Scientists of the Indian Council of Agricultural Research-National Dairy Research Institute (ICAR-NDRI), Karnal, have developed an innovative geothermal energy-based ventilation system that can help dairy farmers in tackling one of the biggest challenges in livestock management, protecting animals from extreme summer heat and winter cold.
The technology has been tested at the ICAR-NDRI’s Livestock Research Centre and has shown encouraging results in maintaining a comfortable environment inside animal sheds throughout the year. Here is everything you need to know about the technology and its benefits.
- Why is temperature important for dairy animals?
According to scientists, animals perform best within a comfortable temperature. Their productivity peaks when temperatures remain around 30–35°C, which is their comfortable zone. When temperatures rise too high in summer or drop significantly in winter, animals experience thermal stress. Under such stressful conditions, animals use a large portion of their energy for regulating body temperature instead of producing milk, growing and reproducing efficiently. As a result, farmers often witness reduced milk yield, lower fertility rates and weak immunity due to drastic variations in temperature.
- What challenge have the scientists solved?
Traditional methods of cooling and heating animal sheds depend on fans, coolers, foggers, heaters or fossil fuels. These systems increase operational costs and require substantial electricity or fuel. The scientists worked on a sustainable, low-cost and energy efficient solution that could provide year-round thermal comfort, while reducing dependence on conventional energy sources.
- What principle are the scientists using?
The geothermal system is based on a simple natural principle. A few metres below the earth’s surface, soil temperatures remain relatively stable throughout the year even when extreme weather conditions prevail above ground. During summer, underground temperatures are cooler than the surrounding air. During winter, the same underground layers remain warmer than the cold outside. The scientists are utilising this natural thermal reservoir as a heat exchanger to maintain optimum temperatures inside animal sheds.
- How does the geothermal system work?
According to Director Dheer Singh, fresh air is pulled into pipes buried underground at a depth where the soil stays at a steady temperature. As the air moves through these buried pipes, it exchanges heat with the soil. In summer, hot outside air cools down by losing heat to the cooler soil, so cooler air enters the shed. In winter, cold outside air warms up by absorbing heat from the warmer soil, so warmer air enters the shed. A blower with a variable frequency drive (VFD) moves this conditioned air into the animal shed and adjusts the airflow as needed. This continuous circulation keeps the shed more comfortable for animals without using much heating or cooling equipment.
- How did scientists determine the ideal depth?
To study how underground temperatures change, the scientists drilled a 12 metre borewell and recorded temperatures at several depths over the year. They found that daily temperature swings were large at the surface but became almost negligible below four metres. The difference between the open air and the temperature at four metres in soil was large –about 9.5°C in June and about 14.4°C in January. These results show that the soil below the surface can act as a natural heat exchanger.
- What was done in the field trial?
After the initial study, scientists buried cast iron pipes about three metres below a livestock shed. Fresh outside air was passed through these underground pipes and delivered to the shed using a controlled ventilation system. The aim was to test the system under real farm conditions.
- What results were achieved?
The trial yielded encouraging results. During peak summer, shed temperatures dropped by nearly 11°C. In winter, shed temperatures increased by about 3°C. The system produced these changes without burning any fuel for heating or cooling. Such improvements can reduce heat stress in dairy animals and provide a more comfortable environment. The continuous flow of fresh air through the buried pipes also improves the air quality inside the sheds. Researchers saw lower levels of harmful gases such as ammonia and hydrogen sulfide, which often build up in livestock housing. Better ventilation can help animals breathe easier, reduce disease risk and improve overall welfare. Scientists estimate that the geothermal ventilation system can cut heating and cooling energy costs by about 50% compared with conventional fossil fuel or electric systems.
