There is the following problem in a textbook on Thermodynamics:
A heat pump is an electrical device that heats a building by pumping heat in from the cold outside. In other words, it’s the same as a refrigerator, but its purpose is to warm the hot reservoir rather than to cool the cold reservoir (even though it does both).
I have a hard time understanding the principal difference between a heat pump and a refrigerator. In a refrigerator, heat is drawn from a cold substance into the refrigerator cabin and then excess heat is pumped out of the device.
Now, in the case of a heat pump, heat is also pumped from a "cold substance" (the cold outside) and it goes into the "cabin" (the building interior). But then how does the building get heated and not refrigerated? I'm really confused by this problem statement, it couldn't be less clear.