<P> An economizer display takes advantage of the fact that refrigeration systems have increasing efficiencies at increasing pressures and temperatures . The power the gas compressor needs is strongly correlated to both the ratio and the difference, between the discharge and the suction pressures (as well as to other features like the refrigerant's heat capacity and the type of compressor). Low temperature systems such as freezers move less fluid in same volumes . That means the compressor's pumping is less efficient on low temperature systems . This phenomenon is notorious when taking in account that the evaporation temperature for a walk - in freezer at − 20 ° F (− 29 ° C) may be around − 35 ° F (− 37 ° C). Systems with economizers aim to produce part of the refrigeration work on high pressures, condition in which gas compressors are normally more efficient . Depending of the application, this technology either allows smaller compression capacities to be able to supply enough pressure and flow for a system that normally would require bigger compressors; increases the capacity of a system that without economizer would produce less refrigeration, or allows the system to produce the same amount of refrigeration using less power . </P> <P> The economizer concept is linked to subcooling as the condensed liquid line temperature is usually higher than that on the evaporator, making it a good place to apply the notion of increasing efficiencies . Recalling the walk - in freezer example, the normal temperature of the liquid line in that system is around 60 ° F (16 ° C) or even higher (it varies depending on the condensing temperature). That condition is by far less hostile to produce refrigeration, than the evaporator at − 35 ° F (− 37 ° C). </P> <P> Several displays permit the refrigeration cycle to work as economizers, and benefit from this idea . The design of this kind of systems demands certain expertise on the matter, and the manufacture of some of the gear, particular finesse and durability . Pressure drop, electric valve controlling and oil drag, must all be attended with special caution . </P> <P> A system is said to be in a two staged set up if two separate gas compressors in serial display work together to produce the compression . A normal booster installation is a two staged system that receives fluid that cools down the discharge of the first compressor, before arriving to the second compressor's input . The fluid that arrives to the interstage of both compressors comes from the liquid line and is normally controlled by expansion, pressure and solenoid valves . </P>

What is the purpose of an economizer on a rooftop unit