Evaporators

Evaporators

Evaporators must be properly selected for the regrigeration load. Too large on evaporator might result in low velocities and possible oil logging. To small an evaporator will have excessive temperature differentials between the evaporating refrigerant and the medium to be cooled. The allowable TD between the entering air and the evaporating refrigerant may also be dictated by the humidity control required.

Internal volime of the evaporator turbing should be at a minimum to keep the system rwfrigerant charge a low as possible, so the smallest diameter tubing that will give acceptable performance should be used. Since pressure drop at low evaporating temperatures is critical for as capacity is concerned, multiple refrigerant ciucuits with fairly short runs are preffered. At the same time, it is essential that velocities of refrigerant in the evaporator be high enoungh to avoid oil trapping.

Vertical headers should have a bottom outlet to allow gravity oil drainage.