Dear steam heating practitioners and believers:
After years of tinkering with steam heating I’m still fascinated by its simplicity, resilience, reliability, and electricity-independence (if the gas boiler is equipped with a millivolt control). Well-designed and maintained steam heating systems can provide superior comfort and efficiency. The opposite is also true, and this is why steam-heated buildings often have open windows during the winter. This is wasteful.
The complaint I usually hear about steam heating is that it offers uneven heat distribution. This is usually because it’s very tricky to move the air out of all the parts of a steam system quickly and easily. Balancing steam distribution is an art many heating professionals have either never learned, or forgotten. Air vents (NYSERDA 1994, PARR 2011), orifices (Oland C.B., 2001) and Temperature Regulating Valve (TRV) (Bobker M., 1995) are not a panacea for this inborn, air-venting flaw. As Albert Einstein said, “We can't solve problems by using the same kind of thinking we used when we created them.”
So, some new thinking:
Until 1900, vacuum was basically ignored in steam heating. But then came a great advance as some systems began to take advantage of vacuum. This greatly improved system efficiency and comfort. Instead of slowly pushing air through multiple vents from the system with steam at 2-psi pressure, low temperature vapor could now pull steam from boiler into radiators. It did this evenly by using 5-7-psi vacuum that moves steam at speeds of up to 160 mph.
In addition, naturally induced vacuum continued to extract extra heat from the boiler long after the burner fire burned down. To appreciate how easier is steam heating system operation under vacuum, try to breathe in/out into manometer/vacuum meter. You can barely get 1.5-2 psi by pushing air out against atmospheric pressure, but effortlessly make 10-12”Hg (5-6 psi) vacuum when breathe in. Nature is an ingenious engineer, worth to be copied.
Today’s vacuum systems are “pseudo” vacuum ones because we separate the vacuum part of the system from the positive pressure of the steam at the inlet of each radiator. This requires steam traps, however, and steam traps present an ongoing maintenance problem. Steam traps on radiators last only 10 years at best, and are often ignored when they fail because of the expense and annoyance of having to repair them. The result is unbalanced, noisy, and very expensive systems.
There is a solution, nevertheless.
I’m one a few people who has seen vapor and condensate flow through transparent plastic piping (Holohan D., 2015). It turned out that vacuum system can self-balance quickly and evenly according system design. This has inspired a new “no steam-traps” type of vacuum system.
I verified the concept in my house (7 years study results) and had it implemented by A&Mservies in a retrofit of 1880th steam system. This technology is now approved for low risk financing. I invite you to use it on your next retrofit project. The benefits are:
Sorry, have to continue my story in next post because of length limits.