Hydronic Heating

So we've been talking about heating and cooling kind of parallel along for a little while. Now we're just gonna talk about heating for a second, just to kind of make sure that we have some clear terms and can be a little more focused. So we're talking about heating system. The various choices we have are hydronic or hot water systems. It isn't always water in the system, but generally we refer to it as hot water. Sometimes they might be kind of a glycol or something like that that you would use because it doesn't freeze as easily.

And if it's a situation where you're worried the power's gonna go out and there'll be some pipes there and it might freeze near the door or something like that, you would choose some material to put in there that wouldn't easily freeze and therefore break all your pipes if you had a bad day. But it also could easily be actually hot water. So hydronic systems are used in a lot of situations and they're often used in combination with other systems. Steam systems are one.

We've talked about this a little bit in some of the other exams. Steam systems are kind of an amazing and great system. I love the steam system because it drives itself. It needs no pump. The sheer fact that the steam wants to rise and the fact that the steam is large, and then when it turns back to condensate, that going from larger to small becomes a driver pulling the steam through the system. It's a little complicated 'cause they have to be gravity fed back to the boiler that's gonna generate the steam again, everything's always flowing downhill.

And they can make a lot of noise and they can have some scalding risk and some other things. But they're pretty interesting and useful. You can move a lot of heat around. You'll find that the steam systems these days are less often used than they used to be for kind of a simple multi-family residence or something like that.

And now they're often used in situations where you really wanna be able to move an awful lot of heat around. So that would be in maybe campus settings or just larger buildings or something where you need to be able to push a lot of heat, 'cause that steam can hold a massive amount of heat in it so you can push a lot of heat around pretty easily. The hydronic does pretty darn well too with how much heat it can hold. And the great thing about both of these is that they're relatively small pipes. The steam is a little bit bigger of a pipe, but comparatively the two sets of pipes are relatively small in size so I can carry very large amounts of heat in just a inch or two inch pipe.

And if I need to go bigger than that, a three inch pipe will carry an enormous amount of hot water. So these are small pipes that can carry a big wallop. Now, if we start thinking about the air-based systems, the air-based systems obviously, you're moving air around. Air is much bigger per amount of heat that you're trying to move, so you're talking many cubic feet compared to cubic inches of water in terms of how much heat they can actually carry with them.

So if a hot water pipe and a heating system is a one inch or a two inch pipe, the ducts are gonna be enormous. They're gonna be much, much bigger. And in some situations, they're gonna end up being so big that they actually really dominate the planning process.

They start becoming the way that you design around because you just have these huge, big ducts that you can practically walk through. In order to fit these things in, in order to carry enough heating in each cubic foot of air as it's moving through, in order to carry enough of that, you have the put in these enormous, big trunk lines that would then branch down and eventually get down to more of a normal size before it gets out to the diffusers, out to the people. But the air-based systems require a lot of space.

The good thing about the air-based systems is that if they leak. We don't want them to leak. We want them to be nice and efficient, so we're always gonna try to have them not leak, but if they do leak, it's not like it's ruining your carpet or it's ruining the computers that it's leaking onto. It's just leaking hot air. So the cost of making duct work is significantly lower than the cost of doing all the plumbing essentially that you have to do for a hydronic system.

So all that plumbing, I have highly specialized people putting that in all around the whole building. And the people who do the duct work are also highly specialized, but they can move much faster in much bigger chunks and they can put that up in a sort of looser, lighter way so that it doesn't have the same cost to it as putting in all that pipe.

And then there's a whole series of other possibilities. We could be talking about electric systems. So those are those essentially little space heater systems that look like little toasters. You don't always see the toaster bit, but they work essentially in that same vein where you put a electrical current through essentially a filament and it generates a certain amount of heat. We can do that. Like I said, it's something that looks kinda like a radiant toaster, but we can also do it as a radiant floor system. We can put it underneath tile, for example.

Electric can make a lot of sense in a lot of places, especially in a vestibule or some place that's away from the main body where you don't really wanna have to bring a hydronic pipe over to it or a great big duct over to it, but it would be nice to have some supplemental heat there. And a little electrical wire is fairly easy to get pretty much anywhere in the building. So the electric makes a lot of sense in certain locations, but then in other situations, most of the country, electric's actually pretty expensive.

So if we're gonna heat our entire building out of electric, that's gonna be a very expensive enterprise. But maybe not if it's a place that doesn't need that much heat. If we're in a place that only has 20 days, 40 days out of the year that it actually needs to really be heated, well, having an electrical system, it may be double the cost of some other systems, but that's just not enough days of heating to warrant worrying about it.

It might be a lot cheaper to put in the electrical system that's gonna not need a plumber to put in all those pipes or have the special tinsmiths to come and put all that duct work in and take up all that roof space. It may be a lot cheaper just to go with the electric system. So in the right setting, the electric system may make perfect sense. There's other locations around the country. to a friend of mine I was teaching with and she lived in Northwest Canada, and there was a lot of hydroelectric power in her area.

And so for her, she grew up with electric heating. Everybody had electric heating. It was like, why would you have anything else in that area? Because there was excess electricity and so the actual cost of the electricity very low in that area. But most of the United States, it's gonna be fairly high. And if you have a reasonably high heating load, probably not gonna wanna heat the whole building from electric.

There are certain situations where it might make sense, but probably not most of the time. But in very specific situations, it may make perfect sense, and certainly in very specific situations in a given building it may make perfect sense. So electric, certainly part of the discussion for heating but not probably part of the general mainstream discussion for NCARB for heating.

IR is infrared systems. Those are radiant systems that are line of sight. You'll see those often in situations like a place where you get your oil change for your car or something like that where having the doors open all the time is gonna let all that warm air out so that putting a lot of warm air into the garage, not really gonna do anything. It's just gonna get lost as soon as you open all the doors. So those IR systems do a radiant warming to all the people and all the things and the tools.

So that makes sense in certain locations. Passive we talked quite extensively about in exam four, and that's another example of ways that you can gather heat from the sun to warm up heat sinks that will hold the heat during the day and then start to give it off at night so you can kind of even out the idea of the overall heat gain coming on from the sun. So you're looking for all these different ways that you can do this, but generally these first three, the hydronic, the steam, and the air, and probably really mostly the hydronic and the air are really what the NCARB exam will be about because those are the most common and sort of that kinda perfect NCARB level of small scale institutional or commercial.

So we're mostly gonna be talking about hydronic hot water heating systems and then air-based heating systems.

So when we talk about the distribution for the heating, we're gonna be talking about duct work for the air-based and piping for the hydronic system. When we talk about the termination for the air-based, it's gonna be diffusers. And for the hydronic, it's gonna be radiators. Now, radiators could be when we say radiator, you probably think of one of those radiators in an old apartment building that sits below a window, but the radiator could be the floor, it could be a baseboard.

Lots of different systems of radiation. So these are our sort of basic systems for the heating. And then we'll take a look through kind of what impact and where the sizing elements would come in when we talk about these different heating systems.

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