How do you figure out GPM 1

[Thorkan]

How do you figure out the GPM going threw a package unit's condenser water coil. I have differential pressure gauges that read in feet of water colume on one guage and inches of water colume on the other. Can i use this infomation to measure the GPM flowing threw this coil?

Thank you for any help you can offer.

Thorkan

 

[dazma]

If your flow system is a closed loop system,

Differential pressure across the condenser coil will be equal to = K* (Kinetic energy)
Where KE = (1/2)*density* (velocity)**2
K = pressure drop co.
If you know the pressure drop across the condenser and the pressure drop coeficient of the condenser you can calculate the velocity of flow through the system in any units from the above mentioned equation.
Hope I have clarified your doubt.

 

[packdad]

This may be kind of obvious, but do you have an ultrasonic flowmeter available?

Also, if you can figure out the suction/discharge pressure of the chilled water pump, you could determine flow that way.

 

[packdad]

(Using the pump curve to determine flow, I mean.)

 

[TBP]

Any manufacturer I know of supplies charts or tables with their literature. All that's normally required is to get the water pressure drop across the condenser and match it to the supplied graph for that unit. If you don't have the literature, get the data off the nameplate on the unit, and call the manufacturer. They should be able to supply the information you require in pretty short order.

 

[Thorkan]

Thank you all for your answer's. All three are very helpful.

Take care,

Thorkan

 

[Adviser]

Is there a simplified way to ascertain GPM given the variables of PSI pressure and diameter of pipe under gravity feed? I know that .433 psi is added for 1 ft of drop and subtracted for 1 ft of rise. Determining the pressure is simple if you know the height of the water column. As an example, I have a 10' water column which develops 4.33 psi. This pressure flows through a 4" ID Schedule 40 PVC pipe. I can determined head pressure. Can anyone assist me in taking this data and determining gpm? Thanks.

 

[abeltio]

Adviser,
You should start a new post with your question so everybody can see it... otherwise it will be seen only by the people that open this particular posting.
Saludos.
a.

 

[TD2K]

Advisor, flow through your system is a function of the dP across it and the length of the 4" pipe and number/type of fittings, valves, etc.

Crane's booklet "Flow of fluids through valves, fittings and pipe" is an excellent reference and has several examples that I think would clarify it for you. If you drop me an email at testdog2000@yahoo.com, I have some of the key pages scanned (but not the entire booklet) and could send them to you.