Ammonia (Refrigerant R-717), used as the refrigerant in cooling systems is a very thin liquid that is a gas at ambient temperature and pressure. To keep it in liquid form, it must be kept at elevated pressure.
Common applications include evaporator liquid overfeed and system filling and emptying. Viking Pumps, by overfeeding the evaporator, ensure that the ammonia in the evaporator coils is liquid, which is more efficient at removing heat than a gas which is often a byproduct of the heat absorption process.
Viking 4924A Series draw liquid ammonia from an accumulator vessel and pump it to the evaporator and back in a closed loop. Liquid and gaseous ammonia are separated in the accumulator and the gas is recompressed and flows to the condenser where it rejects heat, then to a receiver and back to the accumulator in a closed loop.
The Viking pumps’ high efficiency, with air-cooled motor, add almost no heat to the system, increasing overall cooling efficiency. Additionally, slow speeds enable very low NPSHr and prevent gas flashing and cavitation.