Poor mans airconditioning upgrade curiosity-gctid820427

[igiftmon]

My mind has been stuck playing with a crazy, and I mean crazy, idea of how to add airconditioning to a boat with a hydronic system without adding a second reverse cycle airconditioning system. I have several friends in this predicament and asked me to think about this issue with my out of the box mind. What did they do? Lol.

After thinking of various options, I started to wonder what would happen if a special cooling compressor was added to the hydronic heater lines to cool the antifreeze instead of heating it like the diesel furnace does. I figure a wye would have to be installed to shut out which ever system you needed, but I was thinking if the coolant was cooled to about 33f, it would cause the individual heater's radiator to cool to a point the air flow would generate a cool to cold airflow that would in turn cool the various cabins

I don't know if this crazy idea would be significant enough for tropical use, but was thinking it might be fun to try... I may have to design a new compressor, but what the heck, right? thoughts?

~BJ

~BJ

[Norton_Rider]

It should be possible by rigging up a chiller. Read this article. It addresses houses, but the idea is the same:

http://www.achrnews.com/articles/862...with-hydronics

[egbauman]

I live on the Texas gulf coast so we basically run our AC units constantly from May through October.

Making cold antifreeze is only half the battle. You need to generate airflow and remove condensation. I don't know what your hydronic radiators look like but if they are anything like the baseboard heaters that we had when I lived in the northeast, I don't think this will work. Hot air rises which is why radiators work well. If you cool a radiator, you'll have a cold and wet floor but the air at the level of your head will still be hot.

[WhiteRockMike]

Interestingly, I have been thinking about the opposite scenario: adding a diesel hydronic heater but tapping into our existing reverse cycle distribution lines and exchangers to distribute the heat throughout the boat. This would avoid the difficulty and expense of distributing new hydronic lines and heat exchangers throughout the boat.

The reverse cycle heat isn't too bad, but does require lots of dock or generator electrical power.

[ronbo404]

Another consideration is the large amount of condensate (since we deal with high humidity conditions) that will come off the coils that you will have to deal with.

Good luck, keep us posted

Ron

[Woodsea]

As stated above, dealing with condensate will be the problem with the fan coil units. Also chilled water lines must be insulated or they will sweat as well.

It's hard to beat the little self contained ac units that use circulating sea water as the heat sink like bayliner used on the 47 with the factory ac option.

[kev_rm]

on paper it seems harder to cool via hydronic. Getting a 200F fluid to heat is easy, gets you say 130F delta T (diff between ambient and fluid). For the same amount of heat transfer in a cooling situation you'd need -60F fluid - 40F colder than freezing point of 50/50 glycol

[iceclimber]

+1 for the portable unit

[Norton_Rider]

"kev_rm" post=821640 wrote:
on paper it seems harder to cool via hydronic. Getting a 200F fluid to heat is easy, gets you say 130F delta T (diff between ambient and fluid). For the same amount of heat transfer in a cooling situation you'd need -60F fluid - 40F colder than freezing point of 50/50 glycol

I'm not sure how you came up with your numbers, but hydronic cooling in buildings uses water in the 40 deg F range. Here's a good article:

https://www.google.com/url?sa=t&rct=...dUnTuwCHbP4YJA

[Terry_J]

Just some info, Kanter Yachts, who is a high end custom builder mostly specs chillers and air handelers when they build a boat for the tropics.

Terry

[Norton_Rider]

"Terry J" post=821768 wrote:
Just some info, Kanter Yachts, who is a high end custom builder mostly specs chillers and air handelers when they build a boat for the tropics.

Terry

I've been a guest on a 150' yacht and the heating and cooling were hydronic. It used the same air handlers for both.

[Terry_J]

I guess i should point out that chillers and air handlers are a "rich man's" air conditioning system. That's why you find them in custom built 150' yachts and not in $ 2.5 million dollar Sea Rays.

This is NOT a poor man's air conditioning.

Terry

[igiftmon]

"Terry J" post=821860 wrote:
I guess i should point out that chillers and air handlers are a "rich man's" air conditioning system. That's why you find them in custom built 150' yachts and not in $ 2.5 million dollar Sea Rays.

This is NOT a poor man's air conditioning.

Terry

I love the irony....

~BJ

[kev_rm]

"Delta T doesn't matter" - Said no HVAC engineer ever.

[Norton_Rider]

"kev_rm" post=821962 wrote:
"Delta T doesn't matter" - Said no HVAC engineer ever.

Delta T absolutely matters, but your coolant temperature numbers are way lower than what is normally seen.