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  • 51.
    Lindmark, Susanne
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Martin, Viktoria
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Westermark, Mats
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Analysis of heat-driven cooling production coupled to power generation for increased electrical yield2004In: American Society of Mechanical Engineers, Advanced Energy Systems Division (Publication) AES, Anaheim, CA, 2004, Vol. 44, p. 395-404Conference paper (Refereed)
    Abstract [en]

    In striving for sustainable energy systems, the development of advanced technologies for combined heat and power generation is a critical factor. In many regions of the world there is a demand for heating only during a small part of the year and the yearly peak of power demand often occurs during the cooling season. Hence, the concept of trigeneration, i.e. the combined generation of power, heat and/or cooling is of great interest when it comes to obtaining a high yearly overall efficiency. In this paper, system studies are used to evaluate different types of trigeneration systems and the potential for an increasing electrical yield. The trigeneration systems consist of different types of gas engines coupled to different types and numbers of absorption chillers. The concepts are compared with regards to: the potential for increasing the overall electrical yield for a plant; cost-effectiveness; and environmental impact in terms of avoided CO2. Results indicate that the use of a humidified gas engine coupled to absorption chillers is a cost-effective and environmentally promising method to increase the electricity yield of a power cycle.

  • 52.
    Lindmark, Susanne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Westermark, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Martin, Viktoria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Dirodi, Natalia
    System Aspects of Trigeneration based on Humidified Gas Engine with Flue Gas CondensationIn: Energy, ISSN 0360-5442, E-ISSN 1873-6785Article in journal (Other academic)
  • 53. Manyumbu, Edson
    et al.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Fransson, Torsten H.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    A parametric analysis on the regeneration performance of silica gel in a proposed comfort provision strategy for a typical office space in Harare, Zimbabwe2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 126, p. 104-112Article in journal (Refereed)
    Abstract [en]

    This paper reports the influence, design and climate parameters have on the regeneration performance of a proposed strategy for passive comfort provision for an office space. Solar regeneration of an external silica gel bed is later followed by regeneration of internal surfaces laden with silica gel. The internal surfaces regeneration is effected utilizing air dried by the external bed. External bed regenerating air conditions are evaluated based on simple energy balance and buoyancy models. Thermal efficiency is formulated based on its fundamental definition. Silica gel drying models are obtained from literature. MS Excel Spreadsheet program is applied in the present simulations. Internal surfaces regeneration depends largely on; ventilation rate, initial dryness and mass of external silica gel bed. There is an optimum ventilation rate for a given mass of silica gel in the external bed for particular initial moisture content. Channel depth is quite critical to the regeneration effect on the external silica gel bed, with an average influence coefficient of 200%. The specific humidity of the regenerating air has the least coefficient of influence of 82%. Considering the foregoing, the design of the proposed system calls for simulation to estimate performance.

  • 54.
    Martin, Viktoria
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    He, Bo
    Setterwall, Fredrik
    Direct contact PCM-water cold storage2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 8, p. 2652-2659Article in journal (Refereed)
    Abstract [en]

    Comfort cooling demand continues to increase throughout the world Conventional cooling production results in high demand for electrical power during peak hours, leading to high emissions for producing cooling, and potential power shortages in electric grids With a cold storage, the peak power demand is effectively managed and enables free-cooling. This paper examines one concept using phase change materials (PCM) for storing of cold, where the cold carrier (water) is in direct contact with the PCM. This is in order to enable high power for charging and discharging while providing a high storage capacity. A theoretical model highlights important design parameters for reaching large storage and power capacity The capacity increases with the Packing Factor and temperature difference across the storage. For high power, the flow rate, temperature difference, and drop size is important parameters which is also verified in an experimental evaluation. The obtainable power is between 30 and 80 kW/m(3) storage Practical limitations of this concept are shown to be PCM-water bed expansion and non-uniform channeling due to asymmetric and unstable PCM shells.

  • 55.
    Martin, Viktoria
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Setterwall, F.
    Feasibility study of absorption chillers with a low temperature heat source2004In: American Society of Mechanical Engineers, Advanced Energy Systems Division, 2004, p. 461-468Conference paper (Refereed)
    Abstract [en]

    Low temperature energy powering an absorption chiller will make more energy sources available for comfort cooling as compared to conventional heat driven chillers. Solar energy, industrial waste heat and heat from combined power and heat generation are examples of sources for driving energy. Also, the distribution of energy for comfort cooling could be made efficiently by transportation of hot water to the chiller situated near to the customers. Absorption chillers driven by temperatures lower than 90°C (194°F) are in general not available as an "off-the-shelf product." Usually the low temperature driven chillers are custom made to fit to the local conditions with respect to temperatures of the driving energy and of the cooling water. The optimal design of a chiller is dependant on the temperature of the driving energy as well as on the temperature of the available heat sink for cooling the absorber and the condenser. A scheme for optimization of the chiller with respect to the size of the heat transfer surfaces and of the temperature drop of the driving energy and of the cooling water is presented herein. Presented results illustrate the dramatic effect on the size of the absorber by changing the cooling water temperature, and the equally dramatic effect on the size of the condenser and generator by changing the temperature of the driving energy. Clearly, lowering the heat source temperature and/or increasing the heat sink temperature increases the capital cost for a chiller. However, when coupled to combined heat and power generation, reasonable pay-back times have here been demonstrated for low temperature driven absorption chillers due to the increased electricity production in the overall system.

  • 56.
    Martin, Viktoria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Setterwall, Fredrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Compact Heat Storage for Solar Heating Systems2009In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 131, no 4Article in journal (Refereed)
    Abstract [en]

    Energy and cost efficient solar hot water systems require some sort of integrated storage, with high energy density and high power capacity for charging and discharging being desirable properties of the storage. This paper presents the results and conclusions from the design, and experimental performance evaluation of high capacity thermal energy storage using so-called phase change materials (PCMs) as the storage media. A 140 l 15 kW h storage prototype was designed, built, and experimentally evaluated. The storage tank was directly filled with the PCM having its phase change temperature at 58 degrees C. A tube heat exchanger for charging and discharging with water was submerged in the PCM. Results from the experimental evaluation showed that hot water can be provided with a temperature of 40 degrees C for more than 2 h at an average power of 3 kW. The experimental results also show that it is possible to charge the 140 l storage with close to the theoretically calculated value of 15 kW h. Hence, this is a PCM storage solution with a storage capacity of over 100 kW h/m(3), and an average power capacity during discharging of over 20 kW/m(3). However, it is desirable to increase the heat transfer rate within the prototype. A predesign of using a finned-tube coil instead of an unfinned coil show that by using finned tube, the power capacity for discharging can be at least doubled, if not tripled.

  • 57. Oro, Eduard
    et al.
    Miro, Laia
    Farid, Mohammed M.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Cabeza, Luisa F.
    Energy management and CO2 mitigation using phase change materials (PCM) for thermal energy storage (TES) in cold storage and transport2014In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 42, p. 26-35Article in journal (Refereed)
    Abstract [en]

    Low temperature sensitive products transport and storage is an issue worldwide due to changes of the lifestyle population increase. Thermal energy storage (TES) is nowadays one of the most feasible solutions in facing the challenge of achieving energy savings. Many researchers have investigated energy efficiency of different cold units by applying TES systems using phase change materials (PCM). This paper provides an overview of the existing Spanish and European potential energy savings and CO2 mitigation by incorporating TES systems to cold storage and transportation systems. Data on energy savings were compiled from different case studies. Results depend on the scenarios studied and the extent of TES systems implementation; in the case of Europe for instance, yearly CO2 emissions may be cut down between 5% and 22% in reference to 2008 CO2 emissions from cold production considering that the proposed implementation of PCM TES in the case studies found in the literature is done.

  • 58.
    Oró, Eduard
    et al.
    GREA UdL.
    Castell, Albert
    GREA UdL.
    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.
    Cabeza, Luisa
    GREA UdL.
    Stratification analysis in packed bed thermal energy storage systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 476-487Article in journal (Refereed)
    Abstract [en]

    District cooling and heating networks are increasing in many countries, especially in the Scandinavian countries. Some of the systems have become small for the needs of the population and they have to be enhanced in order to reach the cooling or heating necessities. Here, thermal energy storage system of a district cooling network is studied. Phase change material (PCM) is used in order to enhance the energy density and the stratification of the water tank. The experimental set up consists mainly of a cylindrical storage tank with a capacity of 3.73 L filled with spherically encapsulated PCM. The PCM used is PK6 from Rubitherm GmbH with a storage capacity of 175 kJ/kg between −2 °C and 13 °C. Many methods to characterize water tank stratification, such as graphical (dimensional and non-dimensional) and numerical figures based on temperature distribution (degree of stratification, first law efficiencies, second law efficiencies, other efficiencies as MIX number), are used to analysed and characterized two storage tanks, one of them with the inclusion of PCM packed bed during both charging and discharging processes.

  • 59.
    Oró, Eduard
    et al.
    GREA UdL.
    Castell, Albert
    GREA UdL.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Miro, Laia
    GREA UdL.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Cabeza, Luisa
    GREA UdL.
    Enhancement of the stratification with packed bed thermal energy storage systems2012In: InnoStock The 12th International Conference on Energy Storage: Book of Abstract / [ed] Stock Conference, 2012, p. 284-285Conference paper (Refereed)
    Abstract [en]

    Scandinavian countries have a high demand of heating and cooling in indoor thermal comfort, representing 45% of the total energy use in Swedish residential and service sector [1]. Nowadays the utilization of this district cooling or heating networks is increasing in the modern societies and some researchers have been studied its possibilities for future enhancements of the systems [2], [3].

    The improvement of the storage efficiency results in a higher performance of the whole system, and thermal stratification is commonly used for this purpose [4]. Stratification of the water in storage tanks is created by the difference in density between the cold and the hot water. Due to this density difference, cold water remains at the bottom of the tank while the hot water is placed at the top. The larger the temperature difference between these hot and cold water the better the efficiency of the storage. The intermediate region is called the thermocline which has been deeply studied over the years [5], [6]. Some researchers have been focusing on the inlet distribution manifold which has holes drilled around the circumference to remove the momentum of the incoming fluid and inhibits mixing while allowing buoyancy forces. Yee and Lai [7] developed a numerical model for a rigid manifold to investigate the effect of various design parameters on the formation of thermal stratification in a water storage tank. Hence, Brown and Lai [8] investigated the effectiveness of a vertical porous manifold in the formation and maintenance of thermal stratification in a liquid storage tank.

    It is well known that thermal energy storage (TES) plays an important role in both industrial and domestic applications, storing heat and cold when available and using it when needed. Therefore, it is of great interest for the researchers to study this type of TES system, enhancing the stratification and the energy storage density of them. One of the most attractive latent cold TES systems is the spherically capsulated phase change material (PCM) filled packed bed. And it also seems to be one of the most effective and convenient methods of encapsulation [4].  Mehling et al. [9] studied numerically and experimentally the addition of PCM modules at the top of a hot water storage tank with stratification, adding higher storage density in the top layer. Nallusamy et al. [10] studied the thermal performance of a packed bed latent heat TES unit integrated with solar water heating system, concluding that the utilization of packed bed PCM reduces the size of the storage tank appreciably compared to conventional storage tank system. Some other researchers have been focusing in the numerical studies of heat transfer in packed bed latent heat storage [11], [12], [13].

    Hence, in this study a packed bed storage tank with encapsulated PCM is analysed and compared with the same storage system without PCM during a charging process of the low phase change temperature PCM. As the temperature profile does not give the information in the best way to characterize clearly the stratification in a water storage tank dimensionless numbers which condense this information in a single parameter are studied [14]. Therefore the aim of this paper is to analyse the stratification and the thermal characteristics of a water storage tank filled with PCM packed bed and compare it with the same tank without PCM.

  • 60.
    Oró, Eduard
    et al.
    GREA UdL.
    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, Heat and Power Technology.
    Cabeza, Luisa
    GREA UdL.
    Comparative study of different numerical models of packed bed thermal energy storage systems2013In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 50, no 1, p. 384-392Article in journal (Refereed)
    Abstract [en]

    This paper presents, compares and validates two different mathematical models of packed bed storage with PCM, more specifically the heat transfer during charge of the PCM. The first numerical model is a continuous model based on the Brinkman equation and the second numerical model treats the PCM capsules as individual particles (energy equation model). Using the Brinkman model the flow field inside the porous media and the heat transfer mechanisms present in the packed bed systems can be described. On the other hand, using the energy equation model the temperature gradient inside the PCM capsules can be analysed. Both models are validated with experimental data generated by the authors. The experimental set up consists mainly of a cylindrical storage tank with a capacity of 3.73 L full of spherically encapsulated PCM. The PCM used has a storage capacity of 175 kJ/kg between −2–13 °C. The results from the energy equation model show a basic understanding of cold charging. Moreover, three different Nu correlations found in the literature were analysed and compared. All of them showed the same temperature profile of the PCM capsules; hence any of them could be used in future models. The comparison between both mathematical models indicated that free convection is not as important as forced convection in the studied case.

  • 61.
    Rossi Espagnet, Alberto
    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. 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.
    Lacarrière, Bruno
    École des Mines de Nantes - EMN, Energy Systems and Environment - DSEE.
    Techno-economic assessment of Thermal Energy Storage integration into Low Temperature District Heating networks2016In: Book of abstracts: 2nd International Conference on Smart Energy Systems and 4th Generation District Heating / [ed] Henrik Lund, Aalborg Universitetsforlag, 2016Conference paper (Other academic)
    Abstract [en]

    Thermal energy storage (TES) systems are technologies with the potential to enhance the efficiency and the flexibility of the coming 4th generation low temperature district heating (LTDH). Their integration would enable the creation of smarter, more efficient networks, benefiting both the utility and the end consumers. This study aims to develop a comparative assessment of TES systems, both latent and sensible heat based. First, a techno-economic analysis of several TES systems is conducted to evaluate their suitability to be integrated into LTDH. Then, potential scenarios of TES integration are analysed in a case study of a LTDH network. This is complemented with a review of current DH legislation focused on the Swedish case, with the aim of taking into consideration the present situation, and changes that may support some technologies over others. The results of the analysis show that sensible heat storage is still preferred to latent heat when coupled with LTDH: the cost per kWh stored is still 15% higher for latent heat in systems below 5MWh of storage size; though, they require just half of the volume. However, it is expected that the cost of latent heat storage systems will decline in the future, making them more competitive. From a system perspective, the introduction of TES systems into the network results in an increase in flexibility leading to lower heat production costs by load shifting: by running the production units with lower marginal heat production costs for longer periods and with high efficiency, and thus reducing the operating hours of the other more expensive operating units during peak load conditions. These results may also be extended to the case when heat generation is replaced by renewable, intermittent energy sources; thus increasing profits, reducing fuel consumption, and consequently emissions. This study represents a step forward in the development of a more efficient DH system through the integration of TES which will play a crucial role in future smart energy system.

  • 62.
    Udomsri, Seksan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Bales, Chris
    Högskolan Dalarna, Borlänge.
    Martin, Andrew R.
    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.
    Decentralised Cooling in District Heating Network: Monitoring Results and Calibration of Simulation Model2011In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 43, no 12, p. 3311-3321Article in journal (Refereed)
    Abstract [en]

    This article presents the monitoring results of a thermally driven chiller (TDC) driven by district heat from a network supplied by a centralised combined heat and power (CHP) fired with municipal waste. The main objective of this article is to analyse the monitoring results obtained from the demonstration and calibrate a system model that is later used for parametric studies in order to find improved system design and control. The calibration of the system model was made in three stages and all the energy performance figures were within 4% of the measured values. Results show that the TDC system is capable of providing maximum thermal and electrical COP's of 0.50 and 4.6 respectively during the hottest period. For the complete monitoring period during the summer of 2008, the figures were 0.41 and 2.1. The lower figures were due to continuous pump operation inside the TDC even during periods of no cold production and a period when no cold was produced. However the internal pumps inside the TDC have been removed in the new version TDC to increase the electrical COP. System simulation and parametric studies will be employed to further determine how the electrical COP can be improved.

  • 63.
    Udomsri, Seksan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Bales, Chris
    Högskolan Dalarna, Borlänge.
    Martin, Andrew R.
    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.
    Decentralized cooling in district heating network: System simulation and parametric study2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 175-184Article in journal (Refereed)
    Abstract [en]

    This paper presents system simulation and parametric study of the demonstration system of decentralized cooling in district heating network. The monitoring results obtained from the demonstration were calibrated and used for parametric studies in order to find improved system design and control. This study concentrates on system simulation studies that aim to: reduce the electricity consumption, to improve the thermal COP's and capacity if possible; and to study how the system would perform with different boundary conditions such as climate and load. The internal pumps inside the thermally driven chiller (TDC) have been removed in the new version TDC and implemented in this study to increase the electrical COP. Results show that replacement of the fourth with the fifth generation TDC increases the system electrical COP from 2.64 to 5.27. The results obtained from parametric studies show that the electrical and thermal COP's, with new realistic boundary conditions, increased from 2.74 to 5.53 and 0.48 to 0.52, respectively for the 4th generation TDC and from 5.01 to 7.46 and 0.33 to 0.43, respectively for the 5th generation TDC. Additionally the delivered cold increased from 2320 to 8670 and 2080 to 7740. kWh for the 4th and 5th generation TDC's, respectively.

  • 64.
    Udomsri, Seksan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew R.
    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.
    Thermally driven cooling coupled with municipal solid waste-fired power plant: Application of combined heat, cooling and power in tropical urban areas2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 5, p. 1532-1542Article in journal (Refereed)
    Abstract [en]

    Energy recovery from flue gases in thermal treatment plants is an integral part of municipal solid waste (MSW) management for many industrialized nations. Often cogeneration can be employed for both enhancing the plant profitability and increasing the overall energy yield. However, it is normally difficult to justify traditional cogeneration in tropical locations since there is little need for the heat produced. The main objective of this article is to investigate the opportunities and potentials for various types of absorption technologies driven by MSW power plants for providing both electricity and cooling. Results show that cogeneration coupling with thermally driven cooling is sustainably and economically attractive for both electricity and cooling production. The thermally driven cooling provides significant potential to replace electrically driven cooling: such systems are capable of providing cooling output and simultaneously increasing electricity yield (41%). The systems are also capable of reducing the fuel consumption per unit of cooling in comparison with conventional cooling technology: a reduction of more than 1 MWfuel/MWcooling can be met in a small unit. MSW power plant coupled with thermally driven cooling can further reduce CO2 emissions per unit of cooling of around 60% as compared to conventional compression chiller and has short payback period (less than 5 years).

  • 65.
    Vadiee, Amir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin Ning Wei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gunasekara, Samman Nimali
    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 systems in closed greenhouse with component and phase change material design2013Conference paper (Refereed)
  • 66.
    Vadiee, Amir
    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.
    Application of thermal energy storage in the closed greenhouse concept2012Conference paper (Refereed)
  • 67.
    Vadiee, Amir
    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.
    Energy Analysis and Thermoeconomic Assessment of the Closed Greenhouse: The Largest Commercial Solar Building2012In: ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C, 2012, p. 137-146Conference paper (Refereed)
    Abstract [en]

    The closed greenhouse concept has been studied in this paper. The closed greenhouse can be considered as the largest commercial solar building. In principle, it is designed to maximize the utilizatio nof solar energy through seasonal storage. In an ideal fully closed greenhouse, there is not any ventilation window. Therefore, the excess heat must be removed by other means. In order to utilize the excess heat at a later time, long and/or short term thermal storage technology (TES) should be integrated. A developed model has been evaluated due to different situations.The closed greenhouse is compared with conventional greenhouse using a case study respect to the energy analysis. A parameter has been defined in this paper in order to compare performance of the closed greenhouse concept in different conditions. This parameter has been called ESR. Finally a preliminary thermo-economical study has been assessed in order to investigate on feasibility of the closed greenhouse concept.

  • 68.
    Vadiee, Amir
    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.
    Energy analysis and thermoeconomic assessment of the closed greenhouse: The largest commercial solar building2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 102, p. 1256-1266Article in journal (Refereed)
    Abstract [en]

    The closed greenhouse concept has been studied in this paper. The closed greenhouse can be considered as the largest commercial solar building. In principle, it is designed to maximize the utilization of solar energy by use of seasonal storage. In an ideal fully closed greenhouse, there is no ventilation window. Therefore, the excess heat must be removed by other means. In order to utilize the excess heat at a later time, long- and/or short-term thermal storage technology (TES) should be integrated. A theoretical model has been derived to evaluate the performance of various design scenarios. The closed greenhouse is compared with a conventional greenhouse using a case study to guide the energy analysis and verify the model. A new parameter has been defined in this paper in order to compare the performance of the closed greenhouse concept in different configurations - the Surplus Energy Ratio showing the available excess thermal energy that can be stored in the TES system and the annual heating demand of the greenhouse. From the energy analysis it can be concluded that SER is about three in the ideal fully closed greenhouse. Also, there is a large difference in heating demand between the ideal closed and conventional greenhouse configurations Finally, a preliminary thermo-economic study has been assessed in order to investigate the cost feasibility of various closed greenhouse configurations, like ideal closed; semi closed and partly closed conditions. Here, it was found that the design load has the main impact on the payback period. In the case of the base load being chosen as the design load, the payback period for the ideal closed greenhouse might be reduced by 50%. On the other hand, glazing type, ventilation ratio, and the closed area portion have a minor impact on the payback period.

  • 69.
    Vadiee, Amir
    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.
    Energy management in horticultural applications through the closed greenhouse concept, state of the art2012In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 16, no 7, p. 5087-5100Article, review/survey (Refereed)
    Abstract [en]

    The commercial greenhouse has the highest demand for energy as compared to all other agricultural industry sectors. Here, energy management is important from a broad sustainability perspective. This paper presents the state-of-the-art regarding one energy management concept; the closed greenhouse integrated with thermal energy storage (TES) technology. This concept is an innovation for sustainable energy management since it is designed to maximize the utilization of solar energy through seasonal storage. In a fully closed greenhouse, there is no ventilation which means that excess sensible and latent heat must be removed. Then, this heat can be stored using seasonal and/or daily TES technology, and used later in order to satisfy the heating demand of the greenhouse. This assessment shows that closed greenhouse can, in addition to satisfying its own heating demand, also supply the demand for neighboring buildings. Several energy potential studies show that summer excess heat of almost three times the annual heating demand of the greenhouse. However, many studies propose the use of some auxiliary system for peak load. Also, the assessment clearly point out that a combination of seasonal and short-term TES must be further explored to make use of the full potential. Although higher amount of solar energy can be harvested in a fully closed greenhouse, in reality a semi-closed greenhouse concept may be more applicable. There, a large part of the available excess heat will be stored, but the benefits of an integrated forced-ventilation system are introduced in order to use fresh air as a rapid response for primarily humidity control. The main conclusion from this review is that aspects like energy efficiency, environmental benefits and economics must be further examined since this is seldom presented in the literature. Also, a variety of energy management scenarios may be employed depending on the most prioritized aspect.

  • 70.
    Vadiee, Amir
    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.
    Energy management strategies for commercial greenhouses2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 114, no SI, p. 880-888Article in journal (Refereed)
    Abstract [en]

    Growth in population and the ever-increasing development of new production technology leading to rising energy use in the agricultural industry. Although the greenhouse is one of the most energy intensive sectors in the agricultural industry, it is important because of its ability to intensify production. This paper has assessed energy management strategies (including single and combined energy conservation opportunities), with special emphasis on Nordic climates, where fossil fuel-based heating is still significant, despite a recent conversion to biomass boilers. The results show that the "Double thermal screen" and "Double glazing" with 60% reduction in energy demand are the most effective single opportunity for energy conservation. However, the highest improvement (80%) is obtainable using the closed greenhouse concept, with a potential payback of 5-6 years under favorable conditions. It can be concluded that some of the single opportunities can be more practical in terms of their PBP in comparison to a complex concept, requiring a combination of measures, such as the closed greenhouse.

  • 71.
    Vadiee, Amir
    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.
    Solar blind system: solar energy utilization and climate mitigation in glassed buildings2013Conference paper (Refereed)
    Abstract [en]

    In the past few decades, energy scientists have focused on "renewable energy”,and solar energy in particular. Severaltechnologies are commercialized for utilizing solar energy in the buildings by absorbing solar radiation and converting it to heat and electricity. These technologies can be categorized into the passive and active systems. A special case is a commercialgreenhouse, whichcan be considered a passive solar building. A greenhouse is a structure which is covered by a transparent device such as glass in order to use solar energy while controlling the temperature, humidity and other parameters according to the requirements for cultivation andprotection of the particular plants. The cooling demandin the commercial greenhouses is commonly supplied by e.g. ventilation and thermal screen. In the ventilation method a portion of the absorbed solar energy will be lost through ventilation windows and by applying the solar shielding, solar radiation will be blocked. In this study, by considering the solar blind concept as an active system, PVT panels are integrated to absorb thesurplus solar heat(instead of blocking)which is thenstored in a thermal energy storage for supplying a portion of the greenhouse heating demand at a later time. The overall objective of this study is to assess the potential of cutting external energy demand as well as maximizing solar energy utilizationin a commercial greenhouse for Northern climate condition.Thus, a feasibility assessment has been carried out, examiningvarious system configurations with theTRNSYS tool. The results show that the heating demand for a commercial closed greenhouse with solar blind is reduced by 80%, down to 62 kwh/m2as compared to a conventional configuration. Also the annual total useful heat gain and electricity generation by solar blind in this concept is around 20 kwh/m2and 80kwh/m2, respectively. The generated electricity can be used for supplying the greenhouse power demand for e.g. artificial lighting and other devices. Moreover, the cooling demand in a closed greenhouse is reduced by 60% by considering the solar blind system.

  • 72.
    Vadiee, Amir
    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 strategies for effective closed greenhouse design2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, p. 337-343Article in journal (Refereed)
    Abstract [en]

    The closed greenhouse is an innovative concept in sustainable energy management. In principle, it is designed to maximize the utilization of solar energy through the seasonal storage. In a fully closed greenhouse, there is not any ventilation window. Therefore, the excess sensible and latent heat must be removed, and can be stored using seasonal and/or daily thermal storage technology. This stored excess heat can then be utilized later in order to satisfy the thermal load of the greenhouse. Thermal energy storage (TES) system should be designed based on the heating and cooling load in each specific case. Underground thermal energy storage (UTES) is most commonly chosen as seasonal storage. In addition, a stratified chilled water (SCW) storage or a phase change material (PCM) storage could be utilized as short term storage system in order to cover the daily demands and peak loads. In this paper, a qualitative economical assessment of the concept is presented. Here, a borehole thermal energy storage (BTES) system is considered as the seasonal storage, with a PCM or a SCW daily storage system to manage the peak load. A BTES primarily stores low temperature heat such that a heat pump would be needed to supply the heat at a suitable temperature. A theoretical model has been developed using TRNSYS to carry out the energy analysis. From the economical feasibility assessment, the results show that the concept has the potential of becoming cost effective. The major investment for the closed greenhouse concept could be paid within 7-8 years with the savings in auxiliary fossil fuel considering the seasonal TES systems. However, the payback time may be reduced to 5 years if the base load is chosen as the design load instead of the peak load. In this case, a short-term TES needs to be added in order to cover the hourly peak loads.

  • 73.
    Vadiee, Amir
    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
    Ecostorage Sweden AB, Sollentuna, Sweden.
    Solar energy utilization in closed greehouse environment2010In: EUROSUN 2010, 2010Conference paper (Refereed)
  • 74. Vadiee, Amir
    et al.
    Yaghoubi, Mahmoud
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Bazargan-Lari, Yousef
    Energy analysis of solar blind system concept using energy system modelling2016In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 139, p. 297-308Article in journal (Refereed)
    Abstract [en]

    Energy conservation in the horticultural industry is one of the main challenging points regarding to the sustainable development. Commercial greenhouse is known as the most energy consuming and simultaneously the most effective cultivation method which promises 10 times more production yield than open field horticultural methods. Supplementary heating demand, electrical energy demand for artificial lighting system as well as active cooling systems are the main parameters which have to be reduced in order to have more energy efficient system. Usually, in the conventional greenhouse the solar radiation will blocked using a thermal screen to avoid the overheating problem and reduce the cooling demand. In this method, a large portion of solar irradiation will reflected and absorbed by curtain without any useful utilization. By introducing the solar blind system, the excess solar radiation will absorb and convert into useful thermal energy as well as electrical energy. As a matter of fact, the solar blind system consists of a series of thermal photovoltaic modules. The solar blind system will operate based on the defined set point temperature. By exceeding the greenhouse indoor temperature than set point temperature the solar blind thermal photovoltaic modules rotate over their axis to cover the greenhouse roof and block the solar radiation and it keeps blocking the solar irradiation until the indoor temperature drops below the set point. Therefore, the cooling demand will reduce considerably while the absorbed heat and electricity gain though the thermal photovoltaic cells can be utilized later to cover a part of the greenhouse thermal and electrical demand. The main aim of this paper is to assess the solar blind system performance for various set point temperatures. Therefore an energy model has to be developed and TRNSYS is used for this purpose. The results show that by considering 18 degrees C as the set point temperature, the highest thermal and electrical energy performance can be reached. The maximum thermal energy performance of the system is about 86% while the minimum that is corresponded to the highest set point temperature is 38%. By considering the solar blind system operated at 18 degrees C as the set point temperature, the cooling demand in the greenhouse can be almost covered totally, which is the main aim of this concept. However, the electrical demand is reduced almost by 73%. Additionally, by applying the solar blind system concept, the irradiation level inside the greenhouse kept in the optimal level that leads to more uniform cultivation during the whole year.

  • 75.
    Woldemariam, Daniel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew
    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.
    Santarelli, Massimo
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Exergy, thermo-Economic Analysis, and Optimization of Air-gap Membrane Distillation System2014Conference paper (Other academic)
    Abstract [en]

    Exergy and thermo-economic cost analysis are increasingly important tools for the evaluation of a desalination system’s performance and hence economic viability of the method for industrial or commercial applications. Membrane distillation (MD) is one important water desalination method that is still under development, not well established and not yet widely used in industries unlike reverse osmosis (RO). In this study, an exergetic and thermo-economic analysis for a large scale pilot plant air-gap membrane distillation system have been done. Experiments were carried out to get thermodynamic values of water streams. From the experimental data obtained and followed exergy analysis, it was found that the least exergetic efficiency (75%) was obtained for the feed. Maximum exergy efficiency was obtained for the hot side heat exchanger (98%) followed by the pumps. Thermo-economy of the MD water desalination under investigation was also analyzed and compared with other water desalination methods. Finally, the thermo-economic optimization for the MD system under consideration was investigated, and performance improvements were discussed.

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