Heat output of engine

Discussion in 'Diesel Engines' started by ErikdeJong, Sep 21, 2012.

  1. Frosty

    Frosty Previous Member

    So would a dry exhaust disguised as a pop bellied stove.

    Im drained,--- I am exhausted myself ,-- I have expelled all my entire brain farts in this general direction,-- I have nothing left.
  2. ErikdeJong
    Joined: May 2012
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    Location: Halifax

    ErikdeJong Junior Member

    Please read my earlier post(s)
    A regular fuel heater with an efficiency of abt 90% is the main source of heat on board. Storing heat that usually goes overboard will save me about 500-600 liters of fuel for that specially built in diesel heater.

    I will definitely NOT run the engine for the heat only...
  3. ErikdeJong
    Joined: May 2012
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    Location: Halifax

    ErikdeJong Junior Member

    16-17 celcius overnight and during sailing and 20-21 celcius when we are relaxing inside.
    about 85 Celsius
    Pipes to get it to the desired location and there it will run through a radiator.

    I'm not sure yet, right now my freshwater heater is hooked up to the internals of the engine (in the circuit with both the tak out and return point before the coolant passing through the engines thermostat) and that works great. I am thinking now to add a three way valve in that pipeline to the water heater and use that circulated coolant to heat the seawater. In that case a booster pump to maintain enough flow rate would be required. This way I can let the engine get to service temperature without extracting heat. When the engine reaches desired temp, I open the valve to the water heater for shower water etc. and when that one is at the desired temperature (takes only 10 mins) I will divert the water through the seawater tank.

    I will have to sit down and go over your math and see what you mean with all your numbers. Reading through it on my small screen does not make me see the light of what you're trying to say.

    The system is not really meant to rise the temperature but more to maintain it at a certain level.

    Right now I see it as a bigger brother of the freshwater heater that we already have and that one works perfectly fine and satisfying. I expect the big tank to work in a similar way but much slower in both warming up, but in cooling down as well.

    I will come back to you very soon with my thoughts on your numbers! Thanks!
  4. Joakim
    Joined: Apr 2004
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    Location: Finland

    Joakim Senior Member

    With 85 C coolant temperature you will not get more than 75-80 C seawater and the last 5-20 C heating up will be very slow.

    Since you want to have good efficiency for heating of seawater and you want to keep the engine running at desired temperature, you probably need to rethink the whole cooling system of the engine. If you have 1000 liters of close to 0 C seawater and an efficient heat exchanger, the return water will be below 10 C. If you put that to the inner cooling circulation, the engine will cool down way too much. I think you need to use the outer coolng loop (the one going through the seawater heat exchanger anyway). Then you don't need to worry about engine running too cold, but you do need to have enough cooling for the engine when your seawater gets too cold.

    For this will need a thermostat, which regulates the amount of coolant flow to your seawater tank vs. to the current heat exchanger, which is needed once your seawater is hot. The engine will need the coolant back 10-20 C colder depending on its work load and coolant circulation (rpm). Thus when your seawater tank reaches 60-70 C you need to use the current heat exchanger as well.

    For getting efficiently above 60-70 C you need to use flue gas heat as well.
  5. jonr
    Joined: Sep 2008
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    Location: Great Lakes

    jonr Senior Member

    > engine running too cold

    I second that. Minimize run time (and full load) when the engine is below operating temperature. Wear goes way up when cold. You might even be able to use a tank of hot water as an engine preheater to reduce wear (ie, run the coolant system in reverse before starting).
  6. Submarine Tom

    Submarine Tom Previous Member


    All you need is a second heat sink, nothing fancy, complicated or expensive.

    K. I. S. S.

    Free, passive heat.

    That's all.
  7. Frosty

    Frosty Previous Member

    Thats what a thermostat is for. Engines run in minus 60.

  8. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    You're running amok here. The tank would never be below room temp of 18 degrees.

    The Op hasn't really begun to work out the actual plumbing runs yet. There will be plenty of time for a spirited discussion when he does. Figuring the extent of the main cooling loop, what can be hooked up to it, and what needs to be separate loops, is what I'm waiting for. And yes, preheating the block by circulating warm coolant would be a very good thing to include.

    Erik. You will need to give us a pretty good sketch soon of how things lie, particularly with respect to elevations.
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