Study On Basic Theory Of Designing And Running Control Of Imbed Pipe Floor Heating

The compact algorithms for heat release from floor, indoor thermal environment, control characteristic and energy efficiency of room with imbed pipe floor heating system were studied in this dissertation.The heat release from floor is key nodes in designing of imbed pipe floor heating systems. The existing plate fine model is corrected to improving its accuracy by amending the temperature of fine root. Provided the formulae of equivalent heat resistance for heated floor that imbed pipe basing on shape factor. Then, a much handy algorithm was developed firstly for heat release from heated floor. These errors of result of new algorithms with numerical simulation are within 10%. and also meet experiment result well. The heat release from floor thought radiation is validatedabout 70% by analyzing the surface coefficient of heat transfer with convection and radiation.The process of indoor air turbulent flow and heating transfer were analyzed in the typical closed room with floor heating room and radiator heating room respectively. The low Re k-model in software PHOENICS3.3 were applied to simulating indoor air temperature field in this two kinds of heating room contrastively. It shown that temperature gradient at human altitude in floor heating room is lower 3 ~4 C than radiator heating room, temperature adjacent out wall and out window near by radiator is higher 6~7 C than mean indoor temperature, temperature different of room top with mean indoor temperature in top floor radiator heating room is higher 1 ~2 C and thickness is 0.3~0.5m thicker than floor heating room.Set up a mathematical model for indoor thermal environment on the base of analyzing enclosure heat gain and heat loss of each envelope. Programs were developed for floor heating and radiator heating respectively. Due on higher surface temperature (or MRT) in the same room, the calculation results shown the indoor mean air temperature of heating radiator room was 1 ~ 1.3 C higher than floor heating room under operative temperature same .Compared the heating load (and energy consumption) of a same room with floor heating orradiator heating under same operative temperature. Revealed the energy consumption of floor heating room could reduce 5%~10% to radiator heating, and the heating load could reduce 10%~15%. The main season of energy efficiency is due to no apparent high temperature zone in floor heating room, which avoid additional heat loss in outside envelopes, rather than the lower of indoor air temperature.The thermal process model of imbed pipe floor heating room at intermittent operation was set up by analyzing the thermal storage of enclosure. Then, a solution method was give for it basing on Duhamel theorem. The calculation results shown a good indoor thermal environment can be hold when the system, which designed on out door temperature for heating basis, operates half day in night under outer door mean temperature in winter.