Question

Someone on Craigslist wants to sell you a heat pump that has a COP (coefficient of performance) of 3. Your friend, Donny Dont, an eccentric inventor, says, "No, don't get that heat pump. I just invented a normal electric space heater that is 99.99% efficient! I will sell you one for the same price. It is what I use." What should you do?

Group of answer choices

Don't do what Donny Dont does! If you go with his normal electric heater you will end up spending 3 times as much on energy for the same amount of heat.

Do what Donny Dont does. You can't beat that kind of efficiency when heating your home. You will spend a third of the money on energy for the same amount of heat if you use his space heater.

Don't do what Donny Dont does! But do listen to Mike Mistake, who says to find a heat pump with the smallest possible Q_L/Q_H ratio and to run it most often when there is the biggest difference in temperature between the cold outside and the warm inside.

Do what Donny Dont does. You will save 10% for the same amount of heat with his space heater.

Answer 1

Heat pump always superior than electrical heater for space.heating.

If coefficient of performance of heat pump is 3 , then 100 W electrical power input gives 300 W thermal power.

But , if 100 W electrical power is utilized in heater of efficiency 99.99% , we will get only 99.99 W of thermal power.

Hence , if there is an option to have heat pump of COP =3 and electrical heater of efficiency 99.99% ,

one should opt for heat pump rather than electrical heater.