Evaporators and the refrigeration system
Terms in this set (15)
What is the function of the evaporator
The evaporator, absorbs heat into the refrigeration system
efrigerant in the evaporator changes from
Refrigerant in the evaporator changes from a liquid to vapor
The heat that is added to a vapor after all the liquid has boild away is referred to as
What determines the pressure on the low side of the system ?
The metering device
What is typical superheat for a evaporator
8 to 12F of superheat
What does a High superheat indicate
A starved evaporator
A low evaporator superheat indicates
A low evaporator superheat indicated system restriction
Why are multi circuit evaporators used?
Multicircuit evaporators keep excessive pressure drop from occurring in the evaporator
What type of expansion devices do flooded evaporators use?
Use a float metering device to keep the liquid level as high as possible in the evaporator
Dry-type evaporators are also called
Dry-type evaporators are also called direct-expansion evaporators
What happens when an evaporator experiences a heat load increase?
When an evaporator experiences a heat load increase, the suction pressure increases
What is used for low temp. defrost ?
Hot gas defrost or electrical heaters
A mediume temp. refrigerator box operates at which temperatures ?
28 to 40F or 32 to 45
WHat are 7 advantages that a aluminume ,parallel flow, plate/fin evaporator has over a standard round copper tube plate fin evaporator?
Advantages of Aluminum parallel flow, plate/fin evaporator are:
Reduce static pressure thru the coil-which means fewer fan watts and less horsepower. - Reduces coil depth for the evaporator and condenser, which leads to easier cleaning an less air side static pressure. - Reduced internal volume reduces refrigerant charge . - Reduced face area of condenser and evaporator. - smaller footprint for the condensing unit - A 30% coil rate and size reduction - A reduction in packing costs size and weights. - corrosion resistance - lower system costs
list different types of evaporators
forced draft, stamped evaporator, multicircuit, finned tube bare pipe, liquid heat exchangers, drum type evaporator, plate type evaporator in a tank, pipe in pipe evaporator