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A simple effect one stage ammonia-water absorption cooling system fueled by solar energy is analyzed. The considered system is composed by a parabolic trough collector concentrating solar energy into a tubular receiver for heating water. This is stored in a fully mixed thermal storage tank and used in the vapor generator of the absorption cooling system. Time dependent cooling load is considered for the air conditioning of a residential two-storey house. A parametric study is performed to analyze the operation stability of the cooling system with respect to solar collector and storage tank dimensions. The results emphasized that there is a specific storage tank dimension associated to a specific solar collector dimension that could ensure the longest continuous startup operation of the cooling system when constant mass flow rates inside the system are assumed. [ABSTRACT FROM AUTHOR]

The paper presents a mathematical modeling of the optimum tilt for solar collectors for intercepting maximum solar irradiance (power density), at different geographical locations, periods of time and different base-ground types. The solar irradiance received by the collector is estimated based on isotropic sky analysis models, namely Hottel & Woertz model and Liu & Jordan model. The optimum value for the tilt is considered for maximum hourly and respectively daily noon incident solar irradiance. This paper emphasizes the mathematical link between the optima computed under the two considered models assumptions. Also the ground reflectance factor influence on the optimum tilt difference between considered models is presented related to latitude. [ABSTRACT FROM AUTHOR]

The paper presents a comparison between two different orientations of a vegetable greenhouse with respect to East-West axis in Romania. The solar irradiance received by the greenhouse is estimated based on isotropic clear sky analysis model. Interior air temperature profiles are numerically simulated all along a day, in winter and in summer. In order to maintain a constant interior air temperature during vegetation, heating and respectively cooling required loads are computed. Different profiles are obtained for the considered orientations. Based on these profiles, the numerical simulation reveal energy savings for the E-W orientation with respect to N-S one, both in summer and winter periods. The results might be used for designing the cooling and heating equipment ensuring the optimum microclimate inside the greenhouse. [ABSTRACT FROM AUTHOR]