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RANGER1
17-06-2017, 10:05 PM
Have heard people installing flow meters in a system.
What would the main purpose of installing flow meters in a industrial refrigeration system.
Where do you install them, liquid line?

Glenn Moore
17-06-2017, 10:58 PM
Hi Ranger
Have seen a couple of sites, one a brewery where the chilled brine flow was measured so that every part of the plant which used the refrigeration process was separately billed for the amount of refrigeration they used. So by measuring the refrigerant liquid flow to each circuit you could work out the system usage etc. They had a huge consul which displayed the whole circuit and each part of the circuits flow rate could be seen I suppose to see how much beer was produced and bottled on the various lines.
I selected the flow monitoring equipment along with the fridge valves for the consultant a nice order , then a couple of years later Danfoss sold their flow monitoring production to Siemens. If you ever visit the Danfoss factory in Nordborg you will see Siemens now use the old Danfoss factory to produce these high quality products .So any flow can be monitored depending on the system design, mind you it ain't cheap

Segei
18-06-2017, 04:24 PM
I visited many industrial refrigeration plants but I didn't see any flow meters. I know that people use flow meters for energy efficiency studies in universities. Actually it good idea to have these meters but they are not cheap. They should be installed in liquid line for each suction temperature. Than readings of each meter should be recalculated to bring them to one common suction temperature. Meters should be installed to measure only liquid flow. It means liquid should have significant subcooling to prevent flashing.

RANGER1
18-06-2017, 08:42 PM
I visited many industrial refrigeration plants but I didn't see any flow meters. I know that people use flow meters for energy efficiency studies in universities. Actually it good idea to have these meters but they are not cheap. They should be installed in liquid line for each suction temperature. Than readings of each meter should be recalculated to bring them to one common suction temperature. Meters should be installed to measure only liquid flow. It means liquid should have significant subcooling to prevent flashing.

Thanks Segei,
So if they were installed, what can they tell us?
Could it be compressors are not performing as per theoretical design?
Anything else?

Segei
18-06-2017, 11:15 PM
It can be underperforming compressors. However, the most important value of these meters they will be able to prove energy saving that were implemented. At this point we don't have opportunity to show customer improvement of plant efficiency. For example. We can measure energy use of the plant, but we don't know real life refrigeration that was produced during measured period. At this point I suggest my customers to measure energy use before after improvement but refrigeration load should be kept as steady as possible. It is difficult to do for production plants.

RANGER1
19-06-2017, 08:14 AM
On a ammonia production plant we installed 3.
1 on compressor discharge, liquid return to storage plant & one on non condensible line.
This showed what went where.
In old abbatoir not entirely sure what it can give us, as so many different things feeding too.
I guess it's a handy tool if you have it, but thought more simple things could be tried first, as engine room power can be monitored.

Segei
20-06-2017, 03:32 AM
energy use = refrigeration x plant energy efficiency
At the same plant energy efficiency fluctuation of refrigeration load will lead to fluctuation of energy use. However, if flow meters installed for every suction temperature refrigeration can be determined and plant energy efficiency can be evaluated. If people are focused on energy savings, they can change set points and sequences and meters can be helpful to go to the right direction.

Josip
20-06-2017, 05:49 PM
Hi,

many years ago (year 1983.) we installed two Danfoss ultrasonic flow meters on ammonia liquid line to calculate amount of delivered energy.

It was idea to calculate all expenses within production facility of artificial rubber i.e. as Segei wrote above to improve plant efficiency.


.. after that never ever ... maybe due to quite expensive flow meters and lack of interest about plant energy efficiency.

In my opinion installation of any measuring instrument (when sharing energy from one source to different users) can improve use of energy and reduce total costs.

Best regards, Josip