What makes for the most efficient possible geothermal energy system?

Video transcription follows:

Hi, I’m Martin Orio, the business development manager for Water Energy. Our family business has been doing nothing but geothermal for about 38 years now.  What we are really the industry referrers to as a ‘value added distributor’. We do sell the heat pump systems, the geothermal heat pump systems to the installing contractor community for resale, but we also provide end to end design support with that service. The reality is that a properly installed geothermal system depends more on what I do with my delivery and my earth extraction than the box itself.

With a geothermal heat pump, people say “Oh, I get it you bring in the water at 50 degrees and you heat it up to 70, right?”  But actually, no, what we do, is we bring in that 50 degree water, or that 35 degree loop fluid, and we extract heat out of that. It is hard to wrap your head around that, but there’s energy in any mass that is above minus 273 degrees.

So, the further away I am from where I want to be, the more energy I have to use. So, look at an air source heat pump: it’s zero outside, and I want my house to be 70 degrees – that’s a 70 degree trip. Well, if it’s zero outside, and I want it to be 70 in my home – it’s 50 degrees underground, that’s a twenty degree trip.

We’re really just talking about a heat exchanger, and when we talk about that exchanger, we want  to manage the deltas of temperature and pressure on both sides of that box to be the most advantageous, to be what we’d call a ‘sweet spot’, for the refrigerant circuits to make that energy transfer in the most advantageous way, and using the least amount of energy to run that well pump, compressor, and delivery pump, such as a fan or circulator. So those three electric elements are not heaters by any stretch of the imagination, but working together, they’re extracting that free solar energy out of the ground, they’re storing that unwanted solar back in the ground so every mechanical device has frictions and encumbrances that make it less efficient, so when we design the system, we want to make sure that we’re getting just the right amount of fluid, just the right pressure, to be the optimum earth exchange temperature on the earth side, and then let it breath easy on the delivery.

So again, as I depart from that, if I put in duct work a little smaller than it should be, or I don’t do my makeup air systems properly, an I increase the pressure in that ductwork, well now getting the heat off that refrigerant coil with the air stream, I’m going to use more fan energy, and i’m going to have less comfortable delivery off of that coil.  If i don’t’ let it operate in that ideal space, where it’s moving around the refrigerant from a gas to a solid, and back to a gas, to move the energy, then i pay for that in efficiency. And not only that, but in the longevity – think of a refrigerator, if I keep the cat hair vacuumed of the coil of the refrigerator, it’s going to last 30 years. If I choke it off, or don’t let the air flow across the refrigerator coil, i’m going to burn it out. Exactly the same thing is true with a geothermal heat pump.