What's in a name? The ESCO Institute's Clifton Beck questions what can be technically classified as a heat pump.

Heat pump dryers are recent crossovers from the European to the North American market. They're energy-efficient, compact and ventless.

The heat pump dryer then uses a second loop to cool the air, condensing the water out so the it can reheat the air and start the whole cycle over again. Where does the water go? Depends.

“The goal of the collaborative project is to ensure that heat pumps can operate safely throughout their life cycles ... ISE has also been developing a refrigeration circuit for heat pumps ...