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How Thermal Piles Save Space, Energy and Money
Note: Article originally published in Green Home Builder Magazine July-August 2017 Issue
The principle behind thermal piles is simple. The ground below grade maintains a steady year-round temperature of 50 to 55 degrees Fahrenheit, meaning the earth acts like a very large heat sink. Thermal piles, also known as energy piles, use this effect to provide an energy efficient means to hear buildings in the winter and cool them in the summer.
Thermal piles pump a water-glycol mixture or some other fluid through pipes embedded in the piles. The piles are the same temperature as the surrounding soil, so circulated fluid will either cool down or warm up, depending on the season.
Both concrete and steel are used for thermal piles because of their strength and high thermal conductivity.
Thermal piles serve two functions: foundation support and heating and cooling. As energy-efficient, eco-friendly solutions become more important in new construction, the flexibility of these piles will make thermal fixtures increasingly important to architecture.
What Research Says About Thermal Piles
More information is needed to develop materials and the most efficient construction of thermal piles. However, studies into their geothermal behavior and environmental effects have been more than promising.
For instance, some fear that the repeated heating and cooling of piles could compromise their structural integrity. However, research suggests that the soil stop and around the piles mitigates this possibility, while the design of the thermal piles prevents subsidence in and around the foundation.
Thermal piles require polyurethane or steel pipe loops filled with the water-glycol mixture and connected to a heat pump. Compared with more traditional heating and cooling systems, piles can reduce the amount of fuel required to heat or cool a building by up to two-thirds.
One of the thermal piles’ biggest advantages is that they’re part of the building’s foundation, thus avoiding the extra costs of installing additional systems. With increasing energy costs and greater renewable energy requirements for new buildings, the demand for thermal piles is expected to keep growing.
Helical piles, which have also grown in popularity over recent years, have a great potential for use as thermal piles. The steel piles already boast high thermal conductivity, while helix plates act as fins to increase the heating/cooling efficiency.
Helical/thermal piles’ steel comes from recycled material, making the pile a classic example of doing more with less. The piles can be removed and recycled at the end of the building’s design life to reduce the permanent impact on the surrounding environment and ultimately consume fewer resources.
In both densely populated metropolitan areas and smaller, more remote communities, using geothermal energy is an important trend in lowering our overall carbon footprint. Converting helical piles into thermal piles makes taking advantage of that energy even easier and more cost-effective.
Gary L. Seider, P.E., is engineering manager of CHANCE® Civil and Utility Helical Products. Hubbell Power Systems Inc.manufactures a wide array of transmission, distribution, substation, OEM, and telecommunication products used by utilities.
With four U.S. patents and more than 40 years of industry experience, Seider oversees the company’s civil construction and utility application/project engineering staff. His team assists owners, engineers, and contractors with technical assistance, guidance, and recommendations for the proper use of CHANCE Helical Anchors and piles and Atlas Resistance® products.
by Gary L. Seider
With Increasing energy costs and greater renewable energy requirement for new buildings, the demand for thermal piles is expected to keep growing
- Thermal piles serve two functions: foundation support and heating and cooling
- Thermal piles pump a water-glycol mixture or some other fluid through pipes embedded in the piles.
- Thermal piles require polyurethane or steel pipe loops filled with water-glycol mixture and connected to a heat pump
- Research suggests that the soil atop and around the piles mitigates this possibility, while the design of the thermal piles presents subsidence in the and around the foundation.