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A renewable form of energy, ground source(geothermal) heat pumps use the ground as their main energy source.


They do this by utilising geothermal collectors or geothermal probes that are buried into the surrounding land. With ground temperatures remaining stable all year round, ground source heat pumps are able to provide the greatest efficiencies of the heat pump types - unequalled on performance and running costs.

Ground source heat pump systems take heat energy from the ground and pass it through a heat exchanger into a heat pump, which works like a refrigerator but in reverse. These units can also work as water source heat pumps where water, such as lakes, are available as a heat source.


​These solutions provide heating and hot water for your home. Combined geothermal heating and cooling systems are also now available. As well as providing warmth during colder weather, these solutions work in reverse when it’s hot outside and provide cool air to help keep your home at a comfortable temperature year-round.

​At Red Dwarf we have been installing ground source heat pumps for well over a decade as they first made there way into the New Zealand market. As with any system, correct design and knowledge is required from the planning stage to ensure sound operation. Too many times we have come across systems installed incorrectly resulting in poor efficiencies and costly repairs.

Generate heat from the earth

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With any ground source heat pump installation, it’s important to get the sizing of the system right. The correct size of heat pump and ground circuits for your property will depend on the size of your property and your specific heating needs. When calculating this, you’ll need to know how much heat is lost from your property - and this is affected by a range of factors, including how well glazed and insulated it is.


Your geothermal heating installation will be sized to counter the loss of warmth from your property and to ensure that the heating needs of your property are met comfortably even on a cold day in winter.


Longer ground circuits will draw more heat from the ground, but they need more space to be buried in. If there’s a shortage of space, a bore hole may be buried vertically rather than horizontally.


For larger properties, cascade operation can be used or an additional heating source may be required to meet the full heating demand. 



Renewable technologies such as ground-source and air to water heat pumps along with solar are becoming the preferred energy source for many.


However for  these technologies to work efficiently they will only heat water at a lower temperature (around 35-55℃) compared to your standard gas or diesel boiler (around 70-80℃), this is due to absorbing heat from natural environments such as the air, ground or sunlight.


This means to achieve the same heat output and comfort levels in each space you either require larger radiators to compensate for the lower water temperatures and loss of heat output or more efficient ones.

​To put this into perspective, the same radiator running on a hydronic heat pump system with 50℃ flow temperatures will have an output less than half of that if it was running on a boiler system with 75℃ flow temperatures. 

We have a wide range of radiators designed to run with low water temperatures as well as floor heating systems which are all suited to be used with heat pumps.



Heating and cooling with ice


The use of an ice store as an energy source is a particularly innovative solution.

The ice store consists of a tank with built-in heat exchangers which is buried in the garden and filled with ordinary tap water. Special solar air absorbers are installed on the roof of the house, which draw heat from the ambient air and insolation and supply it to the tank. The ice store also draws heat directly from the ground.

Using crystallisation energy for heating-

If not enough energy is provided by the solar air absorbers, the heat pump extracts the energy required for central heating and DHW heating from the water stored in the tank.

If the temperature in the tank falls to freezing point, more energy is obtained from the freezing of the water – hence the term "ice store".

During the transition from water to ice, the amount of crystallisation energy released is equivalent to that required for the inverse process of thawing. With an ice store measuring ten cubic metres – the standard size for a detached house – this corresponds to the energy content of approx. 120 litres of fuel oil.

Solutions with Geothermal

Removing heat from the ground or water, the geothermal heat pump will transfer this heat from 10-12 degrees up to 60 degrees via a refrigeration process. This results in an efficiency of up to 600%.

Expert planning is required for this system to work for you efficiently.


Applications where a geothermal heat pump is used:

  • Heating water for central heating convectors and radiators

  • Floor and wall heating solutions

  • Domestic hot water provision

  • Pool and spa heating

  • Cooling

  • Commercial applications


Solutions that can be added:

  • Solar thermal system integrated for domestic hot water and/or heating/pool and spa heating

  • PV Electric solar array can be added with direct connection to the heatpump for maximum efficiency

  • Domestic hot water circulation pump for fast and efficient hot water service at your sanitary fixtures for your home

  • Heat recovery system - Passive house certified


Easy to use programming:

  • Weather compensation for all out comfort and energy savings of 12%

  • Smart and clear programmer for time control, information, and other settings


Contact us at Red Dwarf for professional advice and knowledge that will help you choose the right energy source for your system.



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