Refrigerant receiver

Looking at Fig. 22.1, the need for the refrigerant receiver is not immediately obvious. It does not appear to serve any process function. Many refrigerant systems are constructed without this vessel. However, it does have several important uses. For one thing, it provides a quiet zone for entrained lubricating and seal oils to settle out. 

Turbulence caused by the boiling of the refrigerant prevents efficient draining of heavy oil from the evaporator. However, if the refrigerant receiver has been designed properly, it can be used to trap out the heavy oil. 

In Fig. 22.1, there are two levels that must be controlled. The evaporator level and the refrigerant receiver level. It is impossible to control 

Now let s assume that there is a refrigerant receiver between the condenser and letdown valve. This traps any uncondensed vapors. The accumulation of these vapors raises the pressure in the receiver. This puts backpressure on the condenser. The higher condenser pressure promotes more complete condensation of the refrigerant vapors. 

Finally, the receiver will accumulate any noncondensable (or hard-to-condense) components that have accidentally entered the system. Air left in the vessels on start-up is one such example. Traces of methane and ethane in a propane refrigerant system is another. These light vapors may be vented from the top of the receiver during normal operations. 

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Carbonate of Ammonia. Tho ScHtral Carbonate is prepared by mixing equal parts Pixl-ammoniac, powdered andw cll dried, and dried carbonate of soda, and subliming, by a grotlually increased heat, from an earthen retort into a refrigerated receiver. 

Refrigerant motor-driven compressor Refrigerant condenser Refrigerant letdown valve Evaporator Refrigerant receiver... 

In Fig. 31.1, there are two levels that must be controlled the evaporator level and the refrigerant receiver level. It is impossible to control both levels with two level-control valves. One level must be held with a level-control valve. The other level must be held by adjusting the system liquid refrigerant inventory. It is usually better to add makeup refrigerant to keep a decent liquid level in the receiver and control the flow of refrigerant into the evaporator. However, reversing this control scheme by adjusting inventory control in the evaporator is also possible. 

An ideal Vuilleumier refrigerator receives energy from a 1000 K high-temperature source and a 77 K low-temperature source. Heat is rejected to an intermediate heat sink at 350 K. If 1 kW is added at the high-temperature end of the refrigerator, determine the maximum refrigeration that can be provided at the cold end. 

The most common problem with reftigeration condensers is condensate backup, rather than fouling (see Chap. 16). This may happen if the condenser outlet line is imdersized. Let s say that the pressure drop due to piping friction losses in this line is 10 psig. The refrigerant is isobutane. The isobutane cannot flash as it enters the refrigerant receiver. 

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