• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.288-296
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• 2019

Radiation cooling has used ceilings or floors as cooling surfaces. In such cases, to avoid moisture condensation on the surface, the surface temperature needs be higher than the dew point temperature or an additional dehumidifier is added. In this study, with a goal for residential application, intentional moisture condensation on the cooling surface was attempted, which increased the cooling capacity and improved the indoor comfortness. This method included two separate refrigeration cycles - convection-type dehumidifying cycle and the panel cooling cycle. Test results on the panel cooling cycle showed that, at the standard outdoor ($35^{\circ}C/24^{\circ}C$) and indoor ($27^{\circ}C/19.5^{\circ}C$) condition, the refrigerant flow rate was 8.8 kg/h, condensation temperature was $51^{\circ}C$, evaporation temperature was $8.8^{\circ}C$, cooling capacity was 376 W and COP was 1.75. Furthermore, the panel temperature was uniform within $1^{\circ}C$ (between $13^{\circ}C$ and $14^{\circ}C$). As the relative humidity decreased, the cooling capacity decreased. However, the power consumption remained approximately constant. In the convection-type dehumidification cycle, the refrigerant flow rate was 21.1 kg/h, condensation temperature was $61^{\circ}C$, evaporation temperature was $5.0^{\circ}C$, cooling capacity was 949 W and COP was 2.11 at the standard air condition. When both the radiation panel cooling and the dehumidification cycle operated simultaneously, the cooling capacity of the radiation panel cycle was 333 W and that of the dehumidification cycle was 894 W, and the COP was 1.89. As the fan flow rate decreased, both the cooling capacity of the radiation panel and the dehumidification cycle decreased, with that of the dehumidification cycle decreasing at a higher rate. Finally, a possible control logic depending on the change of the cooling load was proposed based on the results of the present study.