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N°6 – Geothermal heat pumps training (VTC to A level)

Heat pumps part 1 N°6 – Geothermal heat pumps training (VTC to A level)

Geothermal heat pumps draw energy out of the ground, either on the surface (horizontal collector), or in depth (vertical collector or drawing water from the water table).

Source Avenir Energie

Source Avenir Energie

For systems with a geothermal horizontal collector, we can identify:

  • Systems where the refrigerant fluid circulates in the loops

 
Below we talk of ground/ground HP.

Source Avenir Energie


 
This seldom recommended solution (refrigerant fluid circulates in the loops) has 2 disadvantages:

  • A large quantity of refrigerant fluid, detrimental to the environment, because there is always a risk of leaks.
  • No possibility of reversing the cycle to permit the use of the under-floor heating circuit in cooling mode (it would be too cold).

Remember however, that reversibility of HP is not recommended from an ecological point of view. Air conditioning, in our climates, is a need that should be delayed a maximum, considering the worrying environmental situation (see dossiers on “Global Warming”).

Question  

What problem will an under-floor cooling system face if it is at too low a temperature?

If the under-floor cooling system temperature is too low, there could be condensation on the surface:
– Dangerous on tiled flooring, slipping…
– Harmful to carpet or parquet flooring…



For systems with horizontal geothermal collectors, we can also identify:

  • Systems where the refrigerant fluid circulates in the geothermal loop, but not in the under-floor heating

The heat recovery loop is flow fed by the refrigerant fluid and the under-floor heating by heating water.
We speak of ground/water HP.

Source Avenir Energie

This solution is not ideal due to the large quantity of refrigerant fluid used, but does permit the use of the under-floor heating system as a cooling system.
 
 
For systems with horizontal geothermal collectors, we also recognise:

  • Water (glycolated) / water (heating) systems:

The heat recovery loop is flow fed by glycolated water.
We speak of glycolated water/water HP.

Source Avenir Energie

This solution limits to a maximum the amount of refrigerant fluid in circulation. It permits the use of the under-floor heating system as a cooling system.
 
 

Finally:

  • Heat pumps with vertical collectors are either water/water type or water/air.
    Their evaporator is flow fed by glycolated water.
  • Heat pumps drawing on the water table are obviously either water/water type or water/air.
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