The purpose of this study is to realize a non-condensing environment by developing a new type of desiccant air-conditioning system with higher energy efficiency. In this paper, the overall energy efficiency and IAQ of new type of desiccant outdoor air-conditioning systems combined with CO_2 heat pump are compared with those of the conventional outdoor air-conditioning systems, by simulation at typical hotel rooms over summer period. The results show that system COP of conventional non-condensing system inside the indoor cooling units is very poor against one of conventional condensing system. But system COP of the proposed systems is shown considerably higher than those of the conventional outdoor air-conditioning systems, although non-condensing environment and higher level of IAQ is achieved by the proposed systems. System COP of double rotor type desiccant air conditioning system combined with CO_2 heat pump is shown slightly higher than one of single rotor type desiccant air conditioning system combined with CO_2 heat pump. Heat recovery by sensitive heat 〓xchange rotor on double rotor type is shown higher than low efficiency of CO2 heat pump by higher cooling air temperature brought by sensible heat exchange rotor. But the results also show much of cooling output by CO_2 heat pump are used for cooling exhaust air from desiccant regeneration air. More cooling supply air by cooling output by CO_2 heat pump is expected to bring higher system COP, by making lower enthalpy of supply air directly. Value of electric power input to proposal system is shown one half and removed heat energy from air is shown double against those of the conventional condensing outdoor air-conditioning systems. To make Non-Condensing system become popular and overcome the conventional condensing outdoor air-conditioning systems, higher system efficiency is required. On this study, proposal new type of desiccant outdoor air-conditioner combined with CO_2 heat pump is specified to the best efficiency of itself. But other systems should be studied, to achieve best system efficiency including chilling unit for fan coil unit, by use of more cooling output from CO_2 heat pump for lower enthalpy of supply air.
|Translated title of the contribution||Study on Non-Condensing Air-Conditioning System for Next Generation : Part 4-Study and Comparison in Adapting the CO_2 Heat Pump Combined System for Outdoor Air Conditioning System at whole Summer period by Simulation|
|Publication status||Published - 2009 May|
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