Advances in design of air-heating collectors

Abstract

Principles of the operation of air-heating collectors are discussed. The fundamental differences between the design principles of air-heating as opposed to water-heating collectors are highlighted. The main requirement is the transfer of heat from the solar absorber to the air with minimum thermal losses and minimum pumping power. To achieve this objective, the basic arrangement with flow of air on the shaded side of the absorber is preferred. An optimum design of the absorber-to-air heat exchanger may be obtained by providing the sided of the absorber with slotted or interrupted fins in a staggered arrangement. The design of such heat exchangers should be based on correlations for the developing flow regime in the hydrodynamic and thermal entry regions. Solar absorber to the air with minimum thermal losses and minimum pumping power. To achieve this objective, the basic arrangement with flow of air on the shaded side of the absorber is preferred. An optimum design of the absorber-to-air heat exchanger may be obtained by providing the sided of the absorber with slotted or interrupted fins in a staggered arrangement. The design of such heat exchangers should be based on correlations for the developing flow regime in the hydrodynamic and thermal entry regions.