Electric Heat Pumps: Existing Tech for Energy-efficient Future

Most heating systems in the U.S. use forced-air furnaces that run on natural gas or electricity, or in some casesheating oil. To heat the building, the systems burn fuel or use electricity to heat up air, and then blow the warm air through ducts into individual rooms.

A heat pumpworks more like a refrigerator, which extracts energy from the air inside the fridge and dumps that energy into the room, leaving the inside cooler. To heat a building, a heat pump extracts energy fromoutdoor airorfrom the groundand converts it to heat for the house.

Here's how it works: Extremely cold fluid circulates through coils of tubing in the heat pump's outdoor unit. That fluid absorbs energy in the form of heat from the surrounding air, which is warmer than the fluid. The fluid vaporizes and then circulates into a compressor.Compressing any gas heats it up, so this process generates heat. Then the vapor moves through coils of tubing in the indoor unit of the heat pump, heating the building.

In summer, the heat pump runs in reverse and takes energy from the room and moves that heat outdoors, even though it's hotter outside – basically, functioning like a bigger version of a refrigerator.

Heat pumps require some electricity to run, but it's a relatively small amount. Modern heat pump systems can transfer three or four times more thermal energy in the form of heat than they consume in electrical energy to do this work – and that the homeowner pays for.

In contrast, converting energy from one form to another, as conventional heating systems do,always wastes some of it. That's true for burning oil or gas to heat air in a furnace, or using electric heaters to heat air – although in that case, the waste occurs when the electricity is generated. About two-thirds of the energy used to produce electricity at a power plant islost in the process.

Retrofittingresidencesand commercial buildings with heat pumps increases heating efficiency. When combined with a switch from fossil fuels to renewables, it further lowers energy use and carbon emissions.

Growingrestrictions on fossil fuel useandproactive policiesaredriving sales of heat pumpsin the U.S. and internationally. Heat pumps are currently used in 5 percent of heating systems worldwide, a share that will need to increase to one-third by 2030 and much higher after to reachnet-zero emissions by 2050.

In warmer areas with relatively low heating demands, heat pumps are cheaper to run than furnaces. Tax credits, utility rebates or other subsidies may also provide incentives to help with up-front costs, including federal incentivesreinstated by the Biden administration.

In extremely cold climates, these systems have an extra internal heater to help out. This unit is not as efficient, and can significantly run up electric bills. People who live in cold locations may want to consider地热热泵as an alternative.

的se systems leverage the fact that ground temperature is warmer than the air in winter.Geothermal systemscollect warmth from the earth and use the same fluid and compressor technology as air source heat pumps to transfer heat into buildings. They cost more, since installing them involves excavation to bury tubing below ground, but they alsoreduce electricity use.

New, smaller "mini-split" heat pump systemswork well in all but the coldest climates. Instead of requiring ducts to move air through buildings, these systems connect to wall-mounted units that heat or cool individual rooms. They are easy to install and can be selectively used in individual apartments, which makes retrofitting large buildings easier.

Even with the best heating and cooling systems,installing proper insulation and sealing building leaksare key to reducing energy use. You can also experiment with your thermostat to see how little you can heat or cool your home while keeping everyone in it comfortable.

For help figuring out whether a heat pump can work for you, one good source of information is your electricity provider. Many utilities offer home energy audits that can identify cost-effective ways to make your home more energy-efficient. Other good sources include theU.S. Department of Energyand theAmerican Council for an Energy Efficient Economy. As the push to electrify society gains speed, heat pumps are ready to play a central role.

This article is republished from的Conversationunder a Creative Commons license. You can find theoriginal article here.

Robert Brechais a professor of sustainability at the University of Dayton.