Analysis of a low temperature small approach open cooling tower integrated with radiant cooling and displacement ventilation for space conditioning in temperate climates

چکیده مقاله

Evaporative cooling, using cooling tower systems, has the potential to offer an alternative approach for producing high temperature chilled water, particularly for buildings located in temperate climates, when used in conjunction with cooling technologies such as radiant cooling and displacement ventilation. The current paper examines the performance of an integrated cooling system, where an open forced draught counter flow cooling tower is used for the provision of chilled water for a radiant cooling and displacement ventilation system for the space conditioning of an office building. For this purpose, a low temperature low approach direct evaporative cooling tower has been used which can provide cooling water with low approach temperatures (1-3 K), which represent the temperature difference of tower water outlet temperature and ambient wet bulb temperature is between 1 to 3 K. The performance of the proposed cooling system has been investigated for internal buildings loads up to 66 W•m-2 in order to examine the limitations of the cooling system. Space thermal comfort conditions and system performance metrics were assessed for four different temperate climate types as follows: cool and dry (Helsinki), cool and semi-humid (Birmingham), warm and dry (Prague) and, warm and humid (Paris). The assessment shows that for the proposed system, where a radiant floor was used, can provide acceptable thermal comfort conditions ranging from 83.7% in Helsinki to 76.2% in Birmingham, 81.4% in Prague and 84.5% in Paris, based on the occupant hours over the respective cooling seasons. On the other hand, it can be observed that the proposed system, where a radiant ceiling was used, can provide acceptable thermal comfort conditions ranging from 67.0% in Helsinki to 77.6% in Birmingham, 77.6% in Prague and 80.5% in Paris.