Integration of Mechanical Systems - Requirements

And when we're talking about mechanical systems and when we're talking about those big issues of comfort, and efficiency, and flexibility, those really play themselves out through a series of smaller issues. This is just a small list of them, but, some of those issues might be the idea of bringing in fresh air. Certain situations might be required to bring in pretty large percentages of fresh air, even a typical office space, there's a fairly hefty requirement for bringing in fresh air. That makes sense, if you think about it. You're trying to help people be productive, you're trying to help them stay awake during the afternoon, you're trying to help them kind of have that sort of sense of freshness.

Well the only real way you can do that is by making sure there's fresh air mixed in. Now we don't generally want to mix in 100% fresh air. We're usually gonna have some of the existing air get reconditioned and some fresh air get mixed into it. The percentages might change, but if we did it as 100%, well man, that's gonna be very inefficient. It means, every time in the middle of winter, we're trying to heat up all the way from whatever the cold air temperature is outside, to kind of bring that up to that reasonable level to be able to condition and put it into the space.

So that would be very inefficient, but it might provide very important fresh air aspects. So you can imagine for maybe a hospital, instead of having recycled air, where we're taking air from the waiting rooms where there's a bunch of coughing and sick people, and we're reconditioned that with a tiny percentage of fresh new air, you know, we may actually take only a little bit of return air, and actually have quite a bit of fresh air coming in from the outside, because we just don't wanna have that contaminated air, sort of finding it's way back into the system.

So depends on the situation. In other scenarios where there's not so many people, where there's not so many people breathing, there's not a lot of equipment that's sort of contaminating the air, I may have a very small percentage of fresh air being brought into a process, because it's just not as important as it is in an office setting.

For a residential setting, typically we just have a few people in any given residence. And so there's not that situation where it's like an assembly space or a big office filled with people. This is just a few people in a fairly large space, and so we have to bring in fresh air, in order to make sure it's a safe, and clean and healthy for everybody.

But it's not like we have to bring in 80% fresh air, or anything like that. You know, so you're talking fairly small percentages. But those small percentages become important in terms of keeping everybody healthy, and awake, and satisfied. We're also constantly exhausting air, every situation is exhausting the air. We have a bathroom exhaust, we have kitchen exhaust, we have just general exhaust from office space. And so we have a whole series of different ways that we're pulling air out, we're getting rid of air.

And that's gonna force us to bring in new ventilation air. We're gonna be finding other air to replace that. For being very smart, we're finding a way to have the exhausting air be near the ventilation air so they can exchange heat with each other, so we can kind of preheat the new ventilation, or precool, depending on what season it is, that new ventilation air. But the idea that we are exhausting air out and bringing air in, bring that fresh air in, is an important concept and will show up in pretty much every situation.

Sometimes, we'll have very, very tight buildings and very sort of tightly organized mechanical systems, and in those situations we might have the exhaust systems in, for example, the bathrooms, on a cycle or on all the time, so that they just naturally have some percentage of the air that they are pulling out of the building.

We might have that just straight out of the office spaces, we might have that out of the kitchen, where it's just sort of on a certain setting and is pulling air out at a certain pace. And then we are equally bringing in air to supplant that, to give it that fresh air quality at the same pace. Sometimes that exhaust system is built in to the way that the overall mechanical system, the HVAC system is meant to work, and that can be a very effective situation, especially in a very tight building.

In some situations though, older buildings where it's less tight of a building, there's air leakage, air coming in generally, or in just sort of less controlled situations, it may be that you actually don't want that kind of system, you want to have those exhaust systems be on personal control. Like I walk into a bathroom, and when I turn the light on the exhaust fan starts.

Or when I turn a special switch on the exhaust fan starts. When I turn it off, it stops. Alright, there's gonna be times when I want it to be sort of, on it's own, part of a system, and there's gonna be other times when it's really more about just sort of personal control, and sort of the use, and expectation is that as people use it over time, even though it's not on a constant system, that it would do the need that the constant system does by just the sheer fact that people turn it on and turn it off.

Sort of irregularly over time, that'll give us a chance to exhaust enough air and bring in some new fresh air. But that idea of exhaust air will show up in essentially every building type. Even something, in fact importantly something, like parking garage, even if it's an open air parking garage, I may actually have exhaust systems to help push all that bad air out, so you don't get congregations of air sort of stuck in stairwells and things like that.

That can cause serious problems for folks, especially in a panic. So the air out and in, is definitely gonna be part of that sort of understanding of that mechanical system. And obviously, we're talking about comfort, and I already mentioned the idea that the temperature and the humidity level are sort of tied together. You can't really think about the temperature without also thinking about the humidity level in a space or outside.

So the sense of comfort really comes from understanding both of those and making sure that our systems are working to deal with both. So for example, if we have air conditioning system built into our mechanical process, well that air conditioning system is going to naturally dehumidify a bit, and that's a good thing. Because when we are trying to bring the air temperature down, in order to make something feel more comfortable, it would be a mistake to leave the humidity level up.

You want to bring the humidity level down, with the air temperature, if you don't, it has this sort of horrible clammy feeling. It's really unpleasant. So with the temperature and the humidity, we think of those things together, to the point that if we were having an air conditioning system that dropped the temperature down, if we didn't also have that dropping the moisture level down, it would feel really terrible. It would be a horrible sort of clammy feeling.

So that would be a very unpleasant aspect to the process. And you need to therefore think about both of those thing together and how they work together. Plus, if we're talking about efficiency, we can't really be thinking about efficiency if we're not thinking of the two together, because actually taking the moisture out of the air is one of the more expensive parts of the process. So, we need to have both levels of energy understood in order to really be able to talk about efficiency.

So that whole humidity level, taking that out, well that's all part of that sort of question of condensation, dehumidification is creating condensation. Condensation, if we're not careful about it, we have cool air, and warm moist air, the warm, moist air when it gets near the things that are the cool things, so if you have an outdoor space that's very cold, and I have a cold window, and I have warm, moist air inside that space, it's gonna want to leave condensation behind. So the condensation issues show up in the air condition, they show up in the heating situations.

Condensations very useful in terms of creating a dehumidified space. Or if we need to, actually adding moisture into humidifying into the space, to make sure that things don't dry out too much, or it doesn't get damaged, things like that. So, that level of humidity, with the way the condensation will start to drop out, but that condensation can be really problematic, and start rotting and causing damage, and making things slippery.

And so there's a lot of potential problems if we're not really being careful about how all these overall systems work. And so that's why we have vapor barriers. When you start thinking about a vapor barrier, and I say barrier, when I was in school, we always called them vapor retarders. I think they used to be called vapor barriers, then they started calling them vapor retarders, and then they seem to be calling them vapor barriers again. So the idea is that you're stopping moisture from getting into the wall before it becomes condensation.

Because once it becomes condensation in that wall you're gonna have rot, and damage, and mold, and all of those things. So all of the wall systems are actually part of our overall mechanical systems. So, the mechanical systems overall, there's a lot of different parts to it, we could go on with this list for a long time, but you start seeing how these little moments, actually have pretty big impact. And this would be the spot where we have a chance to review them, and make sure that they are fitting in with the project goals, and that we're not doing anything that's gonna make things super inefficient, and therefore bust our cost analysis.

And that we're actually meeting all the code requirements that we have set forth.

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