Geothermal cooling system for a house in hot parts of the world

As a form of thermal energy, geothermal energy is available in some regions of the earth’s crust at temperature levels that range between 35 °C and 500 °C, even though most geothermal locations provide temperature levels of up to 250 °C. This energy can be utilized both directly by applying it to provide heating and by conversion into electricity in a power cycle.

Now, the researchers in Italy and Turkey have designed a new cooling system using this geothermal energy, that can sustainably keep a house cool in well-known hot parts of the world. The cooling absorption chiller (VAC) was designed to meet the cooling demands of a 140 square meter, detached family home in Izmir, Turkey.

The geothermal cooling system works using the hot geothermal fluid available deep underneath the house. The fluid is transported to the VAC, in which water and ammonia are used as an absorbent and a refrigerant, respectively. Energy and exergy analyses methods are utilized to evaluate the performance of the whole system. Also, some operational properties of the VAC such as pressure, temperature, ammonia concentration, and flow rate are determined.

Based on the parametric studies, the system runs at temperatures of 30 °C, 90 °C, and 2 °C for the condenser, boiler, and evaporator, respectively.

The team estimated that costs would be offset by electricity saved running a conventional air-conditioning unit within six and a half years. It takes an up-front estimated cost of US $ 3500.

Besides, the use of sustainable energy to drive the system means a greatly reduced carbon footprint. As we are facing rising global average temperatures and sharply rising local temperatures due to anthropogenic climate change, it is important for us to find alternative, sustainable ways to keep people cool in their homes, without burning fossil fuels to generate electricity.

The research is published in the International Journal of Exergy.