Research On The Control Strategy Of Ground Source Heat Pump System Based On Building Load

As a new energy-saving emiSion reduction technology,ground source heat pump system technology has become an emerging technology developed rapidly in our country.However,this technology is not perfect in the research of building load and operation control.It is of great significance to study which parameters of equipment to operate to make the best operation performance under different load conditions.This paper is the ground source heat pump system(GSHP system)of Hebei University of Technology in Tianjin as the research object.By analyzing the operation data of the actual ground source heat pump system from 2012 to 2017,it is found that the system heat release is about 27%higher than the heat absorption,and the temperature of soil increased year by year,which increases by 3.12?in five years,COP_H and COP_S generally showed an upward trend but declined in 2014 with a full-year COP_H of 3.88 and a COP_S of 3.41.The operation characteristics of the system under different stages and different parameters are studied.The average unit load rate in 2014 was 51%and the average unit set temperature was 8.05?,all lower than the other years,which was the reason of lower COP_H and COP_S.The simulation model of GSHP system is established using TRNSYS software,according to the experimental data set and control the modules contained in the model.The simulation results obtained under the same initial conditions compared with the experimental results,by the daily and monthly two ways to improve the model and verification,finally the deviation of results between the model simulation and experimental data is le_S than 9%.Using the simulation model,the long-term simulated prediction of the normal mode carried out firstly.The soil temperature increases year by year and the COPs value increases year by year.It is more suitable for the system to operate at the end of the heating season with the soil temperature around 16?.Secondly,the operational strategies of GSHP system during low load period are optimized respectively from the operating parameters and buried pipe partitioning,and it is simulated for 20 years.The results show that compared with the normal mode,the annual COP_S of the system increased by 1.66%under the control strategy of preferred operating parameters,and increased by 4.99%under the control strategy of optimal buried pipe.The operating parameters and buried pipe partition two control strategies combine to determine the GSHP system optimal operation control strategy.After 20years of simulated operation,the annual COP_S is 3.82,which is increased by 4.09%compared with the control strategy of purely preferred operating parameters,which is increased by 0.79%compared with the simple and preferable control strategy of buried pipe division.