23' Sceptre Air Conditioner (Cheap!)

[77SceptreOB]

Ever wish you had an A/C unit for your 23 Sceptre that could cool off the cabin in the summer so you could enjoy an Overnighter or cool off some hot, tired cranky kids on a all day adventure? Well so did I! So I've come up with a cost effective custom concept to make the 23' Sceptre cabin a lot more livable in warmer climates. I got the idea watching some YouTube videos and Tik-Tok shorts. It's basically a forced air system using a cooler and Ice. It works using bag/crushed ice and/or block ice (best).The fan motor is DC power and only draws .75 amps (9 watts) so it wont kill your battery.

Performance: The unit is capable of lowering the forced air 20 degrees for 6 continuous hours (in turbo mode). In "supercharge mode" the difference in the air temp is 33 degrees. In a small cabin this differential makes it VERY pleasant and cool in the cabin even on a warm day or evening. It took me some time and effort to try different configurations to achieve the above results.

Check out the below pics and let me know if you want to try this or want more info.

Jim

[Bikecop1]

Brilliant. I may have to try in my seafari.

[workinpr0gress]

Love it!

[77SceptreOB]

The remainder of 3 medium sizes blocks of ice (12 lbs each ~ 2 gallons*) after 6 hours of cooling. Two blocks can sit on the elevated Teak ice tray. The tray was made to house crushed/bag ice but can work for the Block ice too. Basically the more ice the better! In "supercharged" mode I used 2 blocks and 20 pounds of bag ice to achieve the lowest air flow temp of -33 degrees lower than ambient cabin temp.

* the 12lb Block Ice was home made using a new plastic bathroom trash can as the form and freezing it in my garage chest freezer.

[Capt Terry]

Hey Jim
Pretty clever, no surprise!

[Xcomunic8d]

Yup we use those in Hawaii. Wonderful idea less cost and can multipurpose.

Try freezing 2 liter bottles mostly full so they don’t burst. When they melt you have drinking water…

I have an ice maker so ice is never an issue but solid chunks seem to last longer in there

I made blocks using Rubbermaid containers and silicone molds in my freezer. Now I have an industrial ice maker…500# a day

[qcguy4198]

That looks like an awesome idea. Thanks for sharing. I'm thinking stacking the frozen 2-liter bottles would be the most convenient way to go. I don't have any idea where I'd find block ice, and I like the idea of having bottles of water ( after they thaw) on the boat anyhow. Can you expand a bit on the power draw..??
Thank you.

[77SceptreOB]

Can you expand a bit on the power draw..??
Thank you.

Not sure on any of the specifics other than the .75 amp draw (9 watts). I haven't put a multimeter on it to confirm the power usage. Should be low enough not to kill a "starting" battery and certainly would work off a "house" deep cycle battery.

Try freezing 2 liter bottles mostly full so they don’t burst. When they melt you have drinking water…

Sounds like a great idea,, but I've also heard that if you utilized that method it doesn't cool as well. The plastic surface of the bottle isn't cold enough since ice in the bottle(s) quickly get "insulated" with the warmer water that is in between the remaining ice in the bottle and the plastic shell of bottle. It lacks the intimate direct contact radiating from the cold block of ice. I'm sure it will work, and you get ice cold water to drink but in the long run I would think the unit doesn't work as well.

[kmoose]

Originally Posted by 77SceptreOB

Not sure on any of the specifics other than the .75 amp draw (9 watts). I haven't put a multimeter on it to confirm the power usage. Should be low enough not to kill a "starting" battery and certainly would work off a "house" deep cycle battery.



Sounds like a great idea,, but I've also heard that if you utilized that method it doesn't cool as well. The plastic surface of the bottle isn't cold enough since ice in the bottle(s) quickly get "insulated" with the warmer water that is in between the remaining ice in the bottle and the plastic shell of bottle. It lacks the intimate direct contact radiating from the cold block of ice. I'm sure it will work, and you get ice cold water to drink but in the long run I would think the unit doesn't work as well.

The plastic bottle does slow heat transfer but it is important to figure out the optimal rate heat is transferred into the ice to provide the desired control duration. It may pay to experiment with allowing the cooler and or bottles to drain as the melted liquid contains the transferred heat and also reduces the ice surface area that is exposed.

The whole process can be tweaked to achieve the best results and it’s cool to see you guys working through it with different ideas. Just keep in mind the first principle of thermodynamics…. Heat energy always moves/transfers from hot to cold. So the heat energy in the cabin is being transferred to the cooler. The rate and efficiency of the transfer can be improved with an increase in ambient pressure which the fan provides. Maybe an experiment can be done to reduce flow on the output duct to improve heat transfer in the box.

[jorgeinmiami]

The old time Cuban fishermen have been doing this since I can remember.
And I'm talking 40 years ago.
Its a great idea and it works!!