Fresh air for residential building.
Fresh air for residential building.
(OP)
Hi all, I’m working on HVAC system for luxury residential building.
Unit #1 two floors. Four bathrooms 75 cfm exhaust each. Total exhaust is 300 cfm.
Unit# 2 one floor. Two bathrooms 75 cfm exhaust each. Total exhaust is 150 cfm
Unit#3 one floor. Two bathrooms 75 cfm exhaust each. Total exhaust is 150 cfm
Unit#4 two floors. Four bathroom s 75 cfm exhaust each. Total exhaust is 300 cfm.
The exhaust fan will be controlled by local bathroom light switch.
I’m planning to bring a fresh air to each air handler unit equal to the amount exhausted from the toilet.
Thru a common duct to the roof with a gooseneck, each air handler fresh air takes-off from the main fresh air duct.
My Question is.
How do I treat the outside air to protect the coil from freezing? Should I install electric duct heater slip in type with a booster fan?
If so, how the control would work. Please advice. Thanks!!
Unit #1 two floors. Four bathrooms 75 cfm exhaust each. Total exhaust is 300 cfm.
Unit# 2 one floor. Two bathrooms 75 cfm exhaust each. Total exhaust is 150 cfm
Unit#3 one floor. Two bathrooms 75 cfm exhaust each. Total exhaust is 150 cfm
Unit#4 two floors. Four bathroom s 75 cfm exhaust each. Total exhaust is 300 cfm.
The exhaust fan will be controlled by local bathroom light switch.
I’m planning to bring a fresh air to each air handler unit equal to the amount exhausted from the toilet.
Thru a common duct to the roof with a gooseneck, each air handler fresh air takes-off from the main fresh air duct.
My Question is.
How do I treat the outside air to protect the coil from freezing? Should I install electric duct heater slip in type with a booster fan?
If so, how the control would work. Please advice. Thanks!!





RE: Fresh air for residential building.
You can use an HRV for each air handler
RE: Fresh air for residential building.
You may have not only a coil freezing problem but a heating load higher than the unit can handle.
If your option is a VRF system they have indoor units to treat outside air or even Heat Recovery Units to exchange heat with exhaust.
RE: Fresh air for residential building.
20 cfm/person X 5 = 100 cfm min. outside air.
RE: Fresh air for residential building.
RE: Fresh air for residential building.
The 15°F may be a little low, but it will work most of the year.
RE: Fresh air for residential building.
RE: Fresh air for residential building.
I thought you had a common duct.
RE: Fresh air for residential building.
RE: Fresh air for residential building.
RE: Fresh air for residential building.
I'm thinking of using a small electric duct heater with inline fan to maintain the duct heater velocity in each fresh air take-off to the air handler. (The building will share a common fresh air duct work but the electric coil and fan has to be operated, maintained and serviced by the apartment owner from the take-off)
RE: Fresh air for residential building.
RE: Fresh air for residential building.
RE: Fresh air for residential building.
yes the owner concern about the condominium maintenance fees. each unit will have own exhaust system and fresh air intake.
I came up with an idea to use a small inline fan/electric duct heater with temperature sensor for each unit.
Any comments?