What Is A Geothermal System And How Does It Work?

Every day, the earth absorbs over half of the sun’s energy. Geothermal (also known as geoexchange or earth energy) systems rely primarily on this stored solar energy to heat or cool a building and provide domestic hot water. Geoexchange systems use a loop field and a ground source heat pump to concentrate heat from the earth and transfer it into a building in winter, or to transfer heat from a building into the earth in summer, where it is stored for extraction later. Geoexchange uses the same heat pump system for both heating and cooling. A common example of a heat pump is a refrigerator, which concentrates and extracts heat from the interior, and rejects it into the surrounding space.

By transferring thermal energy rather than creating it through combustion or electrical resistance, geoexchange systems achieve very high efficiencies. For each unit of electrical energy consumed by a heat pump, three to four units of heat energy are moved from the earth to your building.

The two basic types of geoexchange systems are open loop and closed loop. Closed loop systems are preferred for their reliability and low maintenance.

Ground source heat pumps use a network of fluid filled pipes to transfer heat to and from the earth. The pipes can be inserted into vertical boreholes, buried in horizontal trenches, or submerged in the ocean, lakes, or rivers.

What Is The Average Cost Of Installation?

Installation costs are specific to each site.

Factors affecting installation costs include the heating and cooling load assessment, the usage of the system, the inclusion of domestic hot water or not, the type of distribution system used inside the building, and the thermal conductivity of the local soil.

We have prepared a couple of sample payback analyses to give you an idea of the costs and benefits.

The following downloads are in PDF format:

Download Payback Analysis for 5-Ton Geothermal System Using Ocean Loops

Download Payback Analysis for 5-Ton Geothermal System With Vertical Loops

Bottom Line: What Is The Payback Period?

Some people just want to look at the numbers. Are you wondering how cost-effective a geothermal heating and cooling system would be for your project?

We have put together some sample geothermal payback analyses to give you a clearer picture of up-front costs compared to a conventional system, so you can see how soon your geothermal system would pay for itself.

The following downloads are in PDF format:

Download Payback Analysis for 5-Ton Geothermal System Using Ocean Loops

Download Payback Analysis for 5-Ton Geothermal System With Vertical Loops

What Kind Of Equipment Do You Use?

People ask us what a the geothermal equipment looks like and what brands we use.

Over several years of installing geothermal systems, we have used many different brands and models.

We choose equipment on a case-by-case basis, but to give you an idea, here are a few different kinds of heat pumps.

What Are Some Good Geoexchange / Geothermal Links?

Geoexchange Links

Here are some useful resource sites we recommend in addition to the information we have provided here on www.exchangenergy.ca.

Enjoy!

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• Canadian Geoexchange Coalition www.geo-exchange.ca
  
• GeoExchange BC: www.geoexchangebc.ca
  
• BC Hydro: High Performance Building Program: www.bchydro.bc.ca
  
• Natural Resources Canada: Press Release: www.nrcan-rncan.gc.ca
  
• Terra Firma Builders: www.sirewall.com
  
• inter solar: www.intersolar.de
  
• Tekmar Controls: www.tekmarcontrols.com
  
• UPONOR Radiant Floors:  www.uponor.ca
  
• Chillventa 2010: www.chillventa.de

ADDITIONAL LINKS:

• www.digtheheat.com
  A guide to Renewable Energy including geothermal power and ground source heat pumps, solar power, wind energy, biofuels, green investment and government incentives. Clear explanations with examples, illustrations and videos.

Can Geothermal Be Used to Heat And Cool Greenhouses?

Yes. exchangenergy is able to design an efficient geothermal system, bearing in mind the special air-handling concerns involved with greenhouses.

exchangenergy has written an in-depth article on our blog about this topic. Click here to read more about geothermal systems for greenhouses.

Will a Geothermal System Work For Domestic Hot Water (DHW)?

DHW is not incorporated in a typical geothermal heating and cooling system. That said, it is possible to use geothermal for DHW, but there are several factors to bear in mind, and special equipment usually required.

exchangenergy has written an in-depth article on our blog about it. Click here to read more about geothermal systems for DHW.

Is It Possible To Install A Do-It-Yourself (DIY) Geothermal System?

It may not seem like rocket science, but without a certified installer, the proper function of a DIY geothermal project, not to mention the warranties on the equipment involved, is at risk.

exchangenergy has written an in-depth article on our blog about it. Click here to read more about DIY geothermal projects.

What Are ‘Slinky Loops’?

Slinky loops are perhaps the most-photographed component of geothermal systems (they are the coiled loops you may have seen in stock photos of geo systems), but at exchangenergy, we disagree with the predominant use of this technology, largely because we take pride in installing maintenance-free, reliable, “right-size” geothermal systems.

exchangenergy has written an in-depth article on our blog about it. Click here to read more about slinky loops and the laws of physics.

Is It Feasible To Retrofit An Existing Electric- Or Oil-Heated Building With A Geoexchange System?

Sometimes yes, sometimes no. There are several considerations when deciding if a geothermal system would be cost effective in an existing building.

exchangenergy has written an in-depth article on our blog about it. Click here to read more about what to consider when deciding on a geothermal retrofit.

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