In the normal system, in the heat pump mode, the refrigerant flow would be reversed so as to make the condenser, in effect, the evaporator and the evaporator the condenser. Thus, the heat that the evaporator gains from the ambient air will then be pumped into the condenser, which would be in the passenger compartment and thus provide heat. In the secondary loop system, the condenser is the chiller and the front-end heat exchanger is the evaporator (the passenger compartment heat exchanger will be called the cabin heat exchanger). The problem with both these systems is that the front-end heat exchanger cools down the ambient air, which may already be very low in temperature (below 40° F.). This causes this heat exchanger to freeze. This results in inadequate performance and potentially no performance after a while. A way around this is to utilize the heat from the coolant to evaporate the refrigerant in the evaporator. In such a system the front-end heat exchanger is bypassed and is replaced by a refrigerant-to-glycol (RTG) heat exchanger. This allows the coolant, which is warming up to be the source of heat for the evaporation process in the RTG. This, of course, slows down the coolant warm-up rate but is insignificant and results in dumping heat into the passenger compartment with a significantly higher rate because of the compression process.