Performance of a dry cooling and dedicated ventilation system under different operating conditions

Effectiveness of dry cooling and dedicated ventilation (DCDV) system for decoupling dehumidification from cooling to achieve the desired indoor condition and condensate-free objectives for air-conditioning of office environments in Hong Kong has been confirmed in previous simulation and experimental studies by the authors. However, our previous studies assumed a constant outdoor air and chilled water flow rates, and this is not always the case in practice. Whether this assumption could affect the effectiveness of DCDV system is the subject of present investigation. A prototype that could enable the variation of outdoor air and chilled water flow rates, as well as indoor and outdoor conditions, was set up for laboratory experiments. Our results have illustrated the effectiveness of DCDV system in achieving the intended condensate-free objective which was most affected by the space-sensible heat ratio and chilled water flow rate. Little influence was found to be introduced by the outdoor air flow rate and outdoor air conditions. The results, through sensitivity and statistical analysis, were found consistent with results of our previous studies.