Benefits of GeoExchange Systems


Good for the Environment


More than two thirds of the energy delivered to your home by a GXS is renewable solar energy stored in the ground. This is great for your wallet because it is free energy. It is also good for the environment because there are virtually no toxic emissions. Each kilowatthour (kWh) of electricity used to operate a GXS draws more than 3 kWh of free, renewable energy from the ground.

A large part of the cost of energy supplied to your home is the expense of getting it there. Electric transmission lines, gas lines and oil pipelines are costly to build and require extensive rights-of-way. Oil is shipped in tankers halfway around the world so you can heat your home. Trucks delivering fuel to your home need fuel and maintenance. Shipping energy to your home entails real costs. They include not only direct expenses, like building pipelines and maintaining transmission lines, but also indirect costs, like dealing with emergencies. The infrastructure needed to transport energy is large and expensive – for you and the environment. With a GXS, most of the energy you need is moved less than a few hundred metres into your home. The cost of transporting earth energy into your home is the cost of running a circulating pump.

When a conventional airconditioning system is installed in a home, refrigerant lines run from the outdoor condensing unit to the coil in the furnace. GXS, on the other hand, are assembled and tested under controlled conditions, so that a refrigerant leak is much less likely. Also, any leak from a GXS would be much smaller, as it usually contains just one half the refrigerant charge of a conventional air-conditioning unit.

Year-Round Comfort

People living in homes with a GXS often say, “This home is the most comfortable we’ve ever lived in.” There are several reasons for this. The air temperature produced by a GXS is typically about 35°C. The air produced by a fossil fuel furnace or electric furnace is often heated to 50–60°C – much warmer than room temperature. This can create hot spots in a room. Moving around the room, you can often feel temperature differences of 3–4°C.

You may have lived in a home where you were often about to adjust the thermostat just before the furnace came on, and a few minutes later had to take off your sweater. This is caused by oversizing the conventional heating system. Even on the coldest day, an oversized furnace may only run for 15 minutes an hour, because it can produce all the heat you need by running only 25 percent of the time. The thermostat is satisfied quickly when the furnace is on, and may even overshoot the desired temperature by a degree or two, and then the temperature drops several degrees before coming on again. This happens because the cost of installing a larger furnace is almost insignificant, so the “bigger is better” attitude often prevails. If the heat loss of a home is reduced (by upgrading the insulation or windows), the overheating problem is made worse.

The cost of installing a larger GXS, however, makes it prohibitive to oversize a system. As a result, it runs almost continuously, maintaining very even temperatures throughout the home. Several manufacturers build two-speed units with multi-speed fans.

These match the heating and cooling loads of your home virtually year round. In spring and fall, when you do not need the full capacity of the system, the compressor and fan will operate at low speed, providing only as much heating and air conditioning as you need. As the days get colder in winter, or during very hot summer days, the system will operate at high speed.

Most GXS are installed with electronic thermostats that offer more precise temperature control and that switch from heating to air conditioning automatically. You will find that, on days in the spring and fall when you need heat in the morning and cooling in the afternoon, you are
more comfortable.

Operating Cost


As noted earlier, more than two thirds of the energy supplied by a GXS is renewable energy taken from the ground. The other third comes from the electricity used to power the system. You only pay for the electricity you use to operate your system. The other two thirds is free.

How does the cost of heating your home with a GXS compare to the cost of heating it with other fuel options? That depends on the cost of the fuel and on how efficiently your furnace uses it. As a fossil fuel furnace sends the products of combustion (CO, CO2, SO2, NOx, etc.) up the chimney, some heat leaves the house as well. Older furnaces with pilot lights burn some gas continuously, even when your home does not need heating.If you are using an old gas or oil furnace, you can be venting as much as 35 to 40 percent of the fuel you have purchased up the chimney.

If the furnace is greatly oversized, it may waste even more energy, because by the time it reaches operating efficiency, it has already satisfied the thermostat and shuts off.

Electric furnaces and electric baseboard heaters do not require a chimney. All the energy they generate stays in your home – even if the electric motor distributing air through your home is not very efficient. An electric furnace or baseboard system can therefore be considered 100-percent efficient.

A GXS does not create any combustion products. As with the electric furnace, all the electric energy used to run the compressor, the pump and the fan stays in the house. But since the system also draws additional free energy from the ground, it can actually produce more energy than you put into it. Because of this, a GXS can be considered to operate at more than 100 percent efficiency.

The efficiency of a heating system is measured as the Coefficient of Performance (COP). Measuring the energy your GXS produces, and dividing it by the energy you put into it (and pay for) gives you the COP. For example, if you purchase natural gas that could, if burned completely, produce 100 units of heat, but 7 of those units are lost up the chimney, the COP is as follows:

(100 - 7) ÷ 100 = 0.93

GXS intended for open-loop systems have heating COP ratings ranging from 3.0 to 4.0. For closed-loop heating applications the COP rating is between 2.5 and 4.0.

Low Maintenance and Long Service Life

The heat pump in a GXS works like a refrigerator. The heat it takes from the earth is brought into your home in the same way your fridge brings the heat from the food placed in it into your kitchen – by means of the coil at the back of the fridge. The only significant difference, other than capacity, is the addition of a reversing valve that allows your GXS to cool your home and send the heat out of your house and into the earth. The compressor of a heat pump is similar to, but much larger than, a fridge compressor. The only other moving parts are the blower motor and the pump to circulate fluid through pipe buried in the ground. Unlike an air conditioner, the equipment is located inside your home – not exposed to dust, rain, snow and extreme temperatures. If the system (i.e., the earth loop and the distribution system) is designed to match the needs of your home, it will operate with very little maintenance, much like your refrigerator. The only regular maintenance you will have to do is to make sure the air filter is clean (if you have a forced-air system).

Inspections to clean the ductwork and fan and check that the electrical contacts are not worn should be part of an annual service contract. If you install an open-loop or well-water system, the heat exchanger in the heat pump may require regular cleaning by a qualified service contractor.

Several studies have shown that a GXS lasts much longer than a conventional fossil fuel furnace and air-conditioning system, as the GXS is not exposed to rain, snow and extreme outdoor temperature changes. The earth loop, if installed to CSA standards, can be expected to perform well for 50 years or more.

Heating Domestic Hot Water


After space heating and air conditioning, heating water is the largest single energy user in most homes. Water pre-heating capability can be added to your heat pump simply by including a heat exchanger into the refrigerant circuit inside the heat pump. Most heat pump manufacturers offer units with a desuperheater. Whenever the heat pump compressor is running to heat or cool your home, water from a conventional electric water heater is circulated through the desuperheater and heated by the hot refrigerant. When the heat pump is not running, the electric heaters in the hot water tank heat the water. Depending on hot water use, a desuperheater can provide from 30 to 60 percent of the hot water needed in the average home. 

Some manufacturers have taken this concept a step further by offering heat pumps that can produce all of the hot water needed on demand. These heat pumps are designed to switch automatically from heating and cooling air (by means of a forced-air system) to heating water, which can be used for domestic use or for a hydronic (hot-water) heating system.

The initial cost for this type of unit is higher, but with a large demand for hot water, the extra cost can be recovered quickly. These units are ideal for:

  • homes with large families and large demands for domestic hot water; 
  • homes with a hydronic heat distribution system in one part of the home and a forced-air system in others (e.g., radiant floor heat in the garage or basement and forced-air on the main level); and
  • heating an outdoor swimming pool during the summer months.

Non-Intrusive and Quiet


GXS use the earth or ground water to dissipate the heat from your home to cool it. Conventional (air-cooled) air conditioners or air-source heat pumps move the heat inside your home to the outside. A GXS replaces the outdoor condensing units of a conventional system with a ground loop or well-water system that is buried underground. With a GXS, the outdoor compressor, fan noise and space needed for a condensing unit are eliminated, leaving you with a quieter, more peaceful backyard.

Other Benefits


Because all of the mechanical components of a GXS are inside, they are protected from vandalism and the weather. GXS can be applied to almost any house type and location; the type of system you choose depends on the availability of land or water, soil conditions, local regulations and other factors.



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