A new look at vacuum heating
So let’s say you’re in one of America’s older cities and scratching your head over an antique building that has a very confusing steam-heating system. What to do?
Of course, you can change parts and make repairs for the rest of your life, or until management tosses you into the street. Or you can suggest management have you rip out everything in the building and allow you to start anew.
Another option is to try something new that may at first seem impossible. At least that’s the way it struck me. But I was wrong.
Which brings me to the delightful and very smart Igor Zhadanovsky. Igor founded Applied Energy Consulting in 1994 and he’s been talking to me about steam for years. At first, I thought he was nuts, but that was my failing. I wasn’t listening well enough. I knew too much about steam heating. My mind was made up, and that’s always a dangerous thing.
Igor has a master’s degree in chemical engineering from Tufts and a doctorate from the Moscow Petroleum Refining Institute. He is brilliant. He speaks English like Boris Badenov from the old Rocky and Bullwinkle cartoons, and his analogies are wonderful.
In describing his system of vacuum heating, he told me the story about the five monkeys in the cage. Scientists put a bunch of bananas out of reach and then provided a set of stairs. When a monkey climbed the stairs, the scientists sprayed all the monkeys with high-pressure, ice-cold water. Soon, none of the monkeys would go for the bananas.
The scientists replaced one of the original monkeys with a new monkey, who tried to climb the stairs. The four original monkeys beat the crap out of him. The scientists didn’t have to spray the monkeys with water.
Then they replaced another of the original monkeys. The same thing happened.
After a while, they had replaced all the monkeys. Now we had five monkeys who had never been sprayed with cold water, but none would climb the stairs.
“And when we ask monkeys why?” Igor says. “Monkeys say, ‘Because this is how we always do things around here.’”
As I said, he is very smart and quite philosophical.
The reason why I thought he was nuts at first was because he was doing things my books on steam heating said shouldn’t be done, but he was doing them anyway. And they were working, but I didn’t want to hear it because it went against the way we do things around here.
Which, as I considered it, made no sense, so I shut up and started paying attention.
Igor told me, for instance, the management of a 100-year-old building running an old steam system might want to convert the system to hot water, but should they do that, they’ll have these static pressures to consider, which are always a concern in tall buildings. There also will be big pumps using a lot of energy, and a lot of space-and-cost concerns for the additional mechanical equipment. Oh, and a lot of potential leaks.
An inexpensive retrofit
But suppose the building owner converted the existing steam system to a vacuum system? And here he’s not talking the traditional vacuum system. This is something different. Igor is using small-diameter copper tubing to feed low-temperature steam in a deep vacuum to low-cost, European-style panel radiators in place of the old cast-iron radiators so many tenants don’t like to see.
Oh, and the condensate is going to return to the boiler through cheap, 3/8-in. polypropylene tubing, without any steam traps. He mentions that PP-R pipe also would work well, especially in a large building.
Sound crazy? Yeah, that’s what I thought, too. But then he showed me a real system in action in the dead of winter and I was gobsmacked. Here’s what Igor did.
He lives in a 1,150-sq.-ft. apartment in a two-family house in a Boston suburb. He installed his system and watched it for five months during the brutal New England winter of 2013-14. The original heating system was oil-fired steam, with cast-iron radiators and a boiler that was nearly 100 years old. He left the system in place for comparison and installed the new European-style panel radiators and controls around it. He connected the new radiators to the old steam boiler with 3/4-in. and 1/2-in. copper tubing and ProPress fittings.
Where the spaces got tight, he used 5/8–in. O.D. flexible Teflon tubing. Keep in mind the steam is in a vacuum. That means it’s going to be much cooler than 215° F.
As I said, he didn’t use steam traps at the radiators and just let the condensate dribble back to the boiler by gravity through that cheap polypropylene tubing. I could see it flow through the clear plastic. Everything was quiet. Go figure, right?
The system runs at about 185°, which sounds about right for a hot-water system in New England during a brutal winter, doesn’t it? But this was steam.
The way he pulls the rabbit out of the hat is to use a temperature controller that looks at the vapor temperature of the steam as it leaves the boiler. The deeper the vacuum, the lower the temperature of the steam. Igor can vary the temperature of the steam, based on the outdoor air temperature. He makes the vacuum with a small, off-the-shelf vacuum pump in the basement. This little unit runs in three- to eight-minute cycles, and never for more than two hours each day.
So put the system into a deep vacuum and then fire the boiler. The low-temperature steam goes racing through the relatively tiny pipe at low temperature and enters the radiators. I walked upstairs. The radiators were hot; the rooms were very comfortable. We had left The Lovely Marianne up there. She was watching TV. I asked her if she was comfortable. She smiled. There was no annoying noise from the piping, radiation or TLM. Nice.
On a very cold day, the boiler ran up to about 195°. The burner stopped and the steam kept gliding to the radiators because of what the vacuum pump was doing. The vacuum pump shut off, the steam condensed until the system temperature cooled to the lower set-point temperature, and the burner fired again.
Igor collected his data (Igor loves data), hooked up the original system and ran it for two weeks. He then installed a new Peerless steam boiler, still connected to the old system. He ran that for a week, disconnected the old radiators and reconnected the European-style, vacuum radiators.
The new Peerless boiler showed a decrease in fuel usage of 30%. The vacuum retrofit to the new radiators showed an additional fuel savings of up to 30%, depending on the day. The gas company had installed a separate meter and it monitored all of this through an independent vendor. They also were smiling.
From a cold start, the new radiators all got deliciously warm in less than a half hour. Every 10 seconds, Igor monitored and recorded the temperature of the flue gas, steam vapor at the boiler exit and the radiator entrances, and the condensate return. He also recorded the level of vacuum in the system (it plunges to 25 in. Hg), and, of course, the fuel usage.
So with the new boiler, we’re talking about a 60% savings in fuel, without steam traps or condensate pumps. It’s quiet. It’s simple. It’s basically maintenance-free. It’s a relatively inexpensive retrofit, and it will work in any building without having to tear the place apart. It will even work off city steam. Igor calls his system NextGen, which it sure is.
So why aren’t people rushing to his door and begging him to help them save fuel, get rid of the annoying noises and most of the troublesome, labor-intensive elements of a typical steam system?
My guess is most people are making the same mistake I made. They think they know it all and they don’t want to shut up and listen, but I wish they would. Besides, that Boris Badenov accent of his is such fun.
If you’re working with an old building and want to look like a genius to your client, email me (firstname.lastname@example.org) and I’ll make an introduction to Igor. Trust me; this guy is the goods.
Get ready to be gobsmacked.