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Direct cooling of buildings by water evaporation has traditionally been seen as appropriate, only, in dry and arid climates, which experience high levels of wet bulb temperature depression. The technique has generally not been applied in maritime climates where low levels of wet bulb temperature depression are frequently found. However, recent developments in enhancing heat and mass transfer in cooling towers, together with the success of high temperature sensible cooling systems, such as chilled ceiling panels and beams, have prompted a review of the evaporative cooling technique as an effective and low energy means of cooling modern deep plan buildings, in maritime climates. At present, however, there is little in depth research and analysis of the performance, energy efficiency, and availability of this form of cooling in maritime conditions. To address these issues an experimental research programme has been established with a view to demonstrating the potential and optimising the design of this form of cooling under low approach conditions. This paper presents the results of recent experimental research into the electrical consumption of a prototype inverter controlled cooling tower when generating cooling water at the chilled water temperatures required for chilled ceiling panels and beams, under varying load and wet bulb temperature approach conditions. Energy consumption efficiencies are presented for a range of specific conditions and typical annual efficiencies are computed. Results are compared with typical energy consumption efficiencies of conventional, vapour compression based, cooling systems. A considerable potential for the reduction of cooling electrical energy consumption, in maritime climates, is shown.
Costelloe, B. & Finn, D. (2001). Energy reduction by enhanced evaporative cooling of buildings in maritime climates. REMIC: Renewable Energy in Maritime and Island Climates/i>, Belfast, 10-11 September.