Study on a direct-expansion solar-assisted heat pump water heating system
TL;DR: In this paper, an analytical and experimental studies were performed on a directexpansion solar-assisted heat pump (DX-SAHP) water heating system, in which a 2 m2 bare flat collector acts as a source as well as an evaporator for the refrigerant.
Abstract: Analytical and experimental studies were performed on a direct-expansion solar-assisted heat pump (DX-SAHP) water heating system, in which a 2 m2 bare flat collector acts as a source as well as an evaporator for the refrigerant. A simulation model was developed to predict the long-term thermal performance of the system approximately. The monthly averaged COP was found to vary between 4 and 6, while the collector efficiency ranged from 40 to 60%. The simulated results were used to obtain an optimum design of the system and to determinate a proper strategy for system operating control. The effect of various parameters, including solar insolation, ambient temperature, collector area, storage volume and speed of compressor, had been investigated on the thermal performance of the DX-SAHP system, and the results had indicated that the system performance is governed strongly by the change of solar insolation, collector area and speed of compressor. The experimental results obtained under winter climate conditions were shown to agree reasonably with the computer simulation. Copyright © 2003 John Wiley & Sons, Ltd.
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TL;DR: In this paper, a comprehensive review of studies conducted on them were classified and presented in tables, and the results obtained were discussed, which is expected that this comprehensive review will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis, performance assessment and applications of various types of HPWH systems.
Abstract: A heat pump water heater (HPWH) operates on an electrically driven vapor-compression cycle and pumps energy from the air in its surroundings to water in a storage tank, thus raising the temperature of the water. HPWHs are a promising technology in both residential and commercial applications due to both improved efficiency and air conditioning benefits. Residential HPWH units have been available for more than 20 years, but have experienced limited success in the marketplace. Commercial-scale HPWHs are also a very promising technology, while their present market share is extremely low. This study dealt with reviewing HPWH systems in terms of energetic and exergetic aspects. In this context, HPWH technology along with its historical development was briefly given first. Next, a comprehensive review of studies conducted on them were classified and presented in tables. HPWHs were then modeled for performance evaluation purposes by using energy and exergy analysis methods. Finally, the results obtained were discussed. It is expected that this comprehensive review will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis, performance assessment and applications of various types of HPWH systems.
371 citations
Cites background from "Study on a direct-expansion solar-a..."
...Schematic diagram of the DX-SAHP water heater [29]....
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...[29] H H H H H COPmonthly-avg = 4–6; hcoll = 40–60% 15 2005 Huang et al....
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TL;DR: In this paper, the authors present a detailed review exclusively on the design aspects of SWH systems and provide a consolidated summary on the development of various system components that includes the collector, storage tank and heat exchanger.
Abstract: Solar water heating (SWH) systems have a widespread usage and applications in both domestic and industrial sectors. According to Renewable Energy Policy Network data (2010), 70 million houses worldwide were reported to be using SWH systems. Solar water heating is not only environmentally friendly but requires minimal maintenance and operation cost compared to other solar energy applications. SWH systems are cost effective with an attractive payback period of 2–4 years depending on the type and size of the system. Extensive research has been performed to further improve the thermal efficiency of solar water heating. This paper presents a detailed review exclusively on the design aspects of SWH systems. The first part of the paper provides a consolidated summary on the development of various system components that includes the collector, storage tank and heat exchanger. The later part of this paper covers the alternative refrigerant technology and technological advancements in improving the performance as well as the cost effectiveness of the SWH system.
239 citations
Cites background from "Study on a direct-expansion solar-a..."
...From the simulation model it was concluded that the monthly average COP varied between 4 and 6, and the collector efficiency was about 40–60% [39]....
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...DX-SAHP water heater [39]....
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...There exists numerous studies [38–43] related to the indirect mode of SWH systems to improve its performance, and some of the recent research is discussed....
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...[39], in which a 2 m bare flat-plate collector acted as a source as well as an evaporator for the refrigerant (Fig....
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TL;DR: In this article, the authors present a review approach based on a visualisation scheme to systematically represent and classify concepts of solar assisted heat pump (SAHP) systems for low temperature water heating applications.
Abstract: Combination of solar thermal collectors and heat pumps in a single solar assisted heat pump (SAHP) system has been widely used for various purposes including water heating. International Energy Agency, Task 44 of the Solar Heating and Cooling (SHC) Programme, has been working on methods towards most effective use of solar heat pump systems for residential use. The current work aims at reviewing the past and present work conducted on the SAHP systems for low temperature water heating applications. The review approach is based on a visualisation scheme to systematically represent and classify concepts of SAHP systems. Specifically, the key performance data from a number of studies are highlighted and various configurations are compared in order to gain accurate and deep intuitive understanding of SAHP systems. The review faithfully states that having a variety of configurations, parameters and performance criteria may lead to a major inconsistency that increase the degree of complexity to compare and analyse the studies of different systems.
176 citations
TL;DR: An overview of various types of solar assisted water heating systems and their market potential is presented in this article, where the authors analyze the performances along with how unique they are of different types of SWH systems and the later part of the paper covers its economic aspects.
Abstract: One of the most widely known solar thermal applications is solar water heating. In terms of installation expenditures and energy cost over the total life of the system, solar water heating technology has proven to be cost efficient for several domestic and industrial applications. Technological practicability of these systems has long been recognized and is presently employed in commercial sectors of many countries. This paper presents an overview of various types of solar assisted water heating systems and their market potential. Residential solar water heating is a promising age old technology, which has been evolved and developed both in the range and quality as a successful packaged market–product. The first part of this paper analyzes the performances along with how unique they are of different types of solar water heating systems and the later part of the paper covers its economic aspects.
173 citations
Cites background from "Study on a direct-expansion solar-a..."
...There exists numerous works [97–104] related to the indirect mode of SWH systems and some significant investigations are discussed in this section....
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...[100] O O O FPC R-22 COP (monthly avg....
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TL;DR: In this article, a simulation study on the operating performance of a new type of solar-air source heat pump water heater (SAS-HPWH) has been presented, which used a specially designed flat-plate heat collector/evaporator with spiral-finned tubes to obtain energy from both solar irradiation and ambient air for hot water heating.
135 citations
References
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Book•
01 Jan 1980
TL;DR: In this article, the authors present an active and passive building heating system for solar thermal power systems, where the active system is designed by f--chart and the passive one by Utilizability Methods.
Abstract: FUNDAMENTALS. Solar Radiation. Available Solar Radiation. Selected Heat Transfer Topics. Radiation Characteristics of Opaque Materials. Radiation Transmission Through Glazing: Absorbed Radiation. Flat--Plate Collectors. Concentrating Collectors. Energy Storage. Solar Process Loads. System Thermal Calculations. Solar Process Economics. APPLICATIONS. Solar Water Heating----Active and Passive. Building Heating----Active. Building Heating: Passive and Hybrid Methods. Cooling. Industrial Process Heat. Solar Thermal Power Systems. Solar Ponds: Evaporative Processes. THERMAL DESIGN METHODS. Simulations in Solar Process Design. Design of Active Systems by f--Chart. Design of Active Systems by Utilizability Methods. Design of Passive and Hybrid Heating Systems. Design of Photovoltaic Systems. Appendices. Author Index. Subject Index.
9,391 citations
TL;DR: In this article, the authors present an active and passive building heating system for solar thermal power systems, where the active system is designed by f--chart and the passive one by Utilizability Methods.
Abstract: FUNDAMENTALS. Solar Radiation. Available Solar Radiation. Selected Heat Transfer Topics. Radiation Characteristics of Opaque Materials. Radiation Transmission Through Glazing: Absorbed Radiation. Flat--Plate Collectors. Concentrating Collectors. Energy Storage. Solar Process Loads. System Thermal Calculations. Solar Process Economics. APPLICATIONS. Solar Water Heating----Active and Passive. Building Heating----Active. Building Heating: Passive and Hybrid Methods. Cooling. Industrial Process Heat. Solar Thermal Power Systems. Solar Ponds: Evaporative Processes. THERMAL DESIGN METHODS. Simulations in Solar Process Design. Design of Active Systems by f--Chart. Design of Active Systems by Utilizability Methods. Design of Passive and Hybrid Heating Systems. Design of Photovoltaic Systems. Appendices. Author Index. Subject Index.
7,831 citations
Book•
01 Jan 1958
TL;DR: In this paper, the authors present an equipment-oriented textbook that applies theoretical results of engineering theories to refrigeration and air conditioning engineering problems, which enables the student to understand both common and uncommon problems in designing, selecting and applying air conditioning and refrigeration components and systems.
Abstract: This is a thorough revision of the definitive, classic text for any level course on refrigeration, refrigeration and air conditioning, and environmental control in buildings. It is an equipment-oriented textbook that applies theoretical results of engineering theories to refrigeration and air conditioning engineering problems. This enables the student to understand both common and uncommon problems in designing, selecting and applying air conditioning and refrigeration components and systems. The material has been updated to apply to the new Environmental Protection Agency requirements and to the new technology developed in response to the energy crisis. New to this edition is a discussion of solar energy; coverage of the basic principles of acoustics and noise control (in relation to air conditioning systems), fans and ducts, pumps and piping, and air conditioning units. While all the material in the text can be understood and executed without computers, alternate computer solutions are shown for system simulation. SI units are used throughout.
763 citations