RAUGEO Ground Loop Heat Exchange

Low-cost Renewable Energy for Heating and Cooling

Geothermal systems are among the most efficient heating and cooling systems available. Heat from the sun warms the earth and keeps the underground temperature relatively constant throughout the year. A geothermal heat pump system takes advantage of this ground temperature, providing free, renewable energy for heating, cooling and domestic hot water.

RAUGEO is a system of piping placed underground that captures the earth's energy. This system works well on its own or, for optimal efficiency, when used in tandem with our radiant heating and cooling systems.

Tax Incentives
The American Recovery and Reinvestment Act of 2009 (ARRA) allows for an uncapped 30% tax credit for residential heat pump systems through 2016.

Commercial project owners can take advantage of a 10% uncapped U.S. federal tax credit as well as an accelerated depreciation schedule (5 years vs the typical 25+ years), with 50% taken in year 1. Consult your tax adviser.

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Unlike outdoor temperatures that fluctuate with the changing seasons, the temperature of the soil four to six feet beneath the ground remains relatively consistent year-round for a given location. A ground source or earth energy geothermal system taps into earth’s natural heating and cooling properties through an underground loop heat exchanger system connected to an electric heat pump within your home or business.

Energy Transfer – From the Ground to Your Heat Pump

In the winter, a fluid  with antifreeze and water circulating through the ground loop system absorbs stored heat from the ground and carries it indoors. The heat pump, using the same refrigeration principle as your refrigerator, then compresses the heat to a higher temperature for  distribution  throughout the building. In the summer, the heat pump works in reverse, drawing heat from the building and carrying it through the loop system for rejection back into the earth.

Hydronic System Maximizes Energy Efficiency

Unlike conventional systems, geothermal systems don’t use burn  fossil fuels (natural gas, oil, propane) to generate heat. They simply exchange heat to and from the ground, depending on the conditions. Electricity is  used to operate the heat pump’s compressor, a circulating pump for the fluid in the ground loops and the electronics.

Geothermal heat pump systems are among the most efficient heating and cooling systems available. According to the International Ground Source Heat Pump Association, they can reduce energy consumption by up to 50% when compared to conventional systems.
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Components of the RAUGEO system:

1. RAUGEO U-bend vertical ground loop
2. RAUGEO Collect horizontal ground loop
3. Balancing manifold
4. Geothermal heat pump
5. Radiant heating and cooling distribution piping system

Benefits of a Geothermal System

Supplies Energy Efficiently

In heating mode, a geothermal system can be three-to-four-times as efficient as the most efficient conventional system. Because geothermal systems do not burn fossil fuel (i.e. gas, oil, propane) to make heat, they provide three to four units of energy for every one unit used to power the system, through electricity. In cooling mode, geothermal systems can be two- to three-times more efficient than traditional air conditioners or air-to-air heat pumps. This improved efficiency translates directly to reduced operating costs.

Reduces Maintenance Costs

Closed-loop geothermal systems are practically maintenance-free. When installed properly, the buried ground loop of crosslinked polyethylene piping will last for generations. And the other half of the operation-the heat pump’s compressor and circulating pump-is housed indoors, protected from the harsh weather conditions. Usually, periodic checks and air filter changes (for forced air distribution) are the only required maintenance.

Minimizes Environmental Impact
A ground source heat pump system can reduce energy consumption by up to 50% as compared to conventional systems, according to the International Ground Source Heat Pump Association.  In addition, a typical residential system reduces carbon dioxide emissions by more than 200 tons over a 20-year period, which is equivalent to removing two cars from the road.
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Multiple Loop Configurations Fit Most Building Sites

 

A Closed Loop System is the most common type of geothermal system installation. The term "closed loop" is used to describe a geothermal heat pump system that uses a continuous loop of special buried plastic pipe as a heat exchanger.  The pipe is then connected to the indoor heat pump to form a sealed, underground loop through which an antifreeze solution is circulated. During system operation, fluid constantly circulates in buried pipes/loops, absorbing stored heat from the earth during the winter months and carrying it indoors and taking heat from indoors and rejecting it back into the earth during summer.

There are several loop configurations available for closed loop systems:

RAUGEO U-bend Vertical Ground Loop

Where space is limited and energy demand is significant, such as in most commercial applications, vertical ground loops are inserted in boreholes which are several hundred feet deep using a well-drilling rig. The RAUGEO double U-bend design requires up to 30 percent less borehole footage than a single HDPE U-bend. 

RAUGEO Collect Horizontal  Ground Loop

Where there is plenty of open space and suitable soil conditions, ground loops can be installed in long horizontal trenches about 5 to 7 ft (1.5 to 2 m) below ground.  This method requires more available land than other installation methods and can cause a disturbance to lawns and landscaping, but is the most economical option from an installation cost standpoint.

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Components of a REHAU Geothermal System

The RAUGEO system is based on a European ground loop heat exchange design that has been in use for more than 30 years. It includes a manifold instead of a buried HDPE header and RAUGEO PEXa pipe instead of HDPE pipe. When these features are combined, the result is a more secure system that is cost effective and easier to install.


RAUGEO PEXa Pipe

RAUGEO PEXa pipe provides superior resistance to impact, rock impingement and the stresses of earth movement. In addition, its superior flexibility compared to HDPE means fewer fittings and a faster installation time.

  

RAUGEO Double U-Bend

Our unique RAUGEO PEXa Double U-bend extracts more energy than the typical vertical loop, while offering a higher degree of security against loop failure. In North American thermal performance testing,2 RAUGEO Double U-bends installed alongside single HDPE U-bends displayed significantly lower borehole thermal resistivity. Test results demonstrated that the RAUGEO Double U-bend with pipe spacers requires 15 to 40% less borehole footage to extract the same energy as a single HDPE U-bend, allowing drilling costs to be reduced.

  • Pre-formed 1 and 1 1/4 in. U-bends are delivered to the jobsite in continuous coils of up to 520 ft.
  • Double U-bends create redundancy in the event of loop failure
  • PEXa pipe is recognized by IGSHPA as an accepted piping system for ground loop heat exchangers and certified to CSA C448

F2080 Fittings

RAUGEO pipe connects using ASTM F2080 cold-expansion compression-sleeve fittings 

  • Secure connections install quickly without heat or electricity
  • Can be installed in any weather conditions - dry or wet
  • Ready for pressure testing immediately
  • Large inside diameter gives excellent flow rates
  • May be buried underground with use of heat shrink sleeving 

Balancing Manifolds
RAUGEO ground loops begin and end at a manifold that, unlike the typical reverse-return header, provides easy access and superior flow control for system optimization.

  • Allow each ground loop to be individually controlled
  • Balance each circuit with built-in circuit adjusting valves
  • Each circuit can be isolated and purged individually
  • Easily connects to PEXa pipe with F2080 fiting system
  • Brass 1 1/4 in. manifold available for residential applications
  • PRO-BALANCE XP manifolds available in 2 and 3 in. diameters for commercial applications


* Crecraft, Harrison and Mahlmann, Justin. REHAU in-situ Borehole Thermal Performance Testing. Bowman Geothermal, 2009

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RAUGEO With Radiant Heating

A Natural Synergy
If you’re considering using our RAUGEO ground loop system, you’ll also want to look at radiant heating and cooling, and vice versa. To provide comfortable room temperatures, radiant heating works well with relatively low water temperatures and radiant cooling works with moderate water temperatures. It’s precisely in these temperature ranges that your water-to-water geothermal heat pump operates most efficiently.

Greatest Comfort / Lowest Operating Cost
By combining RAUGEO with REHAU radiant heating and cooling, you’ll enjoy the greatest comfort at the lowest operating cost. You’ll also appreciate the reliability of REHAU quality components – durable PEXa pipes, secure EVERLOC joints and manifolds with individually controlled circuits – from the geothermal probe to your thermostat.