Large Skylight Cooling

[UDP10]

I've begun work on a project where the entire roof over a 2800 square foot room (physical therapy) is glass (pitched).

I'm good with caculating the load, but I'm looking for good ways to get the cooling in. I'm thinking with that much glass, regardless of the amount of cooling, the occupants will feel hot, just from the radiant.

Does anyone have experience with this? Do you think splitting the air to throw it up at the glass and down at the space? Combine air system with radiant cooling? I'm pretty much just getting started and looking for ideas.

 

[GMcD]

Not knowing what climate this is being used in: Do an analysis of using an insulated translucent glass product like Kalwall for a nice diffuse translucent light effect with some insulating qualities. Or consider triple glazed glass with some ceramic fritting pattern on the outer glass to reduce direct solar gain but still allow daylighting. Consider the use of suspended film type sealed glass units like Heat Mirror Quad four-element glass units. Find some sealed glass units with the venetian blind shutters in the space between the glazing that can be adjusted to reduce/eliminate the direct solar gain. Spend as much time as you can reducing the incoming loads from the glass, and then consider low level displacement air supply so that much of the room cooling loads are stratified, ie: use a non- fully mixed air supply system so a percentage of the load from the skylight won't be incurred on the AHU coil load sizing. The better the glass, the less you have to worry about condensation/fogging at the glass and framing if this is a cold climate application with stratified warm humid air. The problem is the extensive glass, not what HVAC to apply.

 

[KiwiMace]

I've seen this done before; there is a shopping centre in Singapore where they enclosed the streets with glass roofs.

Supply was ducted from the side/s with nozzles. These things can get some good throw and with a lot of volume, easily getting across the 40-50ft span. The nozzles are basically a ball in a flange so can be directed up to 30deg or so.

There is definitely a noticeable difference between being shaded and in the street, but humidity was gone, the air was cooler and it felt very comfortable.