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Incorporating solar energy technologies to the conventional combined cooling, heating and power (CCHP) system has been considered as an effective solution to mitigate the looming energy and environmental challenges. The mathematical model of a conventional CCHP system hybridized with photovoltaic (PV) panels and solar thermal collectors is built in this study. The particle swarm optimization (PSO) algorithm is employed to find the optimal size of key components of the solar hybrid CCHP system. The simulation work of solar hybrid CCHP systems in three building prototypes across seven climate zones is carried out to find appropriate design schemes of these cases. Besides, some guiding principles of the design of the solar hybrid CCHP system in early stage are summarized. The results show that the system under the following thermal load (FTL) strategy is the first choice in most cases of hospitals and hotels, except for the systems of hotels in the cold and very cold zones. On the contrary, the systems in offices perform better in the following electric load (FEL) mode in the majority of climate zones except for the hot-humid zone. Generally, the average optimal integrated performance (S) values of hospitals, hotels and offices can reach 28.95%, 28.20% and 22.69%, respectively. • The building type and climate can affect the design of solar hybrid CCHP system. • The matching performance of the novel CCHP system is good in hospital and hotel. • Solar assisted systems are useful to hotels in both two operation modes. • Solar hybrid CCHP systems have good energy-saving and environmental performance. [ABSTRACT FROM AUTHOR]

Combined cooling, heating and power (CCHP) is a promising technology to provide energy for various energy consumers for its good economic, energy and environmental performance. However, the widely promotion of CCHP is hindered by its complex design and varying performance under different situations. In this paper, the influence of energy demands, operation strategy and thermal energy storage strategy on optimal design and performance of CCHP systems is studied by using statistical methods 13,472 energy demand samples for 16 types of building across 7 climate zones in the U.S. are used in the paper. On the whole, building energy demands are the most influential factor. Among the building types, the performance of large hotel, hospital and outpatient healthcare is outstanding. Among the climate zones, CCHP systems have better performance in cold and very cold climate zones. For operation strategies, the ATCSR and PESR values of the FTL mode are averagely less than those of the FEL mode, and the differences between the two modes for ATCSR and PESR are on average 0.25% and 1.03%, respectively. Besides, the use of thermal energy storage can improve the integrated performance of CCHP. In the FEL-TES mode, the average increments of ATCSR and PESR are 0.82% and 0.79%, respectively. In the FTL-TES mode, the average increments of ATCSR and PESR mode can reach 3.42% and 3.46%, respectively. The relationship between building energy demand indexes and the design and performance parameters of the CCHP is also explored by stepwise regression method to build regression models and determine the most effective parameters. [ABSTRACT FROM AUTHOR]

A fin tube phase change cold storage unit based upon self-developed C–L acid (capric and lauric acid) PCM with the phase change temperature of 14.97 °C for high temperature cooling application was designed. The charging performance of the cold storage unit was experimentally investigated. Moreover, the performance analysis based upon the charging performance was conducted for the purpose of optimizing the structural parameters. It is shown that the whole charging process of the optimized scheme is faster than that of the experimental unit by 26.3%. In practical applications, two or more such fin tube phase change cold storage units in parallel can be used to meet different cold storage demand of high temperature cooling systems in buildings. [ABSTRACT FROM AUTHOR]

Highlights: [•] We designed a ground-coupled heat pump system with heat recovery technology for a cooling-dominated building. [•] Experiments of heat transfer between the ground heat exchanger and the soil under typical working conditions were carried out. [•] The variations in soil temperature after long-term operation were predicted. [•] Some suggestions on the design of such systems were given. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews the previous work on phase change cold storage for air-conditioning systems focusing on two aspects including phase change materials (PCMs) and applications. Besides the studies on phase change cold storage devices, the typical air-conditioning systems with cold storage are also reviewed, namely the solar air-conditioning system with cold storage, latent cooling storage and transport system and mixed cold storage air-conditioning system. Moreover, the problems with respect to compatibility, heat transfer enhancement, phase change properties of composite PCMs, etc., are discussed for further investigation. [Copyright &y& Elsevier]

Abstract: Solar cooling technology is environmentally friendly and contributes to a significant decrease of the CO2 emissions which cause the green house effect. Currently, most of the solar cooling systems commonly used are the hot water driven lithium bromide absorption chillers. According to the operating temperature range of driving thermal source, single-effect LiBr/H2O absorption chillers have the advantage of being powered by ordinary flat-plate or evacuated tubular solar collectors available in the market. In this paper, besides the review of the existing theoretical and experimental investigations of solar single-effect absorption cooling systems, some new design options with regard to solar collectors, auxiliary energy systems and cooling modes were introduced. And then, other main types of solar absorption cooling systems based on double-effect, half-effect and two-stage absorption chillers were summarized. For buildings with high amounts of cooling load and limited installation area, solar-powered double-effect absorption cooling systems may be considered on condition that the direct irradiation is high enough. Half-effect absorption chillers and two-stage absorption chillers seem to be more suitable for air-cooled solar absorption cooling systems in hot and dry regions which are short of water. It is highly recommended to study the standardised design guidelines according to different areas for the purpose of widespread applications of solar cooling systems. [Copyright &y& Elsevier]

Abstract: A ground source heat pump (GSHP) system was designed and constructed in Minhang archives of Shanghai. As a demonstration project, it is the first archives to use a GSHP system in China. The system consists of two heat pumps with the rated cooling capacity of 500kW for each and 280 boreholes with 80m in depth. In the cooling mode, the heat extraction from the condenser of the heat pump was divided: part of it was rejected to the soil while the rest was used to reheat the air in air handling units. The GSHP system has continuously run for nearly two years. It was shown that the indoor thermal environment met the “Archives Design Code” issued by China national archives. Compared with an air source heat pump system which is widely used in archives buildings, the operating cost of the GSHP system is reduced by 55.8% and the payback time is about two years. Owing to its great potential in energy conservation, such kind of GSHP system is testified to be applicable to the air-conditioning systems of the archives buildings. Besides, the applications of GSHP systems corresponding to different climatic zones of China were analyzed. [Copyright &y& Elsevier]

Abstract: As a simple and practical bioclimatic design methodology, solar chimneys are receiving considerable attention for reducing heat gain and inducing natural cooling or heating in both commercial and residential buildings because of their potential benefits in terms of operational cost, energy requirement and carbon dioxide emission. In practical civil buildings, solar chimneys can be installed on the walls and roofs. For the purpose of improving natural ventilation performance and achieving better indoor thermal comfort, solar chimneys are always applied in the form of integrated configurations. Solar chimneys can also be used to combine with natural cooling systems so as to enhance the cooling effect inside buildings. Besides, active solar systems may be utilized to enhance the ventilation performance of solar chimneys. In this paper, the main configurations and the integrated renewable energy systems based on solar chimneys were summarized. Then the suggestions were given. Generally, solar chimney technology has been regarded as an effective and economical design method in low carbon buildings. As for the integrated energy systems based upon solar chimneys, it is still necessary to carry out more experimental investigations to acquire objective data for the system design. Besides, it is suggested to further study the optimization and control strategy of such integrated systems in different climates. [Copyright &y& Elsevier]

Abstract: During the past few decades, a large number of ground-coupled heat pump (GCHP) systems have been widely applied in various buildings around the world due to the attractive advantages of high efficiency and environmental friendliness. However, most buildings in warm-climate or cold-climate areas have unbalanced loads, dominated by either cooling loads or heating loads. Therefore, it is necessary to employ integrated approaches in the design of GCHP systems to decrease the initial cost of the GCHP systems and, at the same time, to improve the system performance. In this paper, the main integrated approaches of GCHP systems were summarized based on the available references and our experience. Then the suggestions were given. For a heating-dominated building, the combination of a GCHP system with a solar thermal system shows great potential for energy conservation and high-efficiency utilization of the GCHP system. With respect to a cooling-dominated building, the simplest approach is to integrate a GCHP system with a cooling tower although there are more available technologies. It is believed that the high inertia heating or cooling distribution systems such as radiant floors, ceilings or walls are more suitable for GCHP systems. It is highly suggested to establish optimal operational control strategies for integrated GCHP systems according to the climatic conditions, building functions and thermal balance of the ground. [Copyright &y& Elsevier]

Abstract: A constant temperature and humidity air-conditioning system driven by ground source heat pumps was designed and constructed in an archives building in Shanghai, China. The system consists of two water-to-water heat pumps and 280 boreholes with 80m in depth. In order to keep the temperature and humidity constant, the operation mode that one heat pump ran in heating mode and the other one ran in cooling mode was deployed. According to the experimental results under typical winter weather condition of Shanghai, the average COP of the heat pump in heating mode was 5.2. The average temperature and relative humidity of the archives house were 22.8°C and 52.5%, respectively. It was found that the operation mode we deployed could reduce the heat absorbed from the soil by 20%. Theoretical analysis showed that it was helpful for the earth energy conservation with one heat pump operated in cooling mode in winter. It was also shown that the decrease range of temperature of the soil in the middle of two boreholes would reduce with the increase of the distance between two boreholes. The distance between two boreholes is suggested to be 4–5m in Shanghai. [Copyright &y& Elsevier]

Abstract: Solar energy is receiving much more attention in building energy systems in recent years. Solar thermal utilization should be based on integration of solar collectors into buildings. The facades of buildings can be important solar collectors, and, therefore, become multifunctional. In addition, solar collectors can be used to enhance the appearance of the facade when considering their aesthetic compatibility. Currently, installation of collectors on the south tilted roofs, south walls, balconies or awnings of buildings are the feasible approaches for integration of solar collectors into buildings. The most well known solar energy demonstration projects in China are introduced in this paper, which cover different integrated approaches, and solar heating and cooling systems. In China''s cities, the process of rebuilding apartment roofs from flat to inclined offers the ideal opportunity to carry out solar renovation in combination with roof-integrated collectors. It can be seen from the demonstration projects over the last twenty years, that, solar cooling systems were mainly used in public buildings for either absorption or adsorption. Besides, nearly all solar cooling systems are multifunctional. They have been used to supply heating and hot water in other seasons for the purpose of high solar fraction. In the 11th Five-year research project (duration 2006–2010), the government has encouraged solar energy researchers to study, develop, and break through the key technologies involved in the integration of solar thermal technologies with buildings. [Copyright &y& Elsevier]

Abstract: A solar adsorption cooling system which can be switched between a system with heat storage and a system without heat storage was designed. In the system with heat storage, a heat storage water tank was employed as the link between the solar collector circulation and the hot water circulation for the adsorption chillers. However, the heat storage water tank was isolated in the system without heat storage, and the hot water was directly circulated between the solar collector arrays and the adsorption chillers. It was found that the inlet and outlet temperatures for the solar collector arrays and the adsorption chillers in the system without heat storage were more fluctuant than those of the system with heat storage. Also found was that the system with heat storage operated stably because of the regulating effect by the heat storage water tank. However, under otherwise similar conditions, the cooling effect of the system without heat storage was similar to that of the system with heat storage. Compared with the system with heat storage, the system without heat storage has the advantages of higher solar collecting efficiency as well as higher electrical COP. [Copyright &y& Elsevier]

Abstract: In the past decades, solar water collectors were installed for the main purpose of preheating domestic hot water or to cover a fraction of the space heating demand in China. However, solar cooling systems were constructed just for demonstration purposes. Since the building of the first solar-powered absorption cooling system in Shenzhen in 1987, there have been over 10 additional solar cooling demonstration projects constructed. In this paper, the most representative five projects including both absorption and adsorption cooling systems are introduced and summarized. From the demonstrations, solar absorption cooling systems have been shown to be more suitable for large building air-conditioning systems. Comparatively, solar adsorption cooling systems are more promising for small size air-conditioning systems. In order to attain high utilization ratio, it is highly recommended to design solar-powered integrated energy systems in public buildings. In addition, highly efficient heat pumps are considered as the most appropriate auxiliary heat sources for solar cooling systems, for the purpose of all-weather operation. In the 11th Five year research project (duration 2006–2010), solar cooling technologies will be further investigated to achieve a breaking through in the integration of solar cooling systems with buildings. [Copyright &y& Elsevier]

Abstract: In the green building of Shanghai Research Institute of Building Science, the evacuated tubular solar collectors with a total area of 150m2 were installed to provide heating for the covered area of 460m2. The floor heating coil pipes were made of high-quality pure copper with the dimension of Φ 12×0.7mm. Under typical weather condition of Shanghai, the average heating capacity was 25.04kW during the working hours from 9:00 to 17:00, which was sufficient to keep indoor thermal environment. The average electric COP of the floor heating system was 19.76 during the system operation. Compared with the widely used air-source heat pump heating systems with the electric COP of 3.5 in Shanghai, the solar-powered floor heating system shows great potential in energy conservation in winter. With respect to the whole heating period, the solar fraction was 56%. According to the performance analysis of the system with ambient parameters, it was observed that the system performance could be greatly enhanced with the increase of daily solar insolation. However, the system performance varied slightly with average ambient temperature. Compared with average ambient temperature, daily solar insolation had a more distinct influence on the performance of the solar-powered floor heating system. [Copyright &y& Elsevier]

Abstract: The green buildings of Shanghai Research Institute of Building Science include an office building for the demonstration of public building and two residential buildings, which are for the demonstration of flat and villa, respectively. Here, a solar-powered integrated energy system including heating, air-conditioning, natural ventilation and hot water supply was designed and constructed for the office building. However, only solar hot-water systems were installed for the flat and villa. All the three solar thermal systems have continuously run for 2 years. Two different integrated approaches have been put into practice in the two green residential buildings. It is shown that, for new buildings, solar collectors can be mounted on balconies and awnings besides roofs, on condition that solar systems become part of the general building design. The solar-powered integrated energy system has the advantage of high utilization ratio with different functions according to different seasons. It is testified to be capable of taking on about 70% of the yearly building load regarding the involved space under the weather condition of Shanghai. [Copyright &y& Elsevier]

Abstract: Solar energy is receiving much more attentions in building energy systems in recent years. Solar thermal utilization should be based on the integration of solar collectors into buildings. The facades of buildings can be important solar collectors, and therefore become multifunctional. In addition, solar collectors can be used to enhance the appearance of the façade when considering aesthetic compatibility. Currently, the feasible approach for integration of solar collectors into buildings is to install collectors on the south tilted roofs, south walls, balconies or awnings. Experiences on solar thermal utilization were mainly introduced in this paper, which included solar hot water systems with different design methods in residential buildings and solar-powered integrated energy systems in public buildings. Then the suggestions were given. In the cities of China, an ideal opportunity to carry out solar renovation with roof-integrated collectors is in combination with the rebuilding of apartment roofs from flat to be inclined. With regard to multi-storied residential buildings, central hot water supply system and central-individual hot water supply system are more appropriate in view of aesthetic compatibility of solar collectors with building roof and convenience of management. As for public buildings, it is highly recommended to design solar-powered integrated energy systems for the purpose of high solar fraction. [Copyright &y& Elsevier]

Abstract: A solar-powered adsorption air-conditioning system was designed and installed in the green building of Shanghai Research Institute of Building Science. The system contained 150m2 solar collectors and two adsorption chillers with nominal refrigeration capacity of 8.5kW. Based on performance characteristics of the adsorption chiller, the operation mode of the solar-powered air-conditioning system was optimized by maintaining a phase shift of 540s between the two adsorption chillers. Thereafter, the whole system realized stable operation by the balance of heat consumption and refrigeration output. From June to August of 2005, the solar-powered air-conditioning system continuously ran between 9:00 and 17:00. The operation performance of the system under representative working condition showed that the average refrigeration output of the solar-powered air-conditioning system was 15.3kW during an 8h operation and the maximum value exceeded 20kW. Solar fraction for the system in summer was 71.7%, which corresponded to the designed cooling load (15kW). Compared with the ambient temperature, it was deduced that solar radiant intensity had a more distinct influence on the performance of solar-powered air-conditioning system. [Copyright &y& Elsevier]

Abstract: Shanghai is characteristic of subtropical monsoonal climate with the mean annual temperature of 17.6°C, and receives annual total radiation above 4470MJ/m2 with approximately 2000h of sunshine. A solar energy system capable of heating, cooling, natural ventilation and hot water supply has been built in Shanghai Research Institute of Building Science. The system mainly contains 150m2 solar collector arrays, two adsorption chillers, floor radiation heating pipes, finned tube heat exchangers and a hot water storage tank of 2.5m3 in volume. It is used for heating in winter, cooling in summer, natural ventilation in spring and autumn, hot water supply in all the year for 460m2 building area. The whole system is controlled by an industrial control computer and operates automatically. Under typical weather condition of Shanghai, it is found that the average heating capacity is up to 25.04kW in winter, the average refrigerating output reaches 15.31kW in summer and the solar-enhanced natural ventilation air flow rate doubles in transitional seasons. The experimental investigation validated the practical effective operation of the adsorption cooling-based air-conditioning system. After 1-year operation, it is confirmed that the solar system contributes 70% total energy of the involved space for the weather conditions of Shanghai. [Copyright &y& Elsevier]

Abstract: Solar air collectors are important components for solar energy utilization in green houses. In this paper, experimental studies were carried out regarding to a solar air collector (SAC), for which the length of air channel is 1500mm, the width is 500mm, and a variable air channel gap ranges from 100 to 500mm. In the experiment, the uniform heat flux along the air channel is effected by three electric heating plates, which play a role as solar radiation. It is found that the temperature distribution of air and the induced natural air-flow rate are highly dependent on heat input, inclination angle, channel gap, etc. Experimental results indicate that the optimum inclination angle for the SAC is 45°, under which a maximum natural ventilation rate can be created. Also found is that there exists an appropriate channel length, about 1m in this study, beyond which the obtained heat and the natural ventilation rate cannot be increased drastically. Higher the volume of air-flow rate through the SAC, lower the temperature difference between inlet and outlet, consequently, it should be balanced between the air temperature rise and a suitable mechanical air-flow rate in order to obtain maximum heat. Additionally, theoretical analysis based on heat balance equations is testified to agree well with experimental results. [Copyright &y& Elsevier]

This work studies the annual energy performance of a Variable Water Volume (VWV) air source heat pump (ASHP) system by means of experiment and simulation. An advanced R410A ASHP system, integrated with independent normal fan coil unit, small temperature difference fan coil unit and floor radiation heating coil unit indoor terminals, is constructed. Multi-groups of field tests show that system COP varies from 2.0~4.0 for the different operating load under corresponding conditions. Moreover, in order to predict the long term energy performance of the ASHP system, several quasi-steady models are constructed and validated with experimental data. Then the annual energy performances of investigated system are simulated under different climate zones in China. Both experimental and simulation results show that VWV ASHP system can achieve high competitive seasonal energy efficiency for the buildings, which shows the SPF could be more than 3.0. At last, several recommendations based on the simulation results are proposed to the existed heat pump system. [ABSTRACT FROM AUTHOR]

Under the thermal storage strategies in present studies, the power generation unit (PGU) in combined cooling, heating, and power (CCHP) system is turned on/off only based on the state of storage tank; or the operation state of PGU is determined by thermal demand or/and electric demand, which has no relationship with the state of storage tank. For these traditional strategies, either energy demands or state of storage tank is considered for the operation of system. This paper proposes a novel thermal storage strategy (TSS2) for CCHP systems, which determines the operational state of the PGU based upon electric demand, thermal demand and the state of thermal storage device. In this paper, the operation principle of TSS2 is described and compared with the traditional strategies. A hospital in Shanghai was used to evaluate and compared the performance of the system operating under different storage strategies. The results show that TSS2 improves the performance of CCHP system more significantly compared with the traditional strategies. TSS2 can make both PGU and capacity of thermal storage tank be fully used by CCHP system to produce more electric and thermal energy to meet demands of building. Compared with system without thermal storage, the minimum and maximum increase rates of annual total cost saving for traditional strategies are 0% and 14.84%, respectively. However, for TSS2, they can reach 3.79% and 20.22%. Similar conclusions could be achieved for CO 2 emission reduction and primary energy saving. The effect of TSS2 on the CCHP system performance is different under different operation strategies. [ABSTRACT FROM AUTHOR]

In this paper, a feed-in tariff policy which can contribute to both energy and economic performance of a CCHP system is proposed. By applying this feed-in tariff policy, the impact on design optimization (power generation unit capacity and operation strategy) and system performance (economic, energy, and matching performance) of a hospital CCHP system used in different climate zones are evaluated and analyzed. In policy one ( Pol 1 ), no electricity is allowed to be sold. In policy two ( Pol 2 ), the electricity selling price is constant. In policy three ( Pol 3 ), the selling price of electricity is proportional to the PER (Primary Energy consumption Ratio) of the system when the PER is not lower than a critical value. Otherwise, the selling price is zero. The results show that Pol 3 can ensure both energy and economic performances of CCHP system. The effect of feed-in tariff policy to improve the performance of CCHP system reduces gradually from the cold zone to the hot zone. Multi-criteria decision making results show that Pol 3 with reasonable parameters is the best choice in all climate zones except for the hottest zone in this study. When improving PER is attractive, following thermal load operation strategy is the best choice under Pol 3 . In the hottest zone of this study, little excess electricity would be produced and sold to the grid. Feed-in tariff policy has little help to improve the economic and energy performance in this zone. [ABSTRACT FROM AUTHOR]

A dynamic simulation model for the micro-cogeneration unit based on ICE (internal combustion engine) is built as a new component on TRNSYS. This model considers dynamic processes including start-up, cool-down, and overheat protection controls. Through an experiment study, the steady and dynamic performances of the unit are presented and analyzed for calibrating the parameters of the dynamic model. Then the model is validated by the experiment data during steady and dynamic processes. The improvement of prediction accuracy of the model by considering dynamic processes is analyzed. The validation results show that the dynamic model can well predict the characteristics of the unit during start-up, cool-down, and overheat protection control processes. The cumulative prediction errors of the dynamic model decrease with the increase of the start–stop interval. By considering the dynamic processes, 5.18% and 3.2% of Q th and η total cumulative prediction errors are decreased respectively when the start–stop interval is 0.5 h. The primary energy saving ratio and CO 2 emission reduction ratio increases with the increase of the start–stop interval. The start–stop interval for the unit in this paper should be longer than 0.5 h, or the energy consumption of micro-cogeneration unit would be larger than that of conventional system. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel operation strategy based on minimum distance which is flexible and adaptable was proposed. [•] An integrated evaluation criterion reflecting the matching performance was presented. [•] The strategy and criterion was used to optimize the design of the CCHP system. [ABSTRACT FROM AUTHOR]

Abstract: Numerous studies about the ground source heat pump building heating and cooling systems have been constructed in office building, hotel, residential building and school et al. However, few researches about the constant temperature and humidity air-conditioning system driven by ground-coupled heat pumps were carried out. In this paper, a constant temperature and humidity air-conditioning system driven by ground source heat pump was designed and constructed in an archives building in Shanghai, China. During the operation in the cooling mode, the heat extraction from the condenser of the heat pump was divided: part was rejected to the soil while another was used to reheat the air in AHUs. According to the experimental results, the indoor temperature and relative humidity fulfilled the “Archives Design Code”. In summer, the heat rejected to the soil was reduced by 32%, which was helpful for the earth energy conservation. The soil temperature increased only 0.5 °C after the GSHP system operating for a year. The energy cost of the air-conditioning system was 56.1 kWh/m2. Compared with air source heat pump system and water cooled unit with boiler system, the operating cost of ground source heat pump was reduced by 55.8% and 48.4%, respectively. [Copyright &y& Elsevier]

Abstract: Solar absorption cooling systems are available from various reports, in large capacities up to several hundred kilowatts. However, in the range of small capacities (<50kW), only very few systems were reported. In this paper, a mini-type solar absorption cooling system was designed and installed at Shanghai Jiao Tong University. The system contains 96m2 solar collector arrays, one absorption chiller with a rated cooling capacity of 8kW, and a hot storage water storage tank of 3m3 in volume. The chilled water can be delivered either into fan coils or into radiant cooling panels, which are installed to satisfy the demands of the indoor thermal environment of the test room. As for the fan coil cooling mode, it was found that the average cooling output reached 4.27kW during 9h of operation under typical weather conditions for Shanghai. The PMV (predicted mean value, a measure of thermal comfort) inside the test room could be controlled between −0.29 and 0.32. With regard to the radiant cooling mode, an individual supply air unit was installed for the purpose of preventing condensation on the cooling panels. Comparing with the experimental results of the fan coil cooling mode, the average cooling output increased by 23.5%. [Copyright &y& Elsevier]

Abstract: This paper presents the performance analysis on a hybrid air-conditioning system according to the hybrid building energy system of the green building demonstration project in Shanghai, in which a 150m2 solar collector is used to power two 10kW adsorption chillers, a vapor compression heat pump is used to cool air in the evaporating end while the condensing heating at about 80°C is fully used to regenerate a liquid desiccant dehumidification system. In the hybrid system, the sensible cooling to the air is treated mainly by solar adsorption cooling and vapor compression cooling, whereas the latent heat is treated by the liquid desiccant dehumidification system with regeneration from the condensing heat of the heat pump. The results show that the performance of this system is 44.5% higher than conventional vapor compression system at a latent load of 30% and this improving can be achieved by 73.8% at a 42% latent load. The optimal ratio of adsorption refrigerating power to total cooling load for this kind of hybrid systems is also studied in this paper. [Copyright &y& Elsevier]