about geothermal cooling

8/6/2019 About Geothermal Cooling

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about geothermal coolingabout geothermal coolingabout geothermal coolingabout geothermal cooling

geothermal india

cooling india from the ground up


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geothermal india


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.

geothermal india



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geothermal india


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


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


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

about geothermal cooling

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