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Air Balancers and controls contractors are not checking the design, they are executing the design. Last time I did an exam room, we used an AIA guide, and it was 2 ACH of ventilation air and 6 ACH of total air, with no VAV during occupied hours. knowledge is power

HAPS had a "Block "load Calc" software module separate from its lead program. I tried it many years ago and ended up just using the regular loads program and made the building one space. knowledge is power

1) code will tell you when the bathroom exhaust needs to run 2) code tells you what the minimum corridor ventilation is, you may need it increased to provide makeup air depending on your design. 3) depends, you can keep them pressurized. Also some codes do not allow the corridor to be used as a...

Great resource KYROUS From memory CLTD you have to select a few different times of the year to confirm the largest load, and you hope one of the few was close to your worst case. The beauty of software is it calculates the full 8000+ hours of the year. That seems like a lot of work for...

Ive done some kitchens and dont recall any filtration requirement. I suggest specifying Merv 8 pre filters and Merv 13 final filters, and the ownere can decide not to use the MERV 13's. knowledge is power

I size it for 10 cfm/sf of every sf of door open to the outdoors. But really, I put the biggest Cabinet Unit Heater I can fit, or the architect allows. knowledge is power

You are comparing PTACS to a 90 ton air cooled chiller? Seems like a very big difference, especially in cost. ASHRAE Systems? bible has a chapter (one of the first 5) that will help you put together a system comparison chart. You may want to also consider a middle of the road option with a...

Trane has great training resources. http://www.tranebelgium.com/files/book-doc/24/en/24.i2joahta.pdf then you can graduate to: https://www.newbuildings.org/sites/default/files/A-11_LG_VAV_Guide_3.6.2.pdf knowledge is power

Thank you for the input Lionel - we don't have the existing pump efficiencies. But from ASHRAE equation (a governing international engineering body), the existing pump would need to be over 98% to not require space cooling. I don't know pump motor efficiencies, but from the age alone of the...

You are correct Groovy, I just found a chart that said minimum efficiencies for 500 HP motors should be in the 95% efficiency, so I update my calculation to reflect that and am more line with your estimate. I also fail to understand why cooling is currently not required, but we both did the...

Thank you for the insight, Here is additional background that will answer specific questions GROOVYGUY & COMPOSITE PRO & BRIAN PETERSON- I used ASHRAE formulas for heat gain of a motor. See attached. Equation (4) is when the motor is in the conditioned space but the driven machine is...

Hello Electrical Engineers, We are changing out 3 600 HP DC motor pumps and changing them over to AC. My job is to provide the cooling in the room for this massive heat gain, which comes out to about 500,000 Btu/hr, which may require a 50 ton chiller @ 1.2 kW/ton is 60 kW. The existing pump...

For me leaving out the acoustical insulation is a function of: Is the unit located near a sound sensitive space How many elbows is in the ductwork Does it serve noise sensitive spaces. Good questions to ask an acoustical consultant, the next time you work with one on a project. knowledge is power

Replacing the terminal units along with the boiler will probably not be worth it to your client. (depending on the client and project, which you provided no details). I like your idea of replacing the boiler with a condensing boiler for effieicncies (if the boiler is at its life expectancy -...

Bell is a great book, but giving somebody that doesnt know loads, a bunch of rule of thumbs, can really get them in trouble. knowledge is power

I think what I am missing is the importance of the boiler is for the pickup load, when they first fill the digester tank with potentially 50 degF sludge, and the boilers need to pick that up to 95 degF within 24 hours. So I will size the boiler as small as possible to meet that load, so it is...

Also attached is a quick sketch, showing the internal mixer, with the motor located over the cover. The Heat Exchanger is built in the center of the mixer pole with propeller built in. Hot Water is supplied to and from the HX. Again, I don't see the need to control off of the heating water...

Thank you all for your feedback. Yes the draft tube is internal to the digester. See attached photo from the same manufacturer. You were looking at the EDT model, and I am talking about the RDT model, which you suspected. My concern with temperature sensor from a manhole of the roof, will be...

Thank you for providing insight bimr. That is how I would typically control an HVAC equipment such as chiller or hot water system, but I am having trouble understanding the correlation between the return temp from the HX and the digester temperature. To put real numbers into the equation. The...

It is what they call a "draft tube mixer". That portion is selected by another group, My scope is to provide utilities. It has a jacketed heat exchanger dead center, and pumps the sludge (10,500 GPD) from the bottom of the tank, through the center HX and up to the cover so it pushes out to the...