CHENNAI: With concern for non-availability of potable drinking water growing, researchers at Anna University have come up with a smart solution to address the issue using domestic goods like a refrigerator and air conditioner. They claim that drinking water can be produced using heat from solar Photovoltaic (PV) operated Vapor Compression Refrigeration (VCR) system or AC following the simple logic of evaporation and condensation.
R Velraj, Director, Institute for Energy Studies, Anna University, said the heat that is pumped out to the atmosphere by the evaporator in one tonne AC machine can be utilised to generate 20 litres of water per day. Velraj and his team submitted the project proposal titled ‘Desalination through waste heat recovery from solar PV operated VCR system’ to the Department of Science and Technology and a grant of ` 35 lakh has been provided for the project.
Explaining the project, he said in a refrigerator or AC one side is condenser and the another side is evaporator. In countries, where temperatures soar, heat will be absorbed by an evaporator, while in cooler countries the condenser is used to warm the rooms.
“Our concept is to utilise both the condenser and evaporator. The heat that is pumped out to the atmosphere by the evaporator can be utilised for various purposes. A one-tonne refrigeration or air-conditioner can generate 20 litres of water per day if the AC is in operation for six hours on a sunny day,” he said.
Explaining the simple principle of evaporation and condensation which is also called humidification and de-humidification used in this project, he said when water evaporates from the sea at 35 degree Celsius, the atmospheric air is humidified. It happens due to solar energy and this water is accumulated.
The water available near the water bodies in the air is very high and the water which evaporates tries to saturate the air. The same methodology is used here. The heat exchanger is attached to the condenser and air will be allowed to go in and out. “An air nozzle will be attached so that the air going in will absorb water, as a result, the air is saturated. The nozzle will help spray the water to humidify. This makes the air humidified, which is allowed to pass through a tube or nano coated heat pipe when the temperature comes down. Poor quality water is condensed and you get fresh water,” he explained. He said that besides the cost of AC this will cost a maximum of `7,000.