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Old 14-11-2018, 15:29   #31
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Re: Adding engine heating to diesel heater

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Originally Posted by Fluenta View Post
Yes that is of course possible but that is not what I am trying to do as I already have a back up Webasto air system. As per my first post, we already have a hydronic system installed and I am looking to add a heat exchanger to use some of the waste heat from the engine.


The original question on adding to my existing hydronic system: My question is about sizing the heat exchanger: how big of a heat exchanger can one use before adversely impacting the engine ? We have a Perkins 4.236 84HP that previously used 1/2" hose to heat up the hot water tank. The hot water tank is quite a distance from the engine so I am looking to find a place closer to the engine for the new heat exchanger so that should reduce the drag on the coolant pump. However, the two heat exchangers I am looking at online are 30,000 BTU/Hr or 40,000 BTU/Hr. Will that be too much drag on the coolant pump or take too much heat from the engine ?
Ah ha, have you considered motoring south in the winter? LOL
I do believe you need to discuss your needs with someone much smarter than me, someone well versed in heat transfer and fluid flow and system design? May I suggest you discuss this with a marine engineer?
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Old 14-11-2018, 18:28   #32
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Re: Adding engine heating to diesel heater

You may be able to find the answer to your question on the ITR site, accessories.

http://itrheat.com/wp-content/upload...ssoriesF-1.pdf
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Old 15-11-2018, 12:39   #33
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Re: Adding engine heating to diesel heater

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You may be able to find the answer to your question on the ITR site, accessories.

http://itrheat.com/wp-content/upload...ssoriesF-1.pdf

Thanks. Looks interesting. I will call the company to see if it is applicable. Sure Marine has some too.


Winnipeg ! You guys know cold. I have spent lots of time there for meetings and courses.
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Old 16-11-2018, 07:44   #34
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Re: Adding engine heating to diesel heater

Yes, me too, but there was a day when I left after the meeting. Where are you from?
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Old 16-11-2018, 08:14   #35
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Re: Adding engine heating to diesel heater

Quote:
Originally Posted by Fluenta View Post
Yes that is of course possible but that is not what I am trying to do as I already have a back up Webasto air system. As per my first post, we already have a hydronic system installed and I am looking to add a heat exchanger to use some of the waste heat from the engine.


The original question on adding to my existing hydronic system: My question is about sizing the heat exchanger: how big of a heat exchanger can one use before adversely impacting the engine ? We have a Perkins 4.236 84HP that previously used 1/2" hose to heat up the hot water tank. The hot water tank is quite a distance from the engine so I am looking to find a place closer to the engine for the new heat exchanger so that should reduce the drag on the coolant pump. However, the two heat exchangers I am looking at online are 30,000 BTU/Hr or 40,000 BTU/Hr. Will that be too much drag on the coolant pump or take too much heat from the engine ?
The heat exchangers size is not very important nor critical, the correct engine temperature is controlled and protected by the engines thermostat.
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Old 16-11-2018, 08:35   #36
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Re: Adding engine heating to diesel heater

Interesting question... I'm no expert but I did look to see what I could figure out in google.

There are a few aircraft heaters that use Perkins 4.236 and they are capable of producing 350,000 BTU. Using the conversion factor of 2545 BTU per HP I calculate that 85 HP is 216,325 BTU. The 2 numbers are in the same ballpark but not too close to each other.

The key point there is even with the 216,325 BTU number Your 4.236 has a lot of heat available at max HP. Using the 216,325 BTU number I see that it takes 16 HP for 40,000 BTU and The 4.236 makes more than 16 HP at 1000 RPM (closer to 30 HP).

Thus even when you factor in "losses" in heat production (losses like actually doing some work rotating the prop) you have more than enough heat at 1000 RPM to extract 40,000 BTU.

Looking at it I would say that you should pick the heat exchanger that is closest in BTU to the BTU production of your hydronic diesel heater. In any case the 4.236 is not a small engine and has more than enough heat to support a 40,000 BTU engine heat exchanger without causing the engine to run too cool.

As a side note I have a Webasto DBW-2010 hydronic system from SMS and a Perkins 4.236 in my boat. I do not have an engine exchanger.
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Old 16-11-2018, 08:44   #37
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Re: Adding engine heating to diesel heater

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>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>
...we will likely need to run the engine everyday on passage for battery charging so we would like to get the heating and hot water that would go with that.>>>>>>>>>>>>>>>>>>>

You may have forgotten from six years ago that there is not always wind around here and you will be using your engine for more than just battery charging. Since I moved here from SF in 2016, I am using my engine twice as much per year even though there is a "sailing season" of April to October.



Safe journey back.
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Old 16-11-2018, 12:31   #38
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Re: Adding engine heating to diesel heater

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Yes, me too, but there was a day when I left after the meeting. Where are you from?
I am from the interior of BC but over my 23 years in the military I lived in a bunch of different places in Canada.
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Old 16-11-2018, 12:33   #39
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Re: Adding engine heating to diesel heater

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Originally Posted by evm1024 View Post
Interesting question... I'm no expert but I did look to see what I could figure out in google.

There are a few aircraft heaters that use Perkins 4.236 and they are capable of producing 350,000 BTU. Using the conversion factor of 2545 BTU per HP I calculate that 85 HP is 216,325 BTU. The 2 numbers are in the same ballpark but not too close to each other.

The key point there is even with the 216,325 BTU number Your 4.236 has a lot of heat available at max HP. Using the 216,325 BTU number I see that it takes 16 HP for 40,000 BTU and The 4.236 makes more than 16 HP at 1000 RPM (closer to 30 HP).

Thus even when you factor in "losses" in heat production (losses like actually doing some work rotating the prop) you have more than enough heat at 1000 RPM to extract 40,000 BTU.

Looking at it I would say that you should pick the heat exchanger that is closest in BTU to the BTU production of your hydronic diesel heater. In any case the 4.236 is not a small engine and has more than enough heat to support a 40,000 BTU engine heat exchanger without causing the engine to run too cool.

As a side note I have a Webasto DBW-2010 hydronic system from SMS and a Perkins 4.236 in my boat. I do not have an engine exchanger.
Thanks for the information ! I have a Espar M12 so close to capacity to the DBW-2010.
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Old 12-04-2019, 01:02   #40
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Re: Adding engine heating to diesel heater

Just a quick update to our hydronic installation. We recently installed a 30,000 BTU/Hr heat exchanger we received from Sure Marine. All plumbed in and and air purged out (a nice feature is the bleeding points added for both the engine and the heater circuit). Seems to work fine and the engine got up to operating temperature fine and the heater circuit comes up to steady state quickly.



Not an ideal test scenario of course as still sweating in the Marshall Islands: 30C outside air temp and 28 sea temp. Should get a better test on the way north to Alaska.


Thanks everybody your the advice.
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Old 14-04-2019, 23:45   #41
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Re: Adding engine heating to diesel heater

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I currently have a hydonic diesel heater that uses either shore power or a diesel burner. It provides both domestic hot water and cabin heat by means of small radiators and fans. I would like to add the option of using the engine heating so that when I run the engine I also heat my domestic hot water. From what I have been able to glean from the internet, the best way of doing this is to plumb in a separate heat exchanger into the cold water supply to the water tank (this is the way a Hurricaine Combi unit is plumbed into the engine coolant system, according to their online installation manual. It says don't mix the engine coolant with the hydronic heating coolant). Assuming this is correct, I have a few questions:
1. Is the new heat exchanger plumbed in series, or in parallel with the existing engine coolant loop?
2. If in series, do I need to worry about the ability of my engine water pump to handle the extra load?
3. So long as I keep the new plumbing below the level of the engine expansion tank, do I not need to worry about air locks in the system?
4. How do I get the water in the hot water tank to cycle through the heat exchanger in order to heat up the tank? Or do I put it on the hot side of the tank and just have "instant hot water" as opposed to a tankful of hot water?

Thanks for the help.



Just think of your car heater other than old vw the hot coolant lever the engine top area (head) and flows though the heater core and returns back

in to the engine at the front inlet side of the water pump by
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Old 15-04-2019, 00:00   #42
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Re: Adding engine heating to diesel heater

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The heat exchangers size is not very important nor critical, the correct engine temperature is controlled and protected by the engines thermostat.



the thermostat controls the block coolant temp,and your heat excharger is only taking a small amount of heat out, the thermostat will cyclic from fully closed too fully open.
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