The Experts below are selected from a list of 96 Experts worldwide ranked by ideXlab platform
Bja Rn Karlsson - One of the best experts on this subject based on the ideXlab platform.
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retrofitting domestic hot water heaters for Solar water heating systems in single family houses in a cold climate a theoretical analysis
Energies, 2012Co-Authors: Luis Ricardo Bernardo, Henrik Davidsson, Bja Rn KarlssonAbstract:One of the biggest obstacles to economic profitability of Solar water heating systems is the investment cost. Retrofitting existing domestic hot water heaters when a new Solar hot water system is installed can reduce both the installation and material costs. In this study, retrofitting existing water heaters for Solar water heating systems in Swedish single-family houses was theoretically investigated using the TRNSYS software. Four simulation models using forced circulation flow with different system configurations and control strategies were simulated and analysed in the study. A comparison with a standard Solar thermal system was also presented based on the annual Solar fraction. The simulation results indicate that the retrofitting configuration achieving the highest annual performance consists of a system where the existing Tank is used as storage for the Solar heat and a smaller Tank with a heater is added in series to make sure that the required outlet temperature can be met. An external heat exchanger is used between the collector circuit and the existing Tank. For this retrofitted system an annual Solar fraction of 50.5% was achieved. A conventional Solar thermal system using a standard Solar Tank achieves a comparable performance for the same total storage volume, collector area and reference conditions.
Luis Ricardo Bernardo - One of the best experts on this subject based on the ideXlab platform.
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retrofitting domestic hot water heaters for Solar water heating systems in single family houses in a cold climate a theoretical analysis
Energies, 2012Co-Authors: Luis Ricardo Bernardo, Henrik Davidsson, Bja Rn KarlssonAbstract:One of the biggest obstacles to economic profitability of Solar water heating systems is the investment cost. Retrofitting existing domestic hot water heaters when a new Solar hot water system is installed can reduce both the installation and material costs. In this study, retrofitting existing water heaters for Solar water heating systems in Swedish single-family houses was theoretically investigated using the TRNSYS software. Four simulation models using forced circulation flow with different system configurations and control strategies were simulated and analysed in the study. A comparison with a standard Solar thermal system was also presented based on the annual Solar fraction. The simulation results indicate that the retrofitting configuration achieving the highest annual performance consists of a system where the existing Tank is used as storage for the Solar heat and a smaller Tank with a heater is added in series to make sure that the required outlet temperature can be met. An external heat exchanger is used between the collector circuit and the existing Tank. For this retrofitted system an annual Solar fraction of 50.5% was achieved. A conventional Solar thermal system using a standard Solar Tank achieves a comparable performance for the same total storage volume, collector area and reference conditions.
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Retrofitting Domestic Hot Water Tanks for Solar Thermal Collectors. A Theoretical Analysis
Proceedings of the World Renewable Energy Congress – Sweden 8–13 May 2011 Linköping Sweden, 2011Co-Authors: Luis Ricardo Bernardo, Henrik Davidsson, Björn KarlssonAbstract:One of the most expensive components of a s olar thermal system is the storage Tank. Retrofitting conventional domestic hot water heaters when installing a new Solar hot water system can decrease the total investment cost. In this study, retrofitting of existing water heaters using forced circulation flow was investigated. A comparison with a standard Solar thermal system is also presented. Four simulation models of different system configurations were created and tested for the climate in Lund, Sweden. The results from the simulations indicate that the best configuration consists on connecting the collectors to the existing heater throughout an external heat exchanger and adding a small heater storage in series. For this retrofitted system, preliminary results show that an annual Solar fraction of 53% is achieved. In addition, a co nventional Solar thermal system using a standard Solar Tank achieves a comparable performance for the same storage volume and collector area. Hence, it is worth to further investigate and test in practice this retrofitting. Furthermore, using the same system configuration, Solar collectors can also be combined with new standard domestic hot water Tanks at new installations, accessing a world-wide developed and spread industry.
Henrik Davidsson - One of the best experts on this subject based on the ideXlab platform.
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retrofitting domestic hot water heaters for Solar water heating systems in single family houses in a cold climate a theoretical analysis
Energies, 2012Co-Authors: Luis Ricardo Bernardo, Henrik Davidsson, Bja Rn KarlssonAbstract:One of the biggest obstacles to economic profitability of Solar water heating systems is the investment cost. Retrofitting existing domestic hot water heaters when a new Solar hot water system is installed can reduce both the installation and material costs. In this study, retrofitting existing water heaters for Solar water heating systems in Swedish single-family houses was theoretically investigated using the TRNSYS software. Four simulation models using forced circulation flow with different system configurations and control strategies were simulated and analysed in the study. A comparison with a standard Solar thermal system was also presented based on the annual Solar fraction. The simulation results indicate that the retrofitting configuration achieving the highest annual performance consists of a system where the existing Tank is used as storage for the Solar heat and a smaller Tank with a heater is added in series to make sure that the required outlet temperature can be met. An external heat exchanger is used between the collector circuit and the existing Tank. For this retrofitted system an annual Solar fraction of 50.5% was achieved. A conventional Solar thermal system using a standard Solar Tank achieves a comparable performance for the same total storage volume, collector area and reference conditions.
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Retrofitting Domestic Hot Water Tanks for Solar Thermal Collectors. A Theoretical Analysis
Proceedings of the World Renewable Energy Congress – Sweden 8–13 May 2011 Linköping Sweden, 2011Co-Authors: Luis Ricardo Bernardo, Henrik Davidsson, Björn KarlssonAbstract:One of the most expensive components of a s olar thermal system is the storage Tank. Retrofitting conventional domestic hot water heaters when installing a new Solar hot water system can decrease the total investment cost. In this study, retrofitting of existing water heaters using forced circulation flow was investigated. A comparison with a standard Solar thermal system is also presented. Four simulation models of different system configurations were created and tested for the climate in Lund, Sweden. The results from the simulations indicate that the best configuration consists on connecting the collectors to the existing heater throughout an external heat exchanger and adding a small heater storage in series. For this retrofitted system, preliminary results show that an annual Solar fraction of 53% is achieved. In addition, a co nventional Solar thermal system using a standard Solar Tank achieves a comparable performance for the same storage volume and collector area. Hence, it is worth to further investigate and test in practice this retrofitting. Furthermore, using the same system configuration, Solar collectors can also be combined with new standard domestic hot water Tanks at new installations, accessing a world-wide developed and spread industry.
Simon Furbo - One of the best experts on this subject based on the ideXlab platform.
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model predictive control for a smart Solar Tank based on weather and consumption forecasts
Energy Procedia, 2012Co-Authors: Rasmus Halvgaard, Elsa Andersen, Simon Furbo, Peder Bacher, Bengt Perers, John Bagterp Jorgensen, Niels Kjolstad Poulsen, Henrik MadsenAbstract:In this work the heat dynamics of a storage Tank were modelled on the basis of data and maximum likelihood methods. The resulting grey-box model was used for Economic Model Predictive Control (MPC) of the energy in the Tank. The control objective was to balance the energy from a Solar collector and the heat consumption in a residential house. The storage Tank provides heat in periods where there is low Solar radiation and stores heat when there is surplus Solar heat. The forecasts of consumption patterns were based on data obtained from meters in a group of single-family houses in Denmark. The Tank can also be heated by electric heating elements if necessary, but the electricity costs of operating these heating elements should be minimized. Consequently, the heating elements should be used in periods with cheap electricity. It is proposed to integrate a price-sensitive control to enable the storage Tank to serve a smart energy system in which flexible consumers are expected to help balance fluctuating renewable energy sources like wind and Solar. Through simulations, the impact of applying Economic MPC shows annual electricity cost savings up to 25-30%. © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of PSE AG
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Smart Solar Tanks for small Solar domestic hot water systems
Solar Energy, 2005Co-Authors: Simon Furbo, Elsa Andersen, Søren Knudsen, Niels Kristian Vejen, Louise Jivan ShahAbstract:Abstract Investigation of small SDHW systems based on smart Solar Tanks are presented. The domestic water in a smart Solar Tank can be heated both by Solar collectors and by means of an auxiliary energy supply system. The auxiliary energy supply system––in this study electric heating elements––heats up the hot-water Tank from the top and the water volume heated by the auxiliary energy supply system is fitted to the hot-water consumption and consumption pattern. In periods with a large hot-water demand, the volume is large; in periods with a small hot-water demand, the volume is small. Two small SDHW systems, based on differently designed smart Solar Tanks and a traditional SDHW system were investigated by means of laboratory experiments and theoretical calculations. The investigations showed that the yearly thermal performance of SDHW systems with smart Solar Tanks is 5–35% higher than the thermal performance of traditional SDHW systems. Estimates indicate that the performance/cost ratio can be improved by up to 25% by using a smart Solar Tank instead of a traditional Tank when the backup energy system is electric heating elements. Further, smart Solar Tanks are suitable for unknown, variable, large or small hot-water consumption and the risk of oversized Solar heating systems and oversized Tank volumes is reduced by using smart Solar Tanks. Based on the investigations it is recommended to start development of smart Solar Tank units with an oil-fired boiler or a natural gas burner as auxiliary energy supply system.
Ali Akbar Alemrajabi - One of the best experts on this subject based on the ideXlab platform.
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Phase change material for enhancing Solar water heater, an experimental approach
Energy Conversion and Management, 2013Co-Authors: Mohammad Ali Fazilati, Ali Akbar AlemrajabiAbstract:In this research, the effects of using Phase Change Materials (PCM) as storage medium on the performance of a Solar water heater have been experimentally investigated. A type of paraffin wax is used as PCM in spherical capsules as storage material in the Tank of Solar water heater. The Solar Tank is of jacketed shell type. Effect of three Solar radiation intensity, i.e. weak, mean and strong are studied. The energy and exergy efficiencies of water heater and the time length the heater can supply hot water have been compared before and after using of PCM in the Tank. It is observed that by using PCM in the Tank the energy storage density is increased in the Tank up to 39% and the exergy efficiency is enhanced up to 16%. Also, it is observed that Solar water heater with PCM, can supply hot water with specified temperature at 25% longer time. Improvement in thermal stratification has also been observed by examining temperature histories of different water layers in the Tank.
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Phase change material for enhancing Solar water heater, an experimental approach
Energy Conversion and Management, 2013Co-Authors: Mohammad Ali Fazilati, Ali Akbar AlemrajabiAbstract:In this research, the effects of using Phase Change Materials (PCM) as storage medium on the performance of a Solar water heater have been experimentally investigated. A type of paraffin wax is used as PCM in spherical capsules as storage material in the Tank of Solar water heater. The Solar Tank is of jacketed shell type. Effect of three Solar radiation intensity, i.e. weak, mean and strong are studied. The energy and exergy efficiencies of water heater and the time length the heater can supply hot water have been compared before and after using of PCM in the Tank. It is observed that by using PCM in the Tank the energy storage density is increased in the Tank up to 39% and the exergy efficiency is enhanced up to 16%. Also, it is observed that Solar water heater with PCM, can supply hot water with specified temperature at 25% longer time. Improvement in thermal stratification has also been observed by examining temperature histories of different water layers in the Tank. © 2013 Elsevier Ltd. All rights reserved.
