Using the Ground as a Heat Source and Heat Sink
The ground soil, rock or water, all provide a stable heat source for heat pumps. Ground temperatures in most of Ontario range between 40° F. 50° F.
Heat transfer possibilities to and from the ground, back and forth, for space heating and cooling are almost limitless, hindered only by the degree of difficulty in installing the ground heat exchanger.
For
the most part, the energy derived from ground heat exchange
is solar. If you can imagine sitting in front of a window on
a sunny day in winter with the sun streaming into the room,
it feels quite warm. The sun will heat and can sometimes actually
overheat a building in winter.
Now imagine the amount of solar energy per sq. ft. hitting
a cold football field in winter, with a 5° F to 10°
F cooler earth loop circulating underneath it absorbing that
energy.
The amount of natural Btuh. transferring to the ground at that time is enormous. Enough to heat the school it belongs to and then some. Without an earth loop it is just a wasted energy potential.
Friendlier to the Environment? Yes!
While no current heating and cooling technology is totally benign to our environment, GSHP systems certainly are acknowledged to be, the earth friendliest heating and cooling technology by governments and utilities.
Peak Demand
All
utilities experience a peak power demand period for 2 to 4 weeks,
summer and winter.
All competing electromechanical technologies including:
- resistance heating
- air conditioning
- air source heat pumps (ASHP)
require maximum power during Peak periods.
Even though ASHP system's heating performance and reliability have improved over the last 15 years, their heating capacity and efficiency still decline rapidly as the air temperature, (source of heat) outside gets colder.
Moisture in the air starts to freeze on the outdoor coil of an ASHP once the outside air is around 32 deg. F. Ice builds up on the coil reducing airflow and frequent defrosting sequences start to occur.
At those times, in winter an ASHP will automatically reverse cycle into air conditioning mode, taking heat from warm air from inside the house, to warm the outside coil and melt the ice.
Depending on the outdoor temperature and the degree of ice build up, this process can take from a couple of minutes or 20 minutes or longer.
Regardless, an ASHP will require 100% back up heat to maintain comfort in the home while it is defrosting because it is not heating the home at that time, it is cooling the home.
A Geothermal System is therefore a particularly useful heating appliance in colder climates, such as Canada, the Northern United States or Northern Europe, because, unlike air source heat pumps operating in cold climates, a geothermal system can be sized and installed with little or no auxiliary heat requirement, thus reducing peak demand and replacing it with energy, free from the ground.
Winter Peak Demand Reduction
If at the highest heating energy demand times an ASHP requires 100% back up, then it does nothing to reduce peak energy demand.
If a Geothermal System required even 1/2 the auxiliary heat of an ASHP then it would reduce power Peak Demand by around 32%.
That's on top of the energy savings provided by the system.
This is an important matter, because building new power costs about $ 5,000.00 per Kilowatt.
Saving
the same Kilowatt with an earth loop costs around $ 800.00.
GSHP's, heat and cool, (work) by
transferring thermal, (heat) energy
between any building and the surrounding soil. Heat transfer is
a more efficient process
than combustion.
COP = energy output ÷ energy input COP = 3.5 kW output ÷ 1 kW input COP = 3.5
Geothermal Systems independently monitored by utilities have exhibited COP's between 3.0 and 4.0. in the field. That is equivalent to a furnace average efficiency of approximately 350%.
Summer Peak Demand Reduction
Similarly
summer peak demand savings occur because in air conditioning mode
the equipment is liquid cooled.
Engineers and industry have known for years that water cooled
refrigeration equipment demands less power, costs less to operate
and lasts longer than air cooled equipment.
Comparing Geothermal System Efficiency with Fossil Fuel System Efficiencies
Oil, natural gas and propane furnaces, have all benefited from increased efficiency over recent years. This is mostly due to better combustion chamber designs and modern controls.
All fossil fuel systems still lose a percentage of heat to the flue or chimney, leaving any fuel burning appliance less than 100% efficient. Even the best fossil fuel systems available in the world can only boast combustion efficiencies in the mid to high 90% range.
Electrical operating costs for driven components, e.g., the fan and transformer are seldom included in the fuel supplier's operating cost estimates. Fuel suppliers tend to focus on the fuel consumption only.
When all the costs of operation of a gas, oil or propane furnace are taken into account, along with the heat lost due to cycling, the best fossil furnaces in the world will operate in the mid 80% efficient range when seasonally averaged.
GSHP systems move heat with a mechanical advantage. In a sense, they work similarly to a lever or pulley lifting a heavy weight with low effort. GSHP systems provide more energy than they consume, up to 3.5 times more in fact.
It's impossible to burn fuel at 350% efficiency, but a mechanical advantage makes the system the most energy efficient heating technology commercially available.
Government studies have shown that green house gasses and other air pollutants resulting from fuel combustion, are reduced at the point of use by Geothermal Systems and they are therefore recognized as the heating and cooling system that is the least detrimental to the environment.
Undeniably an environmentally friendlier heating and cooling system, the United States, (DOE) recommends widespread adoption of the technology as part of its' C02 reduction strategy to help reduce global warming. For the environment, this is good news.
No longer do we need to transport fossil fuels over long distances, by pipeline or tanker from the producer's well head to the refinery and finally to our homes. Nor is it necessary to succumb to monopolistic pricing policies of fuel producers.
All
the clean, green and renewable energy you will ever need to heat
and cool your home,
office or business – is
right under your feet!
The Right Blend of Performance and Protection
Of
primary importance to the environment is the type of fluid to
be re-circulated through the ground inside an earth loop.
Closed loop systems require antifreeze protection, because earth
loops may operate below the freezing point of water during the
coldest winter months.
A high quality antifreeze will protect the internal components
from freeze damage of coarse, but most antifreeze solutions do
not transfer heat well, they may be quite toxic and are often
quite corrosive.
Further, quite often antifreeze solutions thicken, (viscosity increases), as their working temperature drops, requiring excessive pumping power. As pump sizing must take into account the worst case scenario for fluid viscosity, it is important that the antifreeze not become too thick during winter operation.
The fluid chosen should to protect a geothermal system therefore must offer:
- good freeze protection
- low viscosity at low operating temperatures
- be of low toxicity
Alcool™ De-natured Ethanol
Made from a natural ethanol mixture, Alcool is specially blended for Geothermal products and is the only earth loop solution that Just Geothermal Systems fully endorses because it meets all of the criteria listed above and more.
It is safe, environmentally friendly, non toxic and has excellent heat transfer characteristics. Further, it is very gentle to the internal components of the system. You could open a system 5 years after the system was installed and there would likely be no rust or corrosion visible.
Alcool
is made from a natural grain alcohol mixture that is inexpensive
and mixes easily with water for a fast installation.
It
is the least toxic solution available.
The USDA mandates the use of a similar mixture to grade stamp
meat for human consumption.
Alcool
has the lowest NFPA, (National Fire protection Association)
Health Warning and heat transfer performance is 20% better than
propylene glycol.
Alcool™ biodegrades faster than any other antifreeze solution type.
Contact your geothermal specialists
or Telephone 519-808-3987