Geothermal energy resources are being increasingly tapped for process, space and other heating applications. Engineers are also warming up to its use for space cooling, as recently demonstrated in Spain.

A combination of geothermal energy and solar power have provided sustainable cooling and air-conditioning to the Moncloa Transport Hub in Madrid, Spain. The Geobatt project was launched by Sacyr, Energy Storage Solutions, Universidad Politécnica de Madrid, Universidad Carlos III, and the IMDEA Energy Foundation to demonstrate the exploitation of geothermal energy with flow batteries for the air conditioning of zero-energy tertiary buildings.

Heat pumps connected to geothermal boreholes drilled to a depth of 150 m generate pressure to transfer the thermal fluids to chillers. The heat pumps are powered by a redox flow battery charged by a photovoltaic solar installation, rendering the entire system 100% renewable energy-based. The demonstration project is the first to combine hybrid geothermal heat pumps, redox flow batteries and photovoltaic solar panels.

The system currently has a chiller capacity of 1.2 MW, with the geothermal expansion adding 400 kW of new capacity. The goal for the project would be to scale the installation to cover 33% of all the energy needs of the transport hub.

This project could be replicated and expanded in additional facilities, increasing the number of boreholes and heat pumps and the cooling capacity.