Full Description

A procedure for the design of air-cooled cross-flow condensers for absorption space-conditioning systems was developed in this study. The refrigerant under consideration is a binary fluid mixture of ammonia and water, which is one of the primary fluid pairs being considered for absorption heat pumps. The effect of a two-component mixture on tube-side temperature profiles was investigated in detail. Several alternative fin types were considered for the air side. A comparison of the performance of condensers with these different fin types was made through the computation of heat exchanger mass for equivalent heat duties. Within the limitations of the available heat transfer and friction factor correlations, round-tube heat exchangers with flat, wavy, louvered, and annular fins were designed to meet typical absorption cycle design conditions. The effect of design variables, such as parallel/serpentine flow arrangements of tubes, fin densities, core depth, and other parameters of heat transfer performance and tube- and air-side pressure drops, was investigated. It was shown that wavy fins result in the smallest heat exchanger mass among the fin geometries considered here for the imposed design objectives and constraints.

Units: Dual

Citation: Symposium, ASHRAE Transactions, 1998, Vol 104, pt. 1A, San Francisco