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| Evolo Condominiums Saved Money by Using
Thermally Enhanced HDPE Geothermal Pipe |
I don’t like to admit it, but I’m becoming an “old-timer” in
the geothermal HVAC industry. Regardless,
I have made a commitment to continue to look for better ways to do things. If you need a quick review of geothermal
heating and cooling, this article is a quick and fun read from Mechanical
Hub; it should get you right up to speed.
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| Vertical Geothermal Loop U-bends |
Most geothermal systems start with a vertical closed
loop-field. The biggest expense relative
to geothermal systems is often the unseen, underground heat exchanger, made of
High Density Poly Ethylene (HDPE).
Drilling, HDPE pipe and labor combine to cause these loop-fields run up
the cost of a geothermal HVAC system to roughly 3 times what a standard air
sourced system might cost.
When pipe manufacturer, “Versaprofiles” sent me
some information on their “thermally
enhanced HDPE pipe”, I didn’t have especially high hopes. The pipe costs about twice what standard HDPE
costs. It is however 75% more conductive
that standard HDPE pipe. That translates
to about 11% less drilling. That doesn’t
sound like much, but I went ahead a looked a little further.
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| Loop Comparison Graph |
I called an engineer that had specified the thermally
enhanced pipe on the College of Lake County, Grayslake, IL Campus. Norbert Repka, PhD was hard to pin down, and
when I did get him on the phone, his first comment was, “I don’t know what I’ve
got to tell you about the pipe; we’ve only just finished the drilling.” What I
wanted to know was what made Norbert choose the pipe, and did he see an
advantage. Norbert spent about 10 minutes on the phone with me.
Norbert’s calculations showed that for their purposes, the
pipe provides a 25% improvement in performance, and that they could save about
5% on borehole length. He said that with nearly 100 boreholes drilled they
saved (eliminated) 5 boreholes due to the higher thermal conductivity of the
thermally enhanced HDPE.
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| College saved Tens of Thousands on Loop Field with Thermally Enhanced HDPE |
I looked into multiple projects, many of which showed even
better results. St. Laurent Sports Complex completed in 2013 is another example
of a project that saved considerable resources on loop-field costs.
New York City Transit Authority is planning a test with the
thermally enhanced HDPE pipe on their facilities. It’s no secret that New York is a hot bed of
activity for geothermal efforts, thanks in part to the efforts of NY-Geo.
Anything that can save space and first cost is getting noticed.
Even with Norbert’s conservative calculations, he said the
net savings were about $64,000. That means that if they followed the
manufacturer’s estimated 11% reduction in borehole length (rather than the 5%
they conservatively used), the savings might have been closer to $130,000.
Either way, it was a win; both in time and money. In my opinion the pipe is a
winner.
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| St. Laurent Sports Complex completed in 2013 Saved Money and Improved Efficiency |
This not-so-new pipe (it’s been around since 2009) will be
featured in a product showcase on Wednesday at 3:30 at the IGSHPA Expo in Kansas City next
week.
Industry Stakeholders have created a website with vast
resources to educate the public on geothermal heat pumps. The “Geothermal Day” Website aims to raise awareness about environmental and economic
benefits of geothermal energy and its vital role in building a clean and secure
energy future. We are inviting industry partners, communities, businesses and
educators to join efforts to advance further understanding and acceptance of
geothermal technology as an unlimited, renewable form of energy. Join us by
co-creating and sharing educational resources and participating in interactive
activities in local communities and on-line.
Jay Egg is a geothermal consultant, writer, and the owner of
EggGeothermal. He has co-authored
two textbooks on geothermal HVAC systems published by McGraw-Hill
Professional. He can be reached at jayegg.geo@gmail.com
