An absorption heat pump having a generator, a heat source to heat the generator to drive coolant vapor out of solution, a condenser for cooling the coolant vapor and an expansion valve that expand the coolant fluid as well as an evaporator for at least partial evaporation of the expanded coolant fluid against a medium which is connected to at least one absorber which absorbs the expanded coolant fluid. A hot gas line which branches off from a line for coolant vapor upstream of the condenser and is fluid-connected to the evaporator such that it bypasses the condenser and the expansion valve, a defrosting valve being provided in the hot gas line, by means of which the flow of coolant vapor through the hot gas line can be controlled. The absorption heat pump is operated in a cyclic circulation process.

The present disclosure relates to a system and method to modulate refrigerant pressure comprising: a first heat exchanger, a second heat exchanger, refrigerant, and a modulator valve, wherein the modulator valve is operable connected to the first heat exchanger and operatively connected to the second heat exchanger and is capable of regulating the amount of refrigerant in the first and second heat exchangers.

A refrigeration system comprises a compressor, a condenser, a receiver tank, an evaporator and a heat exchanger. The heat exchanger comprises an inlet positioned downstream of the receiver tank and an inlet positioned downstream of the compressor. The heat exchanger is configured to transfer heat between refrigerant received from the compressor and refrigerant received from the receiver tank, wherein a transfer of heat causes at least a portion of the refrigerant received from the receiver tank to transition from liquid to vapor. This process propels the head pressure of the compressor to increase to compensate for low ambient conditions. The heat exchanger comprises a first outlet in fluid communication with the first inlet, the first outlet configured to dispense the vapor refrigerant toward the receiver tank, and a second outlet in fluid communication with the second inlet and configured to dispense the refrigerant received from the compressor toward the condenser.

A refrigeration system comprises a compressor, a condenser, a receiver tank, an evaporator and a heat exchanger. The heat exchanger comprises an inlet positioned downstream of the receiver tank and an inlet positioned downstream of the compressor. The heat exchanger is configured to transfer heat between refrigerant received from the compressor and refrigerant received from the receiver tank, wherein a transfer of heat causes at least a portion of the refrigerant received from the receiver tank to transition from liquid to vapor. This process propels the head pressure of the compressor to increase to compensate for low ambient conditions. The heat exchanger comprises a first outlet in fluid communication with the first inlet, the first outlet configured to dispense the vapor refrigerant toward the receiver tank, and a second outlet in fluid communication with the second inlet and configured to dispense the refrigerant received from the compressor toward the condenser.