The Influence Factor Research On Radiant Floor Cooling System

This paper takes the floor radiant cooling air conditioning system as the research object,using the software of TRNSYS to some energy consumption simulation by means of one energy-saving demonstration building’s air conditioning system as experiment table.Combining with the experiment and simulation,it analyzes indoor environment condition and floor cooling load.This paper introduces physical and mathematical models for heat transfer of radiant floor,providing theoretical basis to solve heat transfer process.Change of retaining structure impacts indoor environment condition and floor cooling load besides main factors of radiant floor itself such as tube spacing,diameter,supply and return water temperature,supply velocity,covering material.so it has some research value.For a single floor radiant cooling system,radiant floor is influenced solar radiation and thermal transfer by differ temperature.The average temperature of indoor and floor surface,cooling load get larger with the increase of window-wall ratio in the same orientation and in the same window-wall ratio those parameters are largest when the building faces west.Building energy consumption also has the above characteristics.Relative humidity ranges between 65% and 85% by simulating and floor surface is easy to dew.Practical radiant floor air-conditioning engineering does not get one and lose another.Considering supply,consume and condensation comprehensively,the designer chose right building orientation and window-wall ratio,take Sun-shaded measures in the west building.Compared with a single floor radiant cooling system,displacement ventilation and floor radiant cooling system has a small possibility of condensation and a good comfort.The indoor temperature ranges between23℃and 29℃,relative humidity ranges between 50% and 70% in composite system.But indoor temperature and relative humidity are high.For example the indoor temperature is above 30℃easily while window-wall ratio is 0.7 with building facing west.In displacement ventilation and floor radiant cooling system : floor cooling load getslarge with increasing of window-wall ratio but smaller than the single system in the case of large temperature gradient.Because of enough ventilation,it deal with the change of indoor load timely,which demonstrates heat inertia of radiant floor.Decreasing supply temperature makes floor cooling load and relative humidity increase.It needs reduce supply temperature appropriately to avoid condensation.The indoor temperature data of fifth floor were stored up in the real-time monitor.Through the analysis of a large number of experimental data,the indoor temperature distribution are obtained.Under the condition of radiant cooling combining with displacement ventilation,the phenomenon of indoor temperature stratification is extremely significant.This conclusion has a great help to research the trend of room temperature change in vertical direction by further analysis.In the actual project,east and west orientation has a smaller window-wall ratio than south and north orientation.The measuring data of different orientations explains that building is seriously influenced by western sun.The deviation is about 5% for simulation results and practical measured data,which prove reliability of simulation results.