Chest Freezer Mini Split Air Conditioner | Random Video Thursday's
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- Опубликовано: 19 июл 2023
- This is not a build montage video or story of trial and error. But I show in the video that this final concept design works and explain it. It's a very simple setup and is easy to understand.
I avoided explaining my reasoning for doing this to save video time. But I will explain it here...I already had much of this set up from a previous project involving a geothermal test well in my basement. (PS - I only uploaded that video project to Facebook.) So I only needed to add a chest freezer and experiment with different build/design methods.
The reason I am not just using a window AC is because I prefer not to have intermittent loud noise at night. I prefer not to have any extra sunlight entering my room in very early morning hours. I also prefer to not hear the loud birds in the early morning either. I have sleeping issues and have had to overcome the triggers. I also have casement windows which makes it a little more difficult for using a window unit. On top of that, I already have a whole house AC and 3 vents in the bedroom with one booster. All of that is still not enough to keep my bedroom cool enough through the night during a hot summer. I usually leave my windows open during other times of the year at night when pollen, daylight and bird noises is not an issue but it really needs to be at least 20 degrees colder outside to have any effect on cooling the room. Also if the humidity is high outside then its not worth it either. And don't get me started on internal/floor A/C units.
This system is quiet and only uses around 140 watts to run the freezer. The cooling part of the system is small so it fits on a night stand. So not only does it take up little space, it can blow right on you if you want. It's a nice quiet gentle cool breeze. So even if it didn't cool the whole room, it will cool you which is more efficient in my book. Also my original intention was to only use it at night. So during the day the freezer cools the water and then at night the freezer is off while only the pump/fan run to blow cool air all night. I actually had no idea at first that it could just run continuously until I optimized the setup. So it can be used either way. Which is excellent for power outages. If the power went out you can use this for around 12 hours on a very small battery or if you wanted to have the chest freezer on too it would only need a very small generator or something like a 50Ah battery/inverter. It's a lot more efficient when power is an issue because of its conservative power needs.
Here are the affiliate links for the parts:
12v 2x Noctua Fans - amzn.to/3NVot7z
Heat Exchanger - amzn.to/3rCKGQe
Check Valve - amzn.to/3K5gyU2
12v Pump - amzn.to/44tQr1v
Tubing - amzn.to/3XYMIGB
In-line Temperature Control Switch - amzn.to/3pMYsj0
For the tubing, you will need to heat up the end to slip it over the heat exchanger in/out ports. You can use boiling water, gentle flame or a heat gun. Use a little silicone grease or wd40 on the port then heat the tube and then use something like needle-nose pliers to widen the tube-end while its warm and then slip it over the heat exchanger nipple asap. 
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Thanks for watching! On top of the parts list in the video description, I also left some other info not discussed in the video. This would not make sense for everyone to build. If this seems like it fits the bill for you then I hope this helps. Although this uses very low wattage by comparison to a conventional AC, in the long run the operational costs would be comparable. A regular A/C would run intermittently while this would run continuously. There are pros and cons to both situations so it comes down to personal choice. Also this will not cool the entire room noticeably for quite a while and the room would need to be sealed from other spaces (closed door etc.) If you have a larger room to cool and/or the room is not well insulated, then a larger chest freezer would work better. You would simply use the same amount of water as a smaller freezer, but a larger freezer has more wattage and surface area to cool the water. You can cool a room fast with a much larger heat exchanger/fan but you will quickly deplete the capacity of the system in just a few hours...I have tried.
In your case this is doing what you need it to but for other applications it makes more sense to allow the water to freeze (to some extent) keeping in mind that the evaporator coil will be installed hard against the inside casing for heat transfer so the ice will form on the walls first and slowly get thicker, on a domestic chest freezer I’d be very surprised if it was capable of making a solid block, virtually impossible as the ice really starts insulating to some extent. By doing this they would increase the stored capacity because you are no longer relying on just the sensible heat of water but also the latent heat capacity of the ice (which is maybe 10 x the sensible heat per kg).
I’ve considered doing this and using (or converting) a freezer that is 12 or 24V DC, that way you could run it during the day on solar panels and use the stored capacity in the evening when you get home.
I was thinking about getting a chest freezer and running it through my air hammer and my mobile home with a water pump. Fill the chest freezer up. with either a water, alcohol mixture or antifreeze to keep it from freezing then I can just circulate cold Water through the air to the house
You are genius
Very interesting idea
Wonder how this will do in az when the garage is 135°F and keeping the water cold. Would be interesting info.
very strange but, my chest freezer don't heat up the room its in, works like a champ
What if you put 12oz of 48 frozen bottles of water in the deep freezer with the freezer on, will it blow cooler air ?
Idk if I like this bc the heat output by the freezer in the basement ... (Which includes waste heat from the compressor motor, and any heat during a defrosting cycle, and all the heat transferred out of the bedroom at night) will just be heating up the rest of your house via the basement ceiling. Some of it even goes back up into heating your bedroom which costs you more energy.
If anything you should store the freezer outside so that you expend the exact same amount of energy keeping the water cold, but don't pump all that heat into your home in a time you probably want it to be cooler (summer).
Also , you didn't measure watthours used on your setup in the course of a fully 48 hrs or sk. I would think that a simple window air conditioner Will do a better job converting electrical energy into a cool and slightly dehumidified bedroom environment. Plus ... You can get them for like 1/5 the price of what you have there via aarage sale or fb market place. Hell even a brand new one for a size of that room is gonna be pretty cheap.
You do have the battery aspect going for you but I handle power outage just by having a cheap gasoline generator on standby. It gives us a way to charge up everything which even your system is going to require. Any AC works a lot faster than your system would though.
Here's an idea .. why not use a peltier cooler. You can pump the wasted energy into your hot water heater (or heated pool, hot tub?) , and cool down water for cooling your room at the sameeee time / no extra energy needed.
Pelts are very inefficient when it comes to watts per btu.
window ACs make to much noise