How It Works

A NextEnergy system makes use of the largest source of energy available - the ground beneath your feet.

The Ground

A geothermal system uses the energy of the sun, stored in the earth, to keep you in comfort all year round. Even in the winter, when a blanket of snow covers the ground, the earth's temperature remains approximately 10°C (50°F) at only six feet below the surface. This means that you have a steady supply of heat to keep you in comfort, even in the depths of the coldest winter.

The Pipes

A series of pipes buried in the ground. An ethanol solution is circulated through the pipes to make them highly efficient conductors of heat. In the winter, the ethanol in the pipes absorbs the heat from the ground and, now warmed up, the fluid is pumped back through the geothermal unit in the house. In the summer, the heat transfer process takes place in reverse. The fluid in the pipes leaves the house in a warm state, but after circulating underground, is cooled as the pipes exchange heat with the cooler earth.

The Geothermal Unit

The underground loops connect to the main geothermal unit installed in your house, and is connected to your home's forced air (or water radiator) system. It is compatible with your home's distribution system.

Forced Air

As our top performer, the Tranquility 27™ forced-air heat pump delivers the highest efficiency ratings in the industry. Self regulating two stage technology allows the Tranquility 27™ to operate at the most efficient speed for all weather conditions. Equipped with an electronic variable speed fan motor (ICM2), the Tranquility 27™ controls system air flow to assure high operating efficiency and superior dehumidification.

Water to Water

NextEnergy's new Tranquility THW™ water-to-water R410A high temperature heat pump provides high temperature output (140°F), internal controls, and factory-installed options. The Tranquility THW™ includes a special high temperature scroll compressor coupled with heat exchangers designed specifically for water heating, which results in unmatched efficiencies and performance.

Water-to-water-in-floor

Designed for use in heating or cooling applications requiring high efficiency performance, the Genesis GSW is the perfect selection. Commonly used residential applications that require energy efficient water to water heat transfer, the Genesis GSW can be used to pre-heat or cool make-up air or can be installed as a stand-alone boiler / chiller in most hydronic heating applications such as radiant floors and fan coil heating / cooling.

The Distribution System

Heating In Winter

After the pipes have done the heat transfer, and the geothermal unit has done its work maximizing the heat value of the circulated fluid, the heat is then drawn off the heat exchanger in the unit and circulated throughout the house using the existing distribution system.

Cooling In Summer

In the summer, the process is reversed. The hot air in the house is essentially absorbed by the geothermal unit which now circulates much cooler pipe fluid. The heat is transferred first to the pipes then to the ground outside before returning, cooled, to the house.

Distribution

The geothermal unit is connected to the home's existing heating/cooling distribution system, whether it's gravity or forced air, water-based (typically with radiators) or water-to-water in-floor radiant.

Low Maintenance

Cleaning the filter is all that's needed to keep the system in good running order.

Quiet Operation

Pumps quietly circulate fluid through the heat exchanger. No combustion or forced-flame noise is heard. An outdoor air conditioning unit, often noisy, is not required.

Comfort

Geothermal systems eliminate indoor temperature swings and humidity changes that often occur with traditional systems. In addition, the occasional odour caused by combustion of fossil fuel will also be eliminated.

Long System Life

Geothermal units have a life expectancy of at least 20 years.

The Environment

Geothermal systems use a renewable resource, the earth, which is efficient and non-polluting. Replacing a fossil fuel system with geothermal immediately cuts your household energy emissions by 50%, the equivalent of taking four cars off the road. Federal and provincial governments recognize the important role that geothermal plays in reducing home energy use, and have created rebate programs to facilitate installation.

Geothermal Heat Pumps: What are they and how do they work?

(For more information, visit the Canadian GeoExchange Coalition FAQ)

How does it work?

How is the heat transferred between the earth and home?

You mentioned heating and cooling - does it do both?

Do I need separate ground loops for heating and cooling?

What types of ground loops are available?

There are four main types: open, closed, horizontal and vertical.

Does the underground pipe system really work?

The buried pipe or "ground loop" is the most recent technical advancement in heat pump technology. The idea to bury pipe in the ground to gather heat energy began in the 1940's but its only been in the last few years that new heat pump designs and improved pipe materials have been combined to make geothermal heat pumps the most efficient heating and cooling systems available.



Closed Loops

What is a closed loop system?

The term "closed-loop" is used to describe a geothermal heat pump system that uses a continuous loop of special buried plastic pipe as a heat exchanger. The pipe is connected to the indoor heat pump to form a sealed, underground loop through which an antifreeze solution is circulated. Unlike an open-loop system that consumes water from a well, a closed-loop system re-circulates its heat transferring solution within a pressurized piping system.

Where can this loop be located?

That depends on land availability and terrain. Most closed loops are trenched horizontally in yards adjacent to the home. But any area near a home or business with appropriate soil conditions and adequate square footage will work.

How deep and long will my trenches be?

Trenches are normally four to six feet deep and up to 400 feet long, depending on how many pipes are in a trench. One of the advantages of a horizontal loop system is being able to lay the trenches according to the shape of the land. As a rule of thumb, 500-600 feet of pipe is required per ton of system capacity. A well insulated, 2,000 square foot home would need about a three-ton system with 1,500-1,800 feet of pipe.

How many pipes are in a trench?

Normally, a run of pipe is laid at five feet then looped back over itself at three feet once the bottom pipe is covered with soil. This allows more length of pipe to be put in one trench and has no adverse affect on system efficiency. Other loop designs use four or six pipes and allow for shorter trenches if land area is limited.

What if I don't have enough room for a horizontal loop?

Closed-loop systems can also be vertical. Holes are bored to about 120 - 150 feet per ton of heat pump capacity. U-shaped loops of pipe are inserted in the holes. The holes are then backfilled with a sealing solution.

How long will the loop pipe last?

Closed-loop systems should only be installed using high density polyethylene or polybutylene pipe. Properly installed, these pipes will last 50-75 years. They are inert to chemicals normally found in soil and have good heat conducting properties. PVC pipe should not be used under any circumstances.

How are the pipe sections of the loop joined?

The only acceptable method to connect pipe sections is by thermal fusion. Pipe connections are heated and fused together to form a joint stronger than the original pipe. Mechanical joining of pipe for an earth loop is never an accepted practice. The use of barbed fittings, clamps and glued joints is certain to result in loop failure due to leaks.

Will an earth loop affect my lawn or landscape?

No. Research has proven that loops have no adverse effect on grass, trees or shrubs. Most horizontal loop installations use trenches about six inches wide. This, of course, will leave temporary bare areas that can be restored with grass seed or sod. Vertical loops require little space and result in minimal lawn damage.

Can I reclaim heat from my septic system disposal field?

No. An earth loop will reach temperatures below freezing during extreme conditions and may freeze your septic system. Such usage is banned in many areas.

If the loop falls below freezing, will it hurt the system?

No. The antifreeze solution in the loop will keep it from freezing down to about 10 degrees F. Three types of antifreeze solution are acceptable: propylene glycol, calcium chloride and methyl alcohol.

Can I install an earth loop myself?

It's not recommended. In addition to thermal fusion of the pipe, good earth coil contact is very important for successful loop operation. Non-professional installations may result in less than optimum system performance.

I have a pond near my home. Can I put a loop in it?

Yes, if it's deep enough and large enough. A minimum of six feet in depth at its lowest level during the year is needed for a pond to be considered. In pond loops, copper, polyethylene or polybutylene pipe can be used.



Open Loops

What is an open-loop system?

The term "open-loop" is commonly used to describe a geothermal heat pump system that uses groundwater from a conventional well as a heat source. The groundwater is pumped into the heat pump unit where heat is extracted, and then the water is disposed of in an appropriate manner. Since groundwater is a relatively constant temperature year-round, it is an excellent heat source.

What do I do with the discharge water?

There are a number of ways to dispose of water after it has passed through the heat pump. The open discharge method is the easiest and least expensive. Open discharge simply involves releasing the water into a stream, river, lake, pond, ditch or drainage tile. Obviously, one of these alternatives must be readily available and must possess the capacity to accept the amount of water used by the heat pump before open discharge is feasible.

A second means of water discharge is the return well. A return well is a second well bore that returns the water to the ground aquifer. A return well must have enough capacity to dispose of the water passed through the heat pump. A new return well should be installed by a qualified well driller. Likewise, a professional should test the capacity of an existing well before it is used as a return.

How much groundwater does an open-loop system need?

Geothermal heat pumps used in open-loop systems need differing amounts of water depending on the size of the unit and the manufacturer's specifications. The water requirement of a specific model is usually expressed in gallons per minute (g.p.m.) and is listed in the specifications for that unit. Your heating contractor should be able to provide this information. Generally, the average system will use ~10 g.p.m. while operating.

Your well and pump combination should be large enough to supply the water needed by the heat pump in addition to your domestic water requirements. You will probably need to enlarge your pressure tank or modify your plumbing to supply adequate water to the heat pump.

What problems can be caused by poor water quality?

Poor water quality can cause serious problems in open-loop systems. Your water should be tested for hardness, acidity and iron content before a heat pump is installed. Your contractor or equipment manufacturer can tell you what level of water quality is acceptable. Mineral deposits can build up inside the heat pump's heat exchanger. Sometimes a periodic cleaning with a mild acid solution is all that's needed to remove the build-up.

Impurities, particularly iron, can eventually clog a return well. If your water has high iron content you should be sure that the discharge water is not aerated before it's injected into a return well.

Finally, you should opt against using water from a spring, pond, lake or river as a source for your heat pump system unless it's proven to be free of excessive particles and organic matter. They can clog a heat pump system and make it inoperable in a short time.

Does an open-loop system cause environmental damage?

No. They are pollution free. The heat pump merely removes heat from or adds heat to the water. No pollutants are added whatsoever. The only change in the water returned to the environment is a slight increase or decrease in temperature.