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External
Since: Aug 19, 2007
Posts: 7
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(Msg. 1) Posted: Sun Dec 02, 2007 6:38 pm
Post subject: diesel for sailboat, question ..
Archived from groups: rec>boats>building (more info?)
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| Heat exchangers.. if I were to use a small diesel for my sailboat that did
not have a
heat exchanger already attached to the engine ??
How do I size the heat exchanger? Does it go by horse power, size of engine
... cyclinders ..
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>> Stay informed about: diesel for sailboat, question .. |
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External
Since: Jun 22, 2003
Posts: 434
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(Msg. 2) Posted: Sun Dec 02, 2007 7:16 pm
Post subject: Re: diesel for sailboat, question .. [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Sun, 02 Dec 2007 18:38:37 GMT, "Sir Thomas of Cannondale"
<tomcatm.DeleteThis@verizon.net> wrote:
>Heat exchangers.. if I were to use a small diesel for my sailboat that did
>not have a
>heat exchanger already attached to the engine ??
>
>How do I size the heat exchanger? Does it go by horse power, size of engine
>.. cylinders ..
>
>
Diesels are efficient thermal converters. Let's use a 40% thermal
efficiency at generating the rated horse power of the engine,
so it needs to dispose of the other 60% as heat.
Heat out of the exhaust, and heat into cooling water.
The exhaust can take care of itself, so your question amounts to this:
what factor of rated horse power should I allow for an engine cooling
heat exchanger?
Fuel thermal content = 100/40 of rated HP
That's 2.5 times rated HP
Exhaust thermal content = (say half the waste heat) =
(2.5 - 1 ) X 1/2 of rated HP = 0.75 of rated HP
leaving
Cooling heat also 0.75 of rated HP
This estimator gives the cooling requirement of a 10 HP diesel as
10 X 0.75 HP = 7.5HP or
7.5 X746 watts = 5.6 kW
It's a little bit conservative.
Brian W
Clear as mud? |
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External
Since: Aug 19, 2007
Posts: 7
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(Msg. 3) Posted: Sun Dec 02, 2007 7:22 pm
Post subject: Re: diesel for sailboat, question .. [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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Wow.. just as I thought.
===
"Brian Whatcott" <betwys1.TakeThisOut@sbcglobal.net> wrote in message
news:k506l39v9er52bi75fqi0ka6rf73a2g8er@4ax.com...
> On Sun, 02 Dec 2007 18:38:37 GMT, "Sir Thomas of Cannondale"
> <tomcatm.TakeThisOut@verizon.net> wrote:
>
>>Heat exchangers.. if I were to use a small diesel for my sailboat that
>>did
>>not have a
>>heat exchanger already attached to the engine ??
>>
>>How do I size the heat exchanger? Does it go by horse power, size of
>>engine
>>.. cylinders ..
>>
>>
> Diesels are efficient thermal converters. Let's use a 40% thermal
> efficiency at generating the rated horse power of the engine,
> so it needs to dispose of the other 60% as heat.
> Heat out of the exhaust, and heat into cooling water.
>
> The exhaust can take care of itself, so your question amounts to this:
> what factor of rated horse power should I allow for an engine cooling
> heat exchanger?
> Fuel thermal content = 100/40 of rated HP
> That's 2.5 times rated HP
> Exhaust thermal content = (say half the waste heat) =
> (2.5 - 1 ) X 1/2 of rated HP = 0.75 of rated HP
> leaving
> Cooling heat also 0.75 of rated HP
>
> This estimator gives the cooling requirement of a 10 HP diesel as
> 10 X 0.75 HP = 7.5HP or
> 7.5 X746 watts = 5.6 kW
>
> It's a little bit conservative.
>
> Brian W
>
> Clear as mud? >> Stay informed about: diesel for sailboat, question .. |
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External
Since: Jul 11, 2007
Posts: 175
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(Msg. 4) Posted: Mon Dec 03, 2007 12:40 am
Post subject: Re: diesel for sailboat, question .. [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Sun, 02 Dec 2007 18:38:37 GMT, "Sir Thomas of Cannondale"
<tomcatm.TakeThisOut@verizon.net> wrote:
>How do I size the heat exchanger? Does it go by horse power, size of engine
>.. cyclinders ..
Heat to be dissipated, and therefore heat exchanger size, is directly
proportional to the fuel burned. In other words, horsepower.
Casady >> Stay informed about: diesel for sailboat, question .. |
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