General

How does a geothermal system work?
What makes a geothermal system different from conventional systems?
How efficient is a geothermal system and what are the savings?
What are the benefits of a geothermal system?
What does geothermal mean to the environment?
Do geothermal systems require much maintenance?
Are geothermal systems installed in new constructions only? or can they be installed in existing buildings?

Questions about a geothermal heating/cooling system

What is the capacity (size) of the heating and cooling system that is being proposed?
Is the efficiency rating actual or just a manufacturer"s average?
Is MENA Geothermal qualified to design and install geothermal systems?
How long is the payback period for your geothermal heat pump system?
If a home has a radiator distribution system, do air ducks need to be installed?

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

What is a geothermal heat pump?
How does it work?
How is heat transferred between the earth and the home or building?
Does it do both heating and cooling?
Do I need separate ground loops for heating and cooling?
What types of loops are available?
Does the underground pipe system really work?

Closed-loop systems

What is a closed-loop system?
Where can this loop be located?
How deep and how many boreholes can a ground-loop be?
What is a thermal conductivity test?
Do I need a thermal conductivity test?
How many pipes are inserted in a bore-hole?
How long will the loop pipe last?
How are the pipe sections of the loop joined?
Will an earth loop affect my lawn or landscape?
Can I install an earth loop myself?
I have a pond/lake/ocean near my home. Can I put a loop in it?

Open-loop systems

What is an open-loop system?
What do I do with the discharge water?
How much groundwater does an open-loop system need?
What problems can be caused by poor water quality?
Does an open-loop system cause environmental damage?
Are there any laws that apply to open-loop installations?

Parts of the system

What are the components of a geothermal heat-pump system?
Are all geothermal heat pumps alike?
Will I have to add insulation to my home if I install one of these systems?
Can a geothermal heat pump also heat water?
Is a geothermal heat pump difficult to install?
Can a geothermal heat pump be added to my fossil fuel furnace?
I have ductwork, but will it work with this system?
Do I need to increase the size of my electric service?
Should I buy a heat pump large enough to heat my home with no supplemental heat?

How does a geothermal system work?
The earth naturally absorbs 50% of the Sun"s energy and stores it as clean renewable energy, thus the temperature in the earth remains constant throughout the entire year. In Palestine and Jordan, for example, the temperature in the earth is at a constant 17 degrees Celsius throughout the entire year. In the winter, the 17 degrees constant ground temperature is warmer than the 4 degrees outside air, thus by pumping water into a system of pipe installed deep in the earth, we can absorb heat from the warmer ground, channel it to an electrically powered geothermal heat pump, which takes the heat, compresses it and outputs it to the building at 45C. In the summer the same exact system is simply reversed. The 17 degrees constant temperature in the ground is now cooler than the 36C outside hot air, thus we take the buildings heat, returning chilled water to the building, and reject the buildings heat down to the cooler earth.

What makes a geothermal system different from conventional systems?
A geothermal system utilizes the energy stored in the earth, to heat and cool homes and buildings. Electricity is used only to operate the heat-pump unit and circulation pump which are required to facilitate the heat transfer between the building and the earth. So, unlike conventional systems, geothermal systems do not burn fossil fuel to generate heat--they simply transfer heat to and from the earth.

How efficient is a geothermal system and what are the savings?

A geothermal system is more than three times as efficient as the most efficient conventional system. Because geothermal systems do not burn combustible fuel to make heat, they provide three to four units of energy for every one unit used to power the system. When compared to diesel or gas boilers for heating, geothermal systems save 70% on energy consumption. When compared to chillers or mini-split units cooling units, geothermal system save roughly 55% on energy consumption.

According to the U.S. Environment Protection Agency geothermal system are "the most energy efficient, environmentally friendly, cost-effective space conditioning systems available".

What are the benefits of a geothermal system?

Lower Operating Costs: A geothermal system operates more efficiently than ordinary heating and air conditioning systems - up to 70%.

Comfortable: Because the unit uses the relatively stable temperature of the earth as an energy source, you are assured of constant, even winter heating and better humidity control in the summer.

Safe and Clean: No flame, no fuel, no odors, just safe reliable operation year after year.

Flexibility:The same heat pump unit can provide heating, central air conditioning and hot water.

Economical Water Heating:Water heating can be a significant energy expense. Geothermal heat pump units can reduce the high cost of water heating by as much as 66%.

Attractive: The completely self-contained indoor unit needs no noisy, unsightly outside condensing unit.

Environment: The system emits no carbon dioxide, which is considered a major contributor to environmental air pollution.

Long Life: Geothermal heat pumps have a long service of around 20 years and geothermal ground loops are guaranteed to last over 50 years.

What does geothermal mean to the environment?
Because geothermal systems work with nature, not against it, they minimize the threats of acid rain, air pollution and the greenhouse effect. Geothermal systems are completely environmentally friendly. An environmentally friendly refrigerant is used inside the heat-pump.

Do geothermal systems require much maintenance?
No. In fact, geothermal systems are practically maintenance free. When installed properly, the buried ground loop will last for generations. And the other half of the operation--the heat-pump unit"s fan, compressor and pump--is housed indoors, protected from the harsh weather conditions. Usually, periodic checks and filter changes are the only required maintenance for water-to-air heat-pump units.

Are geothermal systems installed in new constructions only or can they be Geothermal systems can be installed in new construction or existing building?
Geothermal systems can be installed in new construction or existing building. Of course, with new constructions, geothermal system will cost less as parts of the ground where the ground -loop will be drilled will already be excavated. Geothermal system can be installed in existing buildings by replacing the old system – such an installed is called a retro-fit installation.

What is the capacity (size) of the heating and cooling system that is being proposed?
Heating and cooling units are designed to provide or reject specific amounts of heat energy per hour. The terms "BTUH", or "kW/h" or "tons of refrigeration" refers to how much heat can be produced or rejected by the unit in an hour. Before you can determine what size heating/cooling unit, you must have a heat loss/heat gain calculation done on the building or home. From that, an accurate determination can be made on the size of the heating/cooling system you"ll need. Most conventional systems are substantially oversized for heating/cooling requirements, resulting in increased operating cost.

Is the efficiency rating on heating and cooling equipment actual or just a manufacturer"s average?
All types of heating and cooling systems have a rated efficiency. Fossil fuel furnaces have a percentage efficiency rating. Natural gas, propane and fuel oil furnaces have efficiency ratings based on laboratory conditions.
Geothermal heat pumps, as well as all other types of heat pumps, have efficiencies rated according to their coefficient of performance or COP. A COP is a ratio between the energy consumed by the system and the energy produced by the system. Most geothermal heat pump systems have COPs of 3.5 - 4.5. That means for every one unit of energy used to power the system, three and one-half to four and one-half units are supplied as energy. Where a fossil fuel furnace may be 50-90 percent efficient, a geothermal heat pump is about 400 percent efficient. Some geothermal heat pump manufacturers and electric utilities use computers to accurately determine the operating efficiency of a system for your home or building.

Is MENA Geothermal qualified to design and install geothermal systems?
Yes. MENA Geothermal engineers have over 15 years of experience in the design and installation of HVAC mechanical systems. Furthermore, MENA employs the only engineers certified as Accredited Installers by the International Ground Source Heat Pump Association (IGSHPA), and as Commercial Geothermal Designers by the Canadian GeoExchange Coalition (CGC) in the Middle East and North Africa Region. MENA"s engineers are graduates from the world"s most accredited engineering programs including the University of Waterloo in Canada.

How long is the payback period for your geothermal heat pump system?
To figure this accurately, you must know how much per year you"ll save in energy costs with a geothermal system in comparison with a conventional heating system and central air conditioner. To calculate your return on investment (payback in number of years), divide the annual savings into the additional investment . In Palestine and Jordan for example, the payback period on a geothermal system is roughly 5 – 7 years. When you install a geothermal system in a new home, the monthly savings in operating costs will generally offset the additional monthly cost in the mortgage, resulting in a monthly positive cash flow immediately. Keep in mind that energy savings is only one of the many benefits you receive from a geothermal system.

If a home has a radiator distribution system, do air ducts need to be installed?
Not always. It may be desirable to install geothermal heat pump room units. For some small homes, one room unit would provide most of the heating and cooling needs. Radiator units could then be used for supplemental heat.

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

What is a geothermal heat pump?
A geothermal heat pump is an electrically-powered device that uses the natural heat storage ability of the earth and/or the earth"s groundwater to heat and cool your home or business.

How does it work?
Like any type of heat pump, it simply moves heat energy from one place to another. Your refrigerator works using the same scientific principle. By using the refrigeration process, geothermal heat pumps remove heat energy stored in the earth and/or the earth"s groundwater and transfer it indoors.

How is heat transferred between the earth and the home or building?
The earth has the ability to absorb and store heat energy. To use that stored energy, heat is extracted from the earth through a liquid medium (usually water) and is pumped to the heat pump or heat exchanger. There, the heat is absorbed by a heat-pump, compressed, and outputted at a very high temperature to heat the air. In summer, the process is reversed and indoor heat is extracted from indoors and transferred to the earth through the liquid medium.

Does it do both heating and cooling?
One of the things that makes a geothermal heat pump so versatile is its ability to be a heating and cooling system in one. You can change from one mode to another with a simple flick of a switch on your indoor thermostat. In the cooling mode, a geothermal heat pump takes heat from indoors and transfers it to the cooler earth through an underground loop system.

Do I need separate ground loops for heating and cooling?
No. The same loop works for both. All that happens when changing from heating to cooling, or vice versa, is that the flow of heat is reversed.

What types of loops are available?
There are two main types: open and closed. The next two sections will give you specifics about each.

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 1940s.The type of pipe that is used in the ground loop is High Density Polyethylene Plastic (HDPE) which is highly durable and guaranteed to last for many decades.

Closed-loop systems

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 water is circulated. Unlike an open-loop system that consumes water from a well, a closed-loop system recirculates its heat-transferring water solution in pressurized pipe.

Where can this loop be located?
That depends on land availability and terrain. Most closed-loops are drilled vertically adjacent to the building. For residential projects with lots of area around them, a horizontal loop can installed. Any area near a home or business with an adequate square meter area will work for a vertical closed loop system.

How deep and how many boreholes can a ground-loop be?
The number of holes and their depth depends on the total amount of energy required to heat and cooling the building or home which is determined from a heat-loss calculation on the building. Generally, vertical bore holes are drilled to a depth of 100 meters and are 6 inches in diameter. Boreholes are separated by a radial spacing of 5 meters to avoid thermal interference.

What is a thermal conductivity test?
A thermal conductivity test is conducted for large ground loops or new drilling areas to facilitate the acquisition of data from the rock formation beneath the site in which you wish to install a vertical ground heat-exchanger or ground loop. The gathered data will provide information regarding the thermal conductivity, thermal diffusivity, and undisturbed temperature of the earth at a depth of 100 meters from the earth"s surface. Thermal conductivity/diffusivity of the ground is essentially the ability of the ground to absorb and/or release energy. This information is necessary in order to accurately design a ground heat-exchanger capable of transferring energy to and from the earth for the purpose of heating and cooling a building.

Do I need a thermal conductivity test?
A thermal conductivity test is usually only conducted for large commercial projects where a large number of boreholes will be drilled.

How many pipes are inserted in a bore-hole?
Normally, two pipes, one supply and one return, are inserted in the borehole with a U-shaped fitting connected to them.

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 for many decades. 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 glue 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 after installation that can be restored with grass seed or sod. Vertical loops require little space and result in minimal lawn damage.

Can I install an earth loop myself?
No. In addition to thermal fusion of the pipe, good earth-to-coil contact is very important for successful loop operation. Nonprofessional installations may result in faulty systems.


I have a pond/lake/ocean nearby. Can I put a loop in it?
Yes, if it"s deep enough and large enough. A minimum of 2 meters in depth at its lowest level during the year is needed for a pond to be considered. The amount of surface area required depends on the heating and cooling load of the structure.

Open-Loop Systems

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 or rejected, 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.) or liters per second (L/s) and is listed in the specifications for that unit. Generally, the average system will use 1.5 g.p.m. per ton of capacity 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.

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. MENA Geothermal can tell you what level of water 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 a 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 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. Some people are concerned that open-loop systems contribute to the depletion of our ground water resources. This issue is not critical in some parts of the world where there are abundant supplies of ground water.

Are there any laws that apply to open-loop installations?
In some countries, all or parts of the installation may be subject to local ordinances, codes, covenants or licensing requirements. Check with your local authorities to determine if any restrictions apply in your area.

Parts of the System

What are the components of a geothermal heat-pump system?
The three main parts are the heat-pump unit, the ground heat-exchanger (open or closed loop), and the distribution system (air ducts, under-floor heating, fan coils, etc.).

Are all geothermal heat pumps alike?
No. There are different kinds of geothermal heat pumps designed for specific applications. Many geothermal heat pumps, for example, are intended for use only with higher temperature ground water encountered in open-loop systems. Others will operate at entering water temperatures as low as -4°C which are possible in closed-loop systems (in which case anti-freeze solution used instead of water).
Most geothermal heat pumps provide summer air conditioning, but a few brands are designed only for winter heating. Geothermal heat pumps can also differ in the way they are designed. Self-contained units combine the blower, compressor, heat exchanger and coil in a single cabinet. Split systems allow the coil to be added to a forced-air furnace and utilize the existing blower.

Will I have to add insulation to my home if I install one of these systems?
Geothermal heat pumps will reduce your heating and cooling costs regardless of how well your home is insulated. However, insulating and weatherizing are key factors in realizing the most savings from any type of heating and cooling system.

Can a geothermal heat pump also heat water?
Yes. Using what"s called a desuperheater, some types of geothermal heat pumps can save you up to 50 percent on your water-heating bill by preheating tank water. Desuperheaters are standard on some units, optional on others. Some geothermal models can provide all of your hot water needs on demand at the same high efficiencies as the heating/cooling cycles.

Is a geothermal heat pump difficult to install?
Most units are easy to install. They can be installed in areas unsuitable for fossil fuel furnaces because there is no combustion, thus, no need to vent exhaust gases.

Can geothermal heat pump be added to my fossil fuel furnace?
Hybrid systems can easily be added to existing furnaces/chiller for those wishing to have a hybrid heating or cooling system. Hybrid systems use the heat pump as the main heating/cooling source and a conventional fossil fuel furnace/chiller as a supplement in extremely cold/hot weather if additional heating/cooling is needed.

I have ductwork, but will it work with this system?
In all probability, yes.

Do I need to increase the size of my electric service?
Geothermal heat pumps don"t use large amounts of resistance heat, so your existing service may be adequate. Generally, a 200-amp service will have enough capacity, and smaller amp services may be large enough in some cases. Your electric utility or contractor can determine your service needs.

Should I buy a heat pump large enough to heat with no supplemental heat?
A heating and cooling load calculation (heat loss, heat gain) must be determined to guide your equipment selection. Geothermal heat pumps can be sized to meet your full heating and cooling requirements. Sizing the heat pump to handle your entire heating/cooling needs will result in higher heating/cooling costs savings, but the savings may not offset the added cost of the larger heat pump unit. Also, an oversized unit can cause dehumidification problems in the cooling mode, resulting in a loss of summer comfort. As a result, the best system is designed to meet your comfort requirement by MENA Geothermal to provide with you optimal savings and lowest investment required.

 
Geothermal Overview
How it Works
How You Benefit
FAQ