{"id":303638,"date":"2024-02-21T08:20:56","date_gmt":"2024-02-21T07:20:56","guid":{"rendered":"https:\/\/climatescience.press\/?p=303638"},"modified":"2024-02-21T08:20:58","modified_gmt":"2024-02-21T07:20:58","slug":"when-and-why-heat-pumps-suck","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=303638","title":{"rendered":"When (And Why) Heat Pumps Suck"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

From The CO2 Coalition<\/a><\/p>\n\n\n\n

By Ron Barmby<\/p>\n\n\n\n

When you need heat pumps the most, they pump heat the least.<\/p>\n\n\n\n

This is according to an unbreakable law of physics that applies to the entire universe without exception, even black holes, and especially to heat pumps.<\/p>\n\n\n\n

Heat pump promoters who claim otherwise must have defeated the second law of thermodynamics<\/a>, which would theoretically also allow them to make time run backward.<\/p>\n\n\n\n

In addition to denunciation by physics, the cost of operating heat pumps<\/a> is often very high compared to natural gas-fired heating<\/a>.<\/p>\n\n\n\n

Heat pumps are often accurately described as an air conditioner in reverse. To understand how a heat pump works<\/a>, it helps to know how an air conditioner works.<\/p>\n\n\n\n

How An Air Conditioner Works<\/h3>\n\n\n\n

An air conditioner transports heat from inside a house to the outside in a continuous circuit using a chemical mixture called a refrigerant.<\/p>\n\n\n\n

The refrigerant is piped into the house as a liquid under high pressure and at a temperature just above the outside air temperature. It expands into a gas across a valve that has a lower pressure on the other side and becomes very cold, about 4\u00b0C (39\u00b0F).<\/p>\n\n\n\n

This part of the air-conditioning unit is called the evaporator because it causes the liquid refrigerant to evaporate into a gas. The cooling is a bit similar to when you let air out of a tire<\/a> and the expanding escaping air feels cold. (If you want to know more details, look up the Ideal Gas Law<\/a>.)<\/p>\n\n\n\n

The pipe with cold gas-phase refrigerant is then passed in front of a fan inside the A\/C unit (or furnace if it\u2019s central A\/C) to cool the room.<\/p>\n\n\n\n

The second law of thermodynamics<\/a> dictates that two bodies at different temperatures will equalize in temperature when brought into contact with each other.<\/p>\n\n\n\n

How fast this equalization occurs is driven by the temperature difference between the two bodies: the bigger the temperature difference, the faster the heat exchange happens.<\/p>\n\n\n\n

The pipe containing the refrigerant gets cold because it\u2019s in contact with the cold refrigerant<\/a>, and the air outside the pipe gets cold because it\u2019s in contact with the cold pipe.<\/p>\n\n\n\n

A fan speeds up the contact of the warm air in the room with the cold pipe and as the heat from the air is transferred to the refrigerant, the refrigerant gets warmer.<\/p>\n\n\n\n

The low-pressure and now warm refrigerant is then piped outside the building to an electrically driven compressor, which reduces the gas in volume and increases its pressure.<\/p>\n\n\n\n

The compressor puts energy into the gas causing it to heat up (the Ideal Gas Law again). The hot high-pressure gas is then cooled to near outside temperature by passing the pipe containing the gas for several loops in front of a fan that uses outside air to cool and condense the gas into a high-pressure liquid (which is why it\u2019s called the condensing unit).<\/p>\n\n\n\n

The high-pressure and near-outside-temperature liquid refrigerant is then piped inside the building and the whole circuit starts over again.<\/p>\n\n\n\n

This circuit is called the Carnot Cycle<\/a> after the French physicist Sadi Carnot who discovered it in 1824. It wasn\u2019t until 1902 that American engineer Dave Carrier produced the first air conditioner.<\/p>\n\n\n\n

How A Heat Pump Works<\/h3>\n\n\n\n

To convert an air conditioning unit into a heat pump, you place the evaporator (which attracts heat) outside of the house and the condenser (which expels heat) inside the house.<\/p>\n\n\n\n

Furthermore, the heat pump refrigerant is chemically different so that it can be cooled in the evaporator to minus 25\u00b0C (minus 13\u00b0F). The refrigerant has to be colder than the outside temperature to absorb outside heat.<\/p>\n\n\n\n

The two perceived advantages of a heat pump are:<\/p>\n\n\n\n