Heat Pumps Key to Electrification

November 24, 2020

If we’re going to get there, we’re going to have to electrify everything.

Heat pumps will be big.

Bloomberg:

Whether you want to reduce the greenhouse gases your home produces or lower the cost of your utilities, a heat pump might seem like a good idea. Here are some important factors to consider before you make a purchase.

A Heat pump is both a Heater and an Air Conditioner.

The most commonly installed are air-source heat pumps, which resemble air conditioner units that sit outside your house. During winter, a liquid refrigerant in a copper coil extracts heat from the atmosphere as warm air naturally moves toward the cold. The heat transforms the refrigerant into a cold gas and a compressor then pressurizes the gas, raising its temperature and heating the air inside the house. The reverse happens in hot months, when heat inside the house is absorbed and transferred outside. That’s increasingly useful in temperate areas of the U.S., where people typically don’t have air conditioners but are being hit with climate-change-fueled heat waves.

In the U.S., air-source heat pumps are especially well-suited to the Southeast and the West, where winters tend to be mild. Claire McKenna, a senior associate at the nonprofit Rocky Mountain Institute, says technology improvements now allow heat pumps to operate effectively even in cold climates. But in regions where temperatures routinely drop below zero degrees Celsius, they’ll need to be equipped with a heated coil to provide extra warmth on frigid days. That would consume more electricity. One alternative is a geothermal heat pump, which extracts heat from the Earth. Geothermal heat pumps cost $10,000 to $25,000—a lot of that is the expense of digging trenches for the necessary underground pipe system—but they can reduce energy costs by 70%. Regardless of the type, you’ll need to decide whether you want to use your home’s existing air ducts or install a so-called ductless system, in which heater units are placed in individual rooms. A heat pump will warm your house as well as a fossil fuel furnace, though its efficiency decreases in colder climates.

Work to do.
New technology can bring costs down, just as solar, wind, and batteries have shown.
A startup called Dandelion is pushing the envelope on ground source heat pumps, (GSHP), which, like solar, can benefit not just from technology, but economic and ownership models.

Vox:

One of Dandelion’s key moves has been to vertically integrate, to pull all those links in the supply chain into one organization. The people who find customers, assess properties, drill ground loops, and install heat pumps all work for Dandelion, so they can coordinate efficiently. 

Vertical integration also means Dandelion can order custom-built, high-quality equipment. “Because they’ve got a game plan to reach much bigger scale,” Skouby says, “they can leverage that and buy down cost. Nobody else has been willing to do that.”

For instance, the company designed its own heat pump. “We looked at what was taking installers a lot of time,” says Kathy Hannun, Dandelion’s founder and president, “and every time, there was an opportunity to take those things and just build them into the heat pump.” There’s less on-site assembly required and it has a smaller form factor than comparable heat pumps. It is also covered in sensors, which provide real-time information on how it performs in the field, something the industry has lacked. It’s also cheaper than its competitors.

The company has ordered purpose-built drills, smaller than typical geothermal drills and able to fit into tighter spaces. Similarly, they have optimized piping, grouting, and other components. The strategy is more like a solar startup’s: Invest big early on to drive down costs and begin scaling up; trust that scale will pay back the investment.

Drilling vertical ground loops — 4 to 6-inch holes around 500 feet deep — Dandelion has substantially cut down on the time and disruption of installation, from weeks or months to one week. The company has got the upfront, delivered cost of a system down to $18,000 from $25,000.

Just as importantly, it has devised a financing model to overcome the upfront cost barrier. It loans the cost of the system to customers, who pay nothing upfront. Instead, they repay the loan at a fixed monthly rate that is lower than their previous heating and cooling costs. They save money from day one.

“They’re targeting the type of customer our industry needs,” says Santry, “medium- to lower-income people that this was not available to.”

The loans are still attached to the homeowner, though. What the industry needs, says Hannun, is a model like rooftop solar’s, with “third-party ownership models where, if you’re a homeowner and you don’t plan on living in your house forever, you can put no money down — just buy solar power, essentially, instead of buying normal electricity.” This kind of “solar as a service” model could work just as well with “heat as a service.”

7 Responses to “Heat Pumps Key to Electrification”

  1. doldrom Says:

    I live in the Netherlands, and community scale heat pumps are on the planning boards basically across the country. Although there are only a handful of neighbourhoods where this is currently employed (many as a pilot), they are looking to do this on a massive scale, using public/private partnerships with the Energy companies, the grid managers (networks separated by law), building corporations (a large part of the housing stock), home owners collectives, municipal government, and central government. The scale will generally be the neighbourhood (a few blocks). The main challenge is to move home heating from gas to electric, but using the ground and ground water as the main source of heat.

    There are quite a number of neighbourhoods that have neighbourhood heating, although most commonly in connection with nearby industry or incinerator plants and the like with excess heat. Also used for greenhouse agricultural. Eastern Europe actually has a lot of such collective city heating in place, though I think it is likely not very efficient.

    Here they we be looking to various forms of financing and ownership, but government mandates, regulations, subsidies, and financing will create the framework. One of the main motivations is to stop exploiting natural gas because subsidence has lead to earthquakes and billions in claims for ruined houses and buildings.

  2. neilrieck Says:

    I did some contract-consulting work for a ground-source heat-pump manufacturer in Canada in the 1990s (that company was an off-shoot of WaterFurnace of Indiana, USA). Heating mode products are compared by a metric known as COP (coefficient of performance) which, at first glance, seems counter intuitive:
    first they measure “the number of watts that would be required to heat your home using pure electric heat” then they divide this by “the number of watts which would be required to heat your home using their pumps and compressors”. At that time COP numbers of 3-4 were common which went over 5 when cheaper compressors were replaced with more expensive scroll compressors.
    https://en.wikipedia.org/wiki/Coefficient_of_performance
    p.s. the wikipedia article indicates that COP is now also used to compare cooling modes.

    • mboli Says:

      I think when I went shopping for heat pumps the manufacturers were quoting HSPF, and COP was what the various online advice guides mentioned. I
      As near as I can tell, they are the same idea: heat output per watt consumed, compared to straight-up electric heat.

      Except that heat output is in units of BTU per watt-hour. Just multiply COP by 3.41 to get HSPF, as near as I can tell.

      I think the industry is converting to HSPF because the bigger numbers look better.

    • rhymeswithgoalie Says:

      I haz lernd today.

  3. mboli Says:

    I have a heat pump + gas furnace combination. Some HVAC equipment makers will sell combination set, with controls that switch back and forth among heat sources.

    The main thermostat is unchanged: it just turns the furnace on and off as usual.

    The furnace controls decide on heat pump or gas furnace according to the outside temperature and how long it has been running. Under 35 degrees outside it switches to gas, and if the house is taking too long to warm up it switches to gas.

    In my area it is majority heat pump through mid-November, then majority gas through mid-March. So it cuts a couple of months of gas usage.

    Geothermal would have been very expensive. It also involved tunnelling under the house. Some installers won’t do that, which gave me pause.

    • greenman3610 Says:

      I wonder if anyone is doing a combo between air source heat pump, with a boost from electric hot water tank when needed?

  4. rhymeswithgoalie Says:

    Part of the problem is the cooking advantages of gas that my foodie family members love: The common rule has been: electric oven for stability and gas cook-top for (visible) control.

    I’m giving one sister an induction cooktop and asking for my Christmas present from her be at least one dish cooked on it. If she doesn’t want to keep it, there are plenty of people/places where she can pass it on, but it’s important to get people practical exposure to new tech so they can be more comfortable making the transition. (She enjoys driving my Leaf when she visits.)


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