Study On Hybrid Ground Source Heat Pump System For Medical Buildings In Chongqing

In the context of the growing demand for energy in the current society,the technology of green energy efficiency is getting more and more attention.Ground source heat pump technology is a kind of renewable energy application in the field of building's cooling,heating.And it has been the key to future industry in China to promote the technology,one of the great application potential.However,the energy consumption of China's medical and health industry is huge,and the use of renewable energy technology can effectively reduce the carbon emission caused by building operation.Exchanger in order to further explore the energy conserving potential of the ground source heat pump technology,make run efficiently in the medical building,medical building in chongqing area,the author of this paper application of buried pipe research on the problems of ground source heat pump system,mainly by using the method of numerical simulation,this study analysis the load characteristics of the medical building,ground heat exchanger to optimize the design of composite ground source heat pump and cooling tower control strategy and so on.Firstly,this paper analyzes the study of medical architecture used in architectural space,architectural time use,the characteristics of the hvac system,and the building of a hospital in chongqing as a typical architecture,using DeST software chongqing regional medical building energy consumption model and calculating dynamic load throughout the year.By analyzing the distribution of natural room temperature,the cooling period of medical buildings in chongqing is determined from June 1st to September 30 th,and the heating season is December 1st to March 10 th.On the basis of considering the nonguarantee rate,the cooling and heating load of the building is determined to be 2056.91 kW and 4484.34 kW respectively.The analysis finds that the medical buildings have the characteristics of the new wind load,the ratio of the load index of each department,the difference between the winter and summer,the characteristics of air conditioning load in the office area and the common office buildings.And from the working characteristic of the ground source heat pump exchanger perspective,analysis and study the construction of dynamic load characteristic,found the exchanger of ground source heat pump system is relatively bad,you need to set up auxiliary cooling measures and improve the operation control mode to improve system efficiency.Secondly,through the constant heat flux method on-site geotechnical thermal response test,according to the data obtained,using the "thermal resistance layering method" 0 ~ 106 m soil can be divided into 6 thermal resistance layer,using CFD software to establish the four different forms of buried pipes layered heat exchanger model,and the validation of the model,found that whole process simulation and measured data of the relative error within the plus or minus 5%,the average error is 2.6%,reliability model is higher and have the conditions of use.Based on the design method of compound ground source heat pump engineering,the paper analyzes the factors affecting the heat transfer of buried pipe,and summarizes the existing problems of the design method.Using Kelvin line heat source theory,focuses on optimization of buried tube of heat exchanger nest of tubes in the scheme design of borehole spacing,the buried pipe buried pipe form,and from heat transfer temperature difference,the total flow and the total heat transfer point of view,selection and optimization of ground heat exchanger design parameters of the heat pump units,using economic methods,finally it is concluded that the engineering design of winter summer best.Finally,detailed analysis of the existing cooling tower composite ground source heat pump exchanger operation control strategy,which is more commonly used include load control,constant temperature control,temperature control and time control method,found the main disadvantages of the existing control method and the insufficiency.Based on this,advances the cooling tower composite ground source heat pump system based on load forecasting control strategy,the strategy mainly includes the load forecasting,cooling tower water temperature prediction,several basic modules.The analysis summarizes the research status of construction load forecasting,and finds that the current load forecasting can meet the control demand.The cooling tower heat transfer model was established by using Merkel's enthalpy equilibrium method,and the calculation formula of the temperature of the outlet water of the cooling tower was obtained.Finally by using FLUENT software,simulation respectively under typical week time control,temperature control,and the new control method of buried pipe heat exchanger,and computing system energy consumption through the cold and heat source system model,it is concluded that the new control method has advantages on energy efficiency.