Unglazed collector/regenerator performance for a solar assisted open cycle absorption cooling system

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Solar Energy (Journal of Solar Energy Science and Engineering); (United States)

DOI:https://doi.org/10.1016/0038-092X(93)90008-C· OSTI ID:6845903

Hawlader, M N.A.; Novak, K S; Wood, B D ^[1]

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1. Arizona State Univ., Tempe (United States)

This study includes the results of an investigation on a prototype solar assisted absorption cooling system. The liquid absorbents, for example, lithium chloride or lithium bromide used in this type of system absorb water, the refrigerant, in the absorber and require energy input for a subsequent desorption process. An ordinary black shingled roof was used as a collector/regenerator for the evaporation of water to obtain a strong solution of absorbent for use in the absorber. The rate of evaporation from the collector/regenerator determines the overall cooling capacity of the system. Experiments were conducted on a 11 m [times] 11 m collector/regenerator to measure solution flow rates and concentrations at inlet and outlet, and temperatures at several locations of the collector. Altogether, there were 100 sets of data taken under various environmental and flow conditions. An iterative solution of the equations describing the conservation of mass and energy led to the prediction of local concentrations of the absorbent solution, and local heat and mass transfer coefficients. Correlations for nondimensional heat and mass transfer parameters were developed in terms of local Reynolds number, Grashof number, Prandtl number, Schmidt number, and N, the ratio of buoyancy force due to mass transfer to buoyancy force due to heat transfer. These heat and mass transfer correlations were used for the simulation of performance of the collector/regenerator. A parametric study of the collector/regenerator performance enabled the identification of important variables. A good agreement between these results and those from a warm, humid climate indicates that the simulation model can be used as a tool for the design of systems operating under similar conditions. The experimental results also show a regeneration efficiency varying between 38 and 67%, and the corresponding cooling capacities ranged from 31 to 72 kW (8.8 to 20 tons).

• OSTI ID: 6845903
• Journal Information: Solar Energy (Journal of Solar Energy Science and Engineering); (United States), Journal Name: Solar Energy (Journal of Solar Energy Science and Engineering); (United States) Vol. 50:1; ISSN SRENA4; ISSN 0038-092X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140901* -- Solar Thermal Utilization-- Space Heating & Cooling
ALKALI METAL COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
EFFICIENCY
EQUIPMENT
EVAPORATION
HALIDES
HALOGEN COMPOUNDS
LITHIUM BROMIDES
LITHIUM CHLORIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
PERFORMANCE
PHASE TRANSFORMATIONS
REGENERATION
REGENERATORS
SOLAR COLLECTORS
SOLAR COOLING SYSTEMS
SOLAR EQUIPMENT
SOLAR REGENERATORS