Simulation Study On Operation Performance Of Floor Radiant Cooling System Supplied Directly By Soil Cold Source

The theory and application of traditional ground source heat pump(GSHP) has been very mature, and GSHP obtains the fast development in china. Based on the traditional GSHP, a new method on the application of GSHP is put forward in this paper, that is, under the condition of meeting the demand of humidity or in transition season, close the chiller unit, and the cooling capacity from soil is supplied into indoor by U type buried tube heat exchanger. Also the room will be cooled by the radiation of floor.In this paper, based on the model of two-dimensional finite line source in the theory of heat transfer of buried pipe, establish the unsteady mathematical model double U type buried tube heat exchanger, and disperse the mathematical equations. In order to solve the equations steadily, the implicit difference method is used. Aiming at radiant cooling of floor in the room, establish the whole unsteady mathematical model which considers the influence of outdoor weather conditions, and also the implicit difference method is used to calculate. The mathematical models above are solved by the Visual Basic 6.0. Through the actual measurement of a practical project in Tianjin, then the models are verified.Simulation study on the performance floor radiant cooling system of soil cold source has been conducted, including establish the indexes of cooling capacity of direct cooling system and the pump model. The influence of buried pipe water flow, soil average temperature and the depth of buried pipe on cooling quantities intake in single well and the influence of soil average temperature on the cooling seasonal performance factor are also studied. Then study on the change of soil temperature with time in the mode of direct cooling and using chiller unit. And study on the affecting factors of floor average surface temperature in the room selected, study the influence of average temperature of floor surface to human thermal comfort in the room, the effect to the number of free cooling hours. And then, the energy consumption under the model of direct cooling and opening the chiller unit is simulated. The results indicate that the direct cooling model can save energy of 54% compared with the model of opening the chiller unit. This study can provide some reference and guidance for the study on operation performance and strategy of floor radiant cooling system in the direct cooling model of soil cold source.