A system and method of using a source of low-pressure refrigerant for a cryotherapy procedure. The system may generally include a fluid reservoir and a fluid flow path in thermal exchange with the fluid reservoir, the fluid flow path including a thermal exchange device in thermal exchange with the fluid reservoir, a compressor in fluid communication with the thermal exchange device, a condenser, a reversing valve located between the compressor and the condenser, and an expansion valve located between the condenser and the thermal exchange device. The method may include transferring a low-pressure refrigerant to a first fluid reservoir, reducing the temperature of the refrigerant within the first fluid reservoir, increasing the temperature of the refrigerant within the first fluid reservoir, and transferring the pressurized refrigerant from the first fluid reservoir to a second fluid reservoir.