Analysis And Anti-condensation Control Of Improved Chilled Radiant Panel Containing Thinner Air Layer

For some common chilled radiant panel(CRP) types, the chilled water brass directly contact with the metal plate, which easily lead to strip cold area and uneven temperature distribution on the CRP surface. In order to overcome this problem, a company developed a modular CRP containing air layer and solved the disadvantage of uneven temperature distribution on the CRP surface. However, due to the large thermal resistance of air, the air layer impeded the heat conduction and greatly reduced the cooling capability of CRP.The classification of radiant cooling system and their advantages and disadvantages were discussed in this paper. The principles of radiant cooling was explained by means of thermal radiation and radiation heat conduction mechanism and the radiation and convection heat exchange calculation methods of CRP were researched.In order to improve the performance of chilled radiant panel(CRP) containing air layer, we firstly established a mathematical heat conduction model of CRP with air layer and evaluated its reliability. The deviation of model and experimental results about CRP cooling capacity and surface temperature was 9.20% and 4.00%, which indicated the model had high reliability. Then we change the contact form of CRP's chilled water brass and thermal plate by two ways and used the verified model to analyze the performance of the transformed CRPs. The results showed that two CRPs' cooling capacity increased 36.92W/m2 and 33.19 W/m2 when the air layer thickness was reduced to 1mm under the optimal parameters; the cooling capacity averagely increase 7.46W/m2 and 7.54 W/m2 as chilled water temperature decreased per 1? and indoor temperature increased per 1?; the CRP's surface maximum temperature difference is constant and have good anti-condensation.In addition, compared with common CRP types, we found that the cooling capability and anti-condensation ability of improved CRP containing thinner air layer was better on their respective optimal operating parameters. In conclusion, CRP containing thinner layer has better performance on the cooling and anti-condensation, and it should be widely used.The essence of surface condensation was analyzed in this paper and the conditions of CRP surface condensation that need to be satisfied were got. The function between the average chilled water temperature, indoor temperature and CRP surface temperature was fitted according to calculated data in this paper, then presented three control strategies to prevent condensation on CRP surface and analyzed their strengths and weaknesses.