Study On Adjustment Strategies And Heating Characteristics Of Different Heating Terminal Units In Hot-summer And Cold-winter Region

Hot summer and cold winter region in China is hot and muggy in summer, cold andwet in winter, and has small diurnal temperature range, heavy annual precipitation andless sunshine. It is nearly the clodest area compared with other regions with the samelatitudes in the world. Nevertheless, this region was not planned with building heatingsystem before. But, as the people’s living standard improving, the residents of theregion have begun to improve the indoor thermal condition by many ways, and as aresult, a trend of directly electrical heating has formed. Thus, the energy consumptiongrows rapidly subjecting to efficiency of electric heating and thermal performance ofthe building envelop. From the perspective of energy consumption, the choice ofenergy-saving and comfortable heating mode must be based on the living habits andcharacteristics of buildings, and the regulation strategies of different heating modeshould be studied combined with the climate feature of the region, which makesheating system operate more energy-efficient.Zone radiant heating floor and fan coil unit were chosen as study objectives andmathematical model as well as indoor heat balance model of heat transfer was builtrespectively. Based on these two models, the influence factors of indoor comfort wereanalyzed and the relation between mean radiant temperature and heat transfercharacteristic of human bodys were obtained.By the actual field measurement of the indoor thermal environment, indoor comfort,and heat transfer characteristics under two kinds of the mentioned terminal units, the conclusion was obtained that the homogeneousness of indoor temperature of zoneradiant heating floor system is better than that of fan coil unit and that when heatingsystem was closed, radiant heating floor system enjoyed relatively lower temperaturefluctuation. Then EnergyPlus software was adopted to simulate the indoor thermalenvironment and energy consumption of the two terminal units, and by the simulation,when Ⅱlevel standard of thermal comfort was used (-1≤PMV＜-0.5), the indoordesign temperature for radiant heating system should be controlled in the range of17℃~19℃and the ration of convection and radiation of human body was36.2%and37.1%, respectively; while the mentioned range and ratio of fan coil units were19.4℃~22℃,30%and44.4%respectiovely. Under the same value of PMV, the energyconservation ratio of floor radiation heating system was related with ventilation rateand the thermal attributes of building insulation structure. The energy conservationration was3.8%,5.6%,7.2%respectively when the ventilation rate was controlled as0.5,1and1.5times hourly. Besides, the energy conservation rate increased as theimprovement of thermal attributes of buildings.Moreover, the heating load distribution characteristic of residential buildings in thisregion was also analyzed. As a reault, different adjustment strategies including thesetting of supplying water temperature of heat pump system based on the change ofoutdoor air temperature and the intermittent operation time schedule of radiationsystem. By calculation, intermittent operation could save energy as much as27.3%,whereas the adjustment of water supplying temperature could10.6%. For fan coil unit,adjustment of water supplying temperature could save energy as much as14.8%.