| The rapid growth of industry and construction has coincided with a growing problem of global pollution caused by greenhouse gas emissions,and the depletion of fossil energy resources over the years.Human beings are urgently looking for clean energy that can replace primary energy.China has committed to the world of carbon emissions of 3060.To better achieve this goal,reducing primary energy consumption during building operations has become a current research focus.Solar energy refers to solar radiant energy,and geothermal energy refers to shallow geothermal energy.Solar energy,with its inexhaustible supply,can be used to heat and water inside buildings,but it is not stable enough.Geothermal energy is characterized by its stability,but long-term use tends to cause soil temperature imbalance.By combining the two forms of clean energy and supplementing the lack of heat provided by geothermal energy with the heat collected by solar energy,the system operation efficiency can be higher than that of a single energy source by making the advantages of the two complementary and disadvantages offset through reasonable operation mode design.In this paper,the annual cooling and heating performance of the solar-ground source heat pump coupling system in hot summer and cold winter areas is analyzed.Based on the influence of different system control strategies on the cooling and heating effect,the annual system control strategy is optimized.A 9-story residential building in Hefei was selected as the research object.TRNSYSbuild software was used for three-dimensional modeling.Typical meteorological data of Hefei obtained by Meteonorm software were used for weather data.The annual cold and heat load data of the building is obtained by load analysis of the running software,so as to establish the solar-ground source heat pump coupling system.On the TRNSYS simulation platform,the photovoltaic photothermal circulation system,the heat pump unit-buried pipe circulation loop system and the domestic hot water production system of the coupling system were constructed respectively.The three systems are connected together to form a solarground source heat pump coupling system.The model reliability is verified by comparing the operation data of similar projects in Hefei area.The selection of two parallel units was carried out based on the minimum temperature rise of soil running in the buried pipe of the coupling system in 20 years and the highest working COP of the heat pump unit.The selection and array layout of PV/T plates were carried out based on the highest comprehensive photoelectric photothermal efficiency when PV/T plates received solar radiation.Two heat pump units with a rated cooling capacity of55.6k W are connected in parallel.The circulation flow of the solar-ground source heat pump coupling system is set to 9000Kg/h,the photovoltaic module array is set to four 18 m×3 m arrays,and the number of U-shaped copper tube rows parallel to the photovoltaic module backplane is set to 12 rows.In the model,three utilization modes of photovoltaic waste heat are designed,which are: the control mode of using photovoltaic waste heat to improve the water outlet temperature of the load side group of the heat pump,the control mode of using photovoltaic waste heat to improve the water inlet temperature of the source side of the heat pump unit and the control mode of photovoltaic waste heat storage across seasons.According to the annual operation results obtained by the model,aiming at low system power consumption,ground soil temperature rise,and COPs operation of the high system,the final control mode of the annual solar-ground source heat pump coupling system was synthesized by selecting the period with good operation effect among the three control modes respectively.The final utilization strategy of photovoltaic waste heat is as follows: under heating conditions when the instantaneous value of photovoltaic surplus heat exceeds 10% of the building heat load,photovoltaic waste heat is used to improve the water outlet temperature of the load side of the heat pump unit.When the instantaneous value of photovoltaic residual heat is less than10% of the building heat load,the photovoltaic residual heat is used to improve the sourceside water inlet temperature of the heat pump unit.The remaining photovoltaic heat is stored in the soil through the buried pipe loop at other times.The results show that compared with the ground source heat pump unit established in the Hefei area,which provides the annual cooling and heat load of the building with a soil source heat pump,the average COP of the system under heating conditions increases by 37.9%,and that under refrigeration condition increases by 29.89%.After 20 years of operation,the soil temperature decreased by 20.8%.Figure 58 table 9 reference 74... |
PDF Full Text Request