Geothermal Heating and Cooling/Refrigeration loops and Heat Pumps

From Wikibooks, open books for an open world
Jump to navigation Jump to search

Refrigeration Loops and Heat Pumps

It was long ago established that moving heat was less expensive than creating it. Your refrigerator at home, and your freezer if you have one, take heat out of an insulated box, and release it into the room. Thus cooling food to make it last longer. The techniques for doing so were invented long ago, and in fact have not changed significantly since the days of steam engines. What has changed is the chemical nature of the refrigerant, and therefore the temperatures at which it is more economical to pump heat, and the efficiency of the compressors.

The refrigeration cycle is very simple, first, a refrigerant vapor is compressed then cooled to form a liquid, then the liquid is pumped through a constriction that changes the high pressure to a low pressure liquid and allowed to expand into its gaseous state, during which it absorbs heat. The selection of whether you put the cool side or the hot side of the loop inside your box, determines whether you heat or cool the box.

A heat pump designed for HVAC, is only a little bit more complex, because it allows you to switch the piping so that during the summer the house is cooled, and during the winter the house is heated. This is possible because a special valve can be switched each season in order to set the direction of the heat.