Li Yangyang, Ju Ran, Liu Chongtao, Tao Xiuping, Song Jianchao
Key Laboratory of Energy Conservation and Waste Management in Agricultural Structures, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, 610000, China.
J Therm Biol. 2025 Jan;127:104039. doi: 10.1016/j.jtherbio.2024.104039. Epub 2025 Jan 8.
Maintaining an optimal indoor thermal environment is crucial for enhancing the welfare and productivity of livestock in intensive breeding farms. This paper investigated the application of a combined geothermal heat pump with a precision air supply (GHP-PAS) system for cooling dairy cows on a dairy farm. The effectiveness of the GHP-PAS system in mitigating heat stress in lactating dairy cattle, along with its energy performance and local cooling efficiency in the free stalls were evaluated. A total of 140 multiparous lactating Holstein cows was tested in two groups. One group was housed in a barn equipped with a GHP-PAS system (GP barn, n = 70), and the other was housed in a barn with a conventional fan-sprinkling system (FS barn, n = 70). Results showed that the ambient temperature of both GP and FS barns were lower than that outside the barn (P < 0.05), with no significant difference between the GP and FS barns (P > 0.05). Compared to cows in the FS barn, those in the GP barn exhibited lower skin temperature, rectal temperature, and respiratory rate (P < 0.05). The mean temperature difference between outflow and inflow water was 2.56 °C of the GHP unit. The average energy efficiency ratios (EER) of the GHP unit and the GHP-PAS system were 5.03 and 2.92, respectively. The daily average electricity consumption was 20.4 ± 1.0 kWh. The field test results indicated that the airflow from a single nozzle of the GHP-PAS system effectively covered a stall space with an average width of 1.84 m at a cow reclining height of 0.5 m, with an average air velocity of 1 m/s. The per-cow hourly electricity consumption for cooling was 2.04 kWh for the GHP-PAS system and 0.36 kWh for the FS system, highlighting that the GHP-PAS system is approximately 5.6 times more energy-intensive than the FS system. In conclusion, the GHP-PAS system showed the potential for alleviating heat stress in dairy cows. Further research is needed to enhance the energy efficiency and cooling effectiveness of the current GHP-PAS system.
维持最佳的室内热环境对于提高集约化养殖场牲畜的福利和生产力至关重要。本文研究了地源热泵与精准送风（GHP-PAS）组合系统在奶牛场奶牛降温中的应用。评估了GHP-PAS系统在缓解泌乳奶牛热应激方面的有效性，以及其能量性能和在自由牛舍中的局部降温效率。总共140头经产泌乳荷斯坦奶牛被分为两组进行测试。一组饲养在配备GHP-PAS系统的牛舍（GP牛舍，n = 70），另一组饲养在配备传统风扇喷淋系统的牛舍（FS牛舍，n = 70）。结果表明，GP牛舍和FS牛舍的环境温度均低于牛舍外（P < 0.05），GP牛舍和FS牛舍之间无显著差异（P > 0.05）。与FS牛舍的奶牛相比，GP牛舍的奶牛皮肤温度、直肠温度和呼吸频率更低（P < 0.05）。地源热泵机组的流出水和流入水之间的平均温差为2.56℃。地源热泵机组和GHP-PAS系统的平均能效比（EER）分别为5.03和2.92。每日平均耗电量为20.4 ± 1.0千瓦时。现场测试结果表明，GHP-PAS系统单个喷嘴的气流在奶牛卧姿高度0.5米处有效覆盖了平均宽度为1.84米的牛舍空间，平均风速为1米/秒。GHP-PAS系统每头奶牛每小时的降温耗电量为2.04千瓦时，FS系统为0.36千瓦时，这突出表明GHP-PAS系统的能源密集度约为FS系统的5.6倍。总之，GHP-PAS系统显示出缓解奶牛热应激的潜力。需要进一步研究以提高当前GHP-PAS系统的能源效率和降温效果。
