Would you say yes please to a steady readily available heat source, that you could tap all year around, that remained at a steady 12 degrees, no transport costs, minimal piping required and few to no waste products? There is such a heat source: geothermal heat.
The ground remains at a relatively constant temperature all year round and this temperature can be used as a heat or cooling source. Taking this available heat and exposing it to a cooler refrigerant, means the heat can be transferred to another area. The heat is effectively pumped from hotter areas to cooler areas by pumping the refrigerant through the system. The technology is the same as runs a domestic refrigerator- just on a larger scale.
While some electricity is used in a heat pump, the energy used is small compared to the heat return. For every kilowatt of electricity used, ground source heat pumps transfer approximately 3.5 kilowatts of heat.
Ground source heat pumps are therefore very attractive in applications where large amounts of energy are required to heat water and/or air such as in swimming pools and recreation centres.
Budgeting for the energy required is also improved, as ground source heat pumps work with a reliable and constant source of heat that changes very little with the seasons.
At Centennial Pool, for example, a ground source heat pump is installed. Water is diverted from the city mains water supply, heat is extracted and the water is returned to the mains supply. The water that returns to the mains supply is reheated by the surrounding earth to the ambient temperature within a few hundred metres.
If an electric boiler were used to warm the pool water, the electricity bills for the centre would be 3.5 times higher than Council presently pays.
The heatingproduced uses a constantly renewed resource and requires comparatively small amounts of energy to operate. As long as the plant is in continuous use, you also have a ready supply of hot water for showers.
Ground source heat pumps are also installed at:
- The Christchurch Town Hall
- Jellie Park Recreation Centre
- Pioneer Pool
- Waltham Pool
- Belfast Pool.
As an alternative to sourcing heat from piped water, heat may also be extracted from a local pond, a well, through coils laid in the earth and filled with water or from large bodies of water. As long as the source is always available and has a relatively constant temperature, this technology is appropriate for use where a continuous supply of heat – or cooling - is required.
The benefits of the project
The benefits of the project include:
- A substantial reduction in electricity use and thus in costs.
- The system uses a renewable heat source.
- The process is carbon neutral because Council uses a carbon neutral electricity source.
- The heat source is at a constant temperature, which means that heat pumps operate at maximum efficiency.
- The technology is quiet and clean.
Things to consider for your business or home
- Do I have the need for a constant heating or cooling load?
- Is there a source of heat that may be readily exploited close to my business or residence?
- Could the technology be used to heat multiple residences or a shopping mall?
- Could I use the heat from a production process, instead of wasting it to the air?
- Could I sell excess heating produced in the operation of my business through heat pump technology?
