Carbon dioxide as a refrigerant is not a new concept. CO2 as an operating fluid in refrigeration systems was used up until the second half of the 19th century. It is with the development of synthetic refrigerants like CFC, HCFC and HFC that CO2 was put to rest as a refrigerant.
But with such unique properties, CO2 has made a comeback as a refrigerant, this time with a major green quirk!
Transcritical CO2 systems were developed in the early 2000s. This system puts CO2 in a transcritical cycle, meaning CO2 is made to undergo different phases with varying pressures and temperatures.
One of the main advantages of the transcritical system is that CO2 is abundantly available in the environment, which it uses plentiful. Waste produced CO2 can also be used in this system reducing the overall greenhouse gases in the environment.
With all these advantages, the transcritical system is still not perfected yet. But we might be closer, with India’s first transcritical refrigeration.
Researchers from the Department of Mechanical Engineering in the Indian Institute of Technology, Madras, presented India’s first CO2 transcritical system at the Gustav Lorentzen conference in Valencia last week.
Prof Dr Prakash Maiya from the Department of Mechanical Engineering at the Indian Institute of Technology, Madras, told R744.com, “It’s a multi-faceted system with all the modes of operation, including supermarket, air conditioning and heat recovery.”
And the developed transcritical system is claimed to be able to operate even with the temperature reaching as high as 45ºC.
“It’s the first of its kind in India, and it’s operating successfully in very high ambient temperatures of up to 45°C,” Maiya said.
The researchers tweaked the system by adding a liquid ejector and flooding the evaporator in the system. This resulted in an improvement of the CO2 cooling stability and an overall reduction in power.
You can read the paper here.
This ultimately could result in applications such as mass cooling, like in supermarkets and cold boxes, typically used in catering and medical storage fields with a green value to it.
Commenting on the potential use of the transcritical system in India, Dr Maiya said that if the system is found to be operating properly and maintenance is free, then yes, the system could benefit the Indian markets.
With synthetic refrigerants being very harmful to the environment, natural refrigerant technologies could be the green replacement that the world is looking for!
When R744.com asked about the cooperation of the government for such refrigerant technologies, Dr Maiya said, “They’re waking up and saying, ‘instead of synthetics, we want to go for the natural refrigerant carbon dioxide’.”
(Edited by Shruti Singhal)