: ICAE2013, 2013Conference paper (Refereed)
    Abstract [en]

    Phase diagrams are invaluable in the design of thermal energy storage systems using phase change materials (PCM). They provide important information such as the phase change composition and constitution of the system, as well as an understanding of phenomena like incongruent melting, phase segregation, and subcooling. In this work, the significance of phase diagrams to evaluate a chemical system’s behavior and it’s suitability as a candidate PCM is analyzed along with discussing example systems based on salt, paraffin, fatty acid and sugar alcohol. For a binary system, a number of specific phase changing behaviors are found appropriate for a PCM due to their sharp, definite melting temperatures and proper melting/freezing behaviors. For example, isomorphous minimum or maximum melting types and eutectics of immiscible (non isomorphous) or partially miscible types are all suitable. A system’s miscibility distribution thus governs its suitability as a PCM since it determines the type of phase change. For determining miscibility and constructing theoretical phase diagrams the Gibbs free energy derivatives as well as experiments are useful. In conclusion it is here presented that phase equilibrium studies should be included in a derived protocol for determining suitable PCM candidates for the future. 

  • 33.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Phase equilibrium in the design of phase change materials for thermal energy storage: State-of-the-art2017In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 73, p. 558-581Article, review/survey (Refereed)
    Abstract [en]

    This paper presents a review of phase equilibrium as a tool for accurately identifying suitable blended phasechange materials (PCMs) to be used for thermal energy storage (TES). PCM storage increases the overall energyefficiency for many applications, however, high cost and complex phase change phenomena in blends oftenundermine the benefits. The study of phase equilibrium as derived from phase diagrams is the key to solve theseissues. It enables the evaluation of PCM-suitability through indication of temperature-composition points, e.g.congruent melting compositions, eutectics and peritectics. To clearly stake out the opportunities of a phaseequilibrium-based design methodology, this paper reviews the state-of-the-art based on findings from fourdecades (1977–2016). On one hand, eutectics, salts-based systems, fatty acids, and alkanes dominate theexisting PCM literature. Here peritectics have often been erroneously praised as suitable PCMs despite the manyproblems depicted from a phase equilibrium point of view. On the other hand, the most PCM-ideal congruentmelting systems, as well as the blends of polyols, fats, metal alloys and organic-inorganic combinations lack fullattention. This work brings forward the knowledge on these insufficiently explored yet extremely suitable phaseequilibrium characteristics. In addition, comprehensive PCM-design thermal properties of these various blendsare presented, as a basis to further extensive explorations, and material category-based predictions.

  • 34.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Pan, Ruijun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Polyols as phase change materials for low-grade excess heat storage2014In: Energy Procedia: Volume 61, International Conference on Applied Energy, ICAE2014, Elsevier, 2014, p. 664-669Conference paper (Refereed)
    Abstract [en]

    Polyols are an emerging phase change materials (PCM) category for thermal energy storage (TES), with moderate phase change temperatures and considerable enthalpies. These can be employed in systems for harvesting surplus energy from, industrial and power generation processes. However, knowledge on the properties of polyols in relation to desirable PCM properties is presently sparse and rather inconsistent. This work summarizes a literature review on polyols as PCM for TES. In addition, preliminary T-History characterization of some selected polyols was done. This study is expected to be an initiation of an extensive polyol phase equilibrium evaluation.

  • 35.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Pan, Ruijun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538 75121 Uppsala, Sweden.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Polyols as phase change materials for surplus thermal energy storage2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 1439-1452Article in journal (Refereed)
    Abstract [en]

    Storing low-temperature surplus thermal energy from industries, power plants, and the like, using phasechange materials (PCM) is an effective alternative in alleviating the use of fossil based thermal energyprovision. Polyols; of some also known as sugar alcohols, are an emerging PCM category for thermalenergy storage (TES). A review on polyols as PCM for TES shows that polyols have phase change temperaturesin the range of 15 to 245 C, and considerable phase change enthalpies of 100–413 kJ/kg. However,the knowledge on the thermo-physical properties of polyols as desirable PCM for TES design is presentlysparse and rather inconsistent. Moreover, the phase change and state change behaviors of polyols need tobe better-understood in order to use these as PCM; e.g. the state change glass transition which manypolyols at pure state are found to undergo. In this work preliminary material property characterizationwith the use of Temperature-History method of some selected polyols, Erythritol, Xylitol andPolyethylene glycol (PEG) 10,000 were done. Complex behaviors were observed for some of the polyols.These are: two different melting temperatures, 118.5–120 C and 106–108 C at different cycles and anaverage subcooling 18.5 C of for Erythritol, probable glass-transition between 0 and 113 C for Xylitol,as well as a thermally activated change that is likely an oxidation, after three to five heating/coolingcycles for Xylitol and Erythritol. PEG 10,000 had negligible subcooling, no glass-transition nor thermallyactivated oxidation. However a hysteresis of around 10 C was observed for PEG 10,000. Therefore thesematerials require detailed studies to further evaluate their PCM-suitability. This study is expected to be an initiation of an upcoming extensive polyol-blends phase equilibrium evaluation.

  • 36.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Experimental Phase Diagram Study of the Binary Polyols System Erythritol-Xylitol2017In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 174, p. 248-262Article in journal (Refereed)
    Abstract [en]

    A comprehensive phase diagram for the binary polyols system erythritol-xylitol has been mapped with a transparent characterization approach. Here, the phase equilibrium of the system has been studied experimentally using a combination of methods: Temperature-history (T-history), X-Ray Diffraction (XRD), and Field-Emission Scanning Electron Microscopy (FESEM), and linked to Tammann plots. Existing literature has previously shown the system to be a non-isomorphous type forming a simple eutectic, by combining experimental data with theoretical modelling. The present investigation shows that the system’s phase diagram is a partially isomorphous type forming a eutectic, but not a non-isomorphous type forming a simple eutectic. Here, the eutectic was found within 25-30 mol% erythritol and at 77 °C, which differs from the previous studies identifying the eutectic respectively at 25 or 36 mol% erythritol and at 82 °C. The reasons for the differences are hard to deduce since the research approach is not presented as fully transparent from the past studies. In the present study, only the temperature-composition plot of the first melting (of the two components in a physical mix, but not of a single blend) indicated the shape of a simple eutectic in a non-isomorphous system. The cycles after the first melting in contrast started from the real blend, and displayed eutectic and solid-solid phase changes in T-history. These were verified as forming solid solutions with XRD and FESEM. This eutectic melts at a temperature suitable for low-temperature solar heating, but displayed glass transition, supercooling, and thermally activated degradation, thus affecting its practical aspects as a PCM.

  • 37.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ignatowicz, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal conductivity measurement of erythritol, xylitol, and their blends for phase change material design: A methodological study2019In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 43, no 5, p. 1785-1801Article in journal (Refereed)
    Abstract [en]

    This work presents and discusses a detailed thermal conductivity assessment of erythritol, xylitol, and their blends: 25 mol% erythritol and 80 mol% erythritol using the transient plane source (TPS) method with a Hot Disk Thermal Constants Analyzer TPS‐2500S. Thereby, the thermal conductivities of xylitol, 25 mol% erythritol, 80 mol% erythritol, and erythritol were here found for respectively in the solid state to be 0.373, 0.394, 0.535, and 0.589 W m−1 K−1 and in the liquid state to be 0.433, 0.402, 0.363, and 0.321 W m−1 K−1. These obtained results are comprehensively and critically analyzed as compared to available literature data on the same materials, in the phase change materials (PCMs) design context. This study clearly indicates that these thermal conductivity data in literature have considerable discrepancies between the literature sources and as compared to the data obtained in the present investigation. Primary reasons for these disparities are identified here as the lack of sufficiently transparent and repeatable data and procedure reporting, and relevant standards in this context. To exemplify the significance of such transparent and repeatable data reporting in thermal conductivity evaluations in the PCM design context, here focused on the TPS method, a comprehensive measurement validation is discussed along various residual plots obtained for varying input parameters (ie, the heating power and time). Clearly, the variations in the input parameters give rise to various thermal conductivity results, where choosing the most coherent result requires a sequence of efforts per material, because there are no universally valid conditions. Transparent and repeatable data and procedure reporting are the key to achieve comparable thermal conductivity results, which are essential for the correct design of thermal energy storage systems using PCMs.

    The full text will be freely available from 2020-02-22 10:37
  • 38.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ignatowicz, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Thermal Conductivity Measurement of Erythritol, Xylitol and Their Blends for Phase Change Materials Design: a Methodological Study2018In: The 14th International Conference on Energy Storage, Adana, Turkey: IEA ECES , 2018, p. 364-378, article id 82Conference paper (Refereed)
    Abstract [en]

    This work presents and discusses a detailed thermal conductivity assessment of erythritol, xylitol and their blends: 25 mol% erythritol and 80 mol% erythritol using the Transient Plane Source (TPS) method with a Hot Disk Thermal Constants Analyzer TPS-2500S. Their thermal conductivities were here found to be respectively: 0.59; 0.37; 0.39 and 0.54 W/(m·K) in the solid state, and to be 0.32; 0.43; 0.40 and 0.36 W/(m·K) in the liquid state. These obtained results are comprehensively and critically analyzed as compared to available literature data on the same materials, in the phase change materials (PCMs) design context. This study clearly indicates that the literature has considerable discrepancies among their presented thermal conductivities, and also as compared to the values found through the present investigation. Primary reason for these disparities are identified here as the lack of sufficiently transparent and repeatable data and procedure reporting, and relevant standards in this context. To exemplify the significance of such transparent and repeatable data reporting in thermal conductivity evaluations in the PCM design context, here focused on the TPS method, a comprehensive measurement validation is discussed along various residual plots obtained for varying input parameters (i.e., the heating power and time). Clearly, the variations in the input parameters give rise to various thermal conductivity results, where choosing the most coherent result requires a sequence of efforts per material, but there are no universally valid conditions. Transparent and repeatable data and procedure reporting is the key to achieve comparable thermal conductivity results, which are essential for the correct design of thermal energy storage systems using PCMs.

  • 39.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Kumova, Sofia
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Gubkin Russian State University of Oil and Gas, Russia.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental Phase Equilibrium Study of Dodecane-Tridecane System for Phase Change Materials Design for Thermal Energy Storage2016Conference paper (Other academic)
  • 40.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Laios, Michail
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Karabanova, Anastasiia
    Technical University of Denmark - DTU.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Blanchard, Didier
    Technical University of Denmark - DTU.
    Design of a bench-scale ammonia-SrCl2 thermochemical storage system using numerical modelling2019In: Eurotherm Seminar #112 - Advances in Thermal Energy Storage, Lleida, 2019, article id D128Conference paper (Other academic)
    Abstract [en]

    This work presents the numerical modelling of a bench-scale thermochemical storage (TCS) system based on the reversible absorption-desorption of ammonia in strontium chloride. The modelling is performed using the ASPEN software and was validated against experimental data from literature on a different TCS system configuration but using the same reaction pair. The modelled TCS system in this work comprises two identical reactors, alternatively operating as absorber or desorber with a storage capacity of 0.5 kWh. The system is designed to store and release heat under 8 bar of NH3 pressure, with the two identical reactors respectively undergoing desorption at 82 °C and absorption at 79 °C. Together with the two reactors, a liquid ammonia storage tank is used as a buffer (10 bar at 25 oC). The desorption half-cycle of the system is made of the desorber (82 °C, 8 bar), a compressor (8-10 bar), a cooler (108-25 °C), a pump (to pump liquid ammonia) and the liquid ammonia storage (25 °C, 10 bar). The absorption half-cycle starts form the liquid ammonia storage tank and goes via an expansion valve (10-8 bar) and then a heater (18-25 °C) towards the absorber (79 °C, 8 bar). In the model, the desorption and absorption are respectively driven by an external heater and cooler, which represent a waste heat source and a heat sink respectively. The efficiency of the TCS system was found to be of 67 % and 61 % for the absorption and desorption half-cycles, respectively. A sensitivity analysis was also conducted to identify optimum operating conditions. In conclusion, this study presents an ammonia-SrCl2 TCS bench-scale system that allows simultaneous heat storage and retrieval, as the basis for the practical construction of the system. This is expected to provide inspiration and operational analysis to accommodate the design of similar TCS systems for storing surplus industrial heat.

  • 41.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Bigdeli, Sedigheh
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermodynamic Assessment of Binary Erythritol-Xylitol Phase Diagram for Phase Change Materials DesignManuscript (preprint) (Other academic)
    Abstract [en]

    Here, the experimental phase equilibrium data of the erythritol-xylitol system were thermodynamically optimized, to explore compositions suitable as phase change materials (PCMs) for thermal energy storage (TES). A previous experimental study revealed that erythritol-xylitol was a partially isomorphous system with a eutectic. In the thermodynamic evaluation, the CALPHAD method was employed coupling the phase diagram and thermodynamic property information. There, both unary and binary systems’ experimental data were taken into account, and all phases were described using the substitutional solution model. Finally, a self-consistent thermodynamic description for the erythritol-xylitol system was achieved. The calculated eutectic point is at 76.7 °C and 26.8 mol% erythritol, agreeing well with the experimental data. The calculated phase diagram better-verifies the systems’ solidus and the solvus, disclosing the stable phase relations. Based on the Gibbs energy minimization, phase diagrams can be predicted for the binary and higher order systems, provided the component subsystems are thermodynamically assessed beforehand. In conclusion, to move forward beyond e.g. non-isomorphous simple eutectic systems, methods using Gibbs free energy minimization from a fundamental point-of-view such as CALPHAD are essential.

  • 42.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Edén, Ted
    Norrenergi AB, Solna, Sweden.
    Sedeqi, Faisal
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Tavares, Miguel
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Mayo Nardone, Pablo Sabino
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Distributed cold storages for district cooling in Sweden- The current context and opportunities for the cold supply expansion2019Conference paper (Other academic)
    Abstract [en]

    This work analyzes the current context of district cooling (DC) in Sweden and thereby proposes opportunities in cost-effective and environmentally friendly expansion of cold supplies. The current state of DHC in Sweden here is mapped via a comprehensive literature assessment coupled with information collection from individual DHC suppliers in Sweden. These findings are concisely discussed herein, mapping the current context of DC in Sweden. The investigation here yields that the cold supply in Sweden today is achieved by employing free cooling (FC, extracting cold from natural cold sources, e.g. deep sea, river or lake water, via heat exchangers), absorption coolers (ACs), compression coolers (CCs) as well as heat pumps (HPs, with or without heat recovery), and cold storages (mainly using water). This technology mix is used in varying shares by different regions, based on the available resources, e.g. large water bodies to drive FC. When excess heat is available, AC is also a preferred choice. HPs are becoming increasingly interesting, for their synergies in simultaneously providing heat and cold. The peak demands of cold are met with cold storages as well as more ‘operationally’ expensive technologies, such as CCs. The cold storages primarily cover the daily cold peaks in summer, driven by the large differences in the cooling loads between the day and night. The current DC provision in Sweden is around 1 TWh, while the total cooling demand is around 3-5 TWh, therefore with a clear deficit in supply. Interestingly, the DC supply is projected to grow up to around 3 TWh by 2030. With population growth, the DC demands will also rise, and fulfilling these cooling demands with cost-effective and renewable solutions is imperative. To inspire the Swedish DC growth, herein certain international examples on power-to-cold (PtC) combining peak shaving with cold storages, e.g. based on water, ice, and thermochemical heat storage systems (TCS) are also discussed. Finally, critical reflections are given, identifying opportunities to improve the current context of DC in Sweden with cost-effective and environmental-friendly solutions.

  • 43.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Stalin, Joseph
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Marçal, Mariana
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Delubac, Regis
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. University of Pau and Pays de l'Adour, France.
    Karabanova, Anastasiya
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Gubkin Russian State University of Oil and Gas, Russia.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Erythritol, Glycerol, their Blends, and Olive Oil, as Sustainable Phase Change Materials2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 135, p. 249-262Article in journal (Refereed)
    Abstract [en]

    In searching for new candidates to be used in latent heat storage, it is desirable to explore food-grade materials of renewable origin. Here, erythritol, glycerol, and olive oil have been characterized as PCMs. An assessment of the production process of erythritol (melting between 117-120 °C with an enthalpy around 300 kJ/kg) indicates its renewable aspects as a PCM. In addition, a simplified cost assessment of high-purity erythritol production, using glycerol, indicates a potential cost reductions up to 130-1820 times lower than the current laboratory-grade prices. Glycerol already is cost-effective. However, the glycerol-erythritol system, evaluated using the Temperature-history (T-history) method, did not exhibit phase change suitable for PCMs. Glycerol, and up to 30 mol% erythritol compositions had no phase change due to glass transition; the remainder froze but with large supercooling; and the system underwent thermally activated change. Hence, to realize glycerol or the glycerol-erythritol system as PCMs, further research is needed primarily to device fast-crystallization. Olive oil is a cost-effective food commodity, with potential for further cost reductions by mass-production. An olive oil sample, containing the fatty acids: linoleic, palmitic, oleic, margaric, and stearic was evaluated using the T-history method. This olive oil melted and froze between -4.5 to 10.4 °C and -8 to -11.9 °C respectively, with the respective enthalpies 105 and 97 kJ/kg. As the specific heat (cp) profiles of olive oil displayed two peaks, the composition adjustment of olive oil could yield a eutectic or confirm a polymorph. In either case, olive oil has a potential to be a PCM e.g. in chilling applications, while its properties such as thermal conductivity need to be determined. As a whole, this study exemplifies the potential of renewable organic materials, in pure and blend forms, as sustainable PCMs, making TES with PCMs sustainable.

  • 44. He, B.
    et al.
    Martin, Viktoria
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Setterwall, F.
    Liquid-solid phase equilibrium study of tetradecane and hexadecane binary mixtures as phase change materials (PCMs) for comfort cooling storage2003In: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 212, no 02-jan, p. 97-109Article in journal (Refereed)
    Abstract [en]

    Phase diagrams (equilibrium diagrams) are a convenient way of depicting the concentration-temperature-pressure relationships of a chemical system at equilibrium. They are invaluable to PCMs thermal storage researches and developers. In the present paper, the liquid-solid phase equilibrium of binary mixture system of tetradedcane and hexadecane has been studied. For theoretical evaluation of the thermodynamic equilibrium between the liquid phase and solid phase of tetradecane and hexadecane, several methods were compared: the UNIFAC group-contribution method, the model of Won, and Pedersen's model. The temperature-composition phase diagram of the binary system has been obtained by the calculation. The diagram illustrates a binary, isomorphous system with a temperature minimum. Differential scanning calorimetry (DSC) was used to study the phase transformation of the binary system. DSC was run at different ramp rates and results indicate that these mixtures melt and freeze over a temperature range and the temperature range depends on the DSC ramp rate, and in a short mixture concentration interval appears low temperature solid-solid peaks. From the DSC results presented, it is concluded that the behaviour of binary mixtures of n-alkanes is far more complicated than considered in earlier studies. The phase diagram and all information from DSC are very important for designing PCM storage system.

  • 45.
    He, Bo
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Martin, Viktoria
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Setterwall, Fredrik
    Phase transition temperature ranges and storage density of paraffin wax phase change materials2004In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 29, no 11, p. 1785-1804Article in journal (Refereed)
    Abstract [en]

    Paraffin waxes have been used in many latent thermal energy storage applications because of their advantageous thermal performances. In this paper, the liquid-solid phase diagram of the binary system of tetradecane and hexadecane has been used to obtain information of the phase transition processes for cool storage applications. The analysis of the phase diagram indicates that, except for the minimum-melting point mixture, all mixtures melt and freeze in a temperature range and not at a constant temperature. The latent heat of fusion evolves throughout this temperature range. Differential scanning calorimetry (DSC) was used to determine the thermophysical properties of the binary system. Depending on the DSC settings throughout the measurements, varying results were obtained. For example, when the DSC runs at a high heating/cooling rate, it will lead to erroneous information. Also, the correct phase transition temperature range cannot be obtained simply from DSC measurement. By combining phase equilibrium considerations with DSC measurements, a reliable design method to incorporate both the heat of phase change and the temperature range is presented.

  • 46.
    Heier, Johan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Högskolan Dalarna, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Energi och miljöteknik.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Combining Thermal Energy Storage with Buildings: A Review2015In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 42, p. 1305-1325Article, review/survey (Refereed)
    Abstract [en]

    Thermal Energy Storage (TES) has been a topic of research for quite some time and has proven to be a technology that can have positive effects on the energy efficiency of a building by contributing to an increased share of renewable energy and/or reduction in energy demand or peak loads for both heating and cooling. There are many TES technologies available, both commercial and emerging, and the amount of published literature on the subject is considerable. Literature discussing the combination of thermal energy storage with buildings is however lacking and it is therefore not an easy task to decide which type of TES to use in a certain building. The goal of this paper is to give a comprehensive review of a wide variety of TES technologies, with a clear focus on the combination of storage technology and building type. The results show many promising TES technologies, both for residential and commercial buildings, but also that much research still is required, especially in the fields of phase change materials and thermochemical storage.

  • 47.
    Heier, Johan
    et al.
    Högskolan Dalarna, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Energi och miljöteknik.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 12010In: Clima2010, Antalya, Turkiet, 2010Conference paper (Other academic)
    Abstract [en]

    As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relatively low but steadily increasing, emphasizing the need to consider energy storage for both heat and cold. The thermal mass of a building is important for passive storage of thermal energy but this has not been considered much when constructing buildings in Sweden. Instead, common ways of storing thermal energy in Swedish buildings today is in water storage tanks or in the ground using boreholes, while latent thermal energy storage is still very uncommon.

  • 48.
    Heier, Johan
    et al.
    Högskolan Dalarna, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Energi och miljöteknik.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermal energy storage in Swedish single family houses: a case study2012In: InnoStock The 12th International Conference on Energy Storage: Book of Abstract, 2012Conference paper (Other academic)
    Abstract [en]

    In a Nordic climate, space heating (SH) and domestic hot water (DHW) used in buildings constitute a considerable part of the total energy use in the country. For 2010, energy used for SH and DHW amounted to almost 90 TWh in Sweden which corresponds to 60 % of the energy used in the residential and service sector, or almost 24 % of the total final energy use for the country.

    Storing heat and cold with the use of thermal energy storage (TES) can be one way of increasing the energy efficiency of a building by opening up possibilities for alternative sources of heat or cold through a reduced mismatch between supply and demand. Thermal energy storage without the use of specific control systems are said to be passive and different applications using passive TES have been shown to increase energy efficiency and/or reduce power peaks of systems supplying the heating and cooling needs of buildings, as well as having an effect on the indoor climate. Results are however not consistent between studies and focus tend to be on the reduction of cooling energy or cooling power peaks. In this paper, passive TES introduced through an increased thermal mass in the building envelope to two single family houses with different insulation standard is investigated with building energy simulations. A Nordic climate is used and the focus of this study is both on the reduction of space heating demand and space heating power, as well as on reduction of excess temperatures in residential single family houses without active cooling systems. Care is taken to keep the building envelope characteristics other than the thermal mass equal for all cases so that any observations made can be derived to the change in thermal mass.

    Results show that increasing the sensible thermal mass in a single family house can reduce the heating demand only slightly (1-4 %) and reduce excess temperatures (temperatures above 24 degrees C) by up to 20 %. Adding a layer of PCM (phase change materials) to the light building construction can give similar reduction in heating demand and excess temperatures, however the phase change temperature is important for the results.

  • 49.
    Johansson, Petter
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Business Development and Entrepreneurship.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Impact of Convective Heat Transfer Mechanism in Latent Heat Storage Modeling2012Conference paper (Refereed)
  • 50.
    Kabalina, Natalia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
    Costa, Mario
    IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development of a polygeneration district heating and cooling system based on gasification of RDF2014In: Proceedings of the 14th International Symposium on District Heating and Cooling,September 7th to September 9th, 2014, Stockholm, Sweden, Stockholm, 2014Conference paper (Refereed)
12 1 - 50 of 75
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf