Heat Pumps Coming of Age?

March 25, 2019

Huge impediment to carbon free economy is heating and cooling existing and new buildings. Gas and oil have to go. What’s the alternative?

Until recently, heat pumps have been a promising, but prohibitively expensive option.
Technology does its thing.

Engadget:

Millions of US citizens still use oil and natural gas to heat their homes during the winter. Many would like to switch to geothermal, a cleaner and ultimately cheaper system that leverages the natural temperature of the earth. A few feet below the surface, the soil sits at a reliable 50- to 60-degree Fahrenheit all year round. Pipes known as ‘ground loops’ push round a special antifreeze solution that absorbs this constant temperature in winter and disperses unwanted warmth in the summer. A large indoor heat pump uses the mixture to boil a refrigerant fluid; the resulting gas is then compressed to higher temperatures and distributed around the home.
Installing the necessary equipment is expensive, however. Dandelion, a company that started inside Alphabet’s X division, is trying to make geothermal cheaper and easier to install. While not the most eye-catching technology, especially compared to electric cars and sea-cooled data centers, it’s arguably one of the most important for the environment.

A typical geothermal system costs between $10,000 and $40,000 to install, depending on the size of your home, the makeup of the soil in your yard and whether you have ductwork for the heat pump to attach to. Dandelion’s system, meanwhile, will set you back $10,994 to $19,744 after relevant tax credits and incentives. Alternatively, you can pay nothing upfront and spend $79 to $137 per month over 20 years. The latter is unusual and highly attractive because it allows cash-strapped homeowners to install a system and start saving on their utility bills straight away.

There’s a trade-off, though: flexibility. Most companies will send an engineer to assess your home and design a bespoke or highly customized system. Dandelion, meanwhile, has a fairly standardized product. “We designed a [geothermal heating] system that works for most homes,” Kathy Hannun, chief executive and co-founder of Dandelion explains. “And a home can either qualify for it or not. If a [customer] qualifies, then they qualify for a very standardized product that will work well in their home.”

The startup has developed its own geothermal heat pump, too, called Dandelion Air. It was built in partnership with AAON, a specialist manufacturer of HVAC (heating, ventilation and air conditioning) systems, and comes in four different sizes. According to Hannun, Dandelion is able to make and sell the pump at “a fraction of the cost of what has been available on the market before,” which contributes to its aggressive pricing plans. Unlike most heat pumps, many of the parts come pre-assembled. The exterior is also made of aluminum, rather than steel, so it’s easier to carry down stairs.

Dandelion Air units are fitted with “state-of-the-art monitoring and controls,” Hannun said, that check the system for problems. These are critical because Dandelion relies on regional companies such as Aztech Geothermal and Lake Country Geothermal to drill the holes and install some of its residential systems. The first time the pump is turned on, it runs through a self-check ‘commissioning sequence.’ Dandelion can then monitor the system remotely and intervene if there’s a problem, maintaining quality and customer trust in the underlying technology.

Households can access their data to see how much they’re spending, and Dandelion surveys its customers to determine how much, on average, they save by switching to geothermal heating. “Having that real data will just, I think, lend a tremendous amount of credibility to an industry that hasn’t had that much credibility in the past,” Hannun explained. “It’s definitely an investment, but it’s one that’s well worth it.”

These improvements are welcome and long overdue in the industry. As Forrest Meggers, an assistant professor in the School of Architecture and the Andlinger Center for Energy and the Environment at Princeton University, explains: “It’s better than something that was just so, so bad already. That’s really it. The HVAC industry is just the slowest moving.”

16 Responses to “Heat Pumps Coming of Age?”

  1. Sir Charles Says:

    Not really expensive. My geothermal is combined with a floor heating. The collecting pipes outside in the garden are just 5 foot deep at an area of 4000 square foot (4 circuits). Altogether around €16,000. At ~450% efficiency the carbon footprint is better than burning natural gas, even though more than half of our electricity is still generated by gas plants. You only need to drill deep if you want to combine electricity generation with heating where you need higher temperatures, e.g. for larger estates or even whole towns.

    • Sir Charles Says:

      Maximum power consumption (incl. hot water booster) is 2.7kW. That’s less than the immersion heaters (3kW) which are used to heat just the hot water supply of a family home in the summer here in Ireland.

    • Kevin Boyce Says:

      Do you really get a measured 4.5 COP? My understanding is the great numbers from geothermal units are somewhat tempered by the power needed for the pumps, and the net result is a bit lower than the advertised numbers.

      I went with inverter-supplied (variable speed compressor) air-source mini-splits for the house I built a couple years ago. In the dead of winter their performance is not as good as a ground-source unit, but averaged over the year I’m given to understand the combined efficiency is about the same. Plus no worries about an underground leak, and a lower initial cost.

      The real way to win with geothermal units is with district heating/cooling, where the system is large enough to store the summer heat in the ground and extract it in winter. That kind of Underground Thermal Energy Storage is probably key to getting to 100% renewables.

      • Sir Charles Says:

        Air to air is ineffective. Hard to guess whether I get the real 450%. But the 2.2kW + 0.5kW for hot water booster are more than sufficient. I agree that district heating (cooling) is a good way forward. With deep core collection you can provide both, electricity and heat. Here in Europe you need heat, not cooling. Air conditioning is hardly needed and hardly used, even in the south of Europe. People in Spain, Italy and Greece are just used in warm temps during the summer. It’s a matter how you build your house.

    • rhymeswithgoalie Says:

      “Not really expensive. … Altogether around €16,000.”

      Part of the problem of improving insulation and HVAC efficiency is that most renters pay for their own utilities, divorcing landlords from the economic incentive to upgrade. The system for paying installments long term (for geothermal or solar panels), might lower the threshold a bit.

  2. Bryson Brown Says:

    Having established a nice garden in the back yard, it’s a bit hard to contemplate digging up most of it to install the collecting pipes… vertical wells might be more attractive for us, but one way or the other I’d really like to put a GT system in. My parents added one to their 1874 farmhouse about ten years ago, but it wasn’t cheap (and my mother isn’t terribly fond of it in winter, since it’s designed– for reasons of efficiency–to blow more air at a lower temperature than the oil furnace they had before; it actually feels chilly to be close to a register when it’s running in winter…).

    • Sir Charles Says:

      For a horizontal ground source heat pump you definitely need floor heating as you’re generating water temps for the circuit of no more than 25, max 30C. Hot water is done by a small additional booster pump. However a vertical GSHP should provide enough temperature. Maybe your parents’ system hasn’t been well dimensioned. I’d get some professional advise there or just install a wee wood stove for additional heat during real cold winter days.

  3. dumboldguy Says:

    Let’s hope this is more than another Solar Roadway scam designed to make a buck for the promoters. IMO, it sounds a bit slick, especially the “pay nothing upfront and $79 to $137 per month over 20 years” part.

    Unless they also go solar at the same time for their electricity (and paying for it over 20 years?), they will still be paying for electricity from the grid (and likely using more of it, particularly in winter).

    My gas usage is for heat only and averages $90 a month. I use electricity for everything else—-hot water, all appliances, and central compressor-type A/C—-it averages $102 a month. It gets both pretty hot and pretty cold here in NO VA, with the heating and cooling seasons both being about five months long. My first complete replacement of the 1972 era furnace/AC was in 1998 and cost $4000. I just had a $400 repair to the furnace this winter and was told that a new system will cost around $7000 next time (but it will be even more efficient than the 1998 version). My average monthly utility bill of $192 and those replacement costs make me think that a geothermal heat pump system is NOT a sound investment, especially since they had to blast to put in the foundation of my house and the utility trenches. Can anyone argue with that?

    • rhymeswithgoalie Says:

      At least geothermal is a real thing, though the cost/benefit must vary a lot with location. The Solar Roadway was a goofy idea through and through.

      Also, limiting installations to those that can take a standardized design is an economically plausible way to reduce production and training costs.

      • dumboldguy Says:

        “Goofy” Solar Roadway raised over $2 million on Indiegogo, and got $900,000 in grants, mostly from government—-over three million in total. Although geothermal IS a “real thing”, I smell some “picking of low-hanging fruit” here, and not something that’s going to make a huge difference.

  4. Brent Jensen-Schmidt Says:

    Well, $7,000 seems like a lot of money and 16,000 Euro is a freak city amount. In Oz the most energy efficient system is reverse cycle. In summer heat is pumped out then in winter it is pumped in by the same unit. Even being used to heat water. Mentioning this to northern hemisphere types results in blank looks. Possibly pumping heat from an ice and snow landscape is energy negative? Anyway, heat pumps have a lot of potential.

    • dumboldguy Says:

      $7000 in 2019, when adjusted for inflation, is not much more than $4000 in 1998, and with any luck, the added cost will also produce a more efficient system—my 1998 replacement was far more efficient than the 1972 original.

      Except for their higher cost and impracticality for many situations, geothermal heat pumps DO have a lot of potential, but “air heat pumps” in general don’t have the potential in the U.S. that they may have in OZ. Remember that the cooling side is just like regular A/C—no difference in the amount of energy needed. On the heating side, they are ineffective once the outside air gets down around freezing, and require natural gas or electric “emergency backup”.

      Remember too that 90% of the U.S. is above 35 N latitude, while maybe 10% of AUS is above 35 S—-we also have the outbreaks of the polar vortex to contend with. Europe is also pretty far north—-hence the blank looks from us northern hemisphere types—-it’s colder here.

      PS When natural gas was in short supply and expensive, air heat pumps were more popular in America—-with the advent of fracking and cheap natural gas, gas heat and regular A/C get it done as well or better.

  5. neilrieck Says:

    I previously did some electronic design work for a Canadian manufacturer who was associated with WaterFurnace Inc ( https://www.waterfurnace.com/ ) of Fort Wayne, Indiana. I was a newbie, and somewhat skeptical, of this technology until I realized it was not a scam. One of the most interesting numbers is a heating spec called COP (coefficient of performance) which compares “the amount of electrical energy expended to run the compressor and pumps etc.” to “the amount of heat produced if this was an all-electric furnace”. Depending on soil composition, degree-days and other local data, most units have a COP of 5 with some approaching 6. (this means that one watt of electrical energy yielded 5-6 equivalent watts of electric heat). Remember that the ground very rarely freezes so there is always heat available for use by these appliances. Now think about cooling mode: In a so-called air conditioner you are trying to move heat from inside air (which might be 20C) into outside air (which might be 30C). With a ground-source unit (which is really a ground-sink unit when in cooling mode) you are moving heat from inside air (which might be 20C) into outside ground (which might be 10C). This is easier to do while much less costly.

    • Brent Jensen-Schmidt Says:

      Very nice to get some actual numbers from a reliable source for a change. ‘Ground’ being an excellent insulator, how is the efficiency after a season of pumping heat in, or out? General/average trends of course.


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