Technology name
Ground Source Heat Pump
Date introduced on the market
Introduced on the market at the turn of the century; patented in 1912
Maturity of the technology
Commercially available
Type of energy that can be produced
- Heating and cooling, and hot water
- Hot water up to 120°F
Typical example/application
Energy from the ground loop can be transferred to the farm residence, workshops, storage shops, pig barns and many other applications in the agricultural sector.
Payback and/or benefits
Using geothermal on the farm for heating and cooling can reduce operating costs and thus increase revenue. Heating and cooling costs could be reduced by as much as 70% in some buildings.
Design, Installation, Operation And Maintenance, Cost
Range of possible dimension/size for the system:
Buildings of 800 sq. ft. or larger can be heated and cooled economically. Drilling costs in different regions of the country will affect the cost of an installed system (cost of drilling).
Considerations when sizing the system:
- Single-phase ground source heat pumps are limited to about 60,000 Btu/h (32°F EWT) output per unit and with the larger farm loads multiple units must be used. In farm yards that have three-phase power, larger geothermal equipment with up to 462,000 Btu/h (32°F EWT) output per unit can be used.
- Land area for vertical ground loop installation: 200-400 sq. ft./10,000 Btu capacity.
- Land area for horizontal ground loop installation: 2,000-4,000 sq. ft./10,000 Btu capacity.
Range of size for an HP System:
- A forced air heat pump for heating and cooling ranges in size from 7,600 Btu/h to 220,000 Btu/h (GLHP).
- Hydronic heat pumps range in size from 5,000 Btu/h to 462,000 Btu/h (GLHP).
Range of performance of the technology per unit installed:
- The COP (Coefficient of Performance) can vary from 2.5 to 5.
- Energy output divided by energy input (5 units of heat output divided by 1 unit of electricity input equals a COP of 5). The higher the COP, the more efficient the equipment.
Range of costs per unit of delivered energy:
- Installation cost of $3,000.00-$5,000.00/10,000 Btu output of equipment.
- Operational cost $100.00-$150.00/10,000 Btu output of equipment on a yearly basis.
Expertise, skills, training required for design:
- HVAC technician capable of performing a proper heat loss and heat gain calculation on the building.
- HVAC technician required to properly size the ductwork for the heat pump.
Expertise, skills, training required for installation:
Properly trained HVAC technicians, manufacturer trained on equipment and ground source loop installation.
Expertise, skills, training required for operation:
Once unit is installed, owner looks after basic operations.
Range of operational and maintenance requirements:
- Very low maintenance, keep air filter clean on a regular basis, dependant on site conditions.
- Labour: approximately ½ an hour per month maintenance for 1 person.
- System should be checked over every 1 or 2 years by a heat pump service technician.
Limitations of the system, typical problems that could arise:
If air filters are not properly cleaned or maintained, the system will run inefficiently and the life expectancy of the equipment will be decreased.
Life expectancy:
Life expectancy for various systems according to ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers http://www.ashrae.org/ is as follows:
Average life expectancy by equipment type:
- Water Source Heat Pump 19 Years
- Air-Air HP/Air Conditioner 15 Years
- Furnace (gas or oil) 18 Years
One thing to note is that these numbers are dated, and as the need for technology grows, the manufacturing practices are becoming increasingly advanced and we are seeing longer equipment life. The market is also demanding higher-end equipment.
Software/tools to do prefeasibility level study or better:
- Prefeasibility: RETScreen www.retscreen.net
- For ground loop design analysis, the following software is available:
-GchpCalc (V. 4.0) www.geokiss.com
-GLHEPRO http://www.igshpa.okstate.edu/publication/software.htm
-Ground Loop Design (V. 2.7) www.groundloopdesign.com
-GS 2000 http://www.canetaenergy.com/index.html
-GEOCALC http://www.fizzymagic.net/Geocaching/GeoCalc/GeoCalc.html
Synergies
Input and output for the technology:
- Heating/cooling and hot water for all types of farm buildings and homes.
- Potential for hybrids. Heat Pumps can be supplemented with solar hot water heating systems. The solar system can heat the ground loop solution and can possibly shorten loop length in high heating load situations (can be beneficial where drilling cost are extremely high).
- A heat pump can heat and cool different buildings at the same time, for example, heating a farm shop and cooling crop storage sheds at the same time.
- Quite often, heat pumps, in combination with in-slab radiant floor heating, can offer economic and temperature uniformity in greenhouses and other applications.
Links To More Information And Recommendations (Red Tape)
Here are few suggested readings and supplier links. More can be found on the Internet by searching for words such as “ground source heat pump,” or “geothermal.”
Links to more information and recommendations:
Sources of Supply:
Recommendations:
- Contact local dealers with many years of experience in heat pump installation and services.
- Any "red tape" to be aware of? As of now there are few regulations but it may change in the future.
Glossary:
-Btu – British Thermal Unit (Measure of Heat)
-Btu/h – Heat Units Per Hour
-DOE – Department of Energy
-COP – Coefficient of Performance = Btu output/Btu input
COP is simply the efficiency rating. A unit that has a COP of 4 would be 400% efficient compared to an electric furnace that has a COP of 1 or 100% Efficiency. The higher the COP, the better.
-EWT – Entering Water Temperature
-GLHP – Ground Loop Heat Pump
-GSHP – Ground Source Heat Pump
-GWHP – Ground Water Heat Pump
-HVAC – Heating Ventilation Air Conditioning
-2 US/GPM @ 44°F/10,000 Btu/h – Water Requirement for Well Systems
-60,000 Btu/h (32°F EWT) – Heat pump output rating at 32°F entering ground loop temperature
-US/GPM – US Gallon Per Minute