The World's #1 Renewable Energy Network for News, Information, and Companies.
Untitled Document

The Efficiency Tango: A Deeper Look at Geothermal Heat Pump Efficiency

A couple weeks ago, I compared the efficiency of the two most advanced geothermal heat pumps (GHPs) recently launched by Waterfurnace Renewable Energy (TSX:WFI, OTC:WFIFF) and Climatemaster, as division of LSB Industries (NYSE:LXU). Like most things in life, it turns out that heat pump efficiency is a lot more complicated than just comparing a couple numbers.

Since I concluded that Waterfurnace’s 7 Series heat pumps were slightly more efficient than Climatemaster’s Trilogy 40 pumps, one of Climatemaster’s district managers pointed me to third party efficiency ratings conducted according to standards set by the Air Conditioning, Heating, and Refrigeration Institute (AHRI).  He compared Waterfurnace’s 4 ton unit (the most efficient 7 Series) to Climatemaster’s 2.5 ton unit (the most efficient Trilogy 40), noting that the former had a 41 EER at ground loop conditions, while the latter had a 42.1 EER, according to AHRI.

He concluded that the Trilogy 40 had a slightly higher cooling efficiency than the 7 Series.

The Efficiency Tango

Had I got it wrong?

I checked with the pros.  Scott Lankhorst, President of geothermal and solar thermal installer Synergy Systems in Kingston, NY said it was “an apples to oranges comparison” between 4 ton and 2.5 ton GHPs.

Lloyd Hamilton, a Certified Geoexchange Designer at Verdae, LLC in Rhinebeck, NY, called this normal marketing.  He says that the only reliable way to compare units is to look at the operational performance data for the designed condition.  The AHRI-compliant EER and COP numbers allow comparison of two units so long as they are at the same capacity, but it does not demonstrate actual performance, “like MPG for cars. … COP, SEER, and EER become worthless when comparing different types of equipment” such as air source and ground source heat pumps, because the testing criteria are different.  He calls the act of picking an choosing GHP models and operating conditions to make your company’s GHP look more efficient the “Efficiency Tango.”

Both agree that the contractor can mess up the rated efficiency of a GHP, or even make it perform above specification, with the wrong (or right) system design and installation.

I don’t have the performance data a geoexchange designer would use, but there are a lot more publicly available efficiency numbers than I used in my last article.  I put them together in a pair of bubble charts:

There are three 7 Series models and two Trilogy 40 models, each of which was tested at full load and part load, under two types of conditions.  The “ground water” series are when the ground water is pumped up out of the ground for heat exchange; the liquid water helps heat transmission and results in a higher rating.  The “ground loop” series is representative of the much more common installation, when an antifreeze fluid (usually propylene glycol) is pumped through the geothermal loop, which results in relatively lower efficiency (although still much higher than other types of heating and cooling equipment.)  Even in ground loop conditions, different heat exchange fluids will result in different effective inefficiencies.  The partial-load results are the sets of two or three smaller bubbles to the right (and a little below) sets of larger bubbles of the same color.

Looking at the charts holistically, I reach the following conclusions:

  • The 7 Series is generally more efficient than the Trilogy 40 for heating.
  • The Trilogy 40 is generally more efficient than the 7 Series for cooling.
  • These units operate at dramatically (about 50%)  higher efficiency under partial load.  Two-stage heat pumps show only modest (5% to 15%) efficiency gains at partial load.  This is likely to lead to higher overall efficiency of these GHPs in practice than the numbers alone might lead you to believe.
  • The Trilogy 40 typically operates at lower fluid flow rates than the 7 Series, which should produce some energy savings from pumping.

Hence, I revise my earlier conclusion to say that, based solely on efficiency, the Climatemaster Trilogy 40 will have a definite edge over the Waterfurnace 7  Series in cooling climates, while the 7  Series has an efficiency edge in heating-dominated climates.

Efficiency Isn’t Everything

That said, for most installations, factors other than efficiency will probably dominate the decision.  As noted above, Waterfurnace expects exclusivity from its dealers, and I expect Climatemaster and its other major competitors often do the same.  This will make it nearly impossible for a residential customer to compare the two without having to weigh other factors such as their confidence in the installer who, as noted above, can make or break a geothermal installation.

Then there is the Trilogy 40′s Q-Mode.  As Dan Ellis, president of Climatemaster told me in an interview, the potential savings from using geothermal to generate hot water year round from the Trilogy’s Q-Mode are likely to dwarf the savings from a point or two of EER or a fraction of a point of COP.  In fact, Climatemaster designed the Trilogy 40 with the whole system energy savings in mind, partially at the expense of efficiency ratings.  In a residential setting, Q-Mode (which is patent-pending to Climatemaster) is likely to make the financial returns decisively favor the Trilogy 40 in a head-to-head comparison.

In commercial settings, which typically have year-round cooling requirements, Q-Mode is unlikely to be important.  Furthermore, the two largest 7 Series heat pumps have higher capacity than the larger of the two Climatemaster Trilogy 40 models.  This should also give Waterfurnace an advantage in commercial settings, which typically have larger cooling loads than residential settings.

Ellis promised to send me some data to help quantify the overall energy savings from Q-Mode, which I plan to return to in a future article.

Conclusion

For residential customers in warm climates, Climatemaster’s Trilogy 40 seems like it will be the better GHP value when it becomes commercially available.  In other cases, the comparison is not as clear cut, and a customer should probably focus on finding a contractor who can deliver the best system design and installation possible.  That is the only way to capture the full benefit from either of these incredibly efficient geothermal heat pumps.

Disclosure: Long LXU, WFI

This article was first published on the author's Forbes.com blog, Green Stocks and AltEnergy Stocks and was republished with permission.

DISCLAIMER: Past performance is not a guarantee or a reliable indicator of future results.  This article contains the current opinions of the author and such opinions are subject to change without notice.  This article has been distributed for informational purposes only. Forecasts, estimates, and certain information contained herein should not be considered as investment advice or a recommendation of any particular security, strategy or investment product.  Information contained herein has been obtained from sources believed to be reliable, but not guaranteed.

Lead image: Geothermal heat pump diagram via Shutterstock

Untitled Document

RELATED ARTICLES

Global Renewable Energy Roundup: China, Kenya, Turkey, India Seeking More Renewables

Bloomberg News Editors China is being encouraged by three industry groups to double the nation’s solar-power goal for 2020 to make up for sh...

With Vast Amounts of Geothermal, Wind and Hydropower, Why No Solar In New Zealand?

James Ellsmoor, Contributor New Zealand has built an international brand on environmentalism and the great outdoors. So it is unsurprising that t...

Don’t Like Obama’s Clean Power Plan? Fine, Here’s Cap and Trade

Mark Drajem and Lynn Doan, Bloomberg Republican governors who boycott the Obama administration’s new power-plant regulations may instead get an offer they...

Renewable Energy Gains Greater Opportunity in US Clean Power Plan

Elisa Wood After a year of being pummeled by opponents, Obama’s final carbon reduction plan emerged this week with an even stron...

PRESS RELEASES

Free ImagineSolar Online Course Demonstration

ImagineSolar will be holding another live demonstration of PV250e: Solar PV Economics a...

Canadian Solar Announces Partnership in 200 MW Tranquility Solar Power Project

Recurrent Energy signed an agreement with Southern Power to partner on the Tranquility ...

AWS Truepower Announces Major Expansion of its Due Diligence Team in Response to Growing Market Demand

AWS Truepower, an international leader in wind and solar energy consulting and engineer...

FEATURED BLOGS

NATiVE Recognized for Excellence at 2015 Greater Austin Business Awards

NATiVE Recognized for Excellence at 2015 Greater Austin Business Awards NEWS RELEASE AUSTIN, Texas – Aug. 27...

Solar Energy Means Jobs, Savings, and a Low-Cost Future [infographic]

There are a lot of utility-sponsored legislative and regulatory attacks on solar energy lately, and we put together t...

How To Get People To Do Stuff

It’s no secret that psychology and sales go hand in hand. If you understand the principles of human psychology ...

FINANCIAL NEWS

Tom Konrad is a private money manager and freelance writer focused on Peak Oil and Climate Change as investment themes. He manages portfolios for individual clients and is Head of Research for the JPS Green Economy Fund (http://jpsgreeneconomyfund...

CURRENT MAGAZINE ISSUE

Volume 18, Issue 4
1507REW_C11

STAY CONNECTED

To register for our free
e-Newsletters, subscribe today:

SOCIAL ACTIVITY

Tweet the Editors! @jennrunyon

FEATURED PARTNERS



EVENTS

GRC Workshop at Indonesian International Geothermal Convention & Ex...

The Geothermal Conceptual Model & Well Targeting The Geothermal Me...

2015 AREDAY Summit

The 12th Annual AREDAY Summit, August 8-13th in Snowmass Colorado. Engag...

StartUp Green

AREI, American Renewable Energy Institute, in partnership with ...

COMPANY BLOGS

Clean Energy Patents Maintain High Levels in First Quarter, Solar L...

U.S. patents for Clean Energy technologies from the first quarter of 201...

Registration Opens for GRC Annual Meeting & GEA Geothermal Energy Expo

GRC Annual Meeting & GEA Expo:   Register Now for the 2015 GRC ...

New Approach to Crowdfunding Renewable Energy Assets

In our business, our goal is to help people improve their quality of lif...

NEWSLETTERS

Renewable Energy: Subscribe Now

Solar Energy: Subscribe Now

Wind Energy: Subscribe Now

Geothermal Energy: Subscribe Now

Bioenergy: Subscribe Now  

 

FEATURED PARTNERS