Abstract: An HVAC system including an evaporator, a condenser, an expansion valve, and a compressor. An HVAC case includes a first heat exchanger having a first height, a second heat exchanger having a second height that is greater than the first height, and an air mix door movable to direct airflow from the second heat exchanger to the first heat exchanger or around the first heat exchanger. In a maximum hot mode, a valve system directs the coolant through the condenser, the first heat exchanger, and the second heat exchanger, and the air mix door directs airflow from the second heat exchanger to the first heat exchanger. In a maximum cold mode, the valve system directs the coolant through the evaporator, the first heat exchanger, and the second heat exchanger.

Abstract: A secondary loop HVAC system including an evaporator, a condenser, an expansion valve, and a compressor. A refrigerant loop is in fluid communication with each of the evaporator, the condenser, and the expansion valve. An HVAC case includes a first heat exchanger and a second heat exchanger. A first coolant loop is in fluid communication with the first heat exchanger, the second heat exchanger, and either the evaporator or the condenser. A valve system is configured to control flow of the coolant through the first coolant loop. In a maximum hot heating mode, the valve system is configured to direct the coolant through the condenser, the first heat exchanger, and the second heat exchanger. In a maximum cold cooling mode, the valve system is configured to direct the coolant through the evaporator, the first heat exchanger, and the second heat exchanger.