# air changes per hour to heat in an apt building

[pesy]

How many air changes are typical in an apt building in NYC?

I live in a 12-story, 88 unit apartment building that has many of its radiators broken (can't be shut off), resulting in many apts being overheated. Therefore, the apts with the broken radiators keep their windows partially open. There are some apts whose radiators don't put out enough heat, and the [steam] boiler setpoint was obviously chosen to provide those under-heated apts with sufficient heat, thereby overheating ther others. I am trying to determine the energy savings by fixing the radiators, with the intent that people will keep their windows closed if it isn't too hot.

Pesy

 

[chicopee]

W/ window closed I would assume 1 air change per hr. W/window partially opened, I would double that value.
I guess we all realize that when tenants do not pay for utilities, they will be wasteful; so I would attempt to have the tenants who open their windows in the winters pay a penalty fee or implement an energy conservation police to control this type of waste.
You will see such wasteful behavior in subsidized housing and to me it seems to me that the FEDERAL GOVERNMENT would want to control such waste but instead people like Kerry would rather increase taxes to pay for such waste.

 

[friartuck]

The ac rate will increase with height due to exposure and 'stack' effect. The winds blow harder at higher levels and the height of the building m,ake the building act as a chimney.
I would guess that 10ac per hour would easily be achieved at the higher floors.

Friar Tuck of Sherwood

 

[walkes]

Pesy,

I attended a seminar by Dan Holohan some years ago. He said that older steam heated buildings were designed such that they would provide sufficient heating with the windows open.

The boiler doesn't really have a "setpoint" in this case, it should just be a matter of fixing/replacing the controls on the radiators and any defective steam traps. The radiator control may just be a handwheel valve such that the heat is on or off.

 

[pesy]

I have no doubt that our boiler is sufficiently oversized to handle the load with the windows open--it would be nice to have the boiler only fire 25% of the time, instead of 50% of the time (I understand all the issues with cycling)

The radiators have valves to close them off--but many of them are broken. I am proposing that we fix them and the fuel savings from reducing the air changes will offset the cost of the repairs. This is especially magnified since the boiler is ancient and we're lucky if we get 75% efficiency.

 

[IRstuff]

Philosophically, it might make more sense to use thermostats with locked max setpoints to control the radiators.

This would rein in the profligates and provide you with what you need.

TTFN

 

[walkes]

Danfoss makes a relatively inexpensive thermostatic control valve that may help your situation.

 

[MintJulep]

Dan Holohan is the acknowledged master of steam heat.

His book is well worth the forty bucks.

Some seminars coming up as well.

http://www.heatinghelp.com/