Experimental Study On Thermal Comfort In A Local Sleeping Space With Capillary Radiant Air Conditioning System

The Personal Comfort System(PCS)only adjusts the thermal comfort for the occupied zone where the human body is located,and relaxes the control requirements for the ambient temperature of the non-occupied zone.It can not only meet the different thermal comfort needs of different people,but also reduce the temperature difference between the inside and outside of the room to reduce energy loss.The research and application of PCS are usually concentrated in the office environment,but recent studies have found that it is more suitable for sleeping environments than office environments.The capillary radiation air conditioning system can improve the uniformity of temperature distribution in the conditioned zone,and avoid the draft problem and conserve energy.It has the potential to adjust the thermal comfort of human body in sleeping environment combined with PCS.However,there are few specific studies on its thermal performance so far.In this thesis,a Radiation-based Personal Comfort System(R-PCS)has been developed.The performance of the system equipped in the sleeping environment has been evaluated through experimental methods.The Predicted Mean Vote(PMV)and the Predicted Percentage Dissatisfied(PPD)have been used to analyze the performance of R-PCS.In addition,the influence of different operating parameters and the environmental parameters on the system performance has been obtained.And the energy-saving potential of R-PCS has also been analyzed in this thesis.The research results show that:(1)The effect of the supply water temperature on the surface temperature of the radiation panel is greater than that of the water flow rate in the capillary tubes.The risk of condensation on the surface of the radiation panel will be encountered if the temperature of supply water is too low.(2)The mean radiation temperature(MRT)in the occupied zone is greatly affected by both the supply water temperature and the temperature of the non-occupied zone while the latter has a greater influence on MRT.(3)The control requirements for the temperature of the non-occupied zone can be relaxed when using R-PCS to adjust the thermal comfort of the human body in the occupied zone.For example,when the supply water temperature is 36 ℃ and the nonoccupied zone temperature was 17.5 ℃,the PMV of the occupied zone can be raised to-0.7 within one hour,which can meet the needs of most people.This helps reduce the temperature difference between the interior and exterior of the room and then reduce energy loss of internal zone.(4)In heating mode,even the highest supply water temperature,i.e.,36 ℃,is lower than that of the conventional HVAC system,which is usually higher than 40 ℃.In cooling mode,even the lowest supply water temperature,i.e.,14 ℃,is higher than that of the conventional HVAC system,which is usually around 7 ℃.This will helps to improve the efficiency to the cold/heat source equipment.