Study On Controlled Operation Of Ground Source Heat Pump-Radiant Floor Air-Conditioning System

The ground source heat pump (GSHP)&radiant floor (RF) air conditioningsystem were studied in this dissertation. The detail work consisted of: theoreticalresearching on the basic operation theory and the control characteristic, establishing thesystem mathematical model, putting forward the control strategy based on the systemheat-transfer characteristic, giving the convective and radiactive heat transfer coefficientof the building envelop, conducting experimental and model research for differentcontrol strategy. Mastery of the working theory and heat transfer characteristic of the GSHP-RF airconditioning system is the important premise for generating the control strategy. Aftersome comparison was taken from heat transfer theory, comfort, energy saving, matchingup with finish for the GSHP-RF system and the ASHP-FC system, the characteristics ofthe control were giving: predictability of the control, restriction from the GSHP,focusing on the indoor design parameters, paying close attention on distribution powerconsumption.The GSHP-RF system heat transfer mathematical model, which consisted of theRF model, the GSHP model, the unit model, was established by analysis of the heattransfer. The RF model was acquired from setting the air for study object, combiningthe radiation and convection formulas. The GSHP model was separated for two parts bythe drill hole, which were solved by the two-dimensional steady-state heat transfermodel and the one-dimensional Kelvin liner heat source model. The unit model wasreflected by the system energy balance, the system coefficient of performance (COP).A control strategy was put forward after analysis of application scope andinfluence factor for the air conditioning system, which was called the set indoor airtemperature variation range control strategy. The strategy set the indoor air temperaturevariation range in advance, and judged the operating state of the unit by comparing theactual indoor air temperature with the set one.Mastery of the convective and radiactive heat transfer coefficient of the buildingenvelop was significant, which helped a lot in both engineering application and modelcalculation. The coefficient was calculated in two terminal styles (SFRF and DFRF),two working conditions (heating and cooling), two phases (running and halt). Twomethods were taken in the calculation of radiant coefficient: the network diagram method and the simplified formula method. The natural convective coefficient table andthe floor radiactive heat transfer coefficient table were taken out finally.Some experimental research was carried out for the GSHP-RF system. Theanalysis of the results was made up with the heating capacity of the system, the heattransfer ability of ground heat exchanger, Soil temperature variation, the system energyconsumption and the indoor air temperature. The system COP in the indoor airtemperature variation range control is0.3higher than in the unit return watertemperature control; the heat transfer ability of ground heat exchanger in the formerstrategy is28%higher, reaches47.8W/m; the system energy consumption in the formeris18.3kW·h lower, which equals27%of the whole energy consumption in the laterstrategy.Analog computation was carried out by importing the specific building type,evaluating the parameters, setting different strategies for the GSHP-RF air conditioningsystem. The result showed the ability for simulation of the GSHP-RF system.52.7kW·helectricity is saved for the system energy consumption in the indoor air temperaturevariation range control strategy when compared with the unit return water temperaturecontrol strategy in the24hours period. The energy saving is remarkable.