The primer consists of a hermetically sealed compressor, heat rejection chamber, drier-filter, expansion device, and heat absorption chamber. Hot vapours from the heat absorption chamber in the tank are sucked by the compressor, are compressed & sent to the heat rejection chamber. Liquid emerging out from the heat rejection chamber passes through the expansion device; it is throttled to low pressure & temperature & sent to heat absorption device where it boils. A drier filter is in the way to throttling device. All the components of heat pump Test Rig are displayed on powder coated fabricated stand. Separate pressure gauges are provided to measure heat absorption device & heat rejection device Pressures at various locations. Rotameter in the liquid line is incorporated to measure the refrigerant flow. Digital temperature indicator displays temperatures at various locations as per the selection viz. temperature before & after compressor and before & after expansion. Energy meter is provided to measure energy consumed by compressor.