Design Optimization Of Geothermal Heat Exchanger In Hybrid Ground-source Heat Pump Systems

With the development of economy and the increase of people's consciousness of environmental protection, more and more attention has been paid to reducing the energy consumption and pollution of heating and air conditioning in buildings. The Ground-Source Heat Pump systems, as an energy conservation and environment friendly technology, get more and more attention of people.The thesis gives detailed analysis and discussion on the real style design of geothermal heat exchangers by theoretical load computation.First, the accurate building load consumption is the foundation of the GHE designing. This thesis introduces methods of the building load computation and the software that using computer technology to simulate. To get the load that put into GHE, we cumulate sum the hourly building load by the software "GeoStar".Second, this thesis analyses the different kinds of factors which affect heating of geothermal heat exchangers by comparing their styles of arrangement.Third, an economic and technical analysis model of the geothermal heat exchangers is built up based on the value engineering. Independently on two conditions of the ideal design, the faxed borehole quantities and the thesis has computed value coefficients of the four buried pipe styles, and pointed out that the value coefficients of the single U-tube is decreasing with the drilling cost increasing, and on the contrary to the double U-tube configurations. Drilling cost and circulating cost are two important factors influencing the value coefficients. Usually the double U-tube is suitable for those districts where the drilling cost is high, or installation ground is limited. The value coefficients of U-tube pipe styles are linked with the bore design depth. Hastily ascertained borehole depth influences the economics and technology. Owing to smaller borehole design length and lower circulating cost, double De25, U-tube pipe style has the highest value coefficient, and is the best scheme; on the contrast, single De25 U-bend pipe style has the lowest value coefficient, and is the worst scheme.The essay also discusses and analyzes the period from calculation to construction drawing of practical projects, by which illustrates the feasiblity of the application of the due U25 pipe in actual engineerings.