Chapter 26

The most common temperature ranges for refrigeration systems are

High, medium,low

A secondary fluid or refrigerant

A low temp antifreeze solution

The _____ of a gas is the highest temperature that the gas can have and still be condensible by the application of pressure

Critical point

On a system with multiple evaporators kept at different temps, what component is used on the higher temp evaporator to prevent pressures from dropping below design

Evap pressure regulator

A system that operates at the lowest possible head pressure by taking advantage of cool ambient temperatures that are used as the condensing medium, is said to operate with

Floating head pressure

Refrigerated air driers typically use a ______ to place a false load on the refrigeration circuit when there is no heat

Hot gas bypass valve

When the compressors are located in the equipment room,the piping is routed

In floor chases or in plastic pipes under the floor

The two common methods for rejecting heat from refrigerated cases are

Inside the store(package unit) outside the store(split system)

The type of cooler that is made up of interlocking panels that are assembled on the job site

Knock down cooler

In low temp walk in systems, the condensate drain like

Must be heated to prevent freezing

CO2, ammonia, butane ,isobutane are all examples of what

Natural refrigerants

The two broad categories of display cases are

Open and closed type

A mullion heater is used to

Prevent the formation of moisture on refrigerated fixtures

Parallel compressor systems that apply two or more compressors to a common suction header, a common discharge header,and a common receiver are called

Rack systems

How are conditions maintained in open display cases where there are high shelves

Sinking cold air creates a curtain effect

A co2 refrigeration cycle that takes place over the refrigerants triple point and below the refrigerants critical point is called

Subcritical cycle

When one large compressor is used, what desirable feature should it have?

Suction muffler

The term used to describe the point at which CO2 exist, all three phases(solid,liquid,gas) simultaneously in equilibrium is

Triple point

exactly matching the refrigeration load with the capacity of refrigeration compressors is referred to as

load matching

compressors on parallel compressor racks, which can be large or small and are usually dedicated to the coldest cases are called

satellite or booster compressors