Heat Transfer Performance And Thermoeconomic Analysis For Ground Source Heat Pump System

Ground source heat pump (GSHP) is more and more attention-getting in theworld as a technique of energy saving and environment protection. Most scholars whoare studying the application of the GSHP are focusing on local performance ofthermodynamics and heat transfer at present. Some dynamic performance and potentialof energy saving of GSHP are also development in China. The development of thestudy of GSHP is now still at the beginning with lacking basic operating data andexperience of design and running. As GSHP system usually needs more initial cost thanair source water cooling heat pump system, its economic performance can bediscounted due to unreasonable design or inconsequent matching which will result inmore running cost. So it is very significant to study the economic performance in theapplication of GSHP. A method which is used in thermoeconomics is presented here toimprove the thermal and economic performance dialectically.According to a GSHP system in an office building, a mathematical model isestablished. Theoretical and experimental investigations are carried on the base of themathematical model and experimental data. The character and law in the operation ofthe two seasons of winter and summer, the heat transfer and operational performanceare carried out. Exergy analysis is also presented on the base of the former researchwhich leads to the direction and methods of energy saving. It is also the base ofthermoeconomic analysis. It is the first time that thermoeconomic method is used in the study of GSHPsystem. Costing of exergy consumption and loses, algebraic methods of exergycosting and autonomous methods of exergy costing are presented to analysis the GSHP.The result is used in the local and whole optimization in which cost par value,earning yield etc are used to discover the internal connections between thermal andeconomic performance.The result of investigation indicated that it's strongly necessary to enhance theoutside heat transfer of the downhole heat exchanger and make all parts matched well.Heat transfer enhancement of the outside of the downhole heat exchanger is veryimportant to the decrease of the initial and running cost, especially in the conditions ofair conditioning. The result also proved that increase of the local exergy efficiencywill not necessarily improve the economic performance of the GSHP system.Optimization should be considered according to the whole system to make economicand thermal performance matched well. It is also further pointed out the key anddirection for enabling the GSHP system by means of study of the performance andenergy saving.