If you take 100 joules of electrical or chemical energy, and then direct them to a heater in a house, it’ll create about 100 joules of heat. That’s 100% efficiency.
But if you use the 100 joules of energy to run a heat pump, it might bring in 300 joules of heat into the house. That’s 300% efficiency, when measured locally at the place you actually care about (inside the house). Zoom out and laws of thermodynamics still make it impossible to create more energy than was put in, but if you look at just the part you care about, it’s possible locally.
Its partly due to how you are measuring efficiency. It mainly moves heat rather than creates it.
Another fun way to get more heat is condensing, a dehumidifier gets over 100% efficiency if you were to use it as a heater. Heard of evaporative cooling right? Well condensing is the opposite, you get extra heat from that.
Refrigeration cycle can get crazy efficiencies like that because it is transferring energy from one side of the system (indoor unit) to the other (outdoor unit). The amount of energy that is transfered is greater than the amount of energy required to push the refrigerant through the system.
How does something achieve 300-400% efficiency?
If you take 100 joules of electrical or chemical energy, and then direct them to a heater in a house, it’ll create about 100 joules of heat. That’s 100% efficiency.
But if you use the 100 joules of energy to run a heat pump, it might bring in 300 joules of heat into the house. That’s 300% efficiency, when measured locally at the place you actually care about (inside the house). Zoom out and laws of thermodynamics still make it impossible to create more energy than was put in, but if you look at just the part you care about, it’s possible locally.
Ok yeah, so you would consider it as two systems, one being the heat pump and the other being the rest of the world.
And instead of creating heat you’re moving it, so your heat pump is operating at above 100% efficiency while the rest of the world is not.
Thanks for the explanation!
Its partly due to how you are measuring efficiency. It mainly moves heat rather than creates it.
Another fun way to get more heat is condensing, a dehumidifier gets over 100% efficiency if you were to use it as a heater. Heard of evaporative cooling right? Well condensing is the opposite, you get extra heat from that.
Refrigeration cycle can get crazy efficiencies like that because it is transferring energy from one side of the system (indoor unit) to the other (outdoor unit). The amount of energy that is transfered is greater than the amount of energy required to push the refrigerant through the system.