Recent content by dynamo78

Sorry for the confusion for not having a well defined question. Based on your input, I was able to research what I want and needed to know. Thank you for all the inputs.

Thanks Moideen. Got it. By definition, Cv is the flow per 1psi PD across the valve. in this case, it's GPM. yeah, I agree with you. I should have included the PDs on the fittings too. I agree that the CV should be 15 as you have shown. Now if the Supply CHw side to the coil is closed, the bypass...

Well, The reason for being is that at 1 psi pressure drop the flow would be 8GPM, and to simulate the coil flow at 125 GPM and 15psi PD, the PD across the valve should be about 15psi PD too. right? Thanks Novice.

Hello fellow members, I just want to recall my HVAC knowledge if it still applies. Say, I have a cooling coil with 33Ft. PD @ 125 GPM, my old school knowledge says that I should a control valve with a CV of 8-9. Will that change if I have VFD in the chiller system? I appreciate any comment to...

Thank You FP. Are you talking of Compressor "Performance Curve?

Hi fellow members. I am being trained in the design of sprinkler and read in the NFPA 13 standard, for dry system, that if the air volume being delivered by the compressor is less than 5.5 CFM at 10 PSI, then an "Air maintenance device" is not required .I calculated the volume of the system to...

@Lukai, Thanks for your input. I agree but I have limited resources to investigate the whole building and I got the assurance that ventilation system is ok meets the building requirement. That's why I came up with that simplistic solutions.

I have to replace several fans that were installed in the 70s. I don't have any cat sheet or drawings to verify their performance and data, manufacturer closed shop. I know their CFM and actual Hp. I figured out that in order to verify the static pressures of each fan, I have to plot the CFM and...

To the OP. Is the author "Stephen Kavanaugh? Thanks.

Beginner here chiming in. Hi dbill. Did you plot the coil performance on the Psychrometric chart? after shutting down the AHU, does the condensate flow freely to the drain? I mean while the AHU is operating does it hold the water in the pan then flows freely if it s off?

Thank you Bros. I really appreciate the inputs. Hope to return the favor later to other engineers.

@ Brony, Thank you and to the others. Till the next follow up question later.

@ Bro dbill74 "Your Qs equation is incorrect; correct equation is Qs = CFM x 1.1 x Delta T air" So based on your comment I cant use the equation: Qs= 500 x GPM x Delta T even for heating? I qualified this in my OP @BronYrAur Now, can I used the energy balance equation Qs (air side)= Qs (water...

Thank you Bro Trashcan man. I know this will be redundant but I'll confirm it anyway. If I was given the total load (Qt=Btu/hr) of a cooling coil then I can use the equation Qt=500 x GPM x delta T in determining the GPM for the coil. Thank you in advance for those inputs.

Can I used this equation to determine Chilled water GPM: Qt= GPM x 500x Delta T Qt= Total heat @ BTU/hr. Latent and sensible heat Delta T= Temp. difference between entering and leaving cooling coil. My point:Since the chilled water can handle sensible and latent load (Qt which is equal to: CFM...