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Thread: Pump for flooded evaporator
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23-02-2010, 07:44 PM #1
Pump for flooded evaporator
Help!!
How to calculate volume flow of the pump for
R-507 for flooded evaporator W=400kW, -40 C
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24-02-2010, 08:32 AM #2
Re: Pump for flooded evaporator
Calculate amount of refrigerant flow through compressor and usually multiply by 4 for a 4 to 1 curculation ratio .
ie ciculate 4 kg refrigerant and only 1 kg turns to gas as a rough rule .
You may have to find out evaporator design circulation rate .
If its only 1 evaporator you may have a problem as pumps of this style could be way to big if small evaporatorLast edited by RANGER1; 24-02-2010 at 08:40 AM.
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24-02-2010, 06:14 PM #3
Re: Pump for flooded evaporator
The long answer…
Find the R-507 thermodynamic tables
Look up suction vapor enthalpy value
Look up the liquid feed enthalpy valve
Subtract the liquid enthalpy from the vapor enthalpy
This is your refrigeration effect
Divide your desired load (400kw) by the refrigeration effect
This is your mass flow rate
Divide your mass flow rate by your liquid density
This is your raw volumetric flow rate
Multiply your raw volumetric flow rate by the recirculation rate (say 4 for flooded)
This is the amount you need to pump.
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26-02-2010, 02:55 PM #4
Re: Pump for flooded evaporator
How much Pump Circulation Rate
should be ?
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26-02-2010, 03:20 PM #5
Re: Pump for flooded evaporator
Circulation rate is a function of the circuit design within the evaporator. I've seen as low as 1.1 to 1 and as high as 5 to 1. 3 to 1 and 4 to 1 are most common for air cooling evaporators.
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26-02-2010, 04:46 PM #6
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26-02-2010, 10:50 PM #7
Re: Pump for flooded evaporator
Probably 4:1 is the most common recirculation rate. Ask your evaporator coil manufacturer. For example, one of the Canadian manufacturers makes down fed aluminum evaporators using 5:1 so it really depends on the evaporator design.
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26-02-2010, 11:48 PM #8
Re: Pump for flooded evaporator
Remember R-507 is expensive, going 4-1 means you need to have a larger pipe to reduce the friction losses though the pipe. Also you will have a larger refrigerant charge. Your evaporator efficiency will go up with 4-1 but so will your costs. consider economizing on the liquid feed to say 2-1 or 3-1. This may save you money in the long run.
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27-02-2010, 11:10 PM #9
Re: Pump for flooded evaporator
Better still, build the freezer for ammonia.
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28-02-2010, 01:10 AM #10
Re: Pump for flooded evaporator
Hi Decosta.
very good explantion of what happens and what is required.
magooLast edited by Magoo; 01-03-2010 at 01:15 AM.
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28-02-2010, 06:08 AM #11
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28-02-2010, 01:10 PM #12
Re: Pump for flooded evaporator
I remember being told that about a skating rink installation in your country but I had hoped the authorities would have seen the light in the case of an industrial situation. Unfortunately not.
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