Yes, they must shed heat. your teapot/old water jackets do it by boiling and releasing the energy in the phase change and release of vapor. Safely. when you don't have pressure, you can do that. If you tie an 80 gallon tank to your water jacket I guess the additional water volume would pose a challenge there (that's a lot of steam) and I can see the heat dump would bypass that issue. but your system already shows a plate heat exchanger to a heat dump. If they just did a heat exchanger to the tank in the first place, that issue is gone and simply boiling would again fail to be a problem.... in a nicely unpressurized system. so you can imagine my confusion at requiring the cost and time and perhaps placement problems required with a heat dump when it shouldn't be required by the very nature of the system. Especially since the system SHOULD automagically dampen itself in the event of a water temperature rise, though a redudant or passive method is even better.
I'm no guru of unpressurized design, sure, it's not that common here in the US. Even so, po' little me can see some arguments that might support a heat dump instead of boiling off, and maybe one of them is the real answer. Your "answers" though, are certainly not betraying some deep understanding of the issue that I would personally want to have before bucking all listing and licensing mechanisms in the states to get a unit from elsewhere that is a class of products not even really covered here in the US. I'm not saying that alone is evidence, hydronics is bigger and europe and they have a lot of stuff we don't that is not only fine but it superior to anything you can buy here in our industry: I'm saying it is a big red flag to tread carefully though, because 'made in europe' is not automatically a good thing either. Euros do plenty of stupid things just like we do. Especially ones that think they are pretty smart.
There are many more than "thousands" of gas boilers in the world and carbon monoxide deaths aren't all that common either. Neither are explosions. If there were only thousands, we probably wouldn't see too many problems there. Those problems that do exist exist primarily because of a lack of maintenance or professional installation (just like that canadian exploded unit). And yet, the existence of that risk is why we have license requirements for handling combustion fuels, it's dealt with in the manufacturer lit, and why we have building codes that discuss relevant topics. Most people would agree that the risk is serious enough that such things are pretty good ideas. those that don't I would call unusually comfortable with risk. Or, "cowboys" if I think they sound like jerks.
people can DIY their own gas boilers and hack the installs and they PROBABLY won't die from that either. Thousands of people do that every year too, right here in the US, and I still think it's a very bad idea. I suppose you would applaud them since anyone reasonably "educated" can do it. But I don't think doing it with units and methods not in common use over here suddenly makes it a good idea even though I myself have many clients who ignored me and did fine, I think (I didn't go out and do combustion analysis on the units they bought, but they didn't die). Some didn't do fine; they still didn't die though. This particular class of product requires some serious understanding of what you are doing to avoid inadvertent problems from simple things like valve placement. Perhaps you would be surprised to hear that most of the time people gutting out something in a field they are totally, or largely unfamiliar with make some mistakes. I do hydronic design to a pretty high degree (in pressurized system) for a living and I would think long and hard about that, specifically because I have seen and been bitten by misunderstandings of design principles on many occasions. |