Residedental geothermal heat pump design recommendations in the Tennessee Valley

 A set of recommendations for loop sizing, piping guidelines, piping arrangements, and antifreeze precautions is provided for Residential & Light Commercial geothermal heat pump installations

These residential closed-loop ground source heat pump (a.k.a geothermal or groundcoupled heat pumps) design guidelines were developed in conjunction with a project sponsored by the Tennessee Valley Authority in conjunction with a TVA Ground Source Heat Pumps promotion.

Previous guidelines were verified and adjusted according to data gathered during this effort and previous similar projects. A set of recommendations for loop sizing, piping guidelines, piping arrangements, and antifreeze precautions is provided. They attempt to balance the conflicting constraints of installation cost and efficiency. These guidelines have recently been extended to regions beyond the TVA service territory.

Loop Lengths

Table 1 provides recommendations for ground loops in the Tennessee Valley Authority service area and beyond. The values use results from this TVA sponsored project coupled with a previous Alabama Power project and the resulting recommendations for Alabama (Kavanaugh, 1991). The length of the trench or bore must be based on the amount of pipe in the trench, burial depth, and average ground temperature and conductivity. The table provides extremes of pipe length per length of trench from 10 ft/ft (i.e. 1000 ft. of pipe in a 100 ft. long trench) to 2 ft/ft. The table was developed for an average burial depth of 5 ft. and ¾” high-density polyethylene (HDPE) pipe. The extremes of normal ground temperature are 44 F for the northern continental US and 70 in southern USA (not including southern Florida and Texas and all of Hawaii). These lengths should provide a maximum loop temperature of 90  F entering the heat pump in
normal applications. In homes with excessive run times this temperature will be 3 to 5 F higher.
The table also includes recommendations for vertical ground loops in ft. of bore per ton for ¾” and 1-1/4” HDPE, which will operate about 5 F cooler than the horizontal loops.

Table 1. Recommended Lengths of Trench or Bore Per Ton For GCHPs
Multiply length of trench by pitch to find required length of pipe.

Installing a geothermal heat pump (horizontal loop) What you need to know.

Installing a slinky loop ground source heat pump.
Digging, pipes, hole size, deep
We run the 50 degree water through a heat pump. By compressing Freon, we draw heat from the 50 degree water, and return it to the underground pipe at say 40 degrees. For cooling, we reverse the hybrid heat pump, and return it to the underground pipe at 60 degrees.

Heat pump maintenance and repair

Why regular service is very important. Avoid Costly Heat Pump Repair: Schedule Heat Pump Maintenance

Spring and fall are the best times to schedule preventive heat pump maintenance. Тhe weather is at its mildest, and the service prepares your heat pump for the upcoming heating and cooling seasons. While I recommend at least one annual visit per year for heat pumps, we do encourage a second visit as well since the system will be used for both heating in the winter and cooling in the summer. These visits should be timed to occur just before the beginning of each season and can be scheduled well in advance as part of an annual maintenance plan. Regularly maintaining the home heat pump provides the following benefits:

• The heat pump operates more efficiently. Maintanance services that improve heat pump efficiency include changing the filter, sealing ductwork leaks and verifying proper refrigerant charge.
• Longer life span of the heat pump
• More efficient. Heat pump equipment, which lowers your bills and helps the environment. Fixing refrigerant leaks, lubricating the motor and cleaning away dirt all help to lower energy consumption.
• Improved comfot. Measures that improve your comfort include verifying correct electric control, calibrating the thermostat and ensuring that no return and supply registers are blocked.

Geothermal heat pump pipes earns spcial sertification

Centennial Plastics Inc. is the first company to earn certification that its CenFuse geothermal heat pump pipes meet minimum performance and safety standards set for polyethylene pipe and fittings for water-based geothermal heat pump (ground source) systems.

The CenFuse geothermal pipes were certified by NSF International, an independent global organization that writes standards, and tests and certifies products for the water, food, health-sciences and consumer-goods markets.

The certification provides engineers, distributors and heat pump contractors assurance that not only the pipe but the entire ground-loop heat pump meet safety and quality levels, according to David Schnase, vice president of sales and marketing for the company in Hastings, Neb.

Geothermal heat pump projects and installations

New York City Could Turn To Geothermal Heating
EarthTechling-30.05.2013
The U.S. Environmental Protection Agency (EPA) has called ground source heat pumpsthe “most energy-efficient, environmentally clean, and ...

Ground sourced heat pump system to save 40% of AC costs for ...
Romania-Insider.com-31.05.2013
The geothermal heat pump consists of a series of underground pipes set in over 60 vertical boreholes with depths of 120 meters, which are ...

Go geothermal to maximize energy efficiency
MetroWest Daily News-18.05.2013
This 55-degree well water is extracted from the earth and pumped through a geothermal heat pump. It is then transferred to air-circulated ...

Feds approve solar-power project proposed near Quartzsite
Cronkite News
... demand for housing and restaurants as it pumps new salaries into the area. ... by the Interior Department, along with geothermal and solar facilities in Nevada. ... Liquid salt in the tower captures the solar heat and uses it to ...

Commercial microgrids: the next big thing?
Lexology
We want to expand, but it has to make sense with the heating systems. .... fuel cells,geothermal heat pumps and CHP or cogeneration facilities.

Boring but brilliant: Four dull-yet-important energy solutions
Carbon Brief (blog)-31.05.2013
Ground source heat pumps, buried in the garden, circulate a mixture of water and antifreeze around a loop of pipe. The liquid absorbs heat ...

System Performance vs. Home Performance: Become a Lifestyle ...
Contracting Business
Solar panels and geothermal are the “cherry on top” when properly applied, .... Of course a high-AFUE modulating heating system is always better. ... lights, a pull-down attic stair, an open sump pump pit or vented crawlspace.

HIGH TEMPS, HIGH-DEF Heating and cooling company releases ...
Alton Telegraph-01.06.2013
King Air Conditioning and Heating in Godfrey unveiled its new ... pumps, generators, boilers, and indoor air-quality and geothermal equipment.

RYDE opens new facility in Kearney
Lexington Clipper Herald-31.05.2013
The building is outfitted with geothermal heat. Water from wells drilled during construction is cycled in and out of the building using pumps that ...

Maximum Comfort and Energy Savings with Two-Stage Heat Pumps
Buildings-09.05.2013
It is important to note that these heat pumps are often geothermal systems. They work by conditioning the air with water, but are capable of ...

Geothermal Heating and Cooling Solutions

Energy efficient Bosch Geothermal Heat Pump Systems offers a cost effective solution for heating, cooling and hot water, by accessing the consistent temperatures of the thermal energy from the earth.

Ground temperature just below the earth's surface remain consistent year round and is a suitable for the geothermal heat pump system's heat source or sink. Naturally occurring, heat is absorbed or rejected from the earth with no effect on the environment.

Heat exchangers or ground loops are installed to transfer heat using high density polyethylene plastic piping. The loops are joined to the heat pump, then fluid travels between the heat pump and the earth.

Two options available:

Water to Air (W:A) Heat Pump: Effectively produces hot or cool air for use through a building via conventional duct work
Water to Water (W:W) Heat Pump: High performance production of heated or cooled water for distribution through a building through piping . High compatible with hydronic heating or cooling that can also be converted into heated or cooled air via fan coil unitsEC Series
Single stage EC Series with high efficiency brings geothermal technology into your residential or commercial project. Available from 2kw to 21KW in vertical, horizontal, split and counter flow configurations.

EC Large Series
Fitted with 2-Stage compressor power, bringing high efficiency into any commercial project. For projects up to 105KW in various configurations.

W:W1-Stage Series
1- and 2-stage W:W Series water-to-water modular reverse cycle heat pumps are used for hydronic heating, make-up air applications, or swimming pool heating. For applications from 7KW to 21KW, suitable for both domestic and commercial installations.

W:W 2-Stage Series
The modular design gives allows users to install units individually or in any combination to match the exact load requirement for your commercial project. Available in 35KW and from 70KW to 123KW.

High performance with cost saving results, Geothermal Heat Pump Systems from Bosch Hot Water intelligence ensures you stay warm or cool without harming the earth.

New Reasons to Take Advantage of Geothermal Heat Pumps

Geothermal drilling has been used in the U.S for quite some time now. In fact, in the 1970’s geothermal drilling was catching on in popularity due to certain advances in drilling technology. Recently, more efficient drilling processes have allowed for more cost-effective geothermal drilling projects. This form of drilling has been historically expensive due to high temperatures and hardened sites. Geothermal energy is a resource that has remained largely untapped. However, Ameridrill Inc. has just announced some new reasons to take advantage of the heat available through geothermal drilling.

For many years, utilizing geothermal energy sources was viewed as being environmentally friendly. Geothermal heat pumps have a much lesser effect on the environment and certain systems can cut greenhouse emissions by up to 40%. However, protecting the environment is not the only advantage of geothermal energy. In fact, geothermal energy sources can drastically cut the costs of both heating and cooling expenses. Geothermal heat pumps have a much lower operating cost than most traditional heating systems. Furthermore, most existing heat pumps can be easily converted to a geothermal system.

Perhaps one of the biggest advantages of geothermal heat pumps is their durability and reliability. When properly installed, a geothermal system can last upwards of fifty years. Additionally, once a geothermal energy source has been identified, the cost of hot water can be drastically reduced.

Although geothermal drilling has become a more efficient process over the years, not all HVAC installers have the experience required to utilize this resource.

The most efficient geothermal heat pump unit

"We're particularly proud that our flagship 7 Series, the first variable capacity geothermal heat pump unit available to homeowners, was recognized with the Most Efficient designation," said Tim Litton, director of marketing at WaterFurnace. "We believe that receiving this honor for yet another product reflects that the WaterFurnace brand represents best-in-class innovation and energy efficiency."

The 700A11 utilizes WaterFurnace's InfiniSpeed technology, a soft-start variable capacity compressor, in concert with a variable speed ECM blower and variable speed loop pump. This allows the unit to scale output to exactly the level needed rather than the "high" or "low" speeds found in normal systems. The capacity range is the industry's widest and can even eliminate the need for auxiliary heat.

Hybrid Geothermal Heat Pumps

Why Geothermal Heat Pumps?

 The advantages of Geothermal Heat Pumps over conventional alternatives make them a very attractive choice for space conditioning and water heating for The advantages of GHPs over conventional alternatives make them a very attractive choice for space conditioning and water heating for both residential and commercial/institutional buildings. However, Geothermal Heat Pumps often have higher first costs than conventional systems making short-term economics unattractive. This disadvantage can be magnified in commercial buildings, many of which have much larger cooling needs than heating needs, especially for buildings located in climates typical of the southern United States. For Geothermal Heat Pump systems using closed-loop vertical ground heat exchangers, this load imbalance can result in a ground temperature increase over time causing system performance deterioration. Increasing the size of the ground heat exchanger or increasing the distance between adjacent heat exchanger boreholes can postpone the temperature increase problem but will also result in higher system cost. An alternative, lower cost approach for such applications can be use of a hybrid GHP design. In hybrid GHPs, the ground heat exchanger size is reduced and an auxiliary heat rejecter (e.g., a cooling tower or some other option) is used to handle the excess heat rejection loads during building cooling operation. The extent to which the ground heat  exchanger size can be reduced in a hybrid Geothermal Heat Pump system will vary with location and climate, but it must be at least large enough to handle the building heating requirements. Hybrid Geothermal Heat Pumps can also be used or sites where the geological conditions or the available ground surface will not allow a ground heat exchanger large enough for the building cooling loads to be installed.A number of recent reports and research papers have been published that deal with both design of hybrid GHPs and operating experience with a few installations. ASHRAE (1995) and Kavanaugh and Rafferty (1997) both discuss advantages of hybrid Geothermal Heat Pumps and present design procedures. The former sizes the auxiliary heat rejecter based on the difference between monthly average heating and cooling needs of the building and offers general guidelines for integration of the heat rejecter into the
system piping. The latter bases heat rejecter sizing on peak loads at design conditions
and the difference between required ground heat exchanger borehole lengths for heating and cooling.

Summary

Based on the results from the two case studies analyzed for this review, the following observations are made.
• Hybrid GHP systems can significantly reduce system first costs even when a tower needs to be purchased. Costs can be reduced by more than 50% for very highly cooling dominated applications such as the small office building in Houston (cooling-to-heating load ratio of 24:1). For applications where a suitable tower already exists (as at the Oceana study site), a hybrid system can result in system cost reductions of more than 50% even when the building is not overly cooling load dominated.
• For heavily cooling dominated sites, hybrid GHPs can result in heat pump and system energy savings compared to full GHPs when the supplementary heat rejecter is operated enough hours to reduce the average heat pump entering fluid temperature during the cooling season.
• The authors of both case studies point out that none of the hybrid system designs they examined have been optimized. A design optimization method is needed to balance GHX size, supplemental heat rejecter size and type, control strategy, and electric rate structure to achieve lowest life-cycle or first cost designs for a given location.

 http://www1.eere.energy.gov/femp/pdfs/hyhgp_tir.pdf

Geothermal cooling

Geothermal cooling system

Geothermal heat pump installations over the world

Canada
Statistical Report on Canada's Geothermal Heat Pump Industry 2011
“The State of the Canadian Geothermal Heat Pump Industry 2011 - Industry Survey and Market Analysis” has been launched by the Canadian GeoExchange Coalition (CGC)
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United Kingdom
Go Geothermal Predicts Rise In PE100-RC Pipework Installations
PE100-RC has the same properties as PE100 in terms of temperature resistance and the requirement for welded connections but crucially it offers better mechanical properties with increased resistance to both stress cracking and point loads.
***
Scotland
Orkney installs geothermal heat pumps for public buildings
It is believed to be the biggest geothermal project of its kind in Scotland. Geothermal heat pumps are being used at the new Kirkwall Grammar School, Stromness Primary school, Papdale Halls, and the new developments at the Pickaquoy Centre.

Geothermal heat pump NEWS

Ministers plot to limit heat pump subsidies over cost fears.
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Ball State University in Muncie, Ind., is on the cusp of turning on what it says will be the largest ground source heat pump in the US, if not the world. The geothermal heat pump will cut the University’s carbon footprint roughly in half, the school says. It will also eradicate almost all of its $3 million annual fuel bill, but will cost about $1 million a year in electricity to run. Heothermal heat pumps – work by running water through pipes below the frost line, which is about six feet underground in Ball State’s locale. This water sits at the soil’s constant 55 degree temperature, meaning that it can be used for heating in winter and cooling during summertime.
***
DESPITE a few concerns from district council, a West Vancouver home on Seaside Place won the right to install an underwater geothermal heat pump system. It's difficult to drill in a lot of the areas of West Vancouver due to rock because of that best medium of heat-transfer is water.
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Feige’s co-chairman, Rep. Paul Seaton, R-Homer, said similar geothermal projects were already being done in his district, and they might be used in more places than initially thought.In the geothermal heat pump system that became operational last May, the airport replaced $130,000 worth of diesel heat with $15,000 worth of geothermal heat , said Catherine Fritz, airport architect.
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Geothermal potentials in Moose Jaw
At least two generations the geothermal heating would prove a cost-effective, environmentally-friendly and local source of energy. While the system would require about 366 kilowatts of electricity to pump the water, the heat energy produced is about 29.25 million kilojoules per hour.
***
MENA Geothermal awarded contract to repair and complete installation of geothermal heat pump system in Jordan.
MENA Geothermal was established in 2008 by its current President, Khaled Al Sabawi, to offer energy efficient, environmentally friendly, and cost effective heating and cooling systems to customers in the Middle East and North Africa region. During the same year, MENA Geothermal was awarded the Energy Globe Award, the world's most prominent and prestigious environmental prize, for its geothermal heating and cooling system at the UCI Headquarters Building in Ramallah, Palestine.

Geothermal heat pump systems - Consulting, Design and Build

Geothermal heat pump systems - Consulting, Design and Build

Hiring Geothermal Heat Pump Drilling Contractors

HVAC contractors, mechanical engineers, architects, developers, and others involved in geothermal heat pump installations should evaluate the qualifications of drilling contractors to protect groundwater and optimize heat pump system operation.

As much as 50% of the total geothermal heat pump market involves the use of vertical borehole subsystems. There are several different configurations of geothermal heat pump system installations involving vertical earth drilling:

* Open loop: single well for water withdrawal, water returned to a surface source
* Open loop: single well for water withdrawal, water returned to a second well
* Standing column: single well for water withdrawal and water return
* Closed loop: vertical borehole
* Direct exchange: vertical boreholes using concentric pipe systems.

A motivation for NGWA promoting these questions and the need to HVAC contractors, mechanical engineers, etc., is to direct them to NGWA-member or NGWA-certified contractors to do the drilling for geothermal heat pump installations. To find drilling contractors, including those who work on geothermal heat pump installations, use

Why Bosch Geothermal Heat Pumps?

Bosch Geothermal Heat Pump systems are the most energy and cost efficient systems on the market and therefore the greenest technology for heating and cooling applications. This technology uses the relatively constant temperature of the earth, which makes it extremely efficient all year long in virtually any climate.

Advantages of Bosch’s geothermal heat pumps


Environmentally Friendly
Bosch’s green technology is the most environmentally friendly way to cool and heat your home. The system has no carbon dioxide emissions or any other negative effects on the environment. Bosch’s geothermal installations reduce greenhouse gas emissions which are responsible for climate change.

Reliability
Ground loop systems have a life expectancy in excess of 50 years. Your Bosch heat pump is manufactured with rigorous standards ensuring high
efficient operation over the life of the unit. Our residential warranty offering is among the best you will find on the market.

Lower Operating Cost
Bosch’s geothermal heat pump helps to save up to 70% on your energy bills for heating, cooling and hot water because of its more efficient operation compared to conventional systems. Simple payback could be as short as 5 to 7 years and you can experience costs savings from the beginning.

Earth Coupling Options
Geothermal heat pump systems use the earth as a heat source and heat sink. In order to transfer heat to or from the house, heat exchangers (ground loops) are installed in the ground. These consist of high density polyethylene plastic pipes. The loops are then connected to the heat pump and fluid is circulated between them transferring the heat between the heat pump and the earth.