The Power Tower, a new building in Linz, Austria, considered a 'milestone in energy efficiency', uses a geothermal heat pump operating with HFC-134a to provide heating and cooling.
The new headquarters of an Austrian utility company is claimed to be the world's first high-rise office block with the characteristics of a passive building, saving emissions of about 300 tonnes CO2 per year compared to a conventional high-rise building of similar dimensions.
Geothermal heat is pumped from 150m deep pits and two groundwater wells are used for heating and cooling. The heat pump has a power of about 330 kW and a COP of 5.7.
The heat pump system is equipped with geothermal sensors measuring 6,900 meters in length, and it can operate in three different modes according to requirements:
- Heat drawn from underground when heating is required
- Heat dissipated underground when cooling is required
- Cooling by reversing the heat pump operation.
In the EU Directive on the promotion of the use of energy from renewable sources, ground-source, air-source and water-source heat pumps are recognized as “renewable energy technology”.

Source: Equipment Manufacturers /