I recently helped to present a class titled Steam and Hot Water Systems; Design, Performance, and Commissioning Issues; one in a series of classes I am involved with at the Pacific Energy Center. Ryan and I have been trying to make the classes more interactive and flexible in terms of being able to address the interests of the people attending them. As a result, I tend to try to develop and expand content based on the feedback from the last class.
So I always have plenty to present, probably more content available than I will have time to deliver. So what I actually end up talking about is driven by where the interactive exercises take us, student questions, and lately, what the students say they are hoping to learn about when I ask them at the beginning of the class.
So, point being that for the latest round of the Steam and Hot Water Systems class, I had added some content about low pressure, one pipe and two pipe comfort heating systems; basically, the type of system you might find in an older residence, older multi-family housing facilities, older hotels, and older schools. I pulled that together because the last time I presented the class, a number of the students had specific comments or questions about that type of system and at the time, I did not have much content developed for it; the class was more focused on hot water than steam and more focused on larger commercial installations rather than residential installations (although physics being physics, the principles are all the same).
But as luck would have it, for the most recent class, the majority of the interest was on other topics so I never got around to presenting the new material. Having said that, since steam heat is rapidly becoming a lost art (more on that in a minute) and there are some really good resources out there for those who are just learning about it, I thought I would go ahead and write a short blog post to connect you with those resources and some of the content I put together but didn’t use in the class.
The Lost Art of Steam Heating
One of the best, if not the best resource out there for you if you are trying to understand or otherwise work with steam heating systems is a book by Dan Holohan titled, appropriately enough The Lost Art of Steam Heating. I have a paperback copy of the original version and a Kindle copy of the revised version. The gallery below, which is made from screenshots from my Kindle version will give you a sense of what the book is like. Click on any image and it will open a slide show with larger images.
The book starts out with a bit of history, including pictures of some of the early steam heating equipment, and then moves on to describe how one and two pipe low pressure steam systems work in an very easy to understand, engaging manner. Generally, if you understand a few basic principles, like stuff will move from where the pressure is high to where the pressure is low and how a manometer works, principles that are nicely explained in layman’s terms in the book, then you can understand how steam systems work.
The author’s HeatingHelp.com website itself is full of resources that complement the book, including pictures and technical articles dedicated to heating systems, steam and otherwise. If you are involved in this business at all, you definitely should have it saved in your list of favorites. And you probably will want and will enjoy a copy of the book.
Bill Coad on Steam
As you probably know if you follow my blog, one of my mentors was Bill Coad. Bill did a lot of technical writing over the course of his career and one of the things he wrote about was steam.
There were a number of his Fundamentals to Frontier’s columns that covered the topic and several chapters in his energy engineering book that included content about steam. In addition, he wrote a fairly extensive article for Heating, Piping, and Air Conditioning magazine on the fundamentals of steam heating.
All of those things are getting harder and harder to find on the internet since some would consider them dated, having been written in the 70’s, 80’s and 90’s and this being a different century and all of that. But since Bill always wrote about things from a fundamentals level, and since Newtonian physics still seems to be a good model for what is going on around us (I just checked by dropping a pencil and it in fact accelerated towards the floor of my office and then stopped upon encountering the floor), the content is generally timeless and thus they are valuable resources.
To facilitate your ability to access them, I have created a Bill Coad’s Writings page on my website and have all of the resources I mentioned above accessible for download from that location.
A Typical One Pipe Steam Radiator
It just so happens that Hotel Carlton, the hotel I stay at when I am in San Francisco, has a one pipe steam heating system. As an aside, I highly recommend it. It’s a cool old building with really great people working in it in an interesting neighborhood; you’ll really feel at home right away I think.
That said, even if it didn’t have the steam heating system, it is a pretty cool place because it was one of the first buildings erected after the 1906 earthquake and its design was targeted at being earthquake and fire proof.
But, in the context of this blog post, it has a one pipe steam heating system and the system was recently upgraded to include self-contained radiator control valves. Here is what one of the radiators looks like if you take the cover off of it (as I am sure most guests do once they realize they have an actual working one-pipe steam radiator in their room).
The pipe with the bronze valve is the “one pipe” serving the radiator, that allows steam to enter it and condensate to leave it. If you think about that for a minute, you can start to see why the details of how you pipe and control a one pipe radiator might matter.
If you look at the other end of the radiator, you see this.
The silver gizmo is a type of air vent, and the gray thingy attached to it, along with the fitting it is mounted to, is a self contained control valve. The little cable weaving away from it and up and to the right is the set point signal, which allows you to adjust the set point from a wall mounted controller, pictured below.
The general idea behind how this works is that steam, not air, even hot air, is what will warm up the room with a radiator in it. If the radiator is full of air, it will not be full of steam and will not provide much if any heat.
The self contained valve basically allows air to exit the radiator, which means steam can enter it until the desired set point is achieved. Then, it stops allowing the air out, which means it also stops letting the steam in.
Its a bit more complicated than that because of what happens to the pressure in the radiator as the steam condenses and things like that. Dan Holohan does a great job of describing it in his book and this instructional PowerPoint from the Danfoss web site is also pretty good.
Danfoss is one of the manufacturers of self contained valves for radiators. In fact a lot of the time, people in the industry will refer to any self contained radiator valve as a Danfoss valve even if it is one made by Watts or Honeywell or one of the other manufacturers in the bussiness.
Its sort of like calling all facial tissue Kleenex; Kleenex is a brand of a type of product called “facial tissue”. But they have been so successful in marketing their product that a lot of people equate “facial tissue” with “Kleenex”. Same thing for “self contained radiator valves” and “Danfoss”.
Steam and the FDE Resource List
If you have a copy of the resource list on our website, you will find that there are a number of links to resources related to steam in it including links to the DOE tip sheets for steam systems, Wayne Kirsner’s web site, and the Armstrong International handbook to name a few.
I should mention that the links it contains to Bill Coad’s resources will no longer work. But as I mentioned above, you can now find all of that information in the Bill Coad Writing’s page on our website.
So there you have it; a few resources for you to look into if you are trying to understand one of the oldest approaches out there for heating a building, an approach that can do a really nice job of it if you apply it properly.
Senior Engineer – Facility Dynamics Engineering