This study examined the effects of a heating system using a ground source geothermal heat pump (GHP). A GHP was installed in a pig house, and a comparative analysis was performed between the GHP and the control (conventional heating system) in terms of the production performance, housing environment, noxious gas emissions, electricity consumption, and economics. The geothermal system performance index, such as the coefficient of performance (COP), inlet, and outlet temperature, were also evaluated. The outflow temperature during each period (weaning, growing, and finishing) was significantly higher than the inflow temperature in all three components of the GHP system. Similarly, the average internal temperature of the GHP-connected pig house was increased (p < 0.05) during each period. The carbon dioxide (CO₂) concentration, electricity usage, and cost of electricity during the 16-week experimental period were reduced significantly in the GHP system relative to the control. The concentrations of ammonia (NH₃) during the growing and finishing period and the concentrations of formaldehyde during the weaning phase were also lower in the GHP-installed pig house (p < 0.05). These results indicate that the GHP system can be used as an environmentally friendly renewable energy source in pig houses for sustainable pig production without harming the growth performance.

High electricity consumption, carbon dioxide (CO₂), and elevated noxious gas emission in the global livestock sector have a negative influence on environmental sustainability. This study examined the effects of a heating system using an air heat pump (AHP) on the energy saving, housing environment, and productivity traits of pigs. During the experimental period of 16 weeks, the internal temperature was found to be higher (p < 0.05) in the AHP house than in the conventional house. Moreover, the average electricity consumption and CO₂ emission decreased by approximately 40 kWh and 19.32 kg, respectively, in the AHP house compared to the house with the conventional heating system. The average NH₃ and H₂S emissions were significantly lower in the AHP house (p < 0.05) during the growth stages. The AHP and conventional heating systems did not have a significant influence (p > 0.05) on the average ultra-fine dust (PM_2.5) and formaldehyde level fluctuations. Furthermore, both heating systems did not show a significant difference in the average growth performance of pigs (p > 0.05), but the weight gain tended to increase in the AHP house. In conclusion, the AHP system has great potential to reduce energy consumption, greenhouse gas (GHG) emissions, and noxious gas emissions by providing economic benefits and an eco-friendly renewable energy source.

This study compared the effects of the cooling mode of a geothermal heat pump (GHP) system with those of a traditional cooling system (ventilation fans) inside a pig house on the internal house temperature, harmful gas emissions, and the growth performance of the pigs. During the 19-week experimental period, the temperature inside the house connected to the GHP cooling system was significantly lower (p < 0.05) than that of a house with a conventional cooling system. Similarly, the temperature–humidity index (THI) was significantly reduced (p < 0.05) in the GHP cooling system-connected pig house. Furthermore, the concentrations of ammonia (NH₃) and hydrogen sulfide (H₂S) were also decreased significantly in the GHP-installed pig house (p < 0.05). However, no differences were observed in the concentrations of particulate matter (PM_2.5) and formaldehyde (p > 0.05). The pigs reared in the GHP-equipped pig house gained significantly more weight (p < 0.05) by the end of the experiment. The GHP cooling system can therefore be implemented as a renewable, environmentally friendly energy source in pig farms for sustainable swine production without adversely affecting the productivity parameters.

The present study examined the cooling effects of an air heat pump (AHP) system. An AHP system was installed in a pig house to compare the effects with a traditional cooling system on the growth performance, noxious gas emission, housing environment and consumption of electricity. During the 19-week experimental trial, the internal temperature in the AHP cooling system-connected pig house was significantly decreased (p < 0.05) than the conventional house. Similarly, the temperature–humidity index (THI) was significantly reduced (p < 0.05) in the growing and late finishing period. The carbon dioxide (CO₂) and electricity consumption were also reduced significantly in the AHP cooling system relative to the control. The concentration of ammonia (NH₃) during the weaning and finishing phase and the concentration of hydrogen sulfide (H₂S) during all periods were lower in the AHP-installed pig house (p < 0.05). From 0–19 weeks, there was no significant difference was observed (p > 0.05) in terms of the growth performance of pigs in both houses. These results show that the AHP cooling system can be implemented as an environmentally friendly renewable energy source in swine farms for sustainable pig production and better air quality without adversely affecting productivity parameters.