De-bunking Myths About Geothermal HVAC
[On November 21, 2014, Don Penn, President of Image Engineering Group in Grapevine, TX made a presentation to the annual conference of the International Ground Source Heat Pump Association (IGSHPA) regarding 10 myths held by the public regarding geothermal heat pumps. This blog entry deals with a selection of five of those 10.]
The Geo Heat Pump Industry’s Dilemma-
For something as simple as the task our equipment performs for the well-known function of comfort conditioning of buildings, it’s still seen by many as more complicated than rocket science. It doesn’t need to be.
The syntax of the word “geo” is correct for our technology because it denotes being under the surface of the earth. That’s where our heat exchanger systems gather or disperse the energy from/to their big thermal battery. However, we suffer from an inability to distinguish ourselves (in the public’s mind) from hot rock, steam-generated electricity and geysers like those at Yellowstone.
We must fight this confusion with two facts at every opportunity. First, the “hot rocks-steam” brand of geo only makes a one-way trip to steam turbines from thousands of feet underground in very few random locations. For such electricity production, the consumption of millions of gallons of water per year is required.
Our heat pumps tap a thermal battery via polyethylene pipe circulating water to and from depths of 6-to-600 feet within a 35-85° temperature range and they consume no water.
Second, our thermal battery is available, worldwide, any day or night, including underwater. We are not limited by rare hot magma near the earth’s crust but instead benefit from incident solar energy striking the surface of the earth where up to 48% of it migrates underground. Though we also discharge unwanted building heat to this underground battery, you might say the maintenance of steady temperatures in the upper crust of the shallow earth is our seasonal solar collector.
Our thermal battery captures solar photons that became infrared energy, moving it underground (but without wiring). You could say that dirt, gravel, or rock is our solar collector, it never needs to be manufactured and installed, and it doesn’t wear out.
Who is Don Penn?
Don is one of our industry’s professional engineers with 25 years’ experience with large-scale geo installations, particularly in schools. His design success continues and his experience verifies what works well and what doesn’t. He is a current Vice President of the IGHSPA Board of Directors, joining a number of others giving back to our industry to increase the deployment of geo heat pumps across the globe.
His presentation (referenced above) was delivered to remind IGHSPA Conference attendees of the gaps in public understanding of our technology. Every misconception can stifle the chance to generate another installation or over-inflate expectations to the point where failure is the default conclusion (and circulated to others as such). Our attention to clear communication and transfer of factual information about our technology will speed the path of deployment.
What the Public may (incorrectly) Think-
(Here’s my custom selection of five myths from Don Penn’s presentation of 10 widely held by the public.)
#1 Geothermal Heating and Cooling can’t work here
Yes it can! No hot rocks or steam nearby is required. We tap the moderate temperature of the shallow earth, anywhere. High latitudes in Sweden are currently among the fastest growing deployments of geo. There are even projects in Riyadh, Saudi Arabia, where the underground temperature is at 85°F and cooling is the challenge.
#2 Geo heat pumps (GHPs) aren’t a renewable resource
Geo equipment is like any other—it is not renewable itself, but it does last longer than any other equipment performing the same function—sometimes for as much as 30 years. The ground loop material is expected to last 200 years or more.
The thermal energy removed or deposited by the ground loop is a zero cost resource with sustainable capacity. It is therefore renewable, free, and perpetually available.
GHPs don’t produce electricity but are four times as powerful a renewable than solar PV or wind turbines. They are leverage devices to avoid the consumption of electricity in heating or cooling. One Kwh of solar PV or wind turbine energy can produce 2-to-3 units of thermal transfer in favorable air temperatures by an air-sourced heat pump. One Kwh fed to a GHP can produce 4-to-6 units of thermal transfer under any weather condition, day or night, with or without sun or wind. Storage is free and perpetual, underground, where it is isolated from weather above ground.
#3 GHPs require excessive maintenance
Not true. Geo units don’t take the beating of high temperature combustion like furnaces and boilers do. They don’t have exposed air conditioning condensers facing extreme weather, and the underground temperature they pull from or deposit to is more moderate, year round. Maintenance departments have been known to reduce HVAC personnel because usually, filter changes are all it takes after a geo retrofit.
#4 Geo systems can’t pencil-out without generous tax credits
If this were true, no public building or non-profit business (where tax credits have no value) would ever install them in new construction or retrofit them to existing buildings. News flash—public schools are among the fastest growing segment of the geo market. Action now provides a greater reduction in future energy costs.
Tax credits last a year or two. Geo savings over conventional technology go on forever. Smart people with foresight understand this and as first cost (the ground loop installation barrier) falls due to creative financing options, more schools and public buildings are going this way.
The problem is inertia, cookie cutter conventional HVAC, and inadequate public exposure to the facts. It’s also that somehow, Americans have developed a bad habit of demanding their energy expenditures “pay them back,” and quickly—something they don’t require of their house, car, or vacation.
Buildings, heat pumps, and ground loops often last beyond a human’s life cycle, so many want a quick return on this investment. We could dress-up this payback calculation dramatically if there was an appropriate tax on carbon.
#5 Any engineer or designer in the building trades can design a GHP system
No way! Unless your designer has experience and is certified by the International Ground Source Heat Pump Association, you are risking the survival and success of your entire HVAC investment. The building’s thermal load, heat pump capacities, and ground loop performance must be closely matched.
Geo heat pump performance far exceeds conventional HVAC equipment, but it must be properly sized. This is most critical in commercial and multi-building installations of substantial size and varied load profiles. Excellent computer programs assist competent designers to make sure the entire system is modeled ahead of construction. Thousands of dollars of unneeded ground loop can be saved by smart engineering in such commercial projects where thermal conductivity testing of the underground formation has been done. Residential installations are usually less complicated and can often be properly designed by certified installer-contractors.
The industry still needs to perform more certification training for new entries as well as “old hands” from the HVAC industry. Poor installations still perpetuate horror stories that dampen enthusiasm far more than those of satisfied customers. An acceleration of geo heat pump utilization will at some point depend on converted conventional mechanical personnel to accommodate a rapid expansion. Their transition cannot be casual; it needs to be fully prepared by training and certification in geo applications. Long-time professionals like Don Penn and IGSHPA are working to provide not only design and installation training, but have recently branched out into certified inspection courses.
With the recently approved Canadian-U.S. #448 Installation Standard, it is expected that more training for more installation specialties will boost job quality and increase building jurisdiction’s confidence in our technology, no matter what kind of building employs it.