ARE 5.0 Project Planning & Design Exam Prep

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Combination Systems Example

9m 15s

In this ARE 5.0 NCARB-approved Project Planning and Design Exam Prep course you will learn about the topics covered in the ARE 5.0 PPD exam division. A complete and comprehensive curriculum, this course will touch on each of the NCARB objectives for the ARE 5.0 Project Planning and Design Exam.

Instructor Mike Newman will discuss issues related to the generation or evaluation of design alternatives that synthesize environmental, cultural, behavioral, technical and economic issues.

When you are done with this course, you will have a thorough understanding of the content covered in the ARE 5.0 Project Planning and Design Exam including design concepts, sustainability/environmental design, universal design, and other forms of governing codes and regulations. 

So we started talking about the idea that there's often more than one system going. So we're often thinking about combinations of different systems, so let's imagine for a moment that we've got our supply air and that's coming down through the light fixture here. So we have supply air coming through that. We've got return air going up through a plenum over here. And maybe we've got a little radiator system over here, let's say it's a hot water pipe with some fin tubes around it.

And we've got maybe also a light shelf there. And that light shelf is going to help us with sunlight, in the summer when we don't want any more solar gain, that high summer sun is going to go right on by our window. But the lower winter sun is going to bounce the sun right into our space and get that natural light bouncing deep into the space.

But intriguingly, it's going to have left its solar gain out here on that shelf. So we're not getting all that solar gain, which in the winter is not great. But we have the rest of that solar gain coming right underneath there. So the fact that we have a shelf there is going to give us natural light, but it'll take away some of the solar gain.

That's great when the summer is there, when we want the natural light but we don't want the solar gain. And we lose some of the solar gain in the winter. But we still get below that element, in the winter we get that solar gain coming through. So here's a system where we've got multiple ways that sunlight is coming in and impacting our space through natural light, through solar gain bringing in heat energy.

We've got a wash in the winter of hot air coming up from underneath the window. Why do we have hot air rising when that's a radiator? Well because cold air from the floor is coming down underneath and it's going to go underneath that spot and get close to that hot water pipe. And it's going to warm up and it's going to create that convective current in front of this window, and that's going to do a couple of different things.

One thing it's going to do is it's going to create a barrier as I was saying earlier. It's going to create a barrier between the body, the person, and the window which is the second body. So this body here and that body there will want to trade energy with each other through radiation, and in the case of the winter that window's going to be cold, and so therefore the person is going to be the warm body giving off its heat energy to that cold body of the window.

So that convective current is going to help dampen that. It's going to help dampen that connection. The other thing it's going to do is that window is cold and the air inside is relatively humid, people are breathing and making coffee and doing whatever it is they're doing in the office, and so moisture is being generated in the space. And so you have a relatively high humidity level compared to the outside in the middle of winter, and relatively high humidity level in that office.

And so as I have the air that goes over next to that window, as the air gets cold next to the window because the window is cold, it will eventually get to the spot where it can't hold the same quantity of moisture and it will leave condensate behind. So you'll start seeing that the windows will get covered in condensate to the point that it makes it hard to actually see out those windows, and it can start causing a lot of damage in terms of rot and damage to drywall and all of those kinds of things, and rust in the window systems.

So having this little baseboard system here below that window will, as I said, not only make the person feel better because they're not radiating all their heat to the cold window, but it's also creating a flow of air that's going to start picking up some of that moisture of this nice warm air that is going to go by all of that moisture. And that warm air has the ability to hold more moisture in it, so it's going to grab that air, grab that moisture as it goes by.

So we will be reducing all of those problems of the condensate on the glass by having that little animal there of baseboard heating. So that baseboard heater is doing a lot of work in terms of creating this convective element that's going to deal with the window, but it's also potentially creating a nice little heat energy coming to the person as well.

So there's a radiant aspect there that's out-radiating the window, because the window is cold, so the body is radiating to the window. But here, the radiator is radiating to the body, so it's going to out-radiate that window situation and going to create quite a lovely warm heat in that space. Would we not want to have the air system going? No of course we'd still add that in as well. Because for one, we want to get the fresh air that we're going to get by mixing in a little bit of outside air into our return system so we're going to constantly be bringing in fresh air into the space, and that air is going to be flowing in and in the winter, that air will come down and then it'll try to blow it down but it'll fall back up towards the top a little bit.

And eventually it'll find its way out through that hole in the ceiling and it'll then eventually find its way to the return system over there.

So air is flowing through, we're getting fresh air into the space, nice warm air, the floor is a little cold but that radiator is helping. The fact that cold air, when it gets down to the floor, starts getting pulled over to the radiator, so you're constantly taking what would be the coldest air in the room and bringing it over to warm it up, and so that's creating this very slow convective current that's going to be bringing at least some percentage of that air back through.

So it won't get super cold down at your feet because of that current that starts going around. So you have a lot of different things happening just because we have a couple of different systems combining together. This isn't 10 systems, this is just a little simple radiator, a light shelf, and a regular air-based system. This isn't quite a common thing to have in any sort of office setting. If we flipped it around and thought about it from the summer standpoint, that summer standpoint I'm blocking the solar gain coming from the sun.

I'm still getting quite a bit of that natural daylight coming in through that system, but I'm not getting the solar gain. I'm putting the air conditioning out by the edge. That air conditioning is going to want to fall, unlike the hot air in the winter it's going to want to fall in the summer, so it's going to fall right down over the window.

That process of having that air flowing over that window is going to be very similar to what we had going in the winter with that baseboard heater. So I'm going to have a wash of air going over that window and creating a sort of convective blanket between the person and the window. It flows down across the window, and then as it comes down and cools off over here, it eventually starts to warm up because the people are warm, the computers are warm, all that.

And it'll start to flow upwards. So we're creating a convective current going the opposite way in the summer than we had in the winter, and then it's finding that return system, going up into the plenum, and finding its way over to the return duct. Then to get mixed with some fresh air, come back through. So these multiple systems doing everything they need to do, one works with the other.

They feed off of each other and you get this air movement in the space, so you don't get really cold spots or really hot spots. And it's pushing everything all the way through. The whole point here is that you get comfort levels for the people, so they have the benefits of having these big windows, but not the problems of losing heat to those in the winter and having too much solar gain in the summer. So you're trying to find ways that each of these individual choices combines together to make a comfortable and better hole.

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From the course:
ARE 5.0 Project Planning & Design Exam Prep

Duration: 30h 26m

Author: Mike Newman