Why are there more circuits in a heat pump outdoor coil compared to an air conditioning outdoor coil?

The presence of more circuits in a heat pump outdoor coil as compared to an air conditioning outdoor coil is primarily intended to minimize refrigerant pressure drop.

In a heat pump system, the outdoor coil operates as both an evaporator during the heating mode and a condenser in the cooling mode. By having more circuits, the heat pump can maintain a high efficiency and ensure that the refrigerant moves through the coil effectively. This allows for a larger surface area for heat transfer, which is critical for the heat pump’s operation, especially in colder temperatures where maintaining higher efficiency is crucial for performance.

Minimizing refrigerant pressure drop is essential because it ensures that the system operates effectively at optimal pressures, leading to better heat exchange and more consistent heating or cooling output. This design consideration is particularly important in heat pumps, which need to reverse their operation depending on the mode, and thus require efficient and effective heat transfer to function correctly in various conditions.

While other options could be relevant to some extent, they do not encapsulate the primary reason for the additional circuits in the heat pump outdoor coil as directly as the aim of minimizing refrigerant pressure drop does.