Richard Simmons Drilling Company, Inc.

Richard Simmons Drilling Company, Inc.60 Drill Rig Drive, Buchanan, Virginia 24066 Telephone (540) 254-2289

Geothermal Heating & CoolingHow it Works

1. Air Source Heat Pump – Heating Mode2. Air Source Heat Pump – Cooling Mode3. Geothermal Heat Pump – Heating Mode4. Geothermal Heat Pump – Cooling Mode5. Advantages of a Geothermal Heat Pump

Heat PumpsBackground

Heat is the flow of energy from one body or substance to another due to a difference in temperature.

To heat the interior of a building, energy must be extracted from a source and transferred to interior air.


First Law of Thermodynamics – Energy cannot be created or destroyed. It exists in the universe in a fixed amount. It can be stored, and can be transferred from one material to another.

Second Law of Thermodynamics - energy generally cannot spontaneously flow from a material at lower temperature to a material at higher temperature.


Water does not move spontaneously, but can be pumped from point A to point B, and can even be made to flow uphill by a water pump, powered by an outside source of energy.

Likewise, energy can be relocated and elevated (from a lower temperature to a higher temperature) by a heat pump.


Consider a heat pump that is heating the interior of a building during winter. Outdoor energy at 45 degrees F will be transferred to indoor air whose temperature is 70 degrees F.

Any substance at any temperature has internal energy. The energy in outdoor air at 45 degees F is readily available and is free, and so can be part of the energy needed indoors. An additional energy input will be required to satisfy the 2nd Law of Thermodynamics. i.e., before energy can be transferred to indoor air, temperature must be elevated to above 70 degrees F.


Energy can be transferred into and out of a refrigerant flowing in a closed loop.

Two heat exchangers plus an additional source of purchased energy are required.

The refrigerant will evaporate in one heat exchanger and condense in the other. Evaporation will occur when the refrigerant absorbs energy and condensation will occur when it gives up energy.


Evaporation will occur at a certain temperature that is dependent on pressure (Ex.- water boils at 212 degrees F at atmospheric pressure. Water temperature can be raised above 212 degrees in a pressure cooker without evaporation occuring.)

Likewise, condensation temperature (dew point) can be controlled by manipulating pressure.

The operation of a heat pump is dependent on manipulation of the pressure, the boiling point, and the dew point of the refrigerant. This allows heat transfers to occur within the range of temperatures typically found inside and outside a building.

Air Source Heat Pump – Heating Mode

Refrigerant Vapor

Outdoor air (Heat Source)

Heat Exchanger(Evaporator)

Indoors Outdoors

Cooled outdoor air

Cold mixture of liquid andvaporized refrigerant

Temperatue = T1

Temperatue = T2

Temperatue = T2Temperature T2 > T1

The refrigerant enters the evaporator at a pressure such that its boiling point temperature is less than T2. It evaporates and exits as a vapor, having absorbed energy from outdoor air.

It will need to circulate through the loop, give up its energy, and return to the evaporator as a cold liquid.


Refrigerant Vapor



Indoors Outdoors

Cooled outdoor air


Temperatue = T1

Temperatue = T2

Temperatue = T2

$$

Compressor

Compression elevates the pressure, the temperature, and the dew point of the refrigerant.

Since T3 > 70 degrees, energy can now be transferred to indoor air and the refrigerant is at a pressure such that it will condense at 70 degrees.

Hot refrigerant vaporTemperatue = T3


Refrigerant Vapor



Indoors Outdoors

Cooled outdoor air


Temperatue = T1

Temperatue = T2

Temperatue = T2

$$

Compressor


Heat Exchanger(Condenser)

Return AirSupply Air(Heat Sink)

Refrigerant gives up most of its absorbed energy to interior air in condenser. Refrigerant exits condenser as a cool liquid.


Refrigerant Vapor



Indoors Outdoors

Cooled outdoor air


Temperatue = T1

Temperatue = T2

Temperatue = T2

$$

Compressor




Cool Liquid Refrigerant

ExpansionValve

The pressure, temperature, and boiling point are suddenly reduced by the expansion valve and the refrigerant is ready to return to the evaporaor.


Refrigerant Vapor



Indoors Outdoors

Cooled outdoor air


Temperatue = T1

Temperatue = T2

Temperatue = T2

$$

Compressor




Cool Liquid Refrigerant

ExpansionValve

Air Source Heat Pump – Cooling Mode

A heat pump is a reversible process. To cool the interior of a building, the refrigerant flow is reversed. The evaporator and condenser swap functions. Interior air at 70 degrees F is the heat source, and exterior air at 90 degrees F is the heat sink.

Air Source Heat Pump – Cooling Mode

Cold mixture of liquid and vaporized refrigerant

Supply air

Warm refrigerant vapor


Hot refrigerant Vapor

Compressor

Outdoor air


Indoors Outdoors

Heated outdoor air(Heat Sink)

Return air(Heat Source) $$

Expansion Valve

Cool, pressurized liquidrefrigerant


An air source heat pump requires a backup heat system when in the heating mode, and when outside air temperature is low.

Air Source Heat Pump – Heating ModeBackup Heating System

Cool, pressurized liquid refrigerant

Hot refrigerant vapor

Heat Exchanger(Condenser)Return air

AuxiliaryHeat Source

Supply air(Heat Sink)

$$

The auxiliary heat source can be electric or a furnace burning fossil fuel.

Geothermal Heat Pump – Heating Mode

The earth's temperature underground is constant at about 56 degrees F. Thus, it is almost always warmer than the air above it during winter, and cooler during summer.

A geothermal system in heating mode utilizes the earth as the heat source. A closed loop circulating water system flows from the evaporator to the earth and back again. Energy is transferred from the earth to the water, then from the water to the refrigerant.

Geothermal Heat Pump – Heating Mode

Warm refrigerantvapor

Compressor

Evaporator

Indoors Outdoors

$

Expansion Valve

Above ground

Below ground

Circulating water return to earth

Circulating water supply from earth

Earth (Heat Source)

The earth replaces outdoor air as the heat source.

An underground circulating water system transfers energy from the earth to the evaporating refrigerant.

Cold refrigerant liquidand vapor mix

Geothermal Heat Pump – Cooling Mode

In a geothermal system in cooling mode, the earth replaces outside air as the heat sink.

Geothermal Heat Pump – Cooling Mode

Hot refrigerantVapor

Compressor

Cool, pressurizedLiquid refrigerant

Condenser

Indoors Outdoors

$

Expansion Valve

Above ground

Below ground

Circulating water return to earth

Circulating water supply from earth

Earth (Heat Sink)

The earth replaces outdoor air as the heat sink.

An underground circulating water system transfers energy from the condensing refrigerant to the earth.

Waste heat returning to earth is exchanged to the hot water heater.

Desuperheater

Hot WaterHeater

Geothermal Heat PumpsUnderground Circulating Water System

There are two types of underground water systems used with geothermal heating and cooling systems:

Closed loopo Vertical – water is circulated through piping in geothermal wells.

o Horizontal – water is circulated in horizontal piping at least five feet underground.

Open loop – water is pumped from the aquifer through a well, utilized by the heat pump system, then

returned to the earth through a well.

Geothermal Heat PumpsAdvantages

• Reduced operating costs – a geothermal system can save 30 to 70% in electricity costs.

• Reduced carbon emissions – power plant emissions are reduced by approximately 44%.

• Reduced demand for foreign oil imports.• No visible machinery or components outdoors.• Backup heating system never required.• Quiet – the compressor is installed indoors in a garage or

storage room and normally cannot be heard.• Tax credits – federal and state governments frequently offer

income tax credits to encourage installation of geothermal systems. A tax consultant should be consulted.

Geothermal Heat PumpsCost Considerations (1)

Installation costs are higher than for air source systems and operating costs are lower. The period to recover excess installation costs depends on the cost of electricity and the size of the building. The recovery period for a system installed now is not static – as electricity costs increase over time, the recovery period decreases.

As of December, 2008, there is a reasonably good chance that the US Congress will enact “cap and trade” or “carbon tax” legislation. Such legislation might significantly increase the cost of electrical power. That would reduce cost recovery periods, and should increase resale value of a building equipped with a geothermal system.

Geothermal Heat PumpsCost Considerations (2)

Cost recovery periods are generally acceptable for larger homes and for institutional buildings, such as school or office buildings. Environmental considerations may influence the building owner when deciding whether a projected recovery period is acceptable.

If a geothermal system will be financed by a long-term mortgage, a study should be made to determine whether the additional cost of the monthly mortgage payment will be offset by monthly savings in the cost of electricity.

Richard Simmons Drilling Co., Inc.What We Do

We install underground circulating water systems that are components of geothermal heating and cooling systems.

We act as a contractor in cooperation with an HVAC contractor, or as subcontractor to a general contractor.

We will be happy to visit with you, or talk to you by phone, to initiate a conversation about geothermal systems.

Call today to begin, telephone (540) 254-2289

Stephen BrooksGeothermal Manager

Richard Simmons Drilling Company, Inc.

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