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Heat pump: Difference between revisions
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An electric heat pump is one way to [[heating|heat a building]]. It works a lot like [[air conditioning]] but in reverse: The hot air goes indoors; the cold air goes outdoors. | An electric '''heat pump''' is one way to [[heating|heat a building]]. It works a lot like [[air conditioning]] but in reverse: The hot air goes indoors; the cold air goes outdoors. | ||
{{considerations}} | {{considerations}} __NOTOC__ | ||
==Energy | ==Energy efficiency== | ||
{{sum| | {{sum|Only in some cases}} | ||
Heat pumps | Heat pumps can be more energy-efficient than electric heaters. But this efficiency gain disappears when the outdoor temperature is cold enough.{{qn}} | ||
' | Worse: When electricity is generated by [[fossil fuels]], electric heating has up to 3 times the carbon emissions of just burning the fossil fuels directly in a [[natural gas]] furnace {{p2|[see why]|Most coal or natural gas power plants are only 33% efficient. They work by boiling water and driving a turbine.{{minor|Exception: Newer "combined cycle" natural gas power plants can get up to 60% efficient. But for heating homes, that's still less efficient than burning the natural gas at home.<br /><br />Also note: Electricity has losses in transmission too (power lines) - typically about 5%.}} }}. Heat pumps are almost never efficient enough to make up for this. | ||
* | Maybe it's worth getting a heat pump if you live in an area where winters are moderate and electricity is generated mostly by renewables or nuclear.<sup>[WORLD MAP needed]</sup> | ||
<tab name="Research needed for this section"> | |||
{{minor|Can be a case study or generalized statistics}} | |||
* Need graph: Heat pump efficiency vs outdoor temperature. | |||
* Life cycle analysis | * Life cycle analysis | ||
** How much energy does it typically take to ''manufacture and install'' a heat pump? | ** How much energy does it typically take to ''manufacture and install'' a heat pump? | ||
** How often (if ever) is it viable/worthwhile to repurpose an air conditioner in the winter, to help with heating? | ** How often (if ever) is it viable/worthwhile to repurpose an air conditioner in the winter, to help with heating? | ||
*** Are there any "reversible" heat pumps that can work for both heating and cooling? {{p2|(why)|~ Manufacturing half as much stuff would certainly reduce life cycle emissions.<br /><br />~ Use cases:<br />- - ~ New construction<br />- - ~ Any time someone has to replace their air conditioner anyway<br />- - ~ Any time someone has to replace their heating system anyway, and doesn't already have an air conditoner but could use one}} | |||
</tab> | |||
==Refrigerant chemicals== | ==Refrigerant chemicals== | ||
{{sum| | {{sum|{{qn}} }} | ||
Because of how heat pumps work,<!-- TODO: add a section about how they work --> they must contain a substance known as a ''refrigerant''. Most refrigerants in use today{{en}} happen to be potent [[greenhouse gases]]. They aren't supposed to leak out into the atmosphere - but they sometimes do, if the heat pump gets old or is disposed of improperly. | Because of how heat pumps work,<!-- TODO: add a section about how they work --> they must contain a substance known as a ''refrigerant''. Most refrigerants in use today{{en}} happen to be potent [[greenhouse gases]]. They aren't supposed to leak out into the atmosphere - but they sometimes do, if the heat pump gets old or is disposed of improperly. | ||
''This section is incomplete. It needs:'' | ''This section is incomplete. It needs:'' | ||
| Line 27: | Line 34: | ||
* Solutions | * Solutions | ||
** Are there any alternatives - [[refrigerants]] that aren't greenhouse gases? And are there tradeoffs? {{npn}} | ** Are there any alternatives - [[refrigerants]] that aren't greenhouse gases? And are there tradeoffs? {{npn}} | ||
==See also== | |||
* [[Heating]] | |||
* [[Map of electricity by source]] | |||
<!-- TALK: rename this page to "heating with heat pumps"? --> | |||