Study On The Technology Of Radiant Floor Cooling System In Daqing Area Residence

The technology of low temperature hot water floor radiation heating has been paid more attention,and has got a large area of application in buildings. Relatively speaking, the radiant floor cooling technology is developing more slowly due to the the condensation problem.Daqing area is located in cold regions of northern China.Because of the low outdoor air temperature,the heating period is longer.And the dry summer climate and the low relative humidity makes the water vapor dew point temperature is high in Daqing.The climate is conducive to the realization of summer cooling by using the radiant floor heating system for cold winter.The main research work and achievements:(1)This paper analyzes the heat transfer process of the floor radiant cooling/heating system,and gives the calculation formula of heat transfer of floor radiant heating and cooling conditions.With the winter and summer’s climate characteristics in Daqing area,from the floor radiant cooling capacity, thermal comfort, and economy, it demonstrates that applying the floor radiant cooling is feasible in Daqing area residential buildings.(2)It studies how the difference supply and return water temperature,coil spacing and floor materials influence the temperature on the surface of the floor by using Fluent. Results show that:①As the the temperature of supply water dropping,the floor surface temperature also decreased significantly.Under the simulated conditions,there is no condensation if the supply and return water temperature is higher than 17℃.②Compared with wood floors,ceramic tile floor is not only beneficial to reduce the thermal resistance and increase cooling capacity, at the same time it can avoid the damage that the condensation to the wooden floor.(3)Choosing a room in a residential district of Daqing as the research object, the application CFD software Fluent in this paper simulate the floor radiant cooling system of indoor temperature field and velocity field. The results show that:①The indoor air velocity is less than 0.25m/s,so it meets the requirements of comfort.②The greater the distance from the surface of the floor, the more uneven temperature distribution.When the outdoor temperature is 31℃, the indoor temperature of work area is 25℃, temperature distribution is very uniform.(4)It determines the influence of 4 factors on the floor surface temperature and temperature uniformity and 3 levels,according to the basic principle of orthogonal experiment,it analyses the average temperature of supply and return water, indoor temperature,coil spacing and filling layer thickness on the floor surface temperature and temperature uniformity, the radiant floor cooling parameters were optimized.(5)This paper studies the energy consumption evaluation method of the floor radiant cooling/heating system,and also puts forward a new evaluation index "cooling/heatingcoefficient per exergy consumption ε".The result shows,the ε of the floor radiant cooling system increases by 133% than that of the fan coil system in summer,and the ε of the floor radiant heating system increases by 41% than that of the radiator system in winter.