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Former Steam Plant in Ohio

Josh_10 Member Posts: 787
We have one in Seattle too that still operates today. In fact it has new users all the time.



  • Melissa_4
    Melissa_4 Member Posts: 1
    Former Steam Plant in Ohio, USA

    I have a question, I'm working on a site in Mariemont Ohio that had a steam plant in operation from approximately 1920's to 1954. I have been told that they heated the homes of Mariemont with the steam that ran through pipes underground to the individual homes. Can someone explain this process to me? The plant used coal to create the steam, how did it not cool down before reaching the homes?
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,528
    Hi, Melissa.

    That's called District Heating. Here's a PDF from our Library that describes a similar system in Detroit:

    District Heating

    New York City has the largest system of this type in the world.
    Retired and loving it.
    EBEBRATT-Ed Member Posts: 15,544

    Don't forget Boston has some as well!

  • jeff_25
    jeff_25 Member Posts: 110

    Also in milwaukee,wi
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Boston Trigen

    From the Trigen web site:

    Trigen-Boston serves approximately 230 commercial, government, institutional and hospitality customers and ensures over one million people are comfortable every day in the City of Boston. In addition to supplying centralized heating for 44 million square feet of space, and cooling for approximately 9 million square feet, Trigen provides specialized energy services. These services include critical climate control, sterilization systems, humidity control, and steam used in food and beverage processes.

    Many of Boston’s prestigious office towers, renowned critical care facilities, world-class hotels, esteemed universities and treasured institutions are among Trigen’s clients. Trigen’s steam generating capacity is in excess of 1,500,000 pounds per hour and the cost-effective energy is delivered through a 22-mile network controlled with advanced systems, ensuring reliable service 24 hours a day, 365 days a year.

    Our business managers and engineers work closely with prominent developers, building owners, managers, public officials, architects and engineers to customize versatile solutions that meet their individual needs. Our expertise enables them to concentrate on their core business.

    In the 21st century, Trigen continues to play a leading role in our city’s expansion and economy, powering Boston with progressive, high-quality energy services.
  • JJ_4
    JJ_4 Member Posts: 146
    Steam delivery

    I am not an expert by any means, but I think the steam gets there without cooling down because it is high pressure steam (100psi??) which results in a higher temp. They have to reduce the pressure once it gets to the destination building.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    To Melissa's Original Question

    Well, now that we all got our local steam systems nationally recognized :) let me take a moment to tackle the original question posed by Melissa:

    Most district steam systems (at least those here in Boston) sell the steam as a by-product of another process, usually electrical generation by steam turbines. That is the case in Boston anyway. The steam starts in the hundreds if not thousands of pounds per square inch (PSI) and once through the turbine, comes out at a much lower pressure.

    If the utility did not sell this excess steam they would have to condense it back into water and recirculate it. That takes cooling water, condensers, cooling towers and a good bit of space. Selling it as steam is far more profitable!

    The steam is sent via a piping network at (at least in Boston) about 150 PSI, arriving at most buildings at about 125 PSI.

    The pipes are insulated and thus retains enough heat to keep most of it as steam. What condenses (is lost to cooling) is drained off by steam traps and dumped to waste. Some of this is taken back to the plant but the further away this is, the less likely. Most is wasted.

    When the steam enters a building (at 125 PSI), it generally has to be reduced to below 15 PSI for heating purposes. Sometimes it is used for electrical generation or to make chilled water for cooling so there are year-round applications too. These latter processes are typically at higher pressures than most heating requirements.

    Steam radiators and convectors in the Empire State Building run entirely on steam pressures of 2-3 PSI. Steam reaches the furthest radiator in minutes, climbing faster than King Kong with or witout Fay Wray in tow.

    To reduce the steam pressure, a pressure reducing or regulating valve (PRV) is used. This valve knocks the pressure down from say 125 to 50 in one stage (for sterilizers or medium pressure processes sometimes) then down to below 15 (usually 8-10) for heating purposes.

    This low pressure steam is often used to make hot water via a heat exchanger or can be reduced further, to 2 or 3 PSI for use in radiators. Most commercial heating equipment uses 5-8 PSI steam due to control valve losses and equipment ratings, such that the net process has sufficient temperature and pressure.

    Regardless of the final process, all of this condensed steam (condensate) has to be disposed of. It is not cost effective to pump it back to the plant which may be by this time blocks if not miles away.

    The condensate has to be cooled below 130 degrees before it is dumped into the sewer to minimize biological growth and possible cracking or metal pipe or melting of any plastic pipe.

    Some buildings hold this condensate in a tank and use it to pre-heat domestic hot water or as a source of unmetered water for cooling towers. Either way, down the sewer it goes.

    That is roughly how it works in Boston. Other cities have different pressures, policies and, let us pray, politics.

  • Brad White_9
    Brad White_9 Member Posts: 2,440
    It is a higher temperature, JJ

    but it is also nearly saturated, meaning that if the temperature is reduced by a degree it will condense.

    When the steam comes off the large water-tube boilers, it is superheated, meaning it has a temperature above it's saturation point. It can be reduced in temperature and pressure without condensing. It has a margin.

    Once it hits it's saturation curve (dependent on both temperature and pressure), it will condense (give up it's latent heat).

    Once the steam goes through a turbine, the pressure is reduced and the result is nearly saturated steam. It may have some superheat, but that disipates quickly.

    One quirk of steam pressure reduction is, when steam goes through a pressure reducing valve, it also can superheat it.

    Take saturated steam at say, 125 PSIG and a corresponding temperature of about 353 degrees F.

    Say the pressure is reduced suddenly to 20 PSIG. Normally, saturated steam at 20 PSIG should have a temperature of about 259 degrees but is, at the instant of release, still about 353 degrees. Thus it has about 94 degrees of superheat. Adiabatic cooling (cooling loss by expansion) rapidly reduced this somewhat but the lower pressure steam still remains at a higher temperature than saturated steam at the same pressure.
  • Perry_3
    Perry_3 Member Posts: 498
    Close... but not quite

    Most district heating systems are supplied directly from large district heating boilers (and it comes from the boiler as saturated steam). Only a very few use steam extracted from other processes (however, if those processes exist it is even more economical to do so than pure district heating).

    The economics of a district heating (and cooling) were based on the fact that it was much cheaper to build one large boiler house (and/or chiller house) - and run piping to many buildings than it was to build separate boiler and chiller houses in each building. This was back in the days of coal fired boilers.

    It was sometimes possible to build a central power plant and district heating/cooling system if the area was not otherwise served well with electricity (For example - the Wisconsin State Capital and some of the State Office Buildings has its own power/heating/cooling plant; Also the University of Wisconsin - Madison was originally constructed this way). However, only about 25% of all district heating systems that I have seen started with a power plant. Most were just district heating & cooling systems due to the pure economics of building buildings without individual boiler and chiller rooms.

    Almost all large cities - and larger multibuilding institutions (such as Universities and huge manufacturing complexes) have district heating and cooling.

    This is still a very cost effective system that tends to be highly efficient compared to many other systems as you can operate the boilers at peak efficiency (but not mod/cons) assuming that the base piping network is in place. Unfortunately, currently within the US it is usually now cheaper to run a gas line to each building and install separate boilers in each building (and separate chiller units). However, every now and then someone will still propose and may still install a district heating (and cooling) system in a new construction situation - especially if their are high occupancy buildings that are fairly densly packed).

  • wow what a

    Wow, what a steamy story from these guys......
  • Christian Egli_2
    Christian Egli_2 Member Posts: 812
    This is eco tourism

    Dayton itself used to have a steam network where steam came from originally three beautiful boiler houses; the hot stuff was flowed into everyone's home, office and factory via tunneled pipes insulated with Zeolite, a local specialty that went around the world quite a bit. The Z stuff is the same as what's glued on the Space Shuttle, it's super insulating and so, heat losses are kept real low particularly since you can pipe train loads of heat through comparatively tiny pipes that are real easy to insulate massively. In the great scheme of things, losses here are minimal (~ish) and steam has no problem traveling for miles without loosing any puff. It flies at car racing speeds.

    Dayton had three pressures, high 120+ PSI, medium 80 PSI (in the older part of the system originally fed by the first plant on Fourth Street, an electric and steam plant, that's still there behind the convention center), and there was also a low pressure ~15 PSI network for smaller buildings. Dayton's claim to fame was that it had the most intensive steam usage per square mile, way outdoing even New York - but steam load wise, it was the about the same as Baltimore, not a giant.

    The most modern plant was the fortified castle structure, with dungeon -slash- concealed water tower, that proudly stood at the I75 - 35 junction. This one is gone, sadly, and it's going to be replaced by an eyesore: another sports field and parking lot. Useless.

    The other plant that was on line is presently being converted into condos and stores. It's downtown on East Third street and is set to be a gorgeous place. Most notably, it stands right next to the GE warehouse that was secretly connected to the all important Manhattan Project of World War II.

    Dayton produced the polonium triggers... and the GE warehouse was used for testing safety and handling procedures. Other prestigious customers feeding off this plant were the DELCO car parts, ignition and starter manufacturing plant (Dayton Engineering Laboratories CO) and the Frigidaire fridge factory. Items that made it into everyone's household, worldwide, and all thanks to a selfless steam plant. :)

    Beyond the efficiencies in scale and operation - compared to other methods of piping heat - district steam systems bring lots of thermal efficiency precisely because they operate at high temperature (350F) without the tremendous complications of handling the bodacious water needed at such similar high temperatures and, importantly, without any costly pumping expense. Last non trivial fact: steam systems have practically zero inertia. System for system, the heat accumulating inertia in hot water turns out to be more than a hundred times that of steam, in a time phase, this means that a reaction delay of steam of one minute can translate into a two hour wait for hot water. Not really a problem, but no benefit either... so, for steam it's nothing but win win win.

    Europe has a mixture of steam and overheated hot water district systems, the water theme being mostly a post war venture. Notably, the city of Paris, with steam on the scale of New York has resolutely gone back to expanding the steam network -- not the low temperature (and thermally inefficient) geothermal loop it tried in the seventies. The heat comes from coal (viz. multifuel) plants and garbage burning plants. Reading the typical connection requirements to infuse oneself with pumped pressurized super hot water (super hot for scraping the additional efficiencies) we find all kinds of hair raising fine print; it's water, but there's nothing benign about it.

    Now, if it's so good, why did Dayton loose its steam? Look largely at our utility that lost itself in a case of Enronitis. Selling the steam real estate, then the gas network, then the power transmission lines, then some of the generation capability... all for a conversion into an Argentine venture fund that sounded soooo smart... but we had to learn the hard way... Now the steam is gone, and property values have taken a big hit without the cheap and efficient heat of the old. Many here got stung real hard on both forced air and forced hot water conversions, so much so, they ran away from buildings too expensive to heat and unrelenting property taxes to induce a cold sweat.

    Don't forget either that a prime motivation for monopolistic utilities to go into steam district distribution is to double cross the large energy users of any incentive to cogenerate heat and power all on their own. Cogeneration that was all very common a hundred years ago unlike today. For regulation to work, all that free wheeling energy had to go... and you and I all know what it's like to buy stuff from the public utilities, it's not a free ride.

    Dayton still has lots of steam. A beautifully functioning steam plant can be seen from the access route to the Wright Brothers Memorial. This system feeds Wright Patterson AFB through the most exciting zigzag of silver pipes lining the hills. Make this visit a day trip, the Wright flight simulator provides more entertainment, if you must. The Wright Brothers had also figured out how steam was the way to heat their home. Smart guys.

    Check out Akron and its Thermal system. It did not go crazy in the nineties and today, valuable steam is still the staple of heat that makes other downtown natural gas users cry every time they open their monthly gas bill.

    Indianapolis also has a magnificent steam scheme: on top of just making steam and power, these smart people produce valuable coke for the steel mills all in one multi tasking feat.

    Nashville has been advertising its just recently renovated and expanded downtown steam heat combined with a separate chilled water cooling system. All brand new, all efficient.

    Your own Cincinnati does not have a downtown heat loop, but it is building and expanding its chilled water system for cooling purposes. Chilling plants are dispersed everywhere, the important ones by the convention center and the riverfront stadium for efficient Ohio river cooling. And for seeing the clouds up close and personal, the Carew tower is propelled by steam. So is the PNC tower with its postcard perfect chimney top.


    Can you tell us more about the Mariemont plant? Where was it located? Did it feed one major industry or institution?

    Thanks for your curiosity.
  • Perry_3
    Perry_3 Member Posts: 498
    Not all gone

    In Wisconsin steam and chilled water can be a public or municipal utility service; and is in several cities yet. But limiited to the older systems that were built - and ususally downtown.

    It is such a shame that so many places abandoned their systems - or did not maintain them.

    I remember when natural gas was piped through central Wisconsin. That killed several of them as the gas company offered to run gas lines to buildings free for singing up.

    However, not all is lost. I have heard planning for one new steam heat/chilled water district for a "old style" subdivision development (instead of 3000 Sq Ft houses on huge lots... build 1000 - 1500 Sq Ft houses on small lots with a central shopping district). Let's see if it all flys.

  • JJ_4
    JJ_4 Member Posts: 146
    International District Energy Association

    I found an interesting website for the "International District Energy Association".


  • John Mills_5
    John Mills_5 Member Posts: 951

    Almost 1/2 of Indy's steam comes from the garbage burner. But there's talk that the garbage people may do something else with their steam such as sell it to the electric company meaning downtown may have to scramble to come up with another source! I think Indy's steam system is 2nd in size behind NY.
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