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  • 1.
    Ahl, Amanda
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Eklund, Johanna
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Yarime, M.
    Balancing formal and informal success factors perceived by supply chain stakeholders: A study of woody biomass energy systems in Japan2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 175, p. 50-59Article in journal (Refereed)
    Abstract [en]

    Small-scale woody biomass energy systems have an inherent ability to aid in emissions reduction while stimulating local economies and, as collective energy systems, are strongly connected to supply chain design based on local conditions and stakeholder integration. Despite an abundance of forest area alongside the promotion of biomass in energy policies, however, woody biomass utilization still remains low in Japan. The woody biomass supply chain, considered as a socio-technical system, involves a complex, cross-sectoral stakeholder network in which inter-organizational dynamics necessitates well-organized management based on an understanding of formal factors such as technology, as well as informal factors such as social relations and culture. In this paper, success factor perceptions from across the woody biomass supply chain are investigated based on semi-structured interviews with four stakeholders in the Kyushu region of Japan. Identified success factors here are: 1) respect of values & traditions, 2) transportation infrastructure, 3) business model integration, 4) relationship & trust, 5) local vitalization and 6) biomass quality control. A convergence as well as divergence of perceptions are observed, involving both formal and informal dimensions. Aiming to balance perceptions and to enable long-term success of woody biomass in Japan, a series of policy implications are drawn, including cross-ministerial integration, knowledge building on wood logistics, forest certification, local coordinators, biomass quality control standards and a feed-in-tariff for heat. This paper suggests a new arena of policy-making based on the importance of considering both informal and formal dimensions in energy policy.

  • 2.
    Anund Vogel, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lind, Hans
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Who is Governing the Commons: Studying Swedish Housing Cooperatives2016In: Housing, Theory and Society, ISSN 1403-6096, E-ISSN 1651-2278, Vol. 33, no 4, p. 424-444Article in journal (Refereed)
    Abstract [en]

    This study examines current governance structures related to multifamily buildings designed by single actors (developers) and operated in cooperative forms. The study analyses the long-term sustainability of the resource regime of study (multifamily buildings) and inked governance structures by applying Ostrom’s eight design principles for long-term survival of self-organized resource regimes (Common-pool resources or CPR’s). The study also searches for signs of movement towards social innovation and collective action in current governance structures. We argue that the structures governing planning, production and operation of housing cooperatives in Sweden do not fulfil the eight design principles for the long-term survival of the resource regime of study, nor do they encourage movement towards social innovation or collective action. In order to ensure the long-term survival of the resource regime of study and to increase innovation in governance structures, five adjustments are proposed; changes in the structures governing risk/profit distribution, communication, collaboration and information between actors in the Swedish cooperative housing sector.

  • 3.
    Anund Vogel, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Blomkvist, Pär
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics.
    Problem areas related to energy efficiency implementation in Swedish multifaily buildings2015In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478Article in journal (Refereed)
    Abstract [en]

    This paper investigates problem areas related to energy efficiency implementation in Swedish multifamily buildings. The paper first presents a generic list of (theoretical) problem areas identified through a literature survey. Using a qualitative approach, the paper also investigates if the problem areas identified in the literature also have an impact on the Swedish building sector. Results from the interview study reveal a strong coherence between problem areas in the literature and those expressed by the interviewees. However, this paper identifies seven novel challenges that cannot be derived from the list of barriers in the literature. Moreover, results reveal that as many as 12 problem areas have their origin in national factors such as agreement structures, incentive schemes, and cost calculation methods.

  • 4.
    Anund Vogel, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Van Bueren, Ellen
    Delft University of Technology.
    Verhoef, Leendert
    Amsterdam Institute for Advanced Metropolitan Solutions.
    Goldberg, Brian
    Office of Sustainability MIT.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sarin, Emma
    HSB Living Lab.
    Co-Creation in Living Labs to Accelerate Innovation2020In: Civil Engineering Research Journal, ISSN 2575-8950, Vol. 10, no 1, article id 555776Article in journal (Other academic)
    Abstract [en]

    Innovation in the construction sector occurs as stepwise reconfigurations of subsystems, but sometimes the effect of many systems coincides and there is so called radical change. Stepwise reconfigurations of individual systems such as windows, insulation, and heat recovery systems have made it possible to heat buildings with preheated inlet air instead of water radiators. Thus, making building more sustainable, cheaper and resource-efficient; the potential for radical change has been achieved. The question is then why not every new building uses preheated inlet air? The reason is not the lack of innovation or new technologies. It is rather connected to malfunctioning structures related to incentives, collaboration, testing, and validation, resulting in norms and standards that aim to reproduce existing technologies, preferring incremental innovations over radical ones.This article argues that testbeds and Living Labs are a way to work on complex, multi-stakeholder and urgent problems in a co-creative way. In these labs there are possibilities to test technologies, in systems, in real buildings and cities. There are possibilities to follow-up, measure and adjust; to live, study, work and develop. The Living Labs have the potential of making new technologies standard to use in the course of years instead of decades and thus minimize unnecessary use of resources linked to the construction and use of buildings. In addition, it will help to make technologies more user-friendly, considering user needs, wishes and experiences, thus contributing to the effectiveness of the technologies developed and tested.

    Download full text (pdf)
    Co-Creation in Living Labs to Accelerate Innovation
  • 5.
    Arias, Jaime
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Choisir entre récupération de chaleur ou pression de condesation flottante en froid commercial2006In: Revue J. du Froid, no 1066, p. 47-54Article in journal (Refereed)
  • 6.
    Arias, Jaime
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Heat Recovery and Floating Condensing in Recent Refrigeration Systems in Supermarkets2005Conference paper (Refereed)
  • 7.
    Arias, Jaime
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Modelling Supermarket Energy Usage2005Conference paper (Refereed)
  • 8.
    Arias, Jaime
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, PerKTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.Sawalha, SamerKTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Annex 31: advanced modelling and tools for analysis of energy use in supermarket systems2010Conference proceedings (editor) (Refereed)
  • 9.
    Arias, Jaime M.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per G.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Heat recovery and floating condensing in supermarkets2006In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 38, no 2, p. 73-81Article in journal (Refereed)
    Abstract [en]

    Supermarkets are great energy users in many countries. The potential for increased energy efficiency is large. One option is to utilize heat recovery (or heat reclaim) from condensers to heat the premises. Obviously this option is only interesting in relatively cold areas such as northern Europe, Canada, etc. An alternative to heat recovery is floating condensing pressure, which improves the coefficient of performance and decreases the energy consumption of the refrigeration system at lower outdoor temperature. Both heat recovery and floating condensing pressure can be utilized interchangeably depending on the heat requirements of the premises. A computer model that calculates the energy consumption in a supermarket with the possibility to simulate different system solutions for the refrigeration system has been developed at the Royal Institute of Technology, Department of Energy Technology. The software CyberMart is used in the present study to compare the potential of heat recovery and floating condensing in Swedish supermarkets. Measurements of different parameters such as temperatures, relative humidity and compressor power have been carried out in different supermarkets with heat recovery to validate the theoretical calculations. The present study shows that heating requirements can be covered completely by heat reclaim from the condenser. However, practical experiences show that installations are less efficient due to poor system solutions and/or control strategies. According to the results from CyberMart, the highest potential of energy saving is obtained from using a systems solution with both heat recovery and floating condensing.

  • 10.
    Arias, Jaime M.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per G.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Modelling and experimental validation of advanced refrigeration systems in supermarkets2005In: Proceedings of the Institution of mechanical engineers. Part E, journal of process mechanical engineering, ISSN 0954-4089, E-ISSN 2041-3009, Vol. 219, no E2, p. 149-156Article in journal (Refereed)
    Abstract [en]

    The effective use of energy and the replacement of CFC and HCFC refrigerants are two factors that have influenced the design and operation of refrigeration systems in supermarkets during recent years. The potential for increasing energy efficiency in refrigeration systems, indoor climate and refrigerated cabinets is large. Since the energy systems of a supermarket are relatively complex, improvements in one subsystem affect other systems, thus making analysis of potential improvements non-additive. A computer model, CyberMart, that predicts building heating and cooling loads, HVAC (heating, ventilation, and air conditioning), and refrigeration system performances of a supermarket, has been developed. The focus of the model is on energy use, environmental impact (TEWI), and life cycle cost (LCC) of the refngeration system. The refrigeration system solutions included in the model are: direct system, completely indirect system, partially indirect system, cascade system, parallel system with mechanical sub-cooling (where the refrigerant in the low-temperature system is sub-cooled with the brine of the intermediate temperature level), and district cooling (that cools the condenser of the refrigeration machines). Measurements of different parameters such as outdoor and indoor temperatures, relative humidity, and compressor power have been carried out in several stores to validate the model. A theoretical description of the model and results from the model and measurements are presented in this paper.

  • 11. Bivens, D.
    et al.
    Lundqvist, PerKTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Supermarket Refrigeration Systems - Climate Change Impact2005Conference proceedings (editor) (Other academic)
  • 12.
    Bäcklund, Katarina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Akademiska Hus.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Showcasing a digital twin for higher educational buildings: developing the concept toward human centricity2024In: Frontiers in Built Environment, E-ISSN 2297-3362, Vol. 10, article id 1347451Article in journal (Refereed)
    Abstract [en]

    Digital twin technology is an emerging technology within the built environment. Yet, there are many unexplored opportunities to utilize digital twins for facilitating the transformation toward a climate-neutral building stock while also meeting the expectations from the building occupants. This article presents a case study of a digital twin, developed for an existing commercial building stock of campus areas in Sweden. The overarching purpose of the digital twin is to support both building occupants and building operators. This two-fold human-centric approach represents a novel approach for building digital twins. The digital twin is based on 3D scanning, and together with geospatial data, a real-like navigational indoor environment is created. Three innovative features are presented: the building analysis module, the digital twin mobile application, and the building operations module. The results show that the digital twin improves the building occupant’s experience by supporting navigation and providing access to the room booking system via this dedicated interface. Building management is also benefited by the digital twin through easier access to building data aggregated into one platform and a state-of-the-art analysis tool for optimizing the use of indoor space. The digital twin holds future potential to achieve operational excellence by incorporating feedback mechanisms and utilizing artificial intelligence to enable intelligent fault detection and prevention. 

  • 13.
    Bäcklund, Katarina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Showcasing a Digital Twin for Higher Educational Buildings: Developing the Concept Towards Human Centricity2024In: Frontiers in Built Environment, E-ISSN 2297-3362, Vol. 10, article id 1347451Article in journal (Refereed)
    Abstract [en]

    Digital twin technology is an emerging technology within the built environment. There are yet many unexplored opportunities to utilize digital twins for facilitating the transformation towards a climate neutral building stock while also meeting the expectations from the building occupants. This article presents a case study of a digital twin, developed for an existing commercial building stock of campus areas in Sweden. The overarching purpose of the digital twin is to support both building occupants and building operators. This twofold human-centric approach represents a novel approach for building digital twins. The digital twin is based on 3D scanning and together with geospatial data, a real-like navigational indoor environment is created. Three innovative features are presented; the building analysis module, the digital twin mobile application and the building operations module. The results show that the digital twin improves the building occupant’s experience by supporting navigation and providing access to room booking system via this dedicated interface. Building management is also benefited by the digital twin through easier access to building data aggregated into one platform and a state-of-the-art analysis tool for optimizing the use of indoor space. The digital twin holds future potential to achieve operational excellence by incorporating feedback mechanisms and utilizing Artificial Intelligence to enable intelligent fault detection and prevention.

      Keywords: 

  • 14.
    Bäcklund, Katarina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    In Search for Untapped Energy-Saving Potential in Green and Smart Higher Educational Buildings—An Empirical Case Study Involving the Building Occupants2023In: Buildings, E-ISSN 2075-5309, Vol. 13, no 12, article id 3103Article in journal (Refereed)
    Abstract [en]

    Energy-intense activities and the unpredictable and complex behavior of building occupants lead to an increase in building energy demand. It is, therefore, crucial to study underlying factors for building energy demand related to the users. Higher educational buildings are relevant to study for several reasons: they host the future workforce and citizens, they are predicted to increase in numbers, and they represent a building type less studied. Furthermore, green-rated buildings equipped with smart building systems also represent a research gap that is relevant to address since such a building design involves IoT-functionalities and digital features for the building occupants to interact with. There is also a conceivable risk that if the users know that the building is green-rated and technologically advanced, this may alter their perception of the building operation and thus their behavior. To study the relationship between building occupants and such green and smart educational structure, a survey was conducted in a Swedish higher educational building; as a result, 300 responses were collected and analyzed. The responses revealed that the building occupants act with energy awareness, and they are conscious about energy-saving behaviors. One building feature in particular was studied: the Digital Room Panels (DRPs). The DRP allows the building occupants to modify the indoor temperature and is, therefore, essential for thermal comfort. One key finding from the survey revealed that 70% of the building occupants did not know how the DRPs operate. This study argues that this result can be explained with a lack of communication and user friendliness. Inadequate interactions with building systems could also result in opportunities for energy saving might not be realized. The findings of this case study led to valuable recommendations and suggestions for future research endeavors.

  • 15.
    Bäcklund, Katarina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Karlsson, Peter
    Akademisk Hus AB.
    Showcasing the First Steps Towards a Digital Twin for Campus Environments2022In: 2022 BuildSim Nordic, 2022Conference paper (Refereed)
    Abstract [en]

    This paper presents a path towards the implementation of a Digital Twin for campus environments. The main purpose of the Digital Twin is to accomplish an advanced analytical tool, which supports building owners, building operators and building users to reach an improved performance of the building. Digital Twins is new to the building and the real estate industry, hence research within this field is scarce. This paper contributes to the research by providing a methodology to implement a Digital Twin of an existing building stock of campus areas in Sweden. The main results obtained so far are presented. They indicate that the potential of a Digital Twin expands beyond the aspects of a navigational digital 3D model, including a state-of-the-art app that is developed from the Digital Twin platform.  

    Download full text (pdf)
    BSN20221010
  • 16.
    Bäcklund, Katarina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Building Occupants, Their Behavior and the Resulting Impact on Energy Use in Campus Buildings: A Literature Review with Focus on Smart Building Systems2023In: Energies, E-ISSN 1996-1073, Vol. 16, no 17, p. 6104-6104Article in journal (Refereed)
    Abstract [en]

    In the light of global climate change and the current energy crisis, it is crucial to target sustainable energy use in all sectors. Buildings still remain one of the most energy-demanding sectors. Campus buildings and higher educational buildings are important to target due to their high and increasing energy demand. This building segment also represents a research gap, as mostly office or domestic buildings have been studied previously. In the quest for thermal comfort, a key stakeholder in building energy demand is the building occupant. It is therefore crucial to promote energy-aware behaviors. The building systems are another key factor to consider. As conventional building systems are replaced with smart building systems, the entire scenario is redrawn for how building occupants interact with the building and its systems. This study argues that behavior is evolving with the smartness of building systems. By means of a semi-systematic literature review, this study presents key findings from peer-reviewed research that deal with building occupant behavior, building systems and energy use in campus buildings. The literature review was an iterative process based on six predefined research questions. Two key results are presented: a graph of reported energy-saving potentials and a conceptual framework to evaluate building occupants impact on building energy use. Furthermore, based on the identified research gaps in the selected literature, areas for future research are proposed.

  • 17.
    Chen, Jianyong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A new ejector refrigeration system with zeotropic mixtures2011In: 23RD IIR INTERNATIONAL CONGRESS OF REFRIGERATION, 2011, p. 2043-2050Conference paper (Refereed)
    Abstract [en]

    A new ejector refrigeration system (NERS) using zeotropic mixture is theoretical studied in the paper.R32/R134a, R32/R152a, R134a/R142b, R152a/R142b, R290/R600a and R600a/R600 are selected as theworking fluids in the analysis. The comparison between this NERS and the conventional ejector refrigerationsystem (CERS) is made under the same operating condition. It is found that this new system has higherCOPs than the CERS. The effect of operating conditions and the composition on the performance of this newsystem are presented. An exergy analysis is carried out to study the loss within each component of thesystem. It is observed that the irreversibility in the ejector represents more than 50% of the total exergy loss.This also emphasizes the necessity for good ejector design and manufacture.

  • 18.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Analysis of supercritical carbon dioxide heat exchangers in cooling process2006Conference paper (Refereed)
    Abstract [en]

    Carbon dioxide transcritical cycles have become more and more investigated during the last decade. For all systems operating with such a cycle, there will be at least one heat exchanger to either heat or cool the supercritical carbon dioxide. Unlike in the sub-critical region, the supercritical carbon dioxide’s thermophysical properties will have sharp variations in the region close to its critical point. This variation has a significant influence on the shape of the heat exchanger’s temperature profile and the heat transfer performance of the heat exchanger. Therefore, the performance of the heat exchanger used for supercritical carbon dioxide cooling or heating process should be evaluated by taking this effect into account. This paper discusses the heat exchangers used for supercritical carbon dioxide refrigeration process including a suction gas heat exchanger in the cycle. Engineering Equation Solver (EES)1 and Refprop 7.02 are used for cycle calculations and for properties calculations.

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    fulltext
  • 19.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    The Co2 Transcritical Power Cycle For Low Grade Heat Recovery-Discussion On Temperature Profiles In System Heat Exchangers2012In: Proceedings of the ASME Power Conference- 2011 Vol 1, ASME Press, 2012, p. 385-392Conference paper (Refereed)
    Abstract [en]

    Carbon dioxide transcritical power cycle has many advantages in low-grade heat source recovery compared to conventional systems with other working fluids. This is mainly due to the supercritical CO2's temperature profile can match the heat source temperature profile better than other pure working fluids and its heat transfer performance is better than the fluid mixtures, which enables a better cycle efficiency. Moreover, the specific heat of supercritical CO2 will have sharp variations in the region close to its critical point, which will create a concave shape temperature profile in the heat exchanger that used for recovering heat from low-grade heat sources. This brings more advantage to carbon dioxide transcritical power systems in low-grade heat recovery.

    Download full text (pdf)
    fulltext
  • 20.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per Gunnar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Carbon dioxide cooling and power combined cycle for mobile applications2006In: Proceedings of 7th IIR-Gustav Lorentzen Conference on Natural Working Fluids, 2006Conference paper (Refereed)
  • 21.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per Gunnar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Johansson, Anders
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Platell, P
    A comparative study of the carbon dioxide transcritical power cycle compared with an organic rankine cycle with R123 as working fluid in waste heat recovery2006In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 26, no 17-18, p. 2142-2147Article in journal (Refereed)
    Abstract [en]

    The organic rankine cycle (ORC) as a bottoming cycle1The expression "bottoming cycle" refers to the power cycle that uses waste industrial heat for power generation by supplementing heat from any fossil fuel.1 to convert low-grade waste heat into useful work has been widely investigated for many years. The CO2 transcritical power cycle, on the other hand, is scarcely treated in the open literature. A CO2 transcritical power cycle (CO2 TPC) shows a higher potential than an ORC when taking the behavior of the heat source and the heat transfer between heat source and working fluid in the main heat exchanger into account. This is mainly due to better temperature glide matching between heat source and working fluid. The CO2 cycle also shows no pinch limitation in the heat exchanger. This study treats the performance of the CO2 transcritical power cycle utilizing energy from low-grade waste heat to produce useful work in comparison to an ORC using R123 as working fluid. Due to the temperature gradients for the heat source and heat sink the thermodynamic mean temperature has been used as a reference temperature when comparing both cycles. The thermodynamic models have been developed in EES2EES - Engineering equation solver. The thermodynamic properties for carbon dioxide in EES are calculated by the fundamental equation of state developed by R. Span and W. Wagner, A new equation of state for carbon dioxide covering the fluid region form the triple-point temperature to 1100 K at pressures up to 800 MPa, J. Phys. Chem. Ref. Data, Vol. 25, No. 6, 1996. http://www.fchart.com/ees/ees.shtml.2 The relative efficiencies have been calculated for both cycles. The results obtained show that when utilizing the low-grade waste heat with the same thermodynamic mean heat rejection temperature, a transcritical carbon dioxide power system gives a slightly higher power output than the organic rankine cycle.

  • 22.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per Gunnar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Platell, P.
    Theoretical research of carbon dioxide power cycle application in automobile industry to reduce vehicle's fuel consumption2005In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 25, no 14-15, p. 2041-2053Article in journal (Refereed)
    Abstract [en]

    The current work discusses means to utilize low-grade small-scale energy in vehicle exhaust gases, to reduce the vehicle's fuel consumption and to make it run more environmental friendly. To utilize the energy in the exhaust gas, a CO2 bottoming system in the vehicle's engine system is proposed. Several basic cycles-according to the different design concepts-are presented, and the efficiencies are calculated using Engineering Equation Solver (EES).1 Several thermodynamic models in EES show that after system optimization, in CO2 Transcritical power cycle with a gas heater pressure of 130 bars and 200 °C expansion inlet temperature, about 20% of energy in the exhaust gas can be converted into useful work. Increasing the pressure in the gas heater to 300 bars and with same expansion inlet temperature, about 12% of exhaust gas energy can be converted. When raising the pressure both in the gas cooler and in the gas heater, the cycle runs completely above the critical point, and the efficiency is about 19%. Besides, in the CO2 combined cycle, the system COP is 2.322 and about 5% of exhaust gas energy can be converted.

  • 23.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A Nobel Gas-Water Heat Exchanger with Minichannels2008Conference paper (Refereed)
  • 24.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn E.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A NOVEL GAS-WATER HEAT EXCHANGER WITH MINICHANNELS2009In: HT2008: PROCEEDINGS OF THE ASME SUMMER HEAT TRANSFER CONFERENCE - 2008, VOL 2, NEW YORK: AMER SOC MECHANICAL ENGINEERS , 2009, p. 157-164Conference paper (Refereed)
    Abstract [en]

    In the current study, a novel gas water heat exchanger with minichannels is designed, built and tested. The heat exchanger is mainly composed of a number of concentric ring shaped plates, which are made tip of several heat exchanger tubes. The ring shaped plates are arranged in parallel and placed in a shell. The heat exchanger is designed as a counter current heat exchanger with laminar flow on the heat exchanger's shell-side (gas side) and therefore has a very low pressure drop on the shell side. The heat exchanger was tested with water and hot air on its tube-side and shell-side respectively. All the necessary parameters like inlet and outlet temperatures on tube-side and shell-side as well as the pressure drop, flow rate of fluids, etc. were measured. Different existing correlations were used to calculate the overall heat transfer coefficient and the results were compared with the measured value. The measured results show that the new designed heat exchanger can achieve a good heat transfer performance and also maintain a low pressure drop on shell-side (gas side).

  • 25.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pridasawas, Wimolsiri
    King Mongkut’s University of Technology Thonburi, Dept. of Chemical Engineering,Bangkok, Thailand.
    Theoretical Study of a Carbon Dioxide Double Loop System2007Conference paper (Refereed)
    Abstract [en]

    In the current research, a carbon dioxide double loop system is proposed. The system contains of two sub systems: a CO2power subsystem and a CO2refrigeration subsystem. The power subsystem is able to utilize the energy from the low-grade heat source to produce power. The power is then transferred to the refrigeration subsystem, partly or totally covering the power consumption of the compressor. Furthermore, it is also possible to take advantage of the temperature glides of both subsystems’ heat rejection processes to produce hot water. Engineering Equation Solver (EES) is employed to analyze the system performance. The results show that the proposed system is a very promising way to provide cooling, heating and hot water in a more efficient way comparing to traditional systems.

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  • 26.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Workie, Almaz Bitew
    Second Law Analysis of a Carbon Dioxide Transcritical Power System in Low-grade Heat Source RecoveryArticle in journal (Other academic)
    Abstract [en]

    Employing Carbon dioxide as a working media in power cycles for low-grade heat source utilization has attracted more and more attentions. However, compared to other well-known cycles that employed in low-grade heat source utilizations, the information about CO2power cycle is still very limited. In the current work, the performance of a CO2power cycle in utilizing the low-grade heat sources is simulated and the results are analyzed with a focus on second law thermodynamics (i.e. exergy and entropy). Different system parameters that influencing the system exergy and entropy change are discussed.

    Engineering Equation Solver (EES) is used for simulation. The simulation results show that the matching of the temperature profiles in the system heat exchangers has crucial influences on their exergy destructions and entropy generations. It is also an essential factor that influences the system thermodynamic efficiencies.

    Download full text (pdf)
    fulltext
  • 27.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pridasawas, Wimolsiri
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Dynamic simulation of a solar-driven carbon dioxide transcritical power system for small scale combined heat and power production2010In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 84, no 7, p. 1103-1110Article in journal (Refereed)
    Abstract [en]

    Carbon dioxide is an environmental benign natural working fluid and has been proposed as a working media for a solar-driven power system In the current work, the dynamic performance of a small scale solar-driven carbon dioxide power system is analyzed by dynamic simulation tool TRNSYS 16 (Klein et al., 2004) and Engineering Equation Solver (EES) (Klein, 2004) using co-solving technique Both daily performance and yearly performance of the proposed system have been simulated Different system operating parameters, which will influence the system performance, have been discussed. Under the Swedish climatic condition, the maximum daily power production is about 12 kW h and the maximum monthly power production is about 215 kW h with the proposed system working conditions Besides the power being produced, the system can also produce about 10 times much thermal energy. which can be used for space heating, domestic hot water supply or driving absorption chillers The simulation results show that the proposed system is a promising and environmental benign alternative for conventional low-grade heat source utilization system (C) 2010 Elsevier Ltd All rights reserved.

  • 28.
    Chen, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pridasawas, Wimolsiri
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Low-grade heat source utilization by carbon dioxide transcritical power cycle2007In: 2007 Proceedings of the ASME/JSME Thermal Engineering Summer Heat Transfer Conference - HT 2007 Volume 1, 2007, p. 519-525Conference paper (Refereed)
    Abstract [en]

    One way to reduce the fossil fuel consumption and mitigate environmental impact is to utilize low-grade heat sources for power production. In this paper, a transcritical carbon dioxide power cycle is analyzed for its potential in utilizing the low-grade heat sources. Solar thermal is selected as a representative of low-grade heat sources. TRNSYS 16(1) and Engineering Equation Solver (EES)(2) are employed using co-solving technique to analyze the dynamic performance of the proposed system. Both daily performance and annual performance of the proposed system under Swedish climate conditions are simulated. The simulation results show that the proposed system can achieve 8% average thermal efficiency and consequently 2.43 kW average power production during the system working period on a randomly selected summer day with a 30 m(2) solar collector. Over the whole year, the maximum daily power production is about 17 kWh and the maximum monthly power production is about 185 kWh.

  • 29.
    Cowan, David
    et al.
    London South Bank Univ, London, England.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Maidment, Graeme
    London South Bank Univ, London, England..
    Chaer, Issa
    London South Bank Univ, London, England..
    REFRIGERANT LEAKAGE AND CONTAINMENT - OVERVIEW OF THE ACTIVITIES OF THE IIR WORKING PARTY ON MITIGATION OF DIRECT EMISSIONS OF GREENHOUSE GASES IN REFRIGERATION2011In: 23RD IIR INTERNATIONAL CONGRESS OF REFRIGERATION, INT INST REFRIGERATION , 2011, p. 3833-+Conference paper (Refereed)
    Abstract [en]

    In recent years Global emissions due to leakage of F-Gases from refrigeration and air conditioning equipment have continued to increase as HCFC and CFC refrigerants are replaced by non-ozone depleting, but higher GWP, HFC refrigerants. Although lower GWP HFO and natural refrigerants such as CO2, ammonia and hydrocarbons are increasingly used in new system designs, the upward trend in the use of HFC refrigerant and consequent emissions are likely to continue for some years in the future. The environmental damage caused by direct emissions from escape of refrigerant can be 30% or more of the total environmental impact of a RAC system. However, effective mitigation measures can reduce this significantly, to the extent that the total equivalent warming impact (TEWI) of systems containing high GWP refrigerants can be similar to (or even lower than) systems containing lower GWP refrigerants. Mitigation measures can take several forms including legislative, fiscal, the use of alternative technologies and refrigerants, improvements in design and work practices and skills training. The IIR has set up a Working Party to research, collate and disseminate information on such mitigation measures. This will be made available via the FRIDOC database. The objectives and progress against these objectives are described in this paper.

  • 30.
    Fernando, W. Primal D.
    et al.
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Han, Han
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Palm, Björn
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Granryd, Eric
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Lundqvist, Per
    KTH, Superseded Departments (pre-2005), Energy Technology.
    The Solubility of Propane (R290) with Commonly Used Compressor Lubrication Oils2003In: Compressors and Their Systems, 2003, Vol. 4, p. 157-166Conference paper (Refereed)
    Abstract [en]

    An ongoing project called "Charge minimisation of a small capacity heat pump" is aimed to minimise the refrigerant charge in heat pumps, refrigeration and air-conditioning systems. The experimental heat pump was run with propane as refrigerant and the designed heat capacity (condenser capacity) was over 5kW. Tests were done to investigate the refrigerant charge distribution in different sections of the heat pump, while it was running. The experiments done so far have shown that the amount of refrigerant in the compressor is higher than expected.

    This paper presents the measured refrigerant masses in a hermetic scroll compressor together in suction line and the calculated refrigerant mass dissolved in the compressor lubrication oil at different evaporation temperatures. Finally, solubility tests of propane with different lubricating oils are presented. The tests show that the propane is more soluble in POE than PAG oils.

  • 31.
    Fernando, W. Primal D.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ameel, Tim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Granryd, Eric
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A Minichannel Aluminium Tube Heat Exchanger - Part 1: Evaluation of Single-Phase Heat Transfer Coefficients by the Wilson Plot Method2008In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 31, no 4, p. 669-680Article in journal (Refereed)
    Abstract [en]

    A prototype liquid-to-refrigerant heat exchanger was developed with the aim of minimizing the refrigerant charge in small systems. To allow correct calculation of the refrigerant side heat transfer, the heat exchanger was first tested for liquid-to-liquid (water-to-water) operation in order to determine the single-phase heat transfer performance. These single-phase tests are reported in this paper. The heat exchanger was made from extruded multiport aluminium tubes and was designed similar to a shell-and-tube heat exchanger. The heat transfer areas of the shell-side and tube-side were approximately 0.82 m(2) and 0.78 m(2), respectively. There were six rectangular-shaped parallel channels in a tube. The hydraulic diameter of the tube-side was 1.42 mm and of the shell-side 3.62 mm. Tests were conducted with varying water flow rates, temperature levels and heat fluxes on both the tube and shell sides at Reynolds numbers of approximately 170-6000 on the tube-side and 1000-5000 on the shell-side, respectively. The Wilson plot method was employed to investigate the heat transfer on both the shell and tube sides. In the Reynolds number range of 2300-6000, it was found that the Nusselt numbers agreed with those predicted by the Gnielinski correlation within +/- 5% accuracy. In the Reynolds number range of 170-1200 the Nusselt numbers gradually increased from 2.1 to 3.7. None of the previously reported correlations for laminar flow predicted the Nusselt numbers well in this range. The shell-side Nusselt numbers were found to be considerably higher than those predicted by correlations from the literature.

  • 32.
    Fernando, W. Primal D.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ameel, Tim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Granryd, Eric
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A minichannel aluminium tube heat exchanger - Part II: Evaporator Performance with Propane2008In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 31, no 4, p. 681-695Article in journal (Refereed)
    Abstract [en]

    This paper presents heat transfer data for a multiport minichannel heat exchanger vertically mounted as an evaporator in a test-rig simulating a small water-to-water heat pump. The multiport minichannel heat exchanger was designed similar to a shell-and-tube type heat exchanger, with a six-channel tube of 1.42 mm hydraulic diameter, a tube-side heat transfer area of 0.777 m(2) and a shell-side heat transfer area of 0.815 m(2). Refrigerant propane with a desired vapour quality flowed upward through the tubes and exited with a desired superheat of 1-4 K. A temperature-controlled glycol solution that flowed downward on the shell-side supplied the heat for the evaporation of the propane. The heat transfer rate between the glycol solution and propane was controlled by varying the evaporation temperature and propane mass flow rate while the glycol flow rate was fixed (18.50 l min(-1)). Tests were conducted for a range of evaporation temperatures from -15 to +10 degrees C, heat flux from 2000 to 9000 W m(-2) and mass flux from 13 to 66 kg m(-2) s(-1). The heat transfer coefficients were compared with 14 correlations found in the literature. The experimental heat transfer coefficients were higher than those predicted by many of the correlations. A correlation which was previously developed for a very large and long tube (21 mm diameter and 10 m long) was in good agreement with the experimental data (97% of the data within 30%). Several other correlations were able to predict the data within a reasonable deviation (within 30%) after some adjustments to the correlations.

  • 33.
    Fernando, W. Primal D.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ameel, Tim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Granryd, Eric
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A minichannel aluminium tube heat exchanger - Part III: Condenser Performance with Propane2008In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 31, no 4, p. 696-708Article in journal (Refereed)
    Abstract [en]

    This paper reports heat transfer results obtained during condensation of refrigerant propane inside a minichannel aluminium heat exchanger vertically mounted in an experimental setup simulating a water-to-water heat pump. The condenser was constructed of multiport minichannel aluminium tubes assembled as a shell-and-tube heat exchanger. Propane vapour entered the condenser tubes via the top end and exited sub-cooled from the bottom. Coolant water flowed upward on the shell-side. The heat transfer areas of the tube-side and the shell-side of the condenser were 0.941 m(2) and 0.985 m(2), respectively. The heat transfer rate between the two fluids was controlled by varying the evaporation temperature while the condensation temperature was fixed. The applied heat transfer rate was within 3900-9500 W for all tests. Experiments were performed at constant condensing temperatures of 30 degrees C, 40 degrees C and 50 degrees C, respectively. The cooling water flow rate was maintained at 11.90 l min(-1) for all tests. De-superheating length, two-phase length, sub-cooling length, local heat transfer coefficients and average heat transfer coefficients of the condenser were calculated. The experimental heat transfer coefficients were compared with predictions from correlations found in the literature. The experimental heat transfer coefficients in the different regions were higher than those predicted by the available correlations.

  • 34.
    Fernando, W. Primal D.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Granryd, Eric
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Performance of a single-family heat pump at different working conditions using small quantity of propane as refrigerant2007In: Experimental heat transfer, ISSN 0891-6152, E-ISSN 1521-0480, Vol. 20, no 1, p. 57-71Article in journal (Refereed)
    Abstract [en]

    The performance of a domestic heat pump that uses a low quantity of propane as refrigerant has been experimentally investigated. The heat pump consists of two minichannel aluminium heat exchangers, a scroll compressor, and an electronic expansion valve. It was charged with the minimum amount of refrigerant propane required for the stable operation of the heat pump without permitting refrigerant vapor into the expansion valve at incoming heat source fluid temperature to the evaporator of +10 degrees C The inlet temperature of the heat source fluid passing through the evaporator was varied from +10 degrees C to -10 degrees C while holding the condensing temperature constant at 35 degrees C, 40 degrees C, 50 degrees C, and 60 degrees C, respectively. The minimum refrigerant charges required at above-tested condensing temperatures were found to decrease when the condensing temperature increased and were recorded as 230 g, 224 g, 215 g, and 205 g, respectively. The results confirm that a heat pump with 5 kW capacity can be designed with less than 200 g charge of refrigerant propane in the system. Due to the high solubility of propane in compressor lubrication oil, the amount of refrigerant which may escape rapidly in case of accident or leakage is less than 150 g.

  • 35.
    Fernando, W. Primal D.
    et al.
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Palm, Björn
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Lundqvist, Per
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Granryd, Eric
    KTH, Superseded Departments (pre-2005), Energy Technology.
    Propane Heat Pump with Low Refrigerant Charge: Design and Laboratory Tests2004In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 27, no 7, p. 761-773Article in journal (Refereed)
    Abstract [en]

    Independently of the choice of refrigerant, environmental and or safety issues can be minimised by reducing the amount of refrigerant charge per heat pump or refrigeration system. In the investigation reported here, a laboratory test rig was built, simulating a water-to-water heat pump with a heating capacity of 5 kW. The system was designed to minimize the charge of refrigerant mainly by use of mini-channel aluminium heat exchangers. It was shown that the system could be run with 200 g of propane at typical Swedish operating conditions without reduction of the COP compared to a traditional design. Additional charge reduction is possible by selecting proper compressor lubrication oils or by using a compressor with less lubrication oil.

  • 36.
    Grozdek, Marino
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Curko, T.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Soldo, V.
    Performance comparison of a static ice-bank and dynamic ice slurry cool thermal energy storage systems2010In: 9th IIR Gustav Lorentzen Conference on Natural Working Fluids (GL2010) Paris, France: International Institute of Refrigeration, 2010, 2010Conference paper (Refereed)
    Abstract [en]

        In this study theoretical evaluation of performance of a three ice based cool thermal energy storage systems is conducted ; (a) static, indirect, external melt ice-on-coil ; (b) dynamic ice slurry type storage with a water and (c) ice slurry distribution system. In order to investigate and assess possible economic and energy saving potential of an ice slurry storage system over conventional static type a computer simulation models were used. The systems were compared for high temperature application, for the purpose of milk cooling in the dairy industry. The product temperature that has to be achieved is +3 °C which requires a secondary coolant temperature to be less than +1 °C. Calculations have been performed on basis of specific user supplied load data for a design day, acquired as an actual case for dairy plant Prehrambeno industrijski kombinat (PIK) in the city of Rijeka, Croatia, and local electricity billing rate structure. The comparison shows that the dynamic cool thermal energy storage system (CTES) is favourable as to energy consumption in all studied cases.

  • 37.
    Grozdek, Marino
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Experimental investigation of ice slurry flow pressure drop in horizontal tubes2009In: Experimental Thermal and Fluid Science, ISSN 0894-1777, E-ISSN 1879-2286, Vol. 33, no 2, p. 357-370Article in journal (Refereed)
    Abstract [en]

    Pressure drop behaviour of ice slurry based on ethanol-water mixture in circular horizontal tubes has been experimentally investigated. The secondary fluid was prepared by mixing ethyl alcohol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 degrees C). The pressure drop tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 30% depending on test conditions. Results from flow tests reveal much higher pressure drop for higher ice concentrations and higher velocities in comparison to the single phase flow. However for ice concentrations of 15% and higher, certain velocity exists at which ice slurry pressure drop is same or even lower than for single phase flow. It seems that higher ice concentration delay flow pattern transition moment (from laminar to turbulent) toward higher velocities. In addition experimental results for pressure drop were compared to the analytical results, based on Poiseulle and Buckingham-Reiner models for laminar flow, Blasius. Darby and Melson, Dodge and Metzner, Steffe and Tomita for turbulent region and general correlation of Kitanovski which is valid for both flow regimes. For laminar flow and low buoyancy numbers Buckingham-Reiner method gives good agreement with experimental results while for turbulent flow best fit is provided with Dodge-Metzner and Tomita methods. Furthermore, for transport purposes it has been shown that ice mass fraction of 20% offers best ratio of ice slurry transport capability and required pumping power.

  • 38.
    Grozdek, Marino
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Melinder, Åke
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Experimental investigation of ice slurry heat transfer in horizontal tube2009In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 32, no 6, p. 1310-1322Article in journal (Refereed)
    Abstract [en]

    Heat transfer of ice slurry flow based on ethanol-water mixture in a circular horizontal tube has been experimentally investigated. The secondary fluid was prepared by mixing ethanol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 degrees C). The heat transfer tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 22% depending on test performed. Measured heat transfer coefficients of ice slurry are found to be higher than those for single phase fluid, especially for laminar flow conditions and high ice mass fractions where the heat transfer is increased with a factor 2 in comparison to the single phase flow. In addition, experimentally determined heat transfer coefficients of ice slurry flow were compared to the analytical results, based on the correlation by Sieder and Tate for laminar single phase regime, by Dittus-Boelter for turbulent single phase regime and empirical correlation by Christensen and Kauffeld derived for laminar/turbulent ice slurry flow in circular horizontal tubes. it was found that the classical correlation proposed by Sieder and Tate for laminar forced convection in smooth straight circular ducts cannot be used for heat transfer prediction of ice slurry flow since it strongly underestimates measured values, while, for the turbulent flow regime the simple Dittus-Boelter relation predicts the heat transfer coefficient of ice slurry flow with high accuracy but only up to an ice mass fraction of 10% and Re-cf > 2300 regardless of imposed heat flux. For higher ice mass fractions and regardless of the flow regime, the correlation proposed by Christensen and Kauffeld gives good agreement with experimental results. (C) 2009 Elsevier Ltd and IIR. All rights reserved.

  • 39.
    Grozdek, Marino
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Soldo, V.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Curko, T.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Performance Comparison of a Static Ice-Bank and Dynamic Ice Slurry Cool Thermal Energy Storage SystemsArticle in journal (Other academic)
  • 40. Hägg, Cecilia
    et al.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    A Comparison Between Single-Phase and Ice Slurry as Secondary Fluid in Supermarket2005Conference paper (Refereed)
  • 41.
    Hägg, Cecilia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Comparaison entre fluide secondaire monophasique et coulis de glace en supermarché2007In: Revue générale du froid, ISSN 0035-3205, Vol. 97, no 1073, p. 47-54Article in journal (Refereed)
    Abstract [fr]

    Le coulis de glace est considéré comme une solution novatrice en tant que frigoporteur diphasique. Cet article évalue si la solution coulis de glace est compétitive vis-à-vis des fluides secondaires monophasiques dans les applications en supermarché en froid positif, avec les deux options habituelles : récupération de chaleur et haute pression flottante. Etant donné que le coulis de glace permet une accumulation efficace, les besoins de production de froid en période de pointe peuvent être déplacés. La comparaison est faite entre 24 heures de temps de fonctionnement habituel et 8 heures assurées pendant la période nocturne. Les temps de fonctionnement différents nécessitent des volumes de stockage différents. Les systèmes ont été comparés, en faisant varier pendant un an les conditions de fonctionnement heure par heure, en utilisant un programme de simulation appelé CyberMart. Ce programme est destiné à simuler les systèmes frigorifiques et énergétiques en supermarché. Il a été développé par la division thermodynamique et réfrigération appliquée de l'Institut royal de technologie de Stockholm (KTH). La simulation a été effectuée sur la base d'un magasin alimentaire virtuel de 2 700 m2d'une puissance frigorifique de 90 kW à Karlstad, en Suède. En comparant les consommations énergétiques, l'étude montre que le coulis de glace est favorable dans tous les cas.

  • 42. Hägg, Cecilia
    et al.
    Melinder, Åke
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Pressure Drop Experiments and Background for Choosing Suitable Fluid for Low Temperature Ice SlurrIn: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081Article in journal (Other academic)
  • 43.
    Hägg, Cecilia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Melinder, Åke
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Martin, C.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A Proper Fluid for Ice Slurry at -35 ºC,2005Report (Other academic)
  • 44.
    Jonsson, Daniel K.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies. Swedish Defence Research Agency,Sweden.
    Gustafsson, Stina
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Wangel, Josefin
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies.
    Höjer, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Sustainable Communications, CESC.
    Lundqvist, Per G.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Svane, Örjan
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Environmental Strategies.
    Energy at your service: highlighting energy usage systems in the context of energy efficiency analysis2011In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 4, no 3, p. 355-369Article in journal (Refereed)
    Abstract [en]

    Increasing energy efficiency has for a long time been identified as an important means of mitigating climate change. However, the full potential for technical energy efficiency has seldom been fully exploited. The traditional approach in energy systems analysis and policy is still largely supply-orientated, i.e. focusing on the management of energy conversion, production and distribution, and final use of energy in the form of energy carriers. This paper contributes to previous discussions on how to highlight and explore the user side in the analysis of energy systems in an efficiency context. The energy usage systems approach, including end-use technologies and the production of service demanded by a human activity system, is used to promote a dynamic bottom-up perspective on energy. In determining the possible potential for change by increasing energy efficiency, the demand for energy should not be considered synonymous with the demand for neither energy carriers, nor the measurable service volumes (such as kilometres travelled, square metre conditioned space, etc.), without considering the sociocultural context in which the service is being used or called upon. In summary, the predominant paradigm dealing with the energy system as a technical system managing resources and providing energy carriers should thus be complemented with the view of a socio-technical system facilitating and/or managing the services.

  • 45.
    Kliatsko, Aleh
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    A Systematic approach to modelling of energy usage by Human Activity System (HAS) and Energy Usage Systems (EUS)2011Conference paper (Refereed)
    Abstract [en]

    The main goal of the paper is to introduce a chosen modelling approach and provide a discussion on this. The article describes modelling of energy use as a consequence of human activities in cities and especially situation where the opportunities for change are significant. We call these Situations of Opportunities (SitOpp). The paper describes a modelling approach aiming at tools to explore these situations further. The methodology is based on the concept of Human Activity Systems (HAS - What people do) and Energy Usage Systems (EUS - the system that supports these activities by aid of energy). The modelling process consists of several steps: conceptual, qualitative and finally quantitative models are built for each SitOpp. The modelling process is supported by the construction of so-called Causal Loop Diagram (CLD) to facilitate multi-stakeholder and cross-disciplinary modelling.

     

    This study presents schematically a process to create conceptual as well as qualitative models, and the modelling process, aiming to quantitatively determine the need for primary energy in three city parts of Stockholm.  The SitOpps are chosen as part of a transformation process to a normative future goal towards the so-called 2000W society (2kW is equivalent to an energy usage of 17 500 kWh per person and year). The CO2 emissions should also be reduced from today’s levels to 1ton/y and person.

     

    One of the main tasks of this project is to develop a methodology to systematically model HAS and EUS, going from the conceptual over the qualitative to the quantitative mode. The project uses the STELLA software program to build the quantitative models. One important aspects of the project is the understanding of the change agents (actors) and the change process. The modelling process is supporting parallel scenario building activities using back-casting techniques.

  • 46.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Advances In Heat Pump Technology And Market Development In Sweden2009In: Proc. 39th congress on heating, refrigerating and air conditioning, Academic Conferences Publishing, 2009Conference paper (Refereed)
  • 47.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Efficient refrigeration technologies: a prerequiste for sustainable development2010In: Industria & Formazione, no 7, p. 18-21Article in journal (Refereed)
  • 48.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    IPCC/TEAP Special Report on Safeguarding the Ozone Layer and the Global Climate System2006Report (Other academic)
  • 49.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Mitigation of greenhouse gases in refrigeration2005Conference paper (Other academic)
  • 50.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Recent And Historical Advances In Heat Pump Technology And Market In Sweden2008Conference paper (Refereed)
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