Integrated hydronic heating diagram - opinions?

Discussion in 'Boat Design' started by antonkov, Jan 8, 2014.

  1. antonkov
    Joined: Mar 2010
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    Location: Vancouver,BC

    antonkov Junior Member

    I am making my first iteration on the heating system design. At this point, I don't worry about the numbers and models as long as the "big picture" makes sense.

    So far, I couldn't find any good read or comprehensive schematics on the integrated heating, only scattered forum posts.

    Would welcome any critics or suggestions (except for "why bother, pay professionals to do it for you"). I am sure I am missing bunch of valves or something that is not obvious without a field experience.

    The tentative engine is about 100-150hp, so not sure is exhaust heat exchanger is applicable.
     

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  2. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    The first question is what service will the boat operate in?

    All this looks fine but will require a massive amount of electric for fans , 5 ! pumps etc.

    OK for a dock queen or boat underway 24/7 , but once you go over to batt power it could be a very short between genset runs.

    Stuff happens , I would look to be able to isolate , to operate with some items missing or inoperative.

    Baseboard heat requires a far smaller circ pump than box heaters , that also require big fans to operate.

    Fine on a tug or ferry , that never anchors overnight.
     
  3. antonkov
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    antonkov Junior Member

    F.Fred, thanks for the response.
    Tug or ferry, heh? Glad I didn't show the pumps from the other hull ;).

    Well, 5 pumps are on the diagram, but they never run all together.
    Aux. on the engine loop is for warming up the engine, rarely required and runs for not too long.
    Raw water pump is to cool the engine or genset, not an issue of the amps draw since one of them would be running by the definition.
    Aux. pump in the heating loop is to transfer heat from a running engine or genset, again not an issue since one of them would be running by the definition.
    Fresh/hot water pumps... , these do draw from the batteries, but not all the time and besides, is there really a way to optimize this without giving up on the hot/cold water?
     
  4. AlexMorozov
    Joined: Jul 2004
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    Location: Spain

    AlexMorozov Custom yachts

    Hi, I make installation of water/heating system based on MV Hydro5 (Ex Mikuni) water heater with 2 x Matrix heater + 1 x radiator in shower. The consumption of heater fan is just 0.6 amp. I think that no need separate pump for hot water and mixing valve.
     
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  5. fredrosse
    Joined: Jan 2005
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    Location: Philadelphia PA

    fredrosse USACE Steam

    Hot Water Pumps

    Grundfos hermetically sealed circulating pumps only draw about 30 watts, vs. over 300 watts for most of the typical USA (Bell & Gosset, etc.) hot water circulating pumps found on many hydronic heating systems. A real advantage when using battery power. Proper sizing of the piping circuits is however required, and in my experience a single small power pump can do very well for heating a boat 60ft or less, as well as heating potable water, with proper design.
     
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  6. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    You don't need the hot water pump on the left, if you have a sealed tank. The fresh water pump will pressurize that. If you don't have a sealed tank, you need some sort of automatic valve to shut off the fresh water so the tank won't overflow.

    You don't need a pump to warm up the engine, you just start it and let it warm up.

    Tempered mixing valves aren't needed, that's what faucets are for.

    The water heater should directly heat water for sinks and showers, convective heating is inefficient. I think the water heater would take the place of the hot water tank, which wouldn't be needed then.

    To pump hot water for heating etc, might take a different pump than a cold water pump.
     
  7. antonkov
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    antonkov Junior Member

    I thought that the whole idea of warming up the engine in a cold climate is to help it start. It's understood that once started it will warm itself.

    Although, like I said, don't have a field experience of using marine diesels in winter. My 115hp outboard starts in winter just fine, wouldn't think of preheating it. But, I did see multiple comments about advantages of warming up the diesel before starting, not sure if it is overrated or not.
     
  8. SamSam
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    SamSam Senior Member

    I'm not sure it's needed in Vancouver. That's just kind of a cool climate. Where I grew up in Minnesota is cold, and tank heaters were a big help, but you never plugged it in unless it was going to be way below freezing. With your setup, where are you going to get the hot water to warm the engine?
     
  9. antonkov
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    antonkov Junior Member

    Hot water to warm the engine would come from the heating loop via the heat exchanger on the left (reverse direction of the heat). Heat sources would be hydronic heater (webasto), genset or just stealing from the HW tank.

    As for the tempered mixing valve, the idea is to allow a higher temperature in the HW tank thus effectively increasing the amount of *warm* water available for the shower(s).
     
  10. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The perfect device for this application is a Webasto Thermotop C.
    Power consumption is 22/32 watts from 12V for the heating unit, 14W for the pump. The output is 2.6 kW (low) or 5.2 kW (high), amazing for a unit the size of a book.

    This is standard equipment in cars with common rail diesels like the Kia Sorento that cannot sustain sufficient cabin temperature in winter and/or take too long to reach operating temperature.
     
  11. michael pierzga
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    michael pierzga Senior Member

    I agree...the webasto type heaters are the best overall solution and should be your primary heat source. Very reliable.

    Your proposed system looks complicated.


    Harvesting hot water from a generator..free waste heat is not a bad idea.

    Storing this heat in a large insulated tank is a good idea.


    How many btu do you need ? Will you be operating in arctic conditions ?

    I live on a boat...its winter..and 1500 watts of electric heat keeps the boat nice and warm. The boat is well insulated. The air temp this morning at 0700 was 9C.

    Insulation to prevent heat loss should be high on your list .
     
  12. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    I agree...the webasto type heaters are the best overall solution and should be your primary heat source. Very reliable.

    Your proposed system looks complicated.


    Harvesting hot water from a generator..free waste heat is not a bad idea.

    Storing this heat in a large insulated tank is a good idea.


    How many btu do you need ? Will you be operating in arctic conditions ?

    I live on a boat...its winter..and 1500 watts of electric heat keeps the boat nice and warm. The boat is well insulated. The air temp this morning at 0700 was 9C.

    Insulation to prevent heat loss should be high on your list .
     
  13. SamSam
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    Location: Coastal Georgia

    SamSam Senior Member

    Am I missing something? Isn't that what faucets do? I'm not aware that hot water faucets have a temperature rating. If the water in the tank is real hot, you just don't turn the hot water faucet on as much. You can crank your house water heater up to the max, where you can instantly scald yourself to death, but you don't need tempered mixing valves to take a shower, you just use your regular faucets.
     
  14. antonkov
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    antonkov Junior Member

    Samsam, you are absolutely right, provided you are the only one who would use the shower. If you have kids or guests, there always be one who forgot about the "convenient" feature of the hot facet.
    Mixing valve is $30 on eBay, why bother explaining everyone how to use shower on board?
     

  15. SamSam
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    SamSam Senior Member

    Using faucets would be a handy skill set to have when on land.

    I looked up tempered mixing valves and they do look handy, I could use one in my RV. By the time my shower temp is fine tuned, my 7 gallon hot water tank is half used.

    The hot water pump still seems un-needed though.
     
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