The Installation Of A Domestic Heat Pump System For Heating And Climate Control

Heat pumps can be operated in two basic modes - they can either take heat from the air outside the house (even though it may not feel warm outdoors!), and put it inside to heat your home, or they could be a ground-source type, which removes heat from the earth and transfers it in the same way. The terrific fact about a heat pump is that they are reversible, taking heat out of your house and putting it back in the air outside, or into the earth. The economics of the system make a great case for a heat pump vs air conditioner, or equally, heat pump vs gas furnace. Only 1.5 meters underground the temperature is approximately 13°C (approximately 55°F) and doesn't fluctuate a lot between winter and summer.

Pipework external to the heat pump itself, called the collector system, can either be quite close to the surface and spread over a large area, or installed in a borehole drilled directly down into the ground, like a well. Less pipe is needed for the bore-hole type, because the temperature variations become increasingly more stable with increasing depth.

A low depth collector system of perhaps one hundred meters in length is normally installed at less than a meter underground, and comprises a grid of a single flexible pipe looped back on itself to make an extended "W". Each section should be far enough from it's neighbor such that heat energy doesn't pass across two loops, but heat transfer occurs between the pipe loops and the ground around them.

Naturally, the diameter and length of the pipe will be determined by the power rating of the pump system, and the area of the collector grid required will be determined by other factors, like soil type. The fabrication of such a collector system is well within the scope of the practical person. Another option is to contract a specialist company to bore a hole up to 100 meters deep - the exact depth depending on your calculations and the characteristics of the ground in your area. A U-shaped pipe is dropped into the bore-hole, which is hooked up to your geothermal heat pump system.

The difference in temperature between the earth 100 meters below and just 1.5 meters below ground will only be about 1 degree, but it is much more stable, hardly varying at all between seasons - this is why the collector pipe needn't be as long as for the shallow grid. After being put into operation, the system is comparatively free of maintenance, except for regular checks each year. Such an system will have a marked effect on your heating and cooling bills, as a big proportion of the heat for your home comes from the earth and not from the Earth's valuable and scarce resources.