| In this paper,Hebei University of Technology Center for energy-saving solar-ground heat pump system experimental platform for the study.,the platform has two heat pump units: large unit(HP1),small unit(HP2);two underground pipe group:Big buried tube group(GHE1),small buried tube group(GHE2).In actual use,according to the connection between two ground source heat pumps and two buried pipe groups,the platform can realize two kinds of system operation in the heating season,one is that two units are respectively connected with two pipe groups Operating system,referred to as the dual unit independently buried tube group solar-ground source heat pump system(System 1),the system used in 2012-2015;the second is the large unit with two underground pipe group connected operation system,referred to It is solar ground source heat pump with single unit and double burried pipe groups(System 2),which is to be used in 2016.By analyzing the operating data,it is found that the HP1 heat pump cycle COP is about 3.25 and the HP2 heat pump cycle COP is 2.99 during system 1 operation.Therefore,after system 2 operation is adjusted in 2016,system 2 is in operation during the heating season,The load factor reached 74.02%,an increase of 10% over the system 1 operation in 2015.The total heat pump cycle COP of system 2 was 7% higher than that of system 1.In view of the energy efficiency of system 2 in operation,this paper further studies its operation mode and operation strategy.Two operating modes are proposed for system 2: solar heating system coupling of double buried pipe group and solar heat storageing coupling double buried pipe group in turn.The system 2 was used to verify the mode in the experimental data in 2016.The simulation data(unit heating capacity,unit cooling capacity,ground source heat exchange,unit power consumption,circulating pump power consumption)and test data The maximum deviation is 14.1%,which satisfies the 15% deviation range required by the simulation study.The TRNSYS software was used to predict the two operating modes for a period of 20 years and found the best operating strategy for both operating modes.The results show that the optimal flow rate ratio of mode 1 pipe group is ? = 0.13.The best start time of mode 2 thermal storage is two hours earlier than the middle of the system running time and the best heat storage duration is 2-3 hours.The system average COP of system 2 operating in mode I and mode II for 20 years is 6.20% and 1.10% higher than that of system 1,respectively,while the thermal efficiency of two operating modes is very different from that of system 1.Explain the same or similar solar thermal storage utilization,different ways of solar thermal storage will still bring different operating results of the system operation.At the end of this paper,two operating modes of system 2 are analyzed from the aspects of initial investment and operating cost.It is concluded that the operating performance of mode one is better than that of mode two.The average power consumption of two years is 5300 yuan less than that of mode two 3.5% of the first model,but more additional investment costs,a comprehensive analysis of the two operating modes differ very little. |
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