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cooling india from the ground up
Geothermal India is Indias leading exponents of distributing,
installing and servicing Geothermal Air-conditioning solutions in
India.
what is Geothermal and how does it work?
Geothermal (or Geo-exchange) is a type of HVAC System
(Heating, Venting, and Air-Conditioning).
The earth absorbs almost 50% of all solar energy and
remains a nearly constant temperature of 10C (50F)
depending on geographic location. Working with an
underground loop system, a geothermal unit utilizes
his constant temperature to exchange energy
between the building and the earth as needed for
heating and cooling.
In the summer, the system expels heat from
buildings to the cooler earth via the loop system.
This heat exchange process is natural and a
highly efficient way to create a comfortable
climate in buildings. A geothermal system
differs from a conventional furnace or boiler
by its ability to transfer heat versus the
standard method of producing the heat and
vice-versa.
In winter, the system reverses and water
circulating inside a sealed loop absorbs
heat from the earth and carries it to the
unit. Here it is compressed to a higher
emperature and sent as warm air to the
indoor system for distribution
throughout the building.
Geothermal is the most efficient Air-
conditioning system because the
ground temperature stays stable and
has no regard for the above ground
ambient temperature. (continued)
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A geothermal heat pump simply takes advantage of this low
emperature energy source and pumps it up to a usable
evel to cool/heat the building. Geothermal Heat Pumps are
very different as compared to "Air to Air" Heat Pumps. "Air
o Air" Heat Pumps absorb energy from the outdoor air
which fluctuates on a daily basis. Geothermal Heat Pumps
draw energy out of the ground which stays relatively
constant year round.
nteresting facts about geothermal air-conditioning. There are more than 1 million installations in the USA
alone
Geothermal technology has been successfully installed in
more than 38 countries, including India
Geothermal technology has successfully been installed in a
variety of different climates from just below the arctic circle
to 1o north of the equator
Geothermal technology has been successfully installed in
areas with all major soil conditions.
The largest installation is at Fort Polk, Louisiana, USA, where
more than 4,000 homes are connected. Other notableinstallations include 4,700 TR (Tons of Refrigeration) used by
Galt House in Louisville, Kentucky, USA
Geothermal technology and its performance has been accredited
and acknowledge by:
US Department of Energy
US Environmental Protection Agency (EPA)
US General Accounting Office (GAO)
American Society of Heating, Refrigerating, and Air
Conditioning Engineers (ASHRAE), whose standards are
closely followed by their Indian counterparts, ISHRAE
American Refrigeration Institute (ARI)
product efficiency: the energy efficiency ratio EER.
Efficiencies are defined by two parameters: The Coefficient of Performance (COP)
and Energy Efficiency Ratio (EER). The steady state EER is defined as cooling
output delivered in British Thermal Units per Hour (Btu/h) divided by the power input
n watts. The COP is defined as the heating output divided by the power input in same
units.
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geothermal india
cooling india from the ground up
In case of a heat pump, this parameter is presented in slightly different ways for the heating and cooling
modes. For cooling, the efficiency parameter is the Energy Efficiency Ratio (EER):
EER = (Total Cooling Capacity in Btu/hr (Watts)) / (Power Input in Watts)
For heating, the efficiency parameter is the Coefficient of Performance (COP):
COP = (Heating Capacity in Btu/hr (Watts)) / (Power input in Btu/hr (Watts))
The general EER Values for different systems are:
Air source conditioning system: 9.5
Cooling tower conditioning system: 10.5
Geothermal system: 18
It should be noted that the EER and COP are dependent on the Entering Water Temperature, Water Flow
Rate, Airflow Rate and Entering Air Temperatures. Therefore, there is a need to be specific when comparing
EER and COP of different units.
The Environmental Protection Agency of the US has recognized Geothermal Technology (also known as
GeoExchange) as the most efficient and environmentally friendly home heating and cooling system
available. According to studies by the Environmental Protection Agency, Geothermal systems achieved a
48% increase in efficiency over gas furnaces, a 75% increase in efficiency over oil furnaces, and 40% greater
efficiency over air source heat pumps.
geothermal vs. conventional air conditioning.
Nearly all conventional residential and light commercial buildings use refrigerant type air conditioning
systems for cooling the interior space. These units all have the familiar outdoor condenser units. Variations
include packaged heating/cooling units and air source heat pumps. All use outside air to cool the refrigerant,
while rejecting heat into the surrounding air. These units will be referred to as "air source" equipment.
Comparisons between Geothermal and conventional air source units are convoluted because of the sharp
decrease in efficiency of air source equipment as a function of outside air temperature. Manufacturers of air
source equipment are quick to post impressive EER and SEER (Seasonal Energy Efficiency Ratios)
numbers on their "high efficiency" models, but a closer examination of the actual performance data shows
that these lofty numbers do not correlate well under realistic installed conditions. A typical example of a 3-ton
air source unit shows manufacturer's EER as 12.0. However, a closer look at performance values yields a
calculated EER value of 10.5, at rated conditions. This would represent a daytime temperature of about 32.2
C.
When the outside temperature rises to 37.7C, the air source EER drops to 9.2, which represents a
reduction in efficiency of 12%. If outside temperature rises to 43.3 C, the air source EER drops even
further to 7.7, which represents a reduction in efficiency of 27%. This means that the unit is requiring
27% more electricity to yield the same cooling.
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geothermal india
cooling india from the ground up
Another aspect of the air source units is that the cooling ability of
he unit is also a function of outside air temperature. A typical
3-ton unit can put out 3 tons of air conditioning when the outside
air temperature (at the condenser) is 35 C. But, if the outside
air temperature rises to 43.3 C, the unit can only put out
approximately 2.6 tons, a reduction of 14%. Condensers that
are clogged with dirt or debris will have even further reduction
n efficiency.
The performance of an appropriately designed geothermal
system is independent of changes in outside air temperature and
humidity. Since the temperature of the earth where the
geothermal occurs is relatively unchanged throughout the year,
Geothermal efficiency of both heating and cooling seasons is
ixed. Typical efficiency for a 3-ton Geothermal Systems in cooling
mode with entering water temperature (EWT) of 20 C is
approximately 17 EER. The following table and chart gives a
comparison of Geothermal to air source units as outside
emperature varies:
EER Comparison Geothermal v. Air Source Cooling
Outside Temp 32.2C 37.7C 43.3C
Geothermal 17 17 17
Air Source 10.5 9 8
As indicated in the table above, Geothermal systems for air conditioning are
considerably more efficient than the conventional air source units. Simple calculations
show that energy costs for a Geothermal are nominally 40% less than air source; 50%
ess than air source at 100 degrees; and can be as much as 55% less than air source
as temperatures rise further.
This efficiency analysis is attempted to examine like units for an "apples and apples"
comparison. It has not included the effect of a Geothermal desuperheater, the hot water
eature capability. With warm-hot climates, if the Geothermal is used to provide supplemental
hot water to a conventional gas or electric water heater, the efficiency disparity becomes evengreater. With the Geothermal desuperheater (HWG Hot Water Generator) in service, hot water
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0
2
4
6
8
10
12
14
16
18
32.2C 37.7C 43.3C
Outside Temperature
EER
Geothermal Air Source
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geothermal india
cooling india from the ground up
Asimn Mansion
2nd Floor, No. 14 Avenue Road
Nungambakkan
Chennai (TN) 600 034
Tel: +91 44 4359 6553
Email: [email protected]
Web: www.geothermalindia.in