Quick vent: I’ve been on this site since the dark ages although I haven’t posted anything in a while. I’ve developed good (but never-met) friends: Quark, Imok, MintJulep, Liliput, Abby, SAK9, IRStuff, etc.. - you all know who you are.
I’m two weeks away from an HVAC PE exam and have been doing...
Have a Closed loop chilled water system, several solder joint failures resulting in leaks. Joints I'm pretty sure are typical lead free pipe solder. 30% propylene glycol solution.
Water chemistry sample:
pH: 11.00
Conductivity: 5,900 umhos/cm
Total Alkalinity: 15,000 mg/L as CaCO3
Calcium...
Have a Closed loop chilled water system, several solder joint failures resulting in leaks. Joints I'm pretty sure are typical lead free pipe solder. 30% propylene glycol solution.
Water chemistry sample:
pH: 11.00
Conductivity: 5,900 umhos/cm
Total Alkalinity: 15,000 mg/L as CaCO3
Calcium...
I'm wondering if anyone has any good data or resources on heat output from sun hitting a) aluminum miniblinds, b) vinyl miniblinds, c) ____ other type of window dressing, etc.
E.g., direct sun impact on type x will be ballpark __BTU/hr-ft2 and type y will be about __BTU/hr-ft2.
Not looking for...
I have a question and would like your opinion about minimum pump flow. Application is a relatively small heating hot water system and variable frequency drive pump, running on loop DP controls. The pump is a very common vertical inline centrifugal. Pump duty point is 40 gpm at 72 ft.
Asked the...
I have a chiller plant application where the surface of the water in the open cell cooling towers is only about five feet higher than the condenser water pumps' inlets.
There's about an 80 foot run of condenser water supply piping leading to the pumps. During operation, pump inlet pressure is...
Hi all, I haven't had much luck with search engine results for what I need, which is to preheat small volumes of make-up water to 200°F. Ideally, a 3-5 gallon steam or electric heated tank (well insulated) that can maintain 200°F pretty steadily.
Don't waste your time googling for me, but if...
Hello all -
Would like to know your thoughts on the following problem.
Putting it as concisely as possible, a chiller plant was replaced with a larger one. The condenser water system, however, re-used the old 6-inch piping to and from the cooling tower due to the cost of digging up piping and...
Greetings all - I apologize for recent lack of activity as life's been busy.
On a recent project, folks expected a certain design differential pressure across hot water pumps and the system had less friction than anticipated. So to make up for that lack of friction and to recover pressure...
Greetings all:
Can anyone tell me how to derive ppm concentration of morpholine from condensate pH? I think they taught me this in the navy but it's been a while. I seem to remember:
C4H9N0 + H20 ---> C4H9NOH+ + OH-
morpholine water morpholinium hydroxyl
pH is...
I have the following that ended up in a building.
Two redundant biosafety level 3 (BL-3) exhaust fans are served by a variable frequency drive (VFD). The VFD is equipped with a disconnect and a hand-off-auto switch, configured for interaction with the building automation system that will allow...
Greetings all,
I hear gas engines run rough when burning rich and run smooth but stall when burning lean. I was curious whether there is common knowledge on what gas engine A:F ratio (rich end) will rough engine running first become apparent... If you have an answer, are there any sources I...
I get the feeling in this forum that many of us were at one time involved in the nuclear field but career opportunities have brought us into other fields... I myself am in HVAC as there seems to be a need for building commissioning. Not many buildings work right after they're first built...
I've always heard electric heat (either baseboard in home applications or electric duct reheat, etc.) is far worse than combustion based heating from a cost perspective. I tend to accept this as fact, because it seems to be widely known. What I wonder is how the costs truly compare between...
Comrades,
I'm reviewing a design that incorporates a heat recovery wheel in a chemical lab school building (post-grad studies)...
I love the idea of heat recovery. I cringe at the thought of using a wheel that spins through a contaminated exhaust air stream into the make-up air stream. The...
Greetings -
Since a recent cold spell in our area (10-20°F daily average) we've been hearing occasional loud bangs in the office from above the ceiling. It's a one-story building with a high ceiling plenum. The ceiling is truss steel holding up corrugated metal. Sort of like your typical K-mart...
Greetings:
My application is a chiller and chilled water system with a standard primary/secondary loop and a flow decoupler.
The design shows the air separator and associated bypass valve (with expansion tank and make-up water line at the top connection of the air separator as commonly seen)...
Application - standard CAV/VAV supply air terminal box with hot water reheat:
I usually see the reheat coil's hot water control valve at the outlet (hot water return pipe) of the coil.
Occasionally I see a "rebel" design that has the hot water control valve on the supply line.
I've...
Application - standard CAV/VAV supply air terminal box with hot water reheat:
I usually see the reheat coil's hot water control valve at the outlet (hot water return pipe) of the coil.
Occasionally I see a "rebel" design that has the hot water control valve on the supply line.
I've...
Greetings All, I'm working on a project where a heating water (HW) pump is used at the basement level of a 12-story building. The HW pump draws suction from a steam-to-HW heat exchanger. This point (the pump suction) is the maximum loop temperature point, as it is right at the outlet to the heat...
