A fogger based misting + cooling system

A fogger based misting + cooling system

In the other thread on cooling planters, one thing led to another and @jtd suggested using foggers to create a fine mist. I have used foggers before, and the problem with them is that the mist barely moves, so there is hardly any cooling.

But that gave me the idea of using gravity to move the mist. Also one fogger won’t be enough for a balcony. And the water can’t be too high over the fogger, or it doesn’t work, so the water capacity of the fogger is very little and it keeps running out, which can’t do in a production system. There is also the additional issue of splattering of the water.

Finding solutions for all this, my idea is to create a fogging system at a height. About a foot or so below the ceiling. The overflowing mist will be pulled down by gravity and spread around a bit by ambient breeze. For my purposes, the breeze moving the mist is not a problem. The water will evaporate faster and provide better humidity and cooling, or condense on the plants, which don’t mind. A little may be wasted from being blown out of the balcony, but short of strong windy days, I don’t anticipate this being a big problem, since the mist will be sheltered from the outside by the plants themselves.

The design of the fogger will resemble a pipe based hydroponics setup, except instead of the pots, we have misters, and the water doesn’t drain out, it is evaporated out. The circular openings will reduce the splatter, while the expansion of water into vapour will increase air pressure forcing the mist out.

The problem of low water storage is solved in two ways. One, the long pipe will contain more water in the “allowed” height. This isn’t much, because there will also be many foggers there. Two, the end of the pipe will use a right angle turn up and a bottle with a diameter so that it fits upside down can fit into it with the mouth at the appropriate water level for our use. Material of the bottle should ideally be glass or something that is sturdy. A regular mineral water bottle will crush under air pressure and release the water.

Think of upending a 20 liter RO water can into the dispenser. Like that, but bottle upturned into the water intake. This is not automatic, but it will have to be refilled less often.

Alternatively, some clever electronics, a water level sensor operating a valve or pump can refill the system when the water level goes down.

Like so:

If this works well, it has the potential to replace the misting sytem for over half the year and will consume a fraction of the electricity. Unless it cools extremely well, the misting system is likely to be necessary still in high temperature/humidity conditions (it loses effectiveness too, but has to work at least minimally due to the sheer mechanics of the method).

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The level of water is easily controlled with the present design of aeroponic electronics. This was built to mist one tower i.e. one mister.
Your design requires multiple misters. Hence the design of driver for misters will change.
How many misters do you need ?

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Some other points I forgot to mention:

  • These foggers usually waste the water that is below their operating level. Due to the installation being in a pipe, the width is automatically narrower at the bottom, wasting less water.
  • More fancy minds could pour silicone into the fogger to cover the bottom, leaving neat sockets to push the foggers into, while wasting next to no water. Not me. I’d prefer to be able to take everything out easily to clean. And whoever has unmolded silicone knows getting it out of the pipe will be no fun. lol. But it can be done.
  • A mesh could be added to the holes allowing mist out easily, but reducing the splatter. This will decrease the working efficiency of the fogger as some mist will condense on the mesh.
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Will measure balcony in morning and come up with a realistic number for length of pipe as well as number of mister.

You are applying the water level sensor to each mister? Why? Water level will be mostly same (we install it like that) and we leave some margin for error. If one mister is in low water, they will all be in low water?

Or am I missing something?

There is one water inlet in this design. No matter how many sensors you add, they all will operate that one. Unless you are looking at separate inputs for water also? Then the pipe design is not so useful…

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Yes my towers are vertical. So one mister in one container sitting on top of one tower. Each tower has 30~40 grow holes.

However in a horizontal design a single sensor will do.

In a vertical tower one inlet per tower. With a motorized valve control for inlet. This allows for variable misting rates, leading to varying water consumption. There is provision for humidity sensor - implementation pending - which makes the system a closed loop.

I would fix the fogger at the bottom of the pipe on the outside. Zero waste.
Pipe levelling would need to be precise.
To reduce dependency on accurate levelling, a threaded coupler could be added to each hole. Fix the fogger on the coupler. The coupler will hold about 20ml of water, enough to last fifteen minutes AFTER the level has fallen to zero in the horizontal pipe, therfore allowing a less demanding levelling.


Got another idea. Maybe we are overthinking this. Could a gadget like this be useful? I think with even a single fogger, quite a bit of area could be covered.

Maybe we could just create one unit, and then, use more separate units as needed. I think something like this would make half my balcony quite happy.

The mist outlet MUST be pointing upwards, not just a horizontal out. That way, you can eliminate splatter altogether.

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An even simpler idea https://www.amazon.in/Zowam-Humidifier-Portable-Ultrasonic-Humidifying/dp/B07TJ49JSH/

Trust the chinese to come up with really useful, compact and cheap gadgets.

Though of course for my use it will have to be modified to include a water backup :smiley:

Thing is, this thing is MOST used in my set up when I have plants coming out of tissue culture. They have been growing in 100% humidity and have no protection against low humidity and will rapidly dessicate and die unless acclimatized slowly. Something like the aeroponics system not being able to go for long without fog.

For my use I cannot affford a humidifier running dry. I want a way to connect plenty of water to the damn thing.


What do you think of this, @jtd?

An alternative to using multiple units could be to fork the must outlet into two directions and place the unit in the middle of the area to be fogged.

Overhead tank can be replaced with the automatic watering you said for this use case.

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This is easy to do in a closed system. This is perfected by @jtd.

The misters need not be inside water. If we can use a submersible pump in a water tank, we can avoid the need for a overhead tank.

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Fogging downwards is much more effecient.

A similar system is used by Mushroom cultivators. Ultrasonic misters / humidifiers are kept near the ceiling and mist flows out continously keeping the room humid for effective mushroom cultivation. Uses fraction of water than traditional methods of cultivation in a room.

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