BITS Hyderabad researchers develop refrigerant‑free, low‑energy cooling tech

Researchers from the Department of Mechanical Engineering at BITS Pilani, Hyderabad Campus, have claimed to have developed a sustainable air-conditioning technology that significantly reduces electrical energy consumption while eliminating the need for conventional refrigerants.

Most existing cooling systems rely on electrically driven compressors and synthetic refrigerants, both of which contribute to high energy use and environmental impact. In contrast, the new technology introduces a novel thermodynamic open-cycle system that uses desiccant-coated heat exchangers to remove moisture from the air.

The system uses powdered silica gel — a widely used moisture-absorbing material — coated onto heat exchanger surfaces to achieve deep dehumidification. This approach enables the system to operate using ultra-low-grade heat at just 40-50°C, temperatures easily available as industrial waste heat or from low-temperature renewable thermal sources, said a press release on Monday.

By shifting the primary energy input from electricity to low-grade heat, the technology drastically reduces electrical power requirements compared to conventional air-conditioning systems. The study demonstrates the system’s ability to condition atmospheric air to meet standard supply-air requirements for air‑conditioned spaces. This makes the technology particularly promising for humid cities such as Mumbai, Kolkata and Chennai, where dehumidification accounts for a substantial portion of cooling demand.

The findings highlight strong potential for developing central air-conditioning systems that are energy‑efficient, refrigerant‑free and compatible with waste‑heat recovery mechanisms. As urbanisation and climate change continue to intensify cooling needs, such innovations could play a meaningful role in building climate‑responsive and sustainable infrastructure.

The research was conducted by Gouse Ahammad Shaik of the Department of Mechanical Engineering at BITS Pilani-Hyderabad, independent researcher Vivekh Prabhakaran and assistant professor Mrinal Ketan Jagirdar, who serves as the corresponding author. The study has been published in the international journal Energy Conversion and Management, added the release.