City Research Online

Abstract

The operation of an air-cooled aqua-ammonia absorption refrigeration system through the use of solar energy has been investigated using Computer modelling techniques. The study conducted has revealed a potential for the system to be powered by a nontracking CPC solar collector with nonevacuated tubular receiver, for applications at near equatorial latitudes.

A conditional equation has been developed to determine the collection times and tilt adjustment requirements for the collector. Also, in the absence of any empirical equation for calculating the collector top loss coefficient, Ut, correlation equations have been developed. The performance analysis indicated an outlet water temperature up to 150°C is obtainable with concentration ratio between 2.5 and 4.7, with 2 to 6seasonal tilt adjustments.

Polynomia property data equations for NHg-H^O mixtures have been developed in a form readily adaptable to a Computer program. Extensive thermodynamic cycle analysis of the aqua-ammonia cycles revealed an average generator temperature of 105°C is required for water-cooled system, and about 120°C for air-cooled cycles. The results also indicated a minimum generator temperature requirement depending on a given set of operating temperatures.

Simulation of the combined system of the CPC collector and aqua-ammonia cycle indicated that application of the system is possible for cooling of office buildings and refrigerated products. The results also showed the storage of refrigerant and solution to be thermodynamically feasible. An economic comparison with a conventional vapour compression system revealed the estimated cost of the solar system to be three times higher. Suggestions have been made for further investigation, as it is hoped that further research work will be inspired from the present work.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QA Mathematics > QA75 Electronic computers. Computer science T Technology > TJ Mechanical engineering and machinery T Technology > TP Chemical technology
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses School of Science & Technology > Engineering

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