My husband and I are building a dojo (that is, converting an ex-carpet store into a dojo). In the process of raising the drop ceiling (so that people could wave wooden sticks around without encountering the fluorescents) we found two lovely skylights in the roof. With the drop ceiling down temporarily, these skylights provided enough August sunlight for us to do electrical work without lights on!
Husband wants to put some translucent panels up in the drop ceiling to allow sunlight through when we restore the drop ceiling panels. (Have to put the drop ceiling back up, because this is the South, and our air conditioning bills will exceed our mortgage if we don’t.) He tentatively used the word “diffusers”.
I started arguing that we couldn’t admit light without heat – that it would be better to have the sunlight hit the unseen topside of the drop ceiling, and have the heated air go out the soffit fan that’s already in place.
We turn to you. Is there some way to put panels in a drop ceiling that permits the passage of more light than heat?
Is there some way to start threads in GD that does the same?
thanks,
gabriela - forensic hat off, aikido hat on
Extend an insulated tube or enclosure down from the skylights to the level of the dropped ceiling. Line the tube with reflective surface. The insulation will keep the heat above the ceiling away from the opening to the room below, and the reflective surfaces will bounce the light down to you.
I’ve seen these on sale at Home Depot on a slightly smaller scale: a cylindrical duct maybe half a metre (a foot and a half) wide, reflective inside, with a light-gatherer that goes above the roof.
BTW, I was just reading in my building-science book about how effective dropped ceilings are at keeping under-roof heat away from the living spaces below. I was quite surprised… but then, there would be little convection up there, and the air layer would serve as insulation, with only radiation transferring energy. Hot air doesn’t convect downwards…
They do sell drop ceiling pannels that allow light to pass through, even if they are not insulated they should help keep some of the heat out of the ‘living’ space. Putting 2 of them together should help out more as a air space should form between them.
I don’t have much to add except that when I was investigating ways to keep my office cooler, I read about sheets of plastic that you stick to your window to let light through but filter it of heat and UV rays.
Could you describe the situation in a bit more detail?
But first, the term ‘diffuser’ refers to an air duct outlet in the ceiling like this.
You have an AC system. Is it a central system (that is, does it blow cold air from a blower thoughout the building)? Do you know how this is ducted through the building? describe both the supply and return ducts if you can.
The space between the drop ceiling and the roof: there is a fan that exhuasts air out of this space?
What I 'm trying to figure out is this: As you already know, the heat gain is already getting into your space, but it’s mostly confined to the area above the ceiling. In some AC designs, the space above the ceiling is used as a return air path back to the AC blower. If it is, then you are already cooling this additional heat load and you can install translucent panels without increasing your electrical bill for cooling. If it isn’t (and the exhaust fan makes me wonder), then adding the panels probably will increase your bill a bit.
I will not use the term “diffuser”. This will make the lives of people who retail building supplies easier.
The space between the drop ceiling and the roof has a fan that exhausts air ou of this space. However, the central air is not designed to use the space above the ceiling as a return air path back to the AC blower. This is likely because the building is a Quonset hut.
I will look for drop ceiling panels that let light through, and I may sandwich them with air in between, or attach sheets of plastic to them that let light through but do not permit much heat.