Capture waste heat from diesel electric generators

  1. Need help to find a way to capture waste heat from diesel electric generators (45 KW) to heat water for small hotel use (45 rooms + kitchen). Exploring all options: jacket water, oil, exhaust. Anyone please help.
  2. jcsd
  3. brewnog

    brewnog 2,775
    Science Advisor
    Gold Member

    Look up CHP plants; your idea is readily available and commercially viable.

    If you already have the generator, you'll likely be looking at the following:

    Boiler to capture exhaust heat
    Heat exchanger(s) to capture jacket water heat

    If the engine has an oil cooler, you'll be able to capture heat from that too; it probably uses the jacket water circuit anyway.
    Last edited: Feb 12, 2007
  4. Thank you for the input. Do you know if this piece of equipment useful for both the water and the oil?
  5. brewnog

    brewnog 2,775
    Science Advisor
    Gold Member

    Possibly. It depends on how you're going to run the engine, and the heat/hot water requirements of the building. You also need to factor in what you're using to back up / supplement the engine when it's not running.

    Those heat exchangers are the right kind of thing though.

    Are you doing this project yourself, or getting a cogen specialist in?
  6. Dont know of a cogen specialist to contact, are you such a person?
  7. brewnog

    brewnog 2,775
    Science Advisor
    Gold Member

    Well I regularly work with such systems, but can't come out and specify, quote for, and install such a thing for you!

    What country are you in? I'll see about recommending some companies to talk to.
  8. have 3 diesel engines. 2 are 45 kw gens and one is 120 kw. one of them is running at all times in a 24 h cycle. hot water is for a 45 room rural hotel + kitchen. water does not need to be above 60 celsius. someone also mentioned running exaust gases into a hot water heater. and hot water into an insulated tank for holding and recirculating in the hot water insulated pipe network the hotel has. hotel is near sea, water has 2600 ppm solids.
  9. hotel is in tulum, mexico. tulum is 130 kms, 1.5 hours from cancun airport.
  10. need a vacation? maybe we can barter.
  11. brewnog

    brewnog 2,775
    Science Advisor
    Gold Member

    Well you don't want to use seawater!

    If you're planning on using existing engines then I take it you've already got boilers and want to use the engines to supplement these? The exhaust boiler is an extremely good way of recovering heat, along with jacket water. Do the engines not already have oil coolers?

    In any case, you need a specialist to visit the site. I don't know of any in Mexico, I'm sure an internet search would yield some positive results though (search for cogeneration, trigeneration, combined heat and power, CHP etc). Firstly, they'll be able to tell you whether such a project is economically viable (based on heat requirements of the hotel, fuel costs, electricity prices and capital). Secondly, they'll be able to advise of the best solution to suit your needs, based on all the above factors, plus the type of engines, their location on the site, what the electricity is used for, and the heat demand profile of the building. Thirdly, they'll be able to specify, design, commission and maintain the plant.

    Yes I do need a vacation. Specifying a cogen plant doesn't sound like much of one to me though!
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