Performance Simulation Research And Optimization Of Solar Ground Source Heat Pump Composite Heating System

With the sustained rapid growth of the national economy in recent years,the demand for energy is increasing.In the current energy structure of China,fossil energy still plays an important role.In order to reduce the impact of fossil energy pollutants on the ecosystem,the technology development and use of Green energy has been a new research hotspot in the energy field.Solar energy reserves are abundant and pollution-free,but at the same time it has the disadvantages of intermittent and instability.In order to complement each other,this paper combines solar energy and geothermal energy and proposes a solar-ground source heat pump coupled system with two water tanks for building heating.The system can maximize the use of solar heating through the adjustment of the operation mode,increase the solar energy utilization share and the system energy efficiency ratio,and reduce the system energy consumption while meeting the heating demand.In the article,the mathematical model of each component in the system is first established,and the operation mechanism of each component is explained.For building dynamic load simulation the building load simulation model is built.In order to explore the performance of the solar-ground source heat pump coupled system in building heating,based on the TRNSYS platform,an instantaneous simulation model of the system is established.The model uses a building in Qingdao as the heating object.The main research contents and conclusions are as follows:1.According to the difference of solar radiation intensity,the dual-tank solar-ground source heat pump coupled system has three operating modes:solar heating,ground-source heat pump heating,and combined solar-ground source heat pump heating.Through the overall performance analysis of the system and typical daily performance analysis,it can be seen that under the initial conditions,In the heating season,the total heat collection of the solar collector is 5180.3k W·h,the total operating time of the collector is 747h,the solar energy guarantee rate is 35%,the total energy consumption of the system is 2538.6k W·h,and the system energy efficiency ratio is as high as 5.9.The maximum instantaneous heat collection efficiency of the solar collector is 53.3%.Compared with the single-tank system,the dual-tank solar-ground source heat pump coupled system has about 8%higher heat collection and relatively lower system power consumption.When the system is running for ten years,the average soil temperature in the first and tenth years is 10.44?and 10.12?,respectively.The average soil temperature in ten years changes little,and the problem of soil cold accumulation is negligible.2.The effect of the area of the solar collector,the volume of the water tank corresponding to the unit area of the collector,the inclination angle of the solar collector,and the flow rate on the system performance are explored.The simulation results show that the larger the collector area,the better the performance indicators of the system.When the area is 58m²,the energy efficiency ratio of the system is as high as 7.8 in the heating season,and the solar energy guarantee rate is 52.0%;when the volume of the water tank corresponding to the unit area of the collector is 70L/m²,the total energy consumption of the system is the lowest;when the inclination angle of the solar collector is 52.5°,the solar radiation is the largest;when the flow rate is 900kg/h,the total energy consumption of the system reaches the minimum.When the start-up temperature difference of the unit increases,the power consumption and total power consumption of the unit decrease,and the total heat supply is basically unchanged.3.The dual-tank solar-ground source heat pump coupled system is compared with single-tank solar-ground source heat pump system,the air source heat pump system,gas boiler system and electric heating system,and analyzed from the following three sides:economy benefit,energy saving benefit and environmental protection benefit.The results show that the dual-tank solar-ground source heat pump coupled system has the best economic benefits and the least annual energy consumption,while the gas boiler system has the best environmental benefits with less pollutant emissions.The annual cost of the coupled system is 2853.6 RMB,the annual power consumption is equivalent to 674.40kg of standard coal,and the annual CO₂,SO₂,and soot emissions are 1659.01kg,13.49kg and 6.744kg,respectively.