Single glazing - HVAC & base board heating 3

[remp]

Hi,

Im am involved in the design of HVAC system for an old building which is being turned into an office. The perimetre of the building has 3 metres high glass, single glazing. Will my conventinal ducted air system deal with the perimetre heating load in winter if sized big enough or will I alwys have a problem with down drafts in winter (-3deg C) unless I install base board heating.
Double glazing is never a problem but i remember seeing an old building long ago with conventional HVAC plus base board heating.Why would they have done this?? Please help>>

 

[walkes]

You will have to watch for condensation on the glass. Control humidity levels within the space. The baseboard radiation provides a nice layer of warm air along the glass.

You would have to check your space conditions to determine what is necessary.

 

[GMcD]

The other issue is the cool convective draft of cold air falling off the glass surface. The other issue that your conventional calculations won't show you is the radiant cooling effect off the inside surface of that crappy glass. If the outdoor tempertaure is -3C in winter, the inside durface tempertaure of that glass will be in the range of 10-12C, even with heating under it, which will equate to a radiant cooling effect for someone sitting next to it of around 30-35 Btuh/Sq.ft. (over 100 watts/sq.m)of glass surface.

My advice is to fix the real problem in the first place and see if the glass can be replaced. If someone is spending a bunch of money on new HVAC and upgrading the building, then do your sums and see if the savings in the capital cost of the HVAC equipment plus the on-going energy savings and comfort improvements will offset the cost of installing better glass. The only impediment to that would be local Heritage folks who want to preserve the windows and frames.

 

[willard3]

This from an Engineer who works in a climate where it gets to -20F in winter....put radiation under the single-glazed window.

If the window is single glazed, it is old.....if it is old, it leaks cold air like a sieve. As already mentioned, keeping the radiant temp of the wall up keeps occupants comfortable.

It is always the best idea to add heat where you are loosing it for comfort....at the outside wall and window.

 

[remp]

willard3,

When you say put radiation under the windows, what kind of mechanical radiator product provides this. We would be looking at electric type, any web sites you know off just to give me an idea?
Also how do you size them? are they for the full heat loss load of just part of it?

remp