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Life Cycle Assessment (LCA) is an effective methodology to assess the energy and environmental impacts of energy systems during their life cycle, including manufacturing, operation and end-of-life. The aim of the paper is the application of a simplified LCA tool, developed in the framework of the International Energy Agency Solar Heating and Cooling Task 48, for comparing different typologies of solar assisted heating and cooling systems. In detail, solar thermal heating and cooling systems located in Palermo (southern Italy) and in Zurich (Switzerland) were compared with conventional systems assisted by grid connected and stand-alone photovoltaic plants. A validation of the tool was also carried out by comparing the obtained results with those of in-depth LCA studies. The results showed that the best system configuration in Palermo is the conventional system assisted by a grid-connected photovoltaic plant. Its impact on global energy requirement is about 83.7% and 74.5% of the corresponding impact of the solar thermal heating and cooling and the conventional system assisted by a stand-alone photovoltaic system, respectively. Different considerations can be made for Zurich, where the solar heating and cooling system performs better than the others; it is characterized by a global energy requirement that is 85.3% and 81.2% of the grid-connected and stand-alone photovoltaic assisted conventional systems, respectively. A similar trend is traceable for the global warming potential indicator. The validation of the LCA tool proved it to be reliable since deviations with a detailed LCA of the same system are contained below a 5% difference in all the comparable systems.

The solar heating and cooling systems are among the best solutions for the current energy and environment issues. In this chapter, the background and overview of the solar heating and cooling systems are given. In these systems, the energy sources are the solar power, and the consuming components include the heating and cooling devices. In order to ensure the steady operation of solar driven systems, the heat storage systems are also necessary. In this case, the different choices of solar energy, solar heating, solar cooling and heat storage are briefly introduced in this chapter. A technology roadmap is given at last which provides a clear connection between these introduced technologies.

This chapter discusses the aspects that should be considered when selecting the latent heat storage for a specific solar heating and cooling application. It positions latent heat storage in relation to solar heating and cooling systems helping determine the storage size and the temperature level. It quantifies temperature losses and indicates how the major sources of irreversibilities can be quantified. It shows how the savings related to energetic performance can be determined. It distinguishes between stationary phase change materials (PCMs) and pumpable slurries of PCMs, and it illustrates the advantages of pumpable PCM slurries. Finally, a method is proposed to estimate the performance of different storage/heat exchanger concepts and a procedure for the selection of a latent heat storage type is proposed.

Advanced energy storage is an essential key technology for adjusting the time discrepancy and instability between solar energy supply and energy demand in solar heating and cooling systems. Among the various energy storage technologies, the thermochemical energy storage method has received more attention because of its distinct advantages of higher energy storage density and low heat loss compared with the conventional sensible and latent energy storage methods. The development of thermochemical energy storage technology is reviewed in this chapter. A lot of theoretical and experimental studies on reactants, chemical reaction kinetics, and system designs are introduced and analyzed, and the future development of thermochemical heat storage is discussed.

A solar tracker can keep the collector’s aperture perpendicular to the incident light to maximize the solar radiation, so it is a key component to improve the performance of solar collector. In this chapter, the composition and types of solar tracking are summarized, and the applications of various technologies are demonstrated respectively.

Renewable energy sources compete with conventional fuels in three distinct markets: hot water and space heating, power generation, and transport fuels. Hot water for sanitary uses as well as space heating for millions of buildings is supplied by systems that employ solar energy. In this chapter, a brief overview of the global solar thermal market is presented. Furthermore, the main solar thermal technologies for heating and cooling are presented, as well as methods that can be used to estimate the environmental impact of various technologies and systems and their implementation on solar technologies.

In the coming years, it is anticipated that if we continue with the same pace of energy consumption, communities will continue to face three major challenges; a mounting increase in energy demands, pollution, and global warming. On a local scale, Egypt is experiencing one of its most serious energy crises in decades. The energy consumed in indoor cooling and heating is the biggest portion of total energy consumption in residential buildings. This paper is an experimental simulation study for building retrofitting in off-grid settlements in semi-arid climates, using Trombe wall as a low-tech passive heating and cooling solution. In this study, we made developments to the conventional classic Trombe wall using occupant-centered design and living lab experimental methods. The thermal efficiency of the proposed Trombe wall design is simulated during winter and summer peaks. In the proposed design we used gray paint instead of typical black paint in addition to 15 cm reversible natural wool insulation and two 3 mm thick roll-up wool curtains. The new design reduced the heating load by 94% and reduced the cooling load by 73% compared to the base case with an annual energy savings of 53,631 kW h and a reduction in CO2 emissions of 144,267 kg of CO2. The living lab test proved that the proposed design of the Trombe wall is economically viable and the payback time is 7 months. It is recommended that the proposed design be monitored for a whole year to have an accurate assessment of its efficiency. A post occupancy evaluation is also needed to measure local residents’ acceptance and perceived comfort after retrofitting.

The national demonstration program for the solar heating and cooling of commercial and residential buildings consists of a series of demonstration projects sponsored in whole or in part by the United States Department of Energy (DOE). The solar energy systems used in the demonstration projects include a wide range of designs and a variety of applications in various climatic regions. This paper describes the national demonstration program, including its objectives, history, and current status. The performance of solar energy systems in the demonstration program is also reviewed.

The widespread utilization of solar heating and cooling of buildings has positive and negative impacts on the planning and cost of production of electric power systems. The positive impact is that of favorable improvements in annual and seasonal load factors. The negative impact is that of unfavorable effects on daily load factors. By means of adequate system design and control strategies the daily effect can be turned around into an advantage. The result is an overall positive impact on the planning and operation of power systems. The paper discusses methodologies and techniques for peak shaving of electrical demand by adequately designed solar systems. It also formulates the generation planning problem in the presence of solar heating and cooling systems.

Task III of the International Energy Agency's Solar Heating and Cooling Programme has recently completed a range of studies on the durability and reliability of solar collectors. Two specific topics treated by the Task are material degradation in solar collectors and qualification tests for whole collector modules. A survey of this work is given.

One of the major fields of interest in Task III of the International Energy Agency's Solar Heating and Cooling Programme has been the development of means to evaluate solar domestic hot water (SDHW) systems using short-term test methods. Within the participating countries of Task III many different approaches to SDHW system testing have been developed in recent years. A review of these methods showed their suitability to different conditions and requirements and suggested desirable features for test methods for common use. Drawing on this experience, the Task has adopted a three-fold approach to the development of SDHW system tests: long-term performance prediction based on test measurements of component parameters, long-term performance prediction based on correlations with test measurements on the whole system, and diagnostic inspection procedures for the system configuration and the performance of the sensors and controllers. A summary of progress in this work is presented.

A solar heating and cooling system delivering part of the thermal energy needs of an industrial plant has been designed. Moderately concentrating parabolic trough collectors of 2000 m2 active area will produce hot water for heating, cooling and hot water production. A 150 ton standard type absorption water chiller is used for cooling during summer time.

The performance of a combined solar heating and cooling system was studied for Mediterranean climatic conditions, using a detailed computer model and hourly weather data. The TRNSYS-CODE was used to model the solar system and the building. The weather data used are from Athens. A reference year based on long term averages was developed. The system consists of flat plate collectors, a LiBr/H 2 O floor area of 540 m 2 . Also the performance of evacuated tube collectors was studied for such systems. The results of the simulation show that high yearly useful collector output (more than 500 KwH/M 2 ) is possible with flat plate collectors. With evacuated tube collectors about 40% more. A rough economic analysis shows that one can expect fuel savings of about 19 USD/m 2 for flat plate collectors, with a solar fraction of 80%.

This paper takes a cautious view of solar thermal energy use as a reasonable alternative to fossil fuels for heating and cooling of buildings. The paper emphasizes two problems. One is the relationship between solar thermal heating and cooling of buildings and electric utility rates. The other is the social and private opportunity costs of solar thermal heating for single-family residences. The paper draws on NSF-funded research on the incentives and barriers to commercial adoption of solar heating and cooling of buildings.

Glass is an essential component of virtually all solar heating and cooling systems and so its properties, its strengths and its limitations should be thoroughly understood by the designers of such systems. Recent advances in glass technology offer those designers new capabilities in dealing with the admission of solar heat and light into spaces where they are needed and in rejecting both heat and light when cooling and darkness are required.

This paper is a report on the analyses and evaluation of collectors used in the national demonstration program for solar heating and cooling of non-residential buildings. The characteristics and performance of 17 solar collectors used in 32 representative demonstration projects are presented. The collectors are compared in cost, design, and thermal performance, and the advantages of each type of collector noted. An evaluation of physical characteristics such as absorber materials, heat transfer fluids, types of insulation, cover plate materials, and collector perimeter design is also presented.

The thermal performance of solar collectors measured according to standard test methods is appropriate for only a narrow range of operational and environmental conditions. It is usually assumed that the test results are fully characterized by the familiar Hottel-Whillier-Bliss equation, but this relationship was developed for flat plate collectors and is inadequate for representing a large number of the collectors currently being produced. In many cases the performance determined by the test may differ from that obtained in actual operational conditions. The work of Task III on the characterization of collector performance is aimed towards evaluating the effect of atmospheric factors (irradiance level, ambient temperature, windspeed) and of operational conditions (collector mass flowrate, tilt) on the thermal performance of a variety of solar collectors. Its objective is the development of improved test procedures and performance representations that account for these effects.

Publisher Summary This chapter discusses the use of solar energy in heating and cooling. Solar energy for heating and cooling has the advantages of a large resource base and widespread distribution. Its disadvantages are that it is spread rather thinly and thus must be collected over relatively large areas, and is erratic, fluctuating day to night and with weather conditions. Solar energy is a “free” fuel, but since it requires such a large collection area it often requires a large capital investment to make use of it. Solar energy is the only large resource among the renewable fuels and will steadily become more important as the technology of collection, storage, and use advances, and as other sources of heat become more scarce and expensive. There is no pollution to discharge. In a heavily solar-dependent urban area there may develop problems over solar access, shading, etc., as well as aesthetic consequences. The major environmental impact is apt to be indirect. A lot of conventional energy with its associated environmental impact will be required if a nation were to undertake the manufacture of a large number of active solar systems.

This paper presents a case study experimental validation of PISTACHE which is a new presizing tool intended for designers and planners. It facilitates pre-design and allows the evaluation of annual performance and the integration potential of solar heating, cooling and domestic hot water closed systems. This new tool has been performed in order to standardize the sizing methodology and the comparison of the SHC&DHW closed systems. The comparison framework used in PISTACHE has been performed using seasonal performance indicators that were issued and gathered from experimental data provided by several operating plants. Thus, PISTACHE is an easy graphical user interface and free downloadable tool. In order to check the reliability of the new developed tool, two configuration modes are investigated in this experimental study: a simple cooling mode (RAFSOL plant) and a double cooling and heating mode (SONNENKRAFT installation). The whole validation process is performed using the GenOpt optimization program to determine the optimum set of internal parameters for PISTACHE tool.

The integration of renewable energy sources (geothermal, biomass, and solar) and desalination systems into novel polygeneration plants is investigated. Two main arrangements are considered: geothermal (GP) and biomass (BP) polygeneration. Both systems include concentrating photovoltaic/thermal solar collectors, a multieffect distillation system for seawater desalination, a single-effect LiBr-H2O absorption chiller, storage tanks, heat exchangers, balance-of-plant devices; a biomass auxiliary heater and geothermal wells are also included, in BP and GP, respectively. The systems can provide electricity and hot water, used for space heating, cooling, domestic hot water production, and drinkable desalted water. Both systems are simulated by means of a zero-dimensional dynamical simulation model. Thermoeconomic, exergy, and exergoeconomic analyses are also presented, aiming at defining the best values of the main design variables. Two case studies are discussed: city of Naples (BP) and Pantelleria island (GP), both characterized by solar and geothermal resources and scarcity of fossil fuels and freshwater.

Solar energy can play a leading role in reducing the current reliance on fossil fuels and in increasing renewable energy integration in the built environment. Hybrid photovoltaic-thermal (PV-T) systems can reach overall efficiencies in excess of 70%, with electrical fficiencies in the range of 15-20% and thermal efficiencies of 50% or higher. In most applications, the electrical output of a hybrid PV-T system is the priority, hence the contacting fluid is used to cool the PV cells to maximise their electrical performance, which imposes a limit on the fluid's downstream use. When optimising the overall output of PV-T systems for combined heating and cooling provision, this technology can cover more than 60% of the heating and about 50% of the cooling demands of households in the urban environment. To achieve this, PV-T systems can be coupled to heat pumps or absorption refrigeration systems as viable alternatives to vapour-compression systems. This work considers the techno-economic challenges of such systems, when aiming at a low cost per kWh of energy generation of PV-T systems for co- or tri-generation in the housing sector. First, the viability and afordability of the proposed systems are studied in ten European locations, with local weather pro files, using annually and monthly averaged solar-irradiance and energy-demand data. Based on annual simulations, Seville, Rome, Madrid and Bucharest emerge as the most promising locations from those examined, and the most efficient system confi guration involves coupling PV-T panels to water-to-water heat pumps that use the PV-T thermal output to maximise the system's COP. Hourly resolved transient models are then defi ned in TRNSYS in order to provide detailed estimates of system performance, since it is found that the temporal resolution (e.g. hourly, daily, yearly) of the simulations strongly affects their predicted performance. The TRNSYS results indicate that PV-T systems have the potential to cover 60% of the heating and almost 100% of the cooling demands of homes at all four aforementioned locations. Finally, the levelised cost of energy for these systems is found to be in the range of 0.06-0.12 e/kWh, which is 30-40% lower than that for equivalent PV only systems.

A great interest has recently arisen for the sustainable supply of energy and fresh water, due to the growing demand from developing countries. Facing this demand by traditional technologies implies evident risks related with the high cost of fossil fuels and their environmental impact. Then, alternative solutions based on the use of renewable sources and innovative technologies must be considered. In this paper a renewable polygeneration system is examined, which includes a solar field based on parabolic trough photovoltaic/thermal collectors, a biomass heater, an absorption chiller and a Multiple Effect Distillation desalination unit. Plant operation under dynamic conditions has been analysed in previous papers; in this paper an exergetic and exergoeconomic analysis is carried out. The exergetic analysis is intended to identify the steps that mostly affect the overall plant exergy efficiency, so as to propose possible improvements. The exergoeconomic cost accounting is aimed at assigning a monetary value to each energy or material flow, thus providing a rational basis for price assignment. Both the exergetic and exergoeconomic analyses are applied to integral values of energy flows, comparing the results obtained in the summer and winter season. Finally, economic viability of the system in different context scenarios is discussed.

Solar energy can play a leading role in reducing the current reliance on fossil fuels and in increasingrenewable energy integration in the built environment, and its affordable deployment is widely recog-nised as an important global engineering grand challenge. Of particular interest are solar energy systemsbased on hybrid photovoltaic-thermal (PV-T) collectors, which can reach overall efficiencies of 70% orhigher, with electrical efficiencies up to 15–20% and thermal efficiencies in excess of 50%, dependingon the conditions. In most applications, the electrical output of a hybrid PV-T system is the priority, hencethe contacting fluid is used to cool the PV cells and to maximise their electrical performance, whichimposes a limit on the fluid’s downstream use. When optimising the overall output of PV-T systemsfor combined heating and/or cooling provision, this solution can cover more than 60% of the heatingand about 50% of the cooling demands of households in the urban environment. To achieve this, PV-Tsystems can be coupled to heat pumps, or absorption refrigeration systems as viable alternatives tovapour-compression systems. This work considers the techno-economic challenges of such systems,when aiming at a low cost per kW h of combined energy generation (co- or tri-generation) in the housingsector. First, the technical viability and affordability of the proposed systems are studied in ten Europeanlocations, with local weather profiles, using annually and monthly averaged solar-irradiance and energy-demand data relating to homes with a total floor area of 100 m2(4–5 persons) and a rooftop area of50 m2. Based on annual simulations, Seville, Rome, Madrid and Bucharest emerge as the most promisinglocations from those examined, and the most efficient system configuration involves coupling PV-T pan-els to water-to-water heat pumps that use the PV-T thermal output to maximise the system’s COP. Hourlyresolved transient models are then defined in TRNSYS, including thermal energy storage, in order to pro-vide detailed estimates of system performance, since it is found that the temporal resolution (e.g. hourly,daily, yearly) of the simulations strongly affects their predicted performance. The TRNSYS results indicatethat PV-T systems have the potential to cover 60% of the combined (space and hot water) heating andalmost 100% of the cooling demands of homes (annually integrated) at all four aforementioned locations.Finally, when accounting for all useful energy outputs from the PV-T systems, the overall levelised cost ofenergy of these systems is found to be in the range of 0.06–0.12€/kW h, which is 30–40% lower than thatof equivalent PV-only systems

4th International Conference on Solar Heating and Cooling for Buildings and Industry (SHC) -- DEC 02-04, 2015 -- Istanbul, TURKEY, WOS: 000387506400026, An overview on the recent results on the engineering and characterization of sorption materials, PCMs and TCMs investigated in the working group WG A1 "Engineering and processing of TES materials" of IEA SHC Task 42 / ECES Annex 29 (Task 4229) entitled "Compact Thermal Energy Storage" is presented. (C) 2016 The Authors. Published by Elsevier Ltd.

The chapter begins by introducing the history and characteristics of solar heating and cooling in China compared with those in other countries. It then reviews the manufacturers, market, and application situations; framework conditions including costs, key drivers, etc.; technologies; and R&D needs for solar heating and cooling in China. The chapter also includes the future developing trends and case studies of particular solar thermal heating and cooling installations in China.

The IEA joint Task 42 / Annex 29 is aimed at developing compact thermal energy storage materials and systems. In Working Group B, experts are working on the development of compact thermal energy storage applications, in the areas cooling, domestic heating and hot water and industry. The majority of application projects were in the field of room heating and domestic hot water. In this article, an overview is given of a large number of applications. The storage technologies used in the applications are latent heat storage, open and closed solid sorption, liquid sorption and salt hydrates and composites thereof. On a broad front, a lot of progress was made in the development of components and systems, providing knowledge and experience regarding the design, numerical modeling, building, testing and economical assessing of components and storage systems. Most important findings are that the interaction of storage materials with the materials of components can be deciding for the technical feasibility, that a number of components, like reactor, heat exchangers and evaporators are less understood than initially thought and need more development, that the inclusion of storage materials in systems generate new challenges like the occurrence of non-condensable gases and thermo-mechanical effects and that standardized and simplified system approaches are needed.

A latent heat storage based on the phase change material Sodium Acetate Trihydrate (SAT) has been tested as part of a demonstration system. The full heat storage consisted of 4 individual modules each containing about 200 kg of sodium acetate trihydrate with different additives. The aim was to actively utilize the ability of the material to supercool to obtain long storage periods. The modules were charged with solar heat supplied by 22.4 m2 evacuated tubular collectors. The investigation showed that it was possible to fully charge one module within a period of 270 minutes with clear skies. In long periods with high level of irradiance several modules were charged in parallel due to the limited heat exchange capacity of the integrated heat exchanger of the modules. After the modules were heated to more than 80° C they were set to passively cool down. Modules reached 30 °C in a period of parallel cool down without the sodium acetate trihydrate solidified in 3 of the 4 modules. Further tests showed that stable supercooling at ambient temperature is possible.

Proceedings of the 4th International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2015) Within the framework of IEA SHC Task 42 / ECES Annex 29, a simple tool for the economic evaluation of thermal energy storages has been developed and tested on various existing storages. On that account, the storage capacity costs (costs per installed storage capacity) of thermal energy storages have been evaluated via a Top-down and a Bottom-up approach. The Top-down approach follows the assumption that the costs of energy supplied by the storage should not exceed the costs of energy from the market. The maximum acceptable storage capacity costs depend on the interest rate assigned to the capital costs, the intended payback period of the user class (e.g. industry or building), the reference energy costs, and the annual number of storage cycles. The Bottom-up approach focuses on the realised storage capacity costs of existing storages. The economic evaluation via Top-down and Bottom-up approach is a valuable tool to make a rough estimate of the economic viability of an energy storage for a specific application. An important finding is that the annual number of storage cycles has the largest influence on the cost effectiveness. At present and with respect to the investigated storages, seasonal heat storage is only economical via large sensible hot water storages. Contrary, if the annual number of storage cycles is sufficiently high, all thermal energy storage technologies can become competitive. This study is part of IEA SHC Task 42 / ECES Annex 29 „Compact Thermal Energy Storage - Material Development and System Integration“ (http://task42.iea-shc.org). The work of ZAE Bayern is part of the project PC-Cools_V and supported by the German Federal Ministry for Economic Affairs and Energy under the project code 03ESP138A. University of Zaragoza thanks the Spanish Government for the funding of their work under the projects ENE2008-06687-C02-02, ENE2011-28269-C03-01 and ENE2014-57262-R. University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). The research leading to these results has received funding from the European Union's Seventh Framework Program (FP7/2007-2013) under grant agreement n° PIRSES-GA-2013-610692 (INNOSTORAGE) and European Union’s Horizon 2020 research and innovationprogramme under grant agreement No 657466 (INPATH-TES). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). The University of the Basque Country acknowledges the financial support of the Spanish’s Ministry of Economy and Competitiveness through the MicroTES (ENE2012- 38633) research project. The responsibility for the content of this publication is with the authors

This chapter is focused on the analysis of thermal energy storage (TES) technologies that provide a way of valorizing solar heat and reducing the energy demand of buildings. The principles of several energy-storage methods and calculation of storage capacities are described. Sensible heat-storage technologies including the use of water, underground, and packed-bed are briefly reviewed. Latent heat-storage systems associated with phase-change materials (PCMs) for use in solar heating and cooling of buildings, solar water-heating and heat-pump systems, and thermochemical heat storage are also presented. Additionally, a three-dimensional heat-transfer simulation model of latent heat TES is developed to investigate the quasi-steady state and transient heat transfer of PCMs. The numerical simulation results using paraffin RT20 are compared with available experimental data for cooling and heating of buildings. Finally, outstanding informations on the performance and costs of TES systems are included.

Widespread use of solar heating and cooling will not automatically occur when the economics become competitive, in part because of the characteristics of the building industry. An Implementation Center designed to improve communication to consumers and within the building industry will speed the use of solar heating and cooling. To be effective, the Center should be regional and provide communication both to the building industry and to solar researchers and manufacturers. The Centers should also provide Evaluation System information to potential users and evaluate solar projects. Two Implementation Centers could be funded at about $2 million each for a state the size of California through a small tax on natural gas and electricity sales.

This article presents the behavior of an existing system combining solar collectors and heat pumps at large scale (10'000 living m², more than 1'000 m² solar collectors) for space heating and domestic hot water production, focusing on summer period. Ongoing detailed monitoring enables to measure its energy performance. The monitoring results for 2012 show a system SPF of 2.9 (2.6 in winter and 4.4 in summer). The direct solar fraction in summer is lower than 50%, which is low considering the oversizing of the solar collector area for domestic hot water production. The high domestic hot water demand (􀁡50 kWh/m²/yr whereas the usual value is around 20) can partly explain this low value, but other factors should also be considered. The results presented in this article are part of a research project aiming to assess the relevance of the concept of coupling solar thermal and heat pumps in various types of building (especially existing buildings with low efficient thermal envelope).

In the field of solar energy applications, the use of geostationary satellite images becomes crucial, since they allow the retrieval of irradiance at the surface, with the best possible spatial and temporal coverage. This study, conducted on data from 18 European and Mediterranean sites, over 8 years of data shows that it is now possible to retrieve hourly global and beam irradiance data with a low uncertainty, typically 17% for the global, and 34% for the beam component, with a negligible bias.

Publisher Summary This chapter describes some measurement techniques and methods that can be employed in the characterization of environmental stress for the durability assessment of components and materials. For service life prediction the knowledge of the environmental stress conditions is of essential importance. In recent years, a lot of research on durability assessment of absorber coatings for solar thermal collectors was made within the framework of the Solar Heating and Cooling Program (SHCP) of the International Energy Agency (IEA). In the case of solar absorbers, the environmental factors that may result in loss in optical performance are of principal interest. These are identified as high temperature, high humidity and moisture, and airborne pollutants. Measurement techniques adapted to these factors will be discussed in detail. The form of data acquisition is not restricted to time-dependent data only. Sometimes the acquisition of extreme values or dose functions is much more appropriate. Even well-defined standard specimens may be used as a sensor.

This report describes the results obtained from simulation and economic optimization of the solar distric heating plant in Lyckebo, 13 km north of Uppsala, Sweden. The work has been performed using the computer program MINSUN, which was developed within the ‘IEA Task VII of the Solar Heating and Cooling programme’, ref. 1. The work has been concentrated to questions concerning the optimal portion of solar energy compared with the price of energy, variations in climate from year to year, and different operating conditions. Another question which has been considered is the optimization of the collector surface for the solar plant. The results show that the optimum solar energy fraction is 80–85 % with current (1986) energy prices. The optimal collector surface area and storage volume for the plant are approximately 25 000 m2 and 100 000 m3 respectively. Further, the calculations have shown that a large propertion of the auxiliary energy can be reduced if the operational strategy can be improved, for example by reducing the return temperature of the distric heating system. The energy price for the optimized plant was then 0.40 SEK/kWh (6 US cent/kWh), calculated using 1986 cost level.

Solar absorber coatings are exposed to stresses, which are - depending on the collector and the local climate - temperature, humidity and moisture, solar irradiation and pollutants. The investigation of the durability of the coatings against these stresses requires accelerated short-term tests. Reproducible indoor tests, in which the loads are applied separately, allow a direct and quick comparison of the respective stability of different coatings and the identification of specific sensitivities to single loads. Constant temperature tests in air as well as humidity and condensation tests were carried out with six commercially available absorber coatings (black chrome, black nickel, coloured stainless steel and nickel-pigmented anodized aluminium). They showed great differences in the stability of the optical properties of the coatings. The degradation data obtained from these tests are contributions to a data base for service lifetime prediction models to be developed in the framework of the Task X of the IEA-programme “Solar Heating and Cooling”.

A unified analysis and parametric study of central solar heating plants with seasonal storage (CSHPSS) Systems has recently been completed by the participants in the International Energy Agency (IEA) Solar Heating and Cooling Programs Task VII. The study culminated nearly three years of information collection, evaluation, preliminary design and analysis, and system simulation. It included systems with stationary and tracking collector arrays; water tank, rock cavern, water pit, drilled earth and rock fields, and natural aquifers storage subsystems; heat pump and direct coupled loads, and loads representing 50 to 5000 residential units with domestic hot water fractions ranging from 0 to 50%. Each configuration was independently optimized using the Swedish/IEA-developed computer code MINSUN. Results of the unified study indicate that a number of CSHPSS configurations are economically competitive with conventional plants now and are clearly economically superior to diurnal solar systems.

The reasons for which solar energy is neglected as compared to conventional energy resources, as well as nuclear energy are displayed. An overview on the use and prospect of solar energy in various fields including solar heating and cooling, solar power production by thermodynamic conversion or photovoltaic cells, agricultural applications and indirect forms of solar energy, i.e. wind, wave, etc. is presented. The difficulties about switching onto solar energy are analyzed. It is thus concluded why solar energy, is still far to answer the world energy needs. The special case of developing countries is also undertaken.

Detailed storage system construction costs for 29 completed solar energy systems for commercial buildings are presented. These costs were obtained during the last three years. Two of the systems were designed by Mueller Associates, Inc. (MAI), and the remainder were the subject of cost analyses by MAI for the U.S. Department of Energy. The systems represent a wide variety of geographic locations and a mixture of new and retrofit, system application, storage vessel type, and storage vessel location. The cost data are analyzed to identify major cost factors. The paper is of use to designers involved in solar heating and cooling system design and to researchers involved in reducing the cost of these systems. The distinction is made between non-performance related cost decisions and those choices that involve cost/performance tradeoffs.

This paper summarizes recent research works of the author on passive solar heating and cooling of buildings. The studies summarized are: Experimental validation of the LASL predictive formulae for Direct Gain; Extention of the LASL correlational formulae into a generalized model; Nocturnal Radiant Cooling; Convective Cooling; Roof-pond cooling; Earth Cooling. The paper presents the methodologies and summarizes the results of these studies.

There have been a number of research and development areas where recent activities have led to or are apparently about to lead to significant advances in the use of domestic solar heating and cooling technologies. Activities in the following areas are discussed: systematic improvements in solar energy system performance, evacuated collectors, flat plate collectors with convection suppression, microflow domestic hot water systems, desiccant cooling, and modeling. The examination of these areas leads into a discussion of future research needs.

This paper is designed to supplement the concepts given in a previous paper to an earlier course in this series by the author ( Page, 1979 ) which dealt with systematic methods for the analysis of different aspects of solar building performance. This chapter starts by stressing the wide range of problems to be solved, especially the need for architectural solutions which are viable throughout the year, both summer and winter, rather than solutions valid for only one season. It then stresses the advantages to be gained from systematic bioclimatic analysis and particularly recommends the analytical techniques proposed by Milne and Givoni (1979) . The chapter then goes on to deal with the systematic classification of solar heating and cooling approaches and discusses the problems of finding viable all the year round solutions based on the various established approaches to solar building design. The chapter finally suggests there remain substantial difficulties in attempting to rely entirely on passive approaches and indicates that hybrid solutions combining active and passive techniques are likely to offer sounder approaches. An appendix presents some new results for window performance over a heating season for different types of vertical south facing glazing at Kew, England, derived from new University of Sheffield, Department of Building Science programs for assessing, in considerable scientific detail, fenestration thermal performance.

Successful passive solar architecture integrates conservation with passive solar heating, natural cooling, and daylighting. The result can be a comfortable and economic building that uses 5096-90% less operating energy than most contemporary buildings. A world-wide interest in passive solar architecture has developed because it provides an alternative to the trend in modern buildings toward an overdependence on lighting, heating, ventilating, and air-conditioning equipment to maintain a livable and productive indoor environment. We review lessons learned from the experiences of designers over the last decade and list guidelines for incorporating passive solar into the design process. Also described are performance results obtained in the monitoring of hundreds of residential and nonresidential buildings. We present design analysis tools, the directions of current research, and a bibliography of books that focus on energy-conscious design.

Publisher Summary This chapter discusses the use of solar energy in cooling of buildings. Of all the possible applications for solar energy, the solar cooling of buildings seems the most attractive. This is a use in which the demand for energy closely matches the supply of solar energy even to the variation within the day. Solar energy is an appropriate source for the heating and cooling of buildings because the temperatures required are usually moderate, and high temperature sources are not required. A combination of solar heating and cooling, which results in higher use factors on the solar energy equipment, is, in most places, more economical than heating or cooling alone. The same basic ideas that are used in solar cooling of buildings can be extended to solar refrigeration for food preservation. The benefits would be substantial if solar cooling can be successfully developed. The chapter discusses the concept of conditioning space for comfort. It describes air conditioning processes. and the building cooling load.

The moderate levels of insolation which characterize a great part of Europe require carefully optimized solar systems in order to attain acceptable levels of performance. The report describes activities of the European Commission Solar Energy Programme which are being carried out at the Joint Research Centre of Ispra, Italy. A Solar Laboratory has been built specifically for the intercomparisons between different solar heating and cooling systems. A description is given of the main features of the laboratory and of the solutions which are being investigated to increase performances. These solutions involve high efficiency collectors with selective surfaces, honey comb structures and Vee-corrugations, together with low operating temperatures, seasonal storage or combined heating and cooling systems in order to insure a year round utilization of the solar system. A description is presented of a solar heating system which operates at 28°C with some results concerning performances. In order to extrapolate results to other climatic conditions or to perform parametric optimizations a mathematical model with monthly basis is used. Some elements of the model are presented.

By surrounding the absorber-heat exchanger component of a solar collector with a glass-enclosed evacuated space and by providing the absorber with a selective surface, solar collectors can operate at efficiencies exceeding 50% under conditions of δT/HT = 75°C·m2/Kw (δT = collector fluid outlet temperature minus ambient temperature, HT = incident solar radiation on a tilted surface). The high performance of these evacuated tubular collectors thus provides the required high temperature inputs (70–88°C) of lithium bromide absorption cooling units, while maintaining high collector efficiency. This paper deals with the performance and analysis of two types of evacuated tubular solar collectors integrated with the two distinct solar heating and cooling systems installed on CSU Solar Houses I and III.

Publisher Summary This chapter discusses the use of solar energy in Cyprus. None of the conventional sources of energy such as coal, oil, or hydroelectricity is available in Cyprus. However, its geographical location and its climatic and weather conditions give it the potential to extensively and effectively utilize solar energy. Alternative energy resources currently used in Cyprus are solar energy for water heating and wind energy for pumping water for irrigation; however, there are promising prospects for other applications such as solar heating and cooling, cooling of buildings, solar heating greenhouses, solar drying, and solar desalination. Water pumping windmills were extensively used until 1955 in some coastal areas on the island. With increasing electrification, however, their use has been diminished and replaced by electric pumps. Solar water heaters modeled on an imported design were first produced and marketed in early 1960.