New Delhi: The health risks and productivity loss due to rapidly increasing heat stress are already reaching alarming levels. With the rise in temperature and increased use of air conditioners in homes and offices, electricity consumption for cooling is projected to triple by 2037-38 (India Cooling Action Plan, Report by MoEFCsC, Government of India, 2019).
An increase in power consumption would put stress on natural resources and lead to higher electricity bills for consumers. To address this, researchers from the Department of Mechanical Engineering at IIT Delhi are developing a new type of high-efficiency air conditioner.
The research team led by Prof. Anurag Goyal, which also includes Ananthakrishnan K, a PhD research scholar in the Department of Mechanical Engineeringd, is currently testing a laboratory-scale prototype of this proposed system, which has shown potential to reduce electricity use by roughly a third.
How does this high-efficiency AC work?
The vapor-compression system-based ACs in use today remove humidity by overcooling the air until moisture condenses, which is a highly energy-intensive process. Prof. Anurag Goyal’s research group in the Department of Mechanical Engineering at IIT Delhi has developed a new concept that utilizes a compact add-on module to directly tackle moisture.
The module uses a salt solution (liquid desiccant) that absorbs water vapor from incoming outdoor air. A thin and selective polymer membrane sits between the air and the salt solution and prevents the salt from carrying over into the building’s air, which is a common concern with existing liquid-desiccant systems.
After the solution is diluted by absorbed moisture, it must be dried to allow continuous reuse. The team uses an innovative system integration concept to continuously revive and recirculate the same salt solution. Instead of adding a burner or an electric heater, the design uses heat that the AC already throws away through its condenser (the outdoor unit) and redirects it to a regenerator module to dry the salt solution again.
The system is designed to precisely match the energy transfer rate in the two parts, vapor compression and desiccant modules, across various outdoor conditions in our country.
“Using the proposed system at typical operating conditions, total electricity consumption decreased from approximately 1200 W for a standard room AC to about 800 W for the hybrid, resulting in around 33% lower energy consumption, while meeting the same indoor comfort targets. Across representative Indian climates, the predicted savings range from 28% (in very humid areas) to 41.5% (in dry and arid areas),” Prof. Anurag Goyal, Department of Mechanical Engineering, IIT Delhi, said.
The reach team anticipates wider adoption of such a sustainable cooling technology, particularly in Indian buildings.
A study titled ‘Model-based analysis of a novel hybrid membrane-liquid desiccant air conditioner for high-efficiency space cooling’ on their work has been published in the Journal of Building Engineering. (Research paper link: https://doi.org/10.1016/j.jobe.2025.114635)
