The Basic Science of Geothermal Heating and Cooling

A good many people here in Alaska, Alaska, have hired Energy Efficiency Associates to make their homes geothermal homes. Still leery of geothermal heating and cooling yourself? Understanding a bit of the science behind it – and the mechanics as well – might help.

We’ve discusseded elsewhere the rewards of geothermal heating and cooling. Suffice it to say here that hardly any other methods of maintaining a comfortable home environment all year long are as efficient, reliable, or economical, particularlly when you gauge the energy savings.

Here’s how geothermal makes that a reality.

Thar’s Gold Heat in Them Thar Hills!

We tap the earth for precious metals. We tap the earth for oil. Now, as never before, we’re tapping the earth for a commodity likely just as valuable to most 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, oh, say, 33,000 feet under our feet – is a mantle of magma. This is a molten and semi-molten brew, mainly of silicates, in which temperatures vary from 1300 degrees Fahrenheit to 2400 degrees Fahrenheit and hotter the deeper you go (not that you’d want to go there!). What this does is keep the ground immediately under the earth’s surface at a fairly stable year-round temperature of between 45 and 75 degrees Fahrenheit. Meaning? Underground temperatures in Alaska (and pretty much everywhere 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’s interior stays at an optimal temperature to keep you and your family comfy throughout the year.

The device that performs the transfer is a geothermal heat pump. It continuously circulates water or some mixture (predominantly antifreeze) between your home and loops of pipe (predominantly fashioned of polyethylene, high-density polyethylene, PVC, or CPVC) buried in the ground. In Winter, the liquid is cold when it enters the ground. As it courses through the loops, it assimilates heat from the earth and is reintroduced to your home warm. In Summer, the process is reversed: warm liquid goes into the loops, where it absorbs the cooler ground temperatures before it’s returned to your home. Want details? You’ll find more specific information on ground loops here.

The key point is that geothermal heating and cooling systems don’t produce energy. They’re not like central heating systems, which generate heat themselves. Instead, geothermal systems heat and cool your home by mobilizing the energy already richly available beneath the earth’s surface. That’s why geothermal systems not only run quieter but also are considerably more trustworthy, need less maintenance, have far longer lifespans, and are more environmentally friendly than conventional HVACs. That’s also why, in the long run, you’ll save a lot more more money by going geothermal.

Curious now? Get hold of Energy Efficiency Associates, your Alaska geothermal heating and cooling professional, today.