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The yearly thermo‐economic performance is dynamically investigated for three solar heating and cooling systems: solar heating and absorption cooling (SHAC), solar heating and ejector cooling (SHEC), and heating and solar vapor compression cooling (HSVC). First, the effects of important design parameters on the thermo‐economic performance of the systems to supply the heating and cooling loads of the building are evaluated. The systems are parametrically analyzed with the weather conditions of Tehran, Iran. The results show that the life cycle costs (LCC) of the SHAC and HSVC systems are alike and much lower than those of the SHEC system. The HSVC system exhibits the best performance from exergetic and solar fraction viewpoints. The comparative analysis shows that the energy efficiencies of the SHAC and SHEC systems are higher in colder climatic conditions. However, the collector efficiency of the HSVC system declines in colder climates, mainly due to the lower solar intensities relative to in hotter climates. Further, the solar fraction of the SHAC system is higher than the SHEC technology under all climatic conditions. Moreover, higher values of solar fractions are obtained under colder weather conditions for the SHEC and HSVC systems. The best economic performance is observed for the SHAC and HSVC technologies, having significantly lower LCCs than the SHEC system. These lower LCCs under colder climatic conditions are due to the lower cost of supplying the heating load compared to the cooling load. Furthermore, all systems exhibit enhanced exergetic performance in colder weather conditions. The yearly thermo‐economic performance is dynamically investigated for three solar heating and cooling systems: SHAC, SHEC, and HSVC. In addition, the effects of important design parameters on the thermo‐economic performance of the systems to supply the heating and cooling loads of the building are evaluated.

In this paper a new simulation model of a novel solar heating and cooling system based on innovative high temperature flat plate evacuated solar thermal collector is presented. The system configuration includes: flat-plate evacuated solar collectors, a double-stage LiBr-H2O absorption chiller, gas-fired auxiliary heater, a closed loop cooling tower, pumps, heat exchangers, storage tanks, valves, mixers and controllers. The novelty of this study lies in the utilization of flat-plate stationary solar collectors, manufactured by TVP Solar, rather than concentrating ones (typically adopted for driving double-stage absorption chillers). Such devices show ultra-high thermal efficiencies, even at very high (about 200°C) operating temperatures, thanks to the high vacuum insulation. Aim of the paper is to analyse the energy and economic feasibility of such novel technology, by including it in a prototypal solar heating and cooling system. For this purpose, the solar heating and cooling system design and performance were analysed by means of a purposely developed dynamic simulation model, implemented in TRNSYS. A suitable case study is also presented. Here, the simulated plant is conceived for the space heating and cooling and the domestic hot water production of a small building, whose energy needs are fulfilled through a real installation (settled also for experimental purposes) built up close to Naples (South Italy). Simulation results show that the investigated system is able to reach high thermal efficiencies and very good energy performance. Finally, the economic analysis shows results comparable to those achieved through similar renewable energy systems.

A design was created to provide a novel passive control that operates a passive solar heating and cooling system for residential homes in Wyoming. Mathematical models were developed to determine the pertinent parameters of a control that will allow air to flow in or out of a house for heating or cooling purposes. The control was designed to be implemented in existing passive solar collector systems. It is composed of bimetallic spiral coils, ideally made of ASTM B388 TM2 ��� an alloy composed of 72% manganese, 18% copper, and 10% nickel for the high expansion component while the low expansion component is composed of 36% nickel and 64% iron, an aluminum shaft, and a damper made from ultra-high-molecular-weight (UHMW) plastic. The control has the ability to be adjusted by a user friendly dial similar to existing thermostat dials. The mathematical models for the control show a maximum deflection of 42 degrees of rotation relative to a coupled 160 degree temperature change within the collector and a 50 degree temperature change within the room that would allow for either heating or cooling. The control design provides an effective way to passively operate a passive solar heating and cooling system.

Using conventional fossil fuels causes both energy crisis and environmental pollution. Renewable energy with the merits of almost unlimited availability and environmental-friendliness provides a perfect solution to the problem. Solar energy is widely recognized as one of the most important renewable energy resources due to its even distribution, safety and serving as sources for others. In past decades, global solar thermal capacity increases rapidly and now it has been widely used worldwide to provide heating and cooling. To understand the current progress of relevant technologies and the future development, this paper briefly summarizes the current situation of solar heating and cooling, and then some new achievements in related areas and potential future market penetration are discussed. It is found that solar hot water heating system's development is in fast lane in recent years with evacuated tube solar collector dominating the mass market. How to integrate solar collecting system with different types of buildings is the main research and development direction for solar building heating system. Large-scale district water heating system and solar PVT system as the most promising solutions attract extensive attentions. For solar cooling, efforts have been made to improve the efficiency of conventional solar thermal cooling methods in terms of adsorption and absorption technology. In addition to technical development, economic analysis of solar heating and cooling system is also discussed. Return of investment period is widely adopted to evaluate the economic performance. Results reveal that low initial cost and advantageous allowance are the most efficient ways to make solar heating and cooling system economically attractive. This paper is presented and recommended by 5th International Conference on Nuclear and Renewable Energy Resources.

In this paper, a novel purposely designed dynamic simulation model for the performance analysis of solar heating and cooling systems is presented. The investigated system layouts are based on single stage LiBr–H2O absorption chillers and on both evacuated tube and concentrating photovoltaic thermal solar collectors. Furthermore, both electric chiller and gas fired heater backup system are considered. Such model is implemented in a computer code written in MATLAB. Here, the optimisation of several system design and operating parameters in terms of energy saving is also carried out. A code to code analysis is performed comparing the obtained simulation results vs. those achieved by a TRNSYS model available in literature. The simulation code for the concentrating photovoltaic thermal solar collectors is validated by experimental data. A good agreement among results is observed in both the cases. A suitable case study referred to a building including both offices and dwellings located in Northern and Southern Italy is presented. High primary energy savings are obtained for some of the investigated system layouts. By evacuated tube collectors solar field such savings can reach 74%, while shifting to concentrating photovoltaic thermal solar collectors they often surpass 100%. The system economic profitability strongly depends on future scale economies and eventual public funding.

In this paper, a parametric analysis of two solar heating and cooling systems, one using an absorption heat pump and the other one using an adsorption heat pump, was performed. The systems under investigation were designed to satisfy the energy requirements of a residential building for space heating/cooling purposes and domestic hot water production. The system with the absorption heat pump was analyzed upon varying (i) the solar collectors’ area, (ii) the volume of the hot water storage, (iii) the volume of the cold water tank, and (iv) the climatic conditions. The system with the adsorption heat pump was evaluated upon varying (i) the inlet temperature of hot water supplied to the adsorption heat pump, (ii) the volume of the hot water storage, (iii) the volume of the cold water tank, and (iv) the climatic conditions. The analyses were performed using the dynamic simulation software TRNSYS in terms of primary energy consumption, global carbon dioxide equivalent emissions, and operating costs. The performance of the solar heating and cooling systems was compared with those associated with a conventional system from energy, environmental and economic points of views in order to evaluate the potential benefits.

Parametric optimization using dynamic simulation of a solar thermal system for producing hot water, space heating and cooling was developed. The system layouts include a single-effect absorption chiller activated by heat generated by flat plate solar collectors and stored in a solar storage tank. Two construction types were compared; the first is the typical construction in Algeria (low thermal mass with U-values of 1.25 W/m 2 K, single glazing), which represents the majority in the country, while the second is a High-Energy-Performance building (with U-values of 0.35 W/m 2 K, double glazing), representing the pilot project called ECO-BAT. Three of Algeria's regions were considered to evaluate the climatic effect of solar systems integration. Algiers represents the coastal region; Djelfa, the highlands region; Tamanrasset, the Sahara region. In parametric study, two solar collectors' field parameters were analysed, including the surface area and the tilt angle. The results indicated that building loads are significantly reduced (12%, 44% and 22% for Algiers, Djelfa and Tamanrasset, respectively). The solar energy contribution is more than 60% for all cases, a significant contribution for an efficient building. In all cases, we observed that the solar fraction reaches more than 45% when the optimum parameters of the solar system are selected.

YÖK Tez No: 579909 Mevcut tez çalışmasında Antalya bölgesinde bulunan bir villanın yıllık ısıtma ve soğutma yükleri, güneş enerjisi destekli absorbsiyonlu sistemle karşılanarak uygulamanın ekonomik analizinin yapılması amaçlandı. Isıtma ve soğutma sistemleri tasarlanırken ilgili standartlara ve yönetmeliklere bağlı kalındı. Binanın yıllık ısı kaybı ve ısı kazançları belirlenerek cihaz seçimleri yapıldı. Kurulan sistemin geleneksel sistemlere göre yatırım maliyeti hesaplanarak düşük faizli kredilendirme sistemiyle yaşam döngüsü araştırıldı. Binanın yalıtım hesapları, TS825 "Binalarda Isı Yalıtım Kuralları" Standardına uygun olarak yapıldı. Binanın ısı kaybı ve ısı kazançları FineHVAC programıyla hesaplandı. Isı kaybı hesabında Avrupa'da zorunlu hale gelen EN12831 hesap metodu, ısı kazancı hesabı içinse CLTD metodu kullanıldı. Güneş kollektör alan tayini ve güneş faydalanma oranı için Ø-f chart metodu uygulanırken, termoekenomik analiz içinse P1,P2 metodu kullanıldı. Yatırım maliyeti hesaplarında ürün ve işçilik tedariği için detaylı pazar araştırması yapıldı. AutoCAD çizim programıyla mekanik sistemler projelendirilerek bulunan sonuçlar için özet tablolar hazırlandı. Uygulanan metod hesaplamaları sonucunda binanın ısı kaybı 20,5 kW, ısı kazancı 40,3 kW olarak bulundu. Yapılan hesaplar 125 m2 güneş kolektörü sistemine ilave 40 kW güneş destekli absorbsiyonlu soğutucu kullanılmasının toplam faydalanmada %36 oranının yakalandığını gösterdi. Yapılan ekonomik analiz hesapları sonucunda güneş absorbsiyonlu sistemin kurulumu için yaklaşık 394.000,00 TL değerindeki yatırım maliyetinin kredilendirme sistemiyle 16. yılda pozitife geçtiği görüldü. In this thesis, the annual heating and cooling loads of a building located in Antalya region were met with solar assisted absorption chiller system and the economic analysis of the application was investigated. During the study, design of heating and cooling systems adhered to related standards and regulations. Heating and cooling loads were all calculated and the necessary equipment were selected. The investment cost of the installed system was calculated in comparison to the conventional systems and the life cycle save analysis of the system was investigated with a low-interest credit system. The insulation requirements of the building was done acoording to TS standards called Heat Insulation Rules in Buildings. The heat loss and gains of the building were calculated using the FineHVAC Program. In the study, EN12831 method, compulsory in Europe, for the calculation of heat loss and CLTD method for the calculation of heat gain have been utilized. Moreover, the Ø-f chart" method and P1,P2 method were used for collector area-solar fraction calculations and thermoeconomic analysis, respectively. Detailed market research was conducted for the supply of products and labor in the investment cost accounts. Mechanical systems are designed with AutoCAD drawing program and summary tables were prepared according to findings. In the light of materials and methods, the heating load of the building was calculated as 20.5 kW and the cooling load was calculated as 40.3 kW. The calculations showed that 36% of the total utilization was achieved by using a 40 kW solar absorption chiller assisted with 125 m2 solar collectors. As a result of the economic analysis, it was seen that the investment cost amounting to 394.000,00 TL has been positive for the 16th year through the credit system.

With the increasing concerns on energy conservation and environmental protection, solar heating and cooling (SHC) system represents an attractive candidate in building sector. In this paper, an integrated SHC system driven by parabolic trough collector (PTC) and double-effect H2O/LiBr absorption chiller was presented. The energy generated by solar collectors was supplied to the absorption chiller during the cooling period, and was directly used for space heating with the integration of plate heat exchanger during the heating period. The mathematical models of the whole system including the collector, the double-effect absorption chiller and the plate heat exchanger were established and were validated by field tests. Based on the proposed models, comparison of the SHC system and the conventional gas-driven absorption heating and cooling system was carried out by case study. The annual performances as well as energetic, economic and environmental assessments of the proposed system were investigated. Results show that, 21.3% of the primary energy consumption and 18.8% of the CO2 emission can be reduced in SHC system. Therefore, the proposed integrated solar heating and cooling system has a promising application prospect in sustainable development in view of its considerable energy saving benefits, potential economic viability and environmental friendly characteristics.

This paper presents thedevelopment of a compact and cheap solar heating system based on photovoltaic panels, heat pump and heating storage through a smart regulation from a technical and economical point of view. The heat pump can be standard and have its own regulation. The building's owner may interact with the regulation through a web service to visualize the monitoring of the installation, update the calendar of the presence and change the operation mode. One of the goals of the regulation is to optimize the consumption of his own electricity production and therefore minimize the electricity taken from the grid. Several means are developed to reach the main objective. On one hand, the regulation takes into account the weather forecast to anticipate the future heating's needs and the photovoltaic production. Weather forecast data allows also to optimize the storage in hot water tanks and in the building structure. On the other hand, the project includes the development of an electronic module which collects the monitoring data and gives the commands to the heat pump and the pumps. This is accomplished without any intrusion in the heat pump's own regulation and therefore the user keeps the constructor's warranty. The new regulation was validated numerically. The expected energy gain due to the weather forecast is about 10%, while the one due to the self-consumption and the heat storage management will bring another 10-15%.

This chapter presents a review of nontracking solar thermal collectors. These collectors are suitable for low to medium temperature applications with a maximum of about 150°C. This range of temperatures is particularly suitable for solar heating and cooling applications. Usually these collectors collect both direct and diffuse solar radiation, so they are very effective collection devices. For this purpose there is no requirement to follow the sun trajectory during the day so they belong to the nontracking collectors. Some of the types presented may require seasonal tracking, ie, changing the tilt angle of a collector a few times per year. The frequency of tracking increases with the concentration ratio. Higher concentration ratio leads to higher collector operating temperature but also to higher tracking accuracy requirements. The types of collectors examined in this chapter are the flat plate collector, which is the most used collector type, and its variations, the diffuse reflector, reverse flat plate collector, compound parabolic collector, and evacuated tube collector.

The objective of Task 44 of the Solar Heating and Cooling program of the IEA is to assess performances and relevance of combined systems using solar thermal and heat pumps, to provide a common definition of performances of such systems, and to contribute to successful market penetration of these new promising combinations of renewable technologies. The Task is also Annex 38 of the Heat pump program and thus called T44A38. It gathers 12 countries and 55 participants.This paper presents the mid term results of the activity, which started in January 2010 and will last until December 2013.

Solar thermal cooling has difficulty to emerge as an economically competitive solution for small systems mainly due to high investment cost and system complexity [1] . Therefore developments of principally new system solutions are needed. This paper describes such a solution with sorption modules directly integrated into a solar thermal collector. The focus of the work has been to find key parameters influencing the module and the system efficiency. A validated model of a sorption collector has been implemented into a simplified system deck providing cooling, heating and domestic hot water to static loads in the system modelling environment TRNSYS [2] . Simulations have been conducted for different boundary conditions and at two locations with different climatic conditions. Thermal losses from the collector as well as internal thermal losses inside the collector were found to be the most important parameters influencing efficiency. The system simulations gave overall thermal cooling efficiencies in the range of 0.12-0.27 and electrical cooling efficiencies in the range of 15-45 depending on collector technology, climate and control strategy.

In this paper, the simulation of the performance of solar-assisted heating and cooling systems is analyzed. Three different plant layouts are considered: (i) the first one consists of evacuated solar collectors and a single-stage LiBr–H2O absorption chiller; here in order to integrate the system in case of insufficient solar radiation, an electric water-cooled chiller is activated; (ii) configuration of the secondly considered system is similar to the first one, but the absorption chiller and the solar collector area are sized for balancing about 30% of the building cooling load only; (iii) the layout of the thirdly considered system differs from the first one since the auxiliary electric chiller is replaced by a gas-fired heater. Such system configurations also include: circulation pumps, storage tanks, feedback controllers, mixers, diverters and on/off hysteresis controllers. All such devices are modelled for maximizing the system energy efficiency. In order to simulate the systems’ performance for dynamic heating/cooling loads, a single-lumped capacitance building is also modelled and implemented in the computer code. A cost model is also developed in order to calculate the systems’ operating and capital costs. All the models and the relative simulations are carried out by TRNSYS. A design of experiment procedure is also included. By such tool the effects of the system operating parameters’ variation on the relative energy efficiency are analyzed. In addition, the set of synthesis/design variables maximizing the system’s energetic performance can be also identified. The annual primary energy saving is chosen as the optimization objective function, whereas collector slope, pump flows, set-point temperatures and tank volume are selected as optimizing system design variables. A case study was developed for an office building located in South Italy. Here, the energetic and the economic analysis for all the three considered system layouts are carried out. The simulations’ results are referred to both the initial and the optimized systems configurations. The highest primary energy saving vs. the reference traditional HVAC system is reached by the first considered system layout. The economic performance of the investigated solar heating/cooling systems is still unsatisfactory. The economical profitability of the considered solar heating and cooling systems can be improved only by significant public finding. From this point of view, the best results were achieved by the second above mentioned system configuration.

Heating, ventilating, and air-conditioning (HVAC) are parts of the major energy consumption in a building. Conventional heating and cooling systems are having an impact on carbon dioxide emissions, as well as on security of energy supply. In this regard, one of the attempts taken by researchers is the development of solar heating and cooling technologies. The objective of this paper is to review the passive solar technologies for space heating and cooling. The reviews were discussed according to the working mechanisms, i.e. buoyancy and evaporative effects. The advantages, limitations and challenges of the technologies have been highlighted and the future research needs in these areas have also been suggested.

In this study the model of a Solar Heating and Cooling (SHC) system and its experimental setup are presented. The SHC system under investigation is a demonstration plant installed in Naples, based on flat plate solar collectors and a single-stage LiBr-H2O absorption chiller. In addition, two vertical tanks are installed as storage system. The balance of system includes: A cooling tower, pumps, valves, safety devices and pipes. The absorption chiller is powered only by solar energy, since there are devices for auxiliary thermal energy. The experimental setup also includes a number of meters (temperature, pressure, flow rate and radiation) to measure, collect and control the prototypal system. The experimental plant is dynamically designed and simulated in order to calculate its energetic and economic performance parameters. This analysis is carried out by means of a zero-dimensional transient simulation model, developed by using the TRNSYS software. Furthermore, a parametric analysis is implemented, aiming at determining the set of the synthesis/design variables that maximize system performances. The model was validated by the first experimental results obtained by the operation of the solar cooling system. Results show that, although flat-plate solar collectors have been specially designed for this kind of application, their operating temperature is often too low to drive the absorption chiller. In addition, the system performance is not particularly sensitive to the storage volume whereas the thermal capacity of the solar field is lower than the absorption chiller demand, determining a very discontinuous operation of the chiller itself.

The paper investigates the energetic and economic feasibility of a solar-assisted heating and cooling system (SHC) for different types of school buildings and Italian climates. The SHC system under investigation is based on the coupling of evacuated solar collectors with a single-stage LiBr–H2O absorption chiller; auxiliary energy for both heating and cooling is supplied by an electric-driven reversible heat pump. The SHC system was coupled with different types of school buildings located in three different Italian climatic zones. The analysis is carried out by means of a zero-dimensional transient simulation model, developed using the TRNSYS software; the analysis of the dynamic behaviour of the building was also included. An economic model is proposed, in order to assess the operating and capital costs of the systems under analysis. Furthermore, a parametric analysis and a subsequent mixed heuristic-deterministic optimization algorithm was implemented, in order to determine the set of the synthesis/design variables that maximize system profitability. The results are encouraging, as for the potential of energy saving. On the contrary, the SHC economic profitability can be achieved only in case of public funding policies (e.g. feed-in tariffs), as always happens for the great majority of renewable energy systems.

Absorption cooling systems based on water/lithium bromide (LiBr) solution typically require an open wet cooling tower to transfer the reject heat to the ambient. Yet, water consumption, the need for water make-up and cleaning, formation of fog, and the risk of Legionella bacteria growth are hindering factors for the implementation of small solar cooling systems. The application of a latent heat storage supporting the heat rejection of the absorption chiller in conjunction with a dry cooling system allows eliminating the wet cooling tower. By that means heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e. night time or off-peak hours. The system concept and the hydraulic scheme together with an analysis of the energetic performance of the system are presented, followed by a report on the operation of a first pilot installation.

Solar Heating and Cooling systems are a virtuous alternative to conventional air conditioning plants, as a renewable energy source (solar energy) is exploited. In this paper the coupling of low temperature solar devices with an innovative desiccant-based air handling unit, which meets the sensible and latent loads of a simulated lecture room, is analyzed through TRNSYS dynamic simulation software. The components have been characterized by means of experimental tests carried out at the test facility of Università degli Studi del Sannio. The desiccant-based air handling unit current set-up allows summer operation only. However, heating operation is also simulated, as comfort conditions can be maintained in the conditioned space exploiting solar thermal energy also in winter, with some modifications to the air handling unit. A parametric analysis is performed to compare different technical solutions (collector types, surface, tilt angle) and to identify the optimal one, taking into account energy, economic and environmental performance with respect to a reference system. The best case in terms of energy and environmental performance is represented by evacuated collectors, achieving a primary energy saving of 64% and a CO2 emissions reduction of 61%; flat-plate collectors are instead the best solution in terms of pay-back period (6 years).

The paper investigates different control strategies for the thermal storage management in SHC (Solar Heating and Cooling) systems. The SHC system under investigation is based on a field of evacuated solar collectors coupled with a single-stage LiBr–H 2 O absorption chiller; auxiliary thermal energy is supplied by a gas-fired boiler. The SHC is also equipped with a novel thermal storage system, consisting in a variable volume storage tank. It includes three separate tanks and a number of mixers and diverters managed by novel control strategies, based on combinations of series/parallel charging and discharging approaches. The aim of this component is to vary the thermal storage capacity as a function of the combinations of solar radiation availability and user thermal/cooling energy demands. The system allows one to increase the number of active tanks when the time shift between solar energy and user demand is high. Conversely, when this time shift is low, the number of active tanks is automatically reduced. In addition, when the solar energy in excess cannot be stored in such tanks, a heat exchanger is also used in the solar loop for producing DHW (Domestic Hot Water). The analysis is carried out by means of a zero-dimensional transient simulation model, developed by using the TRNSYS software. In order to assess the operating and capital costs of the systems under analysis, an economic model is also proposed. In addition, in order to determine the set of the synthesis/design variables which maximize the system profitability, a parametric analysis was implemented. The novel variable-volume storage system, in both the proposed configurations, was also compared with a constant-volume storage system from the energy and economic points of view. The results showed that the presented storage system allows one to save up to 20% of the natural gas used by the auxiliary boiler only for very high solar fractions. In all the other cases, marginal savings are achieved by the variable-volume storage tanks system.

This paper presents a dynamic simulation of an innovative polygeneration system based on solar heating and cooling and PEM fuel cells technologies. The polygeneration system is based on the following main components: evacuated solar collectors, single-stage LiBr–H 2 O absorption chiller and a PEM fuel cell. The fuel cell operates at full load producing electrical energy which is in part consumed by the building lights and equipments. The fuel cell is grid connected in order to perform a convenient net metering. Finally, the system also includes heat exchangers producing domestic hot water in case of scarce space heating/cooling demand. The analysis was carried out by means of a transient simulation model, developed using TRNSYS software and includes the investigation of the dynamic behavior of the building, developed in TRNBUILD. A small university hall, including also a fitness center, was adopted as test case. Energetic and economic models were also developed, in order to assess primary energy savings and the operating and capital costs of the systems under analysis. The results of the case study were analyzed on monthly and yearly basis, paying special attention to the energetic and monetary flows. The results are excellent from the energy saving point of view. On the other hand, the pay back periods can be profitable for the final user only in case of significant public funding.

6 p.; International audience; This work was done in the SOLERA project (http://www.solera-project.eu), Sixth EU Framework Program (FP6), co-funded by EC and coordinated by Fraunhofer ISE. It started in November 2007 and will stop in November 2011. The goal of the project SOLERA is to install, operate and evaluate three different solar cooling systems of different sizes.

Following a program definition phase of 2 years, Task 18 of the International Energy Agency Solar Heating & Cooling program commenced a 5 year research phase in April 1992. Task 18 investigates a wide range of advanced glazing materials and glazing systems which include monolithic and granular aerogels, transparent insulation materials, chromogenic materials, evacuated glazings, low-emittance coatings, solar collector covers, angular selective transmittance thin films, holographic and light guide materials, and frame and edge seal technology. In addition to materials-centered research, Task 18 concentrates on measurement of key glazing properties such as total energy transmittance, U-value, and spectral directional optical properties, and through the use of building energy analysis software tools the identification of appropriate applications, control strategies, and energy and environmental benefits to be derived from advanced glazing products. Fifteen OECD countries are participating in Task 18 which is led by the United Kingdom.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, a state-of-the-art of solar heating and cooling systems is presented. Solar air heaters and different types of solar water collectors are discussed in detail. Storage systems including water, rocks, and heat-of-fusion salts are described as are space heating systems employing solar air heaters, in conjunction with rock or heat-of-fusion salt storage, and the use of water collectors plus hot water storage for space heating and domestic hot water. An indication of the commercialization of various space-heating systems and broad economic projections are presented. The three major solar cooling methods—absorption cooling, solar mechanical systems, and those involving humidification-dehumidification cycles—are also discussed in detail. Finally, an overview of solar heating and cooling activities in Kuwait is also given.

Lockheed is designing a solar heating and cooling system for the city of Santa Clara's new community center. Water heated by solar collectors is used to heat the building in winter and cool the building in summer (using absorption cycle water chillers). This paper shows how optimization techniques can be applied to the operation of a solar driven heating and cooling system such as the Santa Clara facility and outlines practical problems encountered in the design. In the optimization problem the loss function includes not only the cost of heating and cooling but also the equivalent cost of discomfort involved when the temperature is not held at its desired value. The discomfort is assumed to be a quadratic function of temperature. An interesting feature of the resulting optimization problem is a region of singular control because the Hamiltonian is linear in the heating and cooling variable. An optimal control strategy is derived, and numerical examples are presented to show desired building temperatures throughout the day which minimize the sum of energy consumption and the discomfort factor. Additional analysis derives the necessary conditions for the optimal operation of the separate components involved in a solar driven heating and cooling system.

The validation of solar heating and cooling computer programs is still in the early stages of development. Some work has been done in the area but much more is required before a level of confidence can be associated with the use of the programs. A validation methodology is proposed in this report which consists of 4 levels. The first deals with the validation of detailed simulation programs with respect to unmodeled parameters or phenomena. Level 2 addresses the inaccuracies introduced in simplified analysis procedures due to unmodeled parameter variation while level 3 deals with assessment of variation in results due to the field variation of modeled parameters. Level 4 provides a verification of the results of level 3 by comparison studies with field performance data. The result is a quantification of the level of confidence with which the simplified analysis program can be used. To illustrate the Monte Carlo techniques suggested in levels two and three, a case study was prepared. The results from the case study are helpful in appreciating the method proposed and expected results from that method. The validation procedure described in this document will result in the establishment of levels of confidence with which users can predict system performance. The methodology will also assist in the establishment of a meaningful and efficient solar system testing program plan.

Transparent facade collectors can provide solar heating and cooling and lead to primary energy savings even compared to an opaque wall. They can be simulated with a detailed physical model based on laboratory measurements. The demonstration installation in Ljubljana will provide extensive measurement data of transparent facade collectors in an outdoor environment. This allows a comparison with simulations performed with the model validated by laboratory measurements. This paper presents the demonstration installation and the measurement system, which are based on the new modelling abilities and focused on the outdoor validation of such models.

A dynamic simulation model for use in analyzing the performance of specific designs of solar-heated-and- cooled buildings has been developed. The name of the program is SIMSHAC, an acronym for SImulation Model for Solar-Heated-And-Cooled buildings. To use the design program, one has merely to specify the components (that is, each subsystem; for example, collectors, storage units, splitting and mixing valves, house heating and cooling loads, auxiliary heating, auxiliary cooling, heat exchanger, etc.), and the manner in which they are connected and all initial conditions. Program SIMSHAC then writes the program for the specific system to be analyzed. Each subsystem is described by a set of time-dependent differential equations or, possibly, algebraic equations. System state variables include tempera ture, mass flow rate, and enthalpy. The model can handle three types of incident solar radiation data models. These are (1) deterministic (e.g., an algebraic-equation sun model), (2) random simulation (e.g., a model based upon cloud-cover statistics), and (3) actual tabulated input information based upon collected solar data for a specific site. The model has been used for the analysis of five different types of buildings in five locations within the United States. The types include single-family residences, small businesses, three-story apartments, schools, and mobile homes. The locations considered are Atlanta, Georgia; Madison, Wisconsin; Wilmington, Delaware; Mobile, Alabama; and Santa Maria, California. The program has also been used to simulate the solar- heated-and-cooled experimental laboratory presently being built by the National Science Foundation on the campus at Colorado State University.

A broad range of difficulties encountered in active and passive solar space heating systems and active solar space cooling systems is covered. The problems include design errors, installation mistakes, inadequate durability of materials, unacceptable reliability of components, and wide variations in performance and operation of different solar systems. Feedback from designers and manufacturers involved in the solar market is summarized. The designers' experiences with and criticisms of solar components are presented, followed by the manufacturers' replies to the various problems encountered. Information is presented on the performance and operation of solar heating and cooling systems so as to enable future designs to maximize performance and eliminate costly errors. (LEW)

The final results of the additional development work on heat transport fluids for use with active solar heating and cooling systems are summarized. The intended use of the final report is discussed, the deliverable end items are described, program objectives are listed, and means of accomplishment and problems encountered during testing are covered. It is shown that a certain product tested is marketable and is recommended as being suitable for public use.

Since test methods and standards for active solar heating and cooling systems did not exist in 1976, the Department of Energy sponsored research at the National Bureau of Standards (NBS) and other laboratories to aid in the development of research-based standards. This research was intended to facilitate a sound data base for the development of national consensus standards and test methods. In the present report, research by NBS and other laboratories is described for solar domestic hot water systems, solar collectors, thermal storage devices and collector materials. For collectors, the report describes research and test methods for determining the performance of cover plates, absorber materials, collector insulation, gaskets and sealants, rubber hose, containment materials, and heat transfer fluids.

The program was validated against data in seven of the Los Alamos test rooms. General comments are presented on the advantages and disadvantages of the program. (MHR)

Numerous problems in the design, production, installation, and operation of solar energy systems are discussed. Described are hardware problems, which range from simple to obscure and complex, and their resolution.

The paper is focused on the dynamic simulation of a Photovoltaic/Thermal collector (PVT) integrated in a high-temperature Solar Heating and Cooling (SHC) system. The system is based on the following main components: concentrating parabolic PVT (photovoltaic thermal) collectors, a double-stage LiBr-H2O absorption chiller, storage tanks, auxiliary heaters, balance of plant devices. The PVT is made-up by a parabolic dish concentrator and a triple-junction receiver. The polygeneration system provides electricity, space heating and cooling and domestic hot water for a given building, whose simulation is also included in the model. In particular, PVT produces electric energy, which is in part consumed by the building loads (lights and equipments), in part by the system parasitic loads, whereas the eventual excess is sold to the public grid. Simultaneously, the PVT provides the heat required to drive the absorption chiller. The system was simulated by means of a zero-dimensional transient model, that allows the evaluation of temperature profiles and also heat/electrical energy flows for whatever period of the year. It is also possible to evaluate the overall energetic and economic performance on whatever time basis (day, week, month, year, etc.). The economic results show that the system under investigation can be profitable, if a proper funding policy is available. The paper also includes an extensive parametric analysis aiming at evaluating the set of design and operating parameters (solar field area, tank volumes, set point temperatures, etc.) that maximize the energetic and/or economic performance of the system.

Solar cooling technology is currently facing a very exciting challenge. Air conditioning is a large and growing energy consumer, especially in sunny and developing countries. Worldwide efforts to develop renewable energy solutions must address this critical cooling application. A new Generation of Solar Cooling systems including the coupling between Photovoltaic modules and a reversible heat pump is very promising and able to represent a cost competitive solution both reliable and efficient. To address this new generation of solar cooling, a new IEA Solar Heating and Cooling Program Task, called Task 53 has just started for 3.5 years and will be described. This paper will first concentrate on the description of Task 53 with its objectives and work plan then it will show the first results such as the state of the art of the new generation solar cooling systems. Then, a virtual case study on the cost competitiveness of a PV reversible heat pump installed in Madrid for cooling and heating will be presented, underlining that such a solution already would present a payback time of less than 10 years in the Spanish economical today's conditions

In this paper, a Solar Heating and Cooling (SHC) system including photovoltaic/thermal (PVT) collectors is considered, implementing a novel polygeneration system producing electricity, space heating and cooling and domestic hot water. In particular, PVT collectors operating up to 80 °C are considered. A case study for a university building located in Naples (Italy) is developed and discussed. The system is mainly composed by: PVT collectors, a single-stage LiBr–H2O absorption chiller, storage tanks and auxiliary heaters. The system also includes additional balance-of-plant devices: heat exchangers, pumps, controllers, cooling tower, etc. The PVT produces electricity which is utilized in part by the building lights and equipments and in part by the system parasitic loads; the rest is eventually sold to the grid. Simultaneously, the PVT system provides the heat required to drive the absorption chiller. The system performance is analyzed from both energetic and economic points of view by means of a zero-dimensional transient simulation model, developed with TRNSYS. The economic results show that the system under investigation can be profitable, provided that an appropriate funding policy is available. In addition, the overall energetic and economic results are comparable to those reported in literature for similar 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.

This paper investigates the integration of solar and geothermal energy in a novel polygeneration system producing simultaneously: electricity, thermal energy, cooling energy and fresh water. The polygeneration system under analysis includes concentrating photovoltaic/thermal solar collectors (CPVT), a Geothermal Well (GW) a multi-effect distillation (MED) system for seawater desalination, a single-stage LiBr–H2O absorption chiller and additional components, such as: storage tanks, heat exchangers and balance of plant devices. The CPVT produces simultaneously electrical energy and thermal energy, at a maximum temperature of about 100 °C. The electrical energy is delivered to the grid, whereas the thermal energy can be used for different scopes. First, the thermal energy can be used for heating purposes and/or Domestic Hot Water production. As an alternative, solar thermal energy can be used to drive an absorption chiller, producing chilled water for space cooling. Finally, solar energy, in combination with the thermal energy produced by low-enthalpy (about 80 °C) geothermal wells, may be used by the MED system to convert seawater into desalinated water. Geothermal energy is also used to produce Domestic Hot Water at 45 °C. The system is dynamically simulated by means of a zero-dimensional transient simulation model. The simulation model also includes detailed control strategies, for the management of the different technologies included in such a complex system. The system is assumed to be operated in some of the several small volcanic islands in the Mediterranean Sea, assuming Pantelleria (Trapani, Italy) as main case study. Here, the availability of solar and geothermal energy is high whereas the availability of fresh water is scarce and its cost consequently high. Results show an excellent energetic performance of the system under investigation. From the economic point of view, the profitability of the system dramatically increases when user Domestic Hot Water demand is high.