In heat pump applications, which mode is not typically available with a heat recovery system?

In heat pump applications, a heat recovery system is designed to efficiently transfer heat between spaces for both heating and cooling purposes. The primary modes available in a heat recovery system include heating, cooling, and simultaneous heating and cooling, which allows for effective energy management.

The option that indicates "only outdoor heating" is not typically available because heat recovery systems are meant to operate between indoor and outdoor environments, allowing for the capturing and reusing of heat that would otherwise be wasted. While it is possible for certain systems to primarily heat one space or another, the advanced capabilities of heat recovery systems focus on maximizing efficiency and versatility by allowing for the simultaneous management of multiple temperatures in connected spaces, rather than limiting operation to heating only outdoors. This approach enhances energy conservation and comfort within buildings, making such a mode impractical for the stated applications.