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GrEnergy Testimonial
Martin V. Kerr
"Despite an initial set back with the installation date we are delighted with our new system. I cannot praise Steve and Keith enough for the work they did, the advice...
The fundamental process that allows a refrigerator or Heat Pump to work is the evaporation of a liquid to absorb heat. When you put water on your skin it feels cool. This is because as the water evaporates, it absorbs heat from your body. When you put alcohol on your skin (as in some aftershaves or perfumes) it feels even colder. It feels colder because the alcohol evaporates at a lower temperature than water. The refrigerant used in a fridge or heat pump evaporates at an even lower temperature still, around minus 33°C. This would freeze your skin if applied to it so don’t be tempted to experiment!!
The Heat Pump works as follows...
Heat Exchange Operation.
Please refer to the diagram above:
The Compressor compresses the refrigerant gas and when this happens the gas gets hot as shown by the red colour in the diagram.
This hot refrigerant gas then passes to the Condenser. The condenser is a heat exchanger which enables your heating system to extract the heat energy from the refrigerant gas. As heat is absorbed from the gas it condenses back into a liquid, still at high pressure as depicted by the orange then yellow colour.
Having given up a lot of its heat energy, the refrigerant then passes to the Expansion Valve. The expansion valve is basically a small hole. On one side of the hole is high-pressure refrigerant liquid (yellow) and on the other side is a low-pressure area (dark blue). The dark blue side is at low pressure because the compressor is sucking the refrigerant out of that side of the system.
As the liquid refrigerant passes through the hole to the low pressure side, it immediately boils and evaporates (dark blue), its temperature dropping rapidly to minus 33°C as described above. This very cold gas is then channelled to another heat exchanger, the Evaporator, which allows it to absorb heat from the outside air (Air Source Heat Pump – ASHP) or the ground (Ground Source Heat Pump – GSHP). As it absorbs heat, the gas warms up (light blue) after which it is channelled back to the compressor.
The refrigerant gas is sucked up by the Compressor, and the cycle repeats.
