ANALYSIS AND EXPERIMENTAL-VERIFICATION OF AN IMPROVED COOLING RADIATOR

Roof ponds cooled by nocturnal long wave radiation have often been pro posed as a cheap and effective means of providing thermal comfort in b uildings in hot-arid locations Many of the schemes incorporate flat-pl ate radiators through which the water is circulated at night to be coo led This paper analyzes the parameters affecting the performance of su ch a radiator, specifically designed for nocturnal radiative cooling A cheap, simple and flexible design for a cooling radiator was suggeste d as a result of the analysis, and tested at the experimental faciliti es of the Center for Desert Architecture at Sede-Boqer, Israel. The me an nightly cooling output of the radiator - due to the combined effect of radiation and convection - was over 90 watts/m(2) under typical de sert meteorological conditions. The analytical model adapted for this application allows accurate calculation of the fluid temperature at th e outlet of the radiator, as a function of the properties of the radia tor, the meteorological conditions and the operating parameters of the cooling system. (C) 1998 Published by Elsevier Science Ltd. All right s reserved.