Numerical Simulation Of Heat Transfer Of Vertical U-Tube And The Development Of Design Software

There is a real problem in ground-source heat pump (GSHP) applications both in the home or overseas, that is the initial fabricating cost of GSHP system is too expensive, mainly because of the cost of boring heat-transfer hole and paving U-type buried pipes will account for one third in total cost. So, it has been one restraining factor in the system development. The exact computation for ground temperature field and the GSHP system, and the reasonable design for ground heat exchangers are not only reducing cost of GSHP but also effectively strengthening stability of GSHP operating, which ensure the performance of air-conditioning system and the life-span of GSHP system.This paper provides four parts of researches as follow. At first, according to the conservation equations of momentum, energy and continuity, the physical and mathematical models of heat transfer were established for numerical simulation. At the same time, the models were verified the accuracy. Secondly, using fluent to calculate year-round intermittent operating conditions by the established models and analyzing the calculation results. Thirdly, by the most general analytical method in ground source heat pump (GSHP) system design, the soil can be divided into two groups, inside and outside the bore. With the principle of the cylindrical heat source model, G function and the concept of pulsating load, a data processing software was wrote using programming language as VB6.0, which is appropriate to process date both in winter and summer conditions and calculate daily load. Finally, according to the established mathematical model, using VB6.0 prepared for winter conditions and summer conditions in the calculation of design software. The margin of error was given out by comparing with the test data of actual project. At the same time, the practical outlet temperature of buried pipe under the circumstance of annual daily load was obtained based on the calculations of pre-existing projects in the situation of daily load.The fruit achieved in this dissertation have significance to guide the optimization design of GSHP and to impel the development of GSHP application. The researching contents of this paper are expected to make a contribution to the GSHP system design.