Sensitivity Studies of a Low Temperature Low Approach Direct Cooling Tower for Building Radiant Cooling Systems

摘要

Recent interest in cooling towers as a mechanism for producing chilled water, together with the evolution of radiantrncooling, have prompted a review of evaporative cooling in temperate maritime climates. The thermal efficiency ofrnsuch systems is a key parameter, as a measure of the degree to which the system has succeeded in exploiting therncooling potential of the ambient air. The feasibility of this concept depends largely however, on achieving lowrnapproach water temperatures within an appropriate cooling tower, at acceptable levels of energy performance.rnPrevious experimental work for a full scale evaporative cooling system has shown that it is possible to producerncooling water at low process approach conditions (1-3 K), at the higher temperatures required in radiant andrndisplacement systems (14-18℃), with varying levels of annual availability in different temperate climate locations.rnFor such conditions, evaporative cooling has the potential to offer an alternative approach for producing chilledrnwater, particularly in temperate climates, where conventional mechanical air-conditioning systems can, for certainrnbuildings, be considered to be an over engineered solution but where passive cooling is insufficient to offset coolingrnloads. The current paper describes the development of a mathematical model which analyses the behavior of a lowrnapproach open evaporative cooling tower. The model is used to carry out a series of sensitivity studies assessing thernperformance of the cooling tower subject to various weather and climatic boundary conditions.