Dear friends,
In your opinion, what's the best rule to size a liquid receiver for a big plant with ammonia?
Volnei
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Dear friends,
In your opinion, what's the best rule to size a liquid receiver for a big plant with ammonia?
Volnei
Volnei, have you tried this thread.....
http://www.refrigeration-engineer.co...highlight=size
Volnei,
Another great question.
As you have suggested this is for a big system I will not include a discussion or comments on full system pump down capability. The systems are simply becoming too large for this.
The actual pump down volume would of course depend on the requirements of the system and the piping installation.
If for example, the system was installed with the main liquid line feeding the whole facility; the pump down volume of the receiver would then be dependent on the largest possible volume that could be anticipated to be pumped down in the facility. Maybe a large flooded shell & tube chiller.
The largest volume could also be a single area of the facility, say a large freezer or cooler (all of the evaporators in one of these areas).
If different areas of the facility are fed liquid refrigerant off of the main line, any one of these areas could be selectively chosen as the pump down volume.
Perhaps one of the low-side vessels has a larger liquid volume contained in it, rather than the evaporators. The vessel volume could then become a controlling factor.
I don't think this is a question that has a single answer other than to say, it depends on the facility and installation.
If the low-side vessels are provided with a sufficient design pressure (equal to the receiver) they could also be used for pump down service.
Hi Guys:)
What I have been taught is to size on the largest group of cooler to defrost at anyone time + the volume of the pumped liquid line:)
Kind Regards. Andy:)
This is a intersting question. i have sized receivers from almost critical charge to huge.
I think you have to consider the estimated liquid volume considering the coils at 20 percent, half of the volume of the lines and an additional amount %%%%.
Normally i have found that the pump vessels can also be used for storage and usually are. The new regs are vaugue in the usa for how big, so I think you have to consider the plant the location, and OSHA. Good Luck
At least the vessels are about the cheapest component in the big systems.
bruce boldy
i am now with Trane in the usa
Refrigeration was more fun....
I would hesitate to use a blanket statement of 20% to be used for calculating the liquid volume. If the coils are flooded or bottom fed the hold up volume can be a lot higher.Quote:
Originally Posted by BruceBoldy
I also have a question.
What regulations are there in the US that tell you how big the receiver has to be?Quote:
The new regs are vague in the USA for how big
The only thing I am aware of is the requirement for the receiver to have sufficient volume of at least 125% of the receiver holding capacity.
100% would be the required storage volume for the refrigerant and the extra 25% is for the gas space for expansion.