Phase change storage solar heat pump hydronics based on cloud computing

In this work a new highly compact solar thermal heat pump system for space heating and domestic hot water preparation will be presented in detail. It was developed within the European project “MacSheep”. The aim of the project is to build four different solar heat pump systems, which achieve 25 % electric energy savings compared to the state of the art solar heat pump heating systems, while still being cost-competitive. Within the MacSheep project, four different developing groups developed different system concepts to reach this project goal. The system, which is presented in this paper, was developed and designed by the following partners; Energie Solaire SA (industrial partner), Institute of Thermal Engineering (research partner) and the Institute for Solar Technology SPF (research partner). A key component of the system is a novel brine-to-water heat pump prototype with a speed controlled compressor, an economizer refrigerant cycle and a desuperheater. The heat pump was optimized for low source temperatures, in order to be compatible with concepts that use only unglazed selective collectors as heat source. A key element was the integration of heat pump, storage, and hydraulic connections into one compact system design. Further developments are: a combi-storage, which is optimized for heat pump use, and selective unglazed c ollectors with a new selective coating. The compact designed heat storage, heat pump and hydraulic solution is placed under one high performing insulating shell built of vacuum insulation panels. The annual simulation results, which were validated with component tests in the lab, show very promising results for the whole system. The electric savings compared with the state of the art system are expected around 28 % and the improvement of the seasonal performance factor (SPF) of the whole system is around + 40 %. These values will be compared with a whole system hardware in the loop benchmark test in autumn 2015.

Performance of combined solar-heat pump systems

Experimental research on a solar air-source heat pump system with phase change energy storage

In the north of Graz, Austria, a large scale solar thermal system (gross collector area: 3885 m²) was installed in 2009 primarily to supply solar heat to a district heating (DH) network especially in summer and to cover part of the heat demand of the on-site buildings. In order to reduce the auxiliary heat needed for the on-site buildings and to prolong the operation time of the solar thermal system, a heat pump, which uses the solar collector loop as exclusive heat source, was installed later on. This way solar heat that is available at temperatures too low for direct solar charging of the TES (thermal energy storage) can still be used. After having performed dynamic system simulations of the installation without the heat pump in TRNSYS to validate the simulation model, the heat pump was implemented into the simulation model. Applying different control strategies to the solar heat pump system an increase of the solar fraction for the heating period (October to March) from 20.5 % without the heat pump up to 33.0 % with heat pump could be reached in the simulations. The interaction between solar thermal system and heat pump in this special configuration turned out to be challenging in terms of control optimization; hydraulic decoupling of the two units is recommended. Based on onsite measurements the performance of the system in February 2013 is evaluated

Economic evaluation and annual performance analysis of a novel series-coupled PV/T and solar TC with solar direct expansion heat pump system: An experimental and numerical study

Wuhan City located in the central of China and its climate was hot summer and cold winter. Heat pump air-conditioners were main equipments for heating or cooling in Wuhan City. Solar assisted heat pump was an energy conservation technology. However, the development and application of solar assisted heat pump at residential buildings was limited by many factors, such as sunshine duration, system construction, running model and solar energy collector, etc. Therefore, a study of analysis for the application of solar assisted heat pump system was carried out to analysis its economical efficiency and applicability in Wuhan City. The general influencing factors on the running of solar assisted heat pump were discussed. The result showed that Solar assisted heat pump could reduce the limitation of solar energy heater and heat pump, especially in heating model in winter. Solar assisted heat pump could improvide the performance of heat pump system and the utilization ratio of solar enery.

A solar-air source heat pump with thermosiphon to efficiently utilize solar energy

Society’s use of fossil fuels has led to increasingly high levels of CO2 in the atmosphere. These levels have been linked to global average temperature rises, and increases in the severity and frequency of major weather events. To combat these effects, nations around the world have committed to reducing their CO2 emissions, and transition to renewable energy. This thesis focuses on the development of a novel solar heating system, which combines a hybrid solar panel and cascade heat pump. The thesis begins by presenting a high-level literature review of solar and heat pump technologies, followed by the initial design development of the system. Two design iterations are presented, illustrating that the final design was selected because it exhibits improved peak heat output, and reduced sensitivity to panel temperature. Next, a manuscript-based chapter is presented that focuses on utilizing the proposed solar heating system for water distillation. Case studies are presented that compare the performance of the proposed system with a solar still at four different locations. The final conclusion from these studies is that using the proposed system offers area-based performance improvements of 780% compared to a basic solar still. A second manuscript-based study is then presented, which focuses on utilizing the proposed solar heating system for domestic hot water production. Additional case studies are detailed that compare the proposed system to an evacuated tube design, and a single heat pump. The conclusions from these studies are that the proposed system exceeds the performance of the evacuated tube system by up to 64%, and that the proposed system is most beneficial during seasons with higher average dry-bulb temperatures, and increased solar irradiation. A final manuscript-based study is then presented, which focuses on a methodology for improving alternate mode thermal performance estimates for hybrid solar panels. The conclusion from this study is that the proposed methodology can successfully estimate thermal performance within 5% of actual values. Each of these studies contributes to the project goal of developing a novel solar energy heating system, which can be further developed to reduce global CO2 emissions, and reduce the effects of climate change.

Application of air conditioning is widespread in the United States; any new system for heating buildings must be at least compatible with it to be commercially viable. A wide variety of options exists to provide air conditioning along with solar heating for buildings. The effectiveness and efficiency of coupling these air conditioning options with solar heating depends strongly on which solar heating system is being contemplated. This paper discusses the relative merits and the state of development of several solar boosted heat pump systems with regard to their ability to provide air conditioning using conventional vapour compression refrigeration cycles. A brief description is given of the status of solar fired air conditioning. Clues to an approach to cool storage in solar air conditioning systems are given by an assessment of cool storage for reducing peak electrical loads from conventional air conditioning equipment. A system using hydrated salts in a rolling cylinder thermal energy storage device for compact and effective cool storage is described. References are given to provide the interested reader with more detailed information.

A simulation study on performance improvement of solar assisted heat pump hot water system by novel controllable crystallization of supercooled PCMs

Solar Collectors cooled directly with Refrigerant 12 and acting as the evaporator of a solar source heat pump system has been experimentally investigated. The refrigerant cooled solar collector may be operated at an evaporation temperature lower than its ambient temperature and thus has an efficiency higher than that of the flat plate solar collectors in conventional systems.

A parallel solar augmented heat pump system has been experimentally evaluated in TECH House IV for three heating seasons between fall 1979 and spring 1982. Several changes were made in the operation of the system during the three year period. During 1979–1980, the use of on-peak purchased energy was minimized by charging the pebble bin in the off-peak period with a resistance duct heater. This configuration resulted in 83 percent of the purchased energy occurring in the off-peak period but the seasonal performance factor was only 1.61. During 1980–1981, the system was operated in the normal mode without the use of the off-peak heater. The seasonal performance factor then increased to 2.56. During 1981–1982, the mode of operation was the same as 1980–1981, but new outer cover sheets were installed and the inner cover sheet was eliminated resulting in a single glazed collector. The seasonal performance factor for the 1981–1982 season was measured to be 2.11.

Study and optimization of the influence of the water tank temperature on the performance of a solar assisted multi-source heat pump drying system

Experimental thermal performance of a solar source heat-pump system for residential heating in cold climate region

Comparison of Conventional Flat-Plate Solar Collector and Solar Boosted Heat Pump Using Unglazed Collector for Hot Water Production in Small Slaughterhouse