I have the SMACNA "HVAC Systems Duct Design Guide" That includes a good explanation and also duct fitting loss coefficient numbers. There are also free guides, like from McGill
But I wanted to compare what SMACNA says to what ASHRAE recommends. I use Revit for design and that allegedly uses the...
I'm aware of the general pros and cons for both types. Most older HVAC systems we have use ethylene glycol due to slightly better efficiency. But there also is the concern the toxicity could be a hazard (handling errors, spills etc.). Some newer systems we have use propylene glycol for that...
In 1-2 years support for T700 will end. I had used it for multiple years for load calculation and energy simulations. It has its limitations, but it works. any error is easily resolved.
The real only limitation is that one enters the rooms manually without "seeing" the building. gbXML also is...
De-aerators would best when water is hot and at low pressure. So ideally they would be downstream of the boiler, and upstream of the pump. but that puts the pump on the hot side of the boiler, which will degrade seals.
So since most of our hydronic system problems are degrading pump seals i...
I'm working on a project requiring make-up air for garage and work spaces. We typically use direct-fired MUA. I'm in WI, so we do have quite some heating requirement.
This project also includes installation of a new boiler plant. So at just a bit higher cost I could use hydronic MUA with glycol...
I'm looking for a good way to track over the course of a project what decisions were made and why. for example: someone decided a year ago a pipe should be increased for future capacity. Next year this will be installed and in the field someone wonders if the pipe could be made smaller... then...
I have a washbay application. in there it is wet and salty (from cleaning salt trucks). Due to the water I have a hard time finding a heating solution that needs electricity (i.e. unit heater etc.)
Anyway, I'm contemplating to install hydronic radiators. not a real challenge, except that I...
I need to buy a new load calculation software. Mainly for load calcs and equipment sizing in small and medium sized commercial buildings. Software should use RTS and other modern methods and provide good documentation for review and "sanity check".
some features i really would like:
- Some...
Hello,
I'm a licensed engineer in WI and mainly design HVAC systems. I like to venture into plumbing design as that often is part of the project. What resources (esp books) should I look into?
WI has its own plumbing code (not IPC). I also have a lot of the WI-specific design manuals (which...
For VAV supply with ducted return the return ducts get balanced based on design flow. With that during design conditions each space should be relatively neutral to other spaces and we minimize infiltration and exfiltration (i.e. uncontrolled air paths). But as described here during partial load...
typically I see designs that require garage exhaust to be taken not higher than 18" above floor. I believe the reasoning is CO is lighter and with such low intake of the exhaust air we capture CO better. I wanted to verify the exact requirement, but can't find a code that details the 18"? I only...
Could you review and comment on my design idea?
I have an existing building with hydronic heat that requires about 140-150°F supply temp. I also add some unit heaters that I design for 140°F. Overall that part may have a dT of 25°F (that design is a bit screwed up, and we add perimeter heat -...
I'm not sure why I can't reply to my old thread anymore. But I found the problem.
We found the pitot tubes in the VAV boxes are breaking off and therefore the pressure sensor doesn't get a reading anymore. It was a Carrier VAV box (if you want to know which product to avoid) and all the 20 or...
I have a project that requires an NG generator ~100 kW. this is pure convenience so they can operate during outages. It won't run any life-safety or other required equipment. It seems NEC 702 calls them "optional Standby systems"
I plan to locate it in a room where the electric service is, with...
This may be a doublepost as no on responded in Valve forum.
For some of my projects I'm literally buying all the valves and so i got into more detail into very specific valve model numbers. My main goal is very long life and very little downtime.
i like to select equipment that also works on...
I'm selecting some valves for HVAC. For flanged valves the better ones have SS-Balls. But for the smaller ones (1/2" up to 2.5" copper pipe) I like to use bronze valves and most have chrome-plated brass balls. Only few have SS-balls. The valves only will be operated occasionally (isolation...
I wonder what the general opinion is on if to use bronze or brass instead of steel. On most projects designed by consultants I see that strainers. etc. are just of steel. For chilled or geothermal piping this means it corrodes like hell due to condensation (and strainers need to be accessible...
I have that idea to enhance a regular ERV wheel with a refrigeration heat recovery (or rejection in summer). I drew up (attached) how that could look like and wonder if the best and brightest have come across that or have an opinion. Basic idea is:
1. Use ERV wheel to recover some energy and...
We have an office building where many of the VAV box flow stations don't read the flow anymore (just read 0). I also measured the dP manually and didn't really get much of a reading. My suspicion is that over the years the pitot-tubes in the flow rings got dirty.
this seems to be the only...
I'm designing a ventilation system of a garage. I'm considering an ERV wheel.
The garage houses diesel trucks. When the system runs the air should be relatively clean (up to 0.75 cfm/ft²) , there only will be limited idling. The garage has two oppsing overhead doors and is not longer than 200'...
