The Basic Science of Geothermal Heating and Cooling

A number of homeowners here in San Antonio, TX, have signed on with Southwest Mechanical Services to make their homes geothermal homes. Still need convincing about geothermal heating and cooling yourself? Understanding something of the science behind it – and the mechanics as well – would probably help.

We’ve talked elsewhere about the merits of geothermal heating and cooling. It’s quite sufficient to say here that hardly any other methods of maintaining a climatically comfortable home environment year-round are as efficient, reliable, or ultimately budget-friendly, especially when you gauge the energy savings.

Here’s how geothermal makes that a reality.

Thar’s Gold Heat in Them Thar Hills!

We mine the earth for precious metals. We drill the earth for oil. Now, to an unprecedented degree, we’re tapping the earth for something no doubt just as valuable to many of us: the energy to heat and cool our homes that doesn’t call for oil.

You see, right below the earth’s crust – that would be about 33,000 feet under our feet – is a mantle of magma. This is a molten and semi-molten brew, primarily of silicates, in which temperatures run from 1300 degrees Fahrenheit to 2400 degrees Fahrenheit and hotter the deeper you go (not that you’d want to go there!). What this serves to do is keep the ground immediately under the earth’s surface at a fairly consistent year-round temperature of between 45 and 75 degrees Fahrenheit. So? Underground temperatures in San Antonio (and most places stateside, in any event) are warmer than the ambient air above ground in Winter and cooler than the ambient air above ground in Summer.

Time to Get Pumped!

This, then, is what geothermal heating and cooling systems do: they transfer heat from the ground  to your home or heat from your home to the ground, as the season dictates. Either way, your home stays at the best possible temperature to keep you and your family comfy month after month.

The apparatus that executes the transfer is a geothermal heat pump. It continuously circulates water or some solution (commonly antifreeze) between your home and loops of piping (commonly fashioned of polyethylene, high-density polyethylene, PVC, or CPVC) placed in the ground. In Winter, the liquid is cold when it enters the ground. As it travels through the loops, it sucks up heat from the earth and is returned to your home warm. In Summer, the process is reversed: warm liquid goes into the loops, where it takes in the cooler ground temperatures before it’s returned to your home. Want details? You’ll find more specific information on ground loops here.

The primary point is that geothermal heating and cooling systems don’t produce energy. They aren’t like central heating systems, which generate heat themselves. Instead, geothermal systems heat and cool your home by making use of the energy already richly available beneath the earth’s surface. That’s why geothermal systems are not only quieter but also a lot more trustworthy, need less maintenance, have much longer lifespans, and are more environmentally friendly than old-school HVACs. That’s also why, in the end, you’ll save lots more more money by going geothermal.

Curious now? See Southwest Mechanical Services, your San Antonio geothermal heating and cooling authority, today.