Final answer:
A water source heat pump does not require a defrost cycle.
Step-by-step explanation:
A heat pump that does not require a defrost cycle is called a <strong>water source heat pump</strong>. Instead of relying on the outdoor air as a heat source, a water source heat pump uses water from a natural source, such as a lake or a well, as its heat source. Since water doesn't freeze as easily as air, a defrost cycle is not necessary.