屋顶光伏—土壤源热泵系统在不同气候区分娩猪舍的应用

    Photovoltaic-ground-coupled heat pump system for farrowing pig house in different climate zones

    • 摘要: 可再生能源逐步替代常规能源,是规模化猪场未来的趋势。为了探索土壤源热泵系统(ground-coupled heat pump systems,GCHPs)和附加光伏屋顶(building attached photovoltaic, BAPV)系统在规模化猪场的应用,该研究提出一种屋顶光伏—土壤源热泵系统(building attached photovoltaic-ground-coupled heat pump systems,BAPV-GCHPs)保障某分娩猪舍的冷/热需求,并选择绥化、青岛和重庆分别作为严寒、寒冷和夏热冬冷地区3类典型气候区代表城市,对比了该系统在3类气候区的运行特性,分析了BAPV系统对GCHPs运行性能及综合效益的影响。研究结果表明,3个地区BAPV发电量由大到小依次为:青岛、绥化、重庆;GCHPs耗电量由大到小依次为:绥化、青岛、重庆;绥化、青岛、重庆3个地区的年太阳能分数分别为0.62、0.71、0.53;BAPV系统的加入明显提高了GCHPs的性能系数、一次能源利用率和CO2减排量;3个地区BAPV-GCHPs相对于GCHPs年性能系数分别提高了64.2%、97.6%和39.6%;一次能源利用率分别提升了1.6倍、2.4倍和1.1倍。与GCHPs相比,BAPV-GCHPs可分别减少5.82、6.45和2.17 t CO2排放量。研究结果为该系统在中国不同气候区分娩猪舍的推广应用提供了一定参考。

       

      Abstract: More attention has been focused on the development and application of renewable energy all over the world, with the increasing concern for energy shortage and climate change. The large-scale pig farms can also be expected to extend the renewable energy. This study aims to meet the cooling/heating demand of a farrowing pig house in different building climate zones. A novel combination of Building Attached Photovoltaic (BAPV) systems and Ground-Coupled Heat Pump systems (GCHPs) was proposed to enhance the complementary effects of solar and geothermal energy, due to the difference in the cooling/heating load. Firstly, the borehole heat exchanger fields were optimized in the design of GCHPs, according to the cooling/heating load and ground thermal properties. Three cities were taken Suihua, Qingdao, and Chongqing located in the typical climate zones of severe cold areas, cold areas, and hot summer and cold winter zones. The result showed that a large difference was observed in the number of borehole heat exchangers for the farrowing pig house in the three cities, indicating the independence of BAPV systems. The ratio of heating and cooling load caused the different number of borehole heat exchangers, due to the limited inlet fluid temperature of a heat pump. Next, the Building Attached Photovoltaic-Ground-Coupled Heat Pump systems (BAPV-GCHPs) were modelled to investigate the system performance in the farrowing pig house located in different climate zones using Trnsys. The model was composed of a BAPV system, house load, and GCHPs. Electricity generation from the BAPV system were mainly supplied to the GCHPs, in order to expand the application of renewable energy in different climate zones. A comparison was made between the electricity generation and energy consumption. The potential of the two renewable energies was quantitatively investigated using the performance efficiencies in different operation periods. Finally, the presented system was compared with the operating performances in three climate zones, in order to clarify the effect of the BAPV system on the operating performance and comprehensive benefits of GCHPs. In the BAPV system, the power generation in Qingdao was the largest and followed by Suihua and Chongqing. The power consumption of GCHPs in Suihua was much higher than in the other cities. The annual solar factor of Suihua, Qingdao, and Chongqing were 0.62, 0.71, and 0.53, respectively. Additionally, the BAPV system contributed to the increased performance factors, the primary energy ratio, and CO2 emission reductions for GCHPs. Compared with the GCHPs, the annual performance factors of BAPV-GCHPs in Suihua, Qingdao, and Chongqing were improved by 64.2%, 97.6%, and 39.6%, respectively. The BAPV-GCHPs system was more suitable for application in severe and cold areas than that in hot summer and cold winter zones. The primary energy ratio in Suihua, Qingdao, and Chongqing increased by 1.6, 2.4, and 1.1 times, respectively, whereas, the CO2 emission was reduced by 5.82, 6.45, and 2.17 t, respectively. This trend was attributed to the BAPV contribution. This finding can provide a new pathway toward the application of renewable energy in farrowing pig houses, and then contribute to energy saving and carbon reduction in animal husbandry. The findings can provide strong references to promote and apply in different climatic zones in China.

       

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