Using a dehumidifier as a water chiller

I thought I give this a shot and see what happened.

Basically all you do is move the cooling coil that collects moisture, carefully bend it into your reserv or whatever you want to do.

I did it so it functions like an actual chiller and is easy to move. I bent the cooling coil into the water collection bucket and drilled supply and return lines into the collection bucket.

I took photos of most of the steps.

So in this photo is a LG 570w dehumidifier. All the outer casing have been removed (just removing screws). You can see the front coil is bent down, it originally is flush against the top coil.





Now in order for the coil to fit into the collection bucket, I had to do a lot of trimming of small plastic fins inside the bucket





And whatever dehumidifier you choose, there will be some sort of switch to tell it when the bucket is full and to turn off. Splice the wires together if it is a standard float switch.

I added supply and return ports to the control bucket. Supply is 1/2" and the return is 1" once I cut the end off like seen in the next photos



Here I have it setup up to demonstrate it does chill the water. You can see I cut off the end of the return line to make it 1" and I have a pump supplying water.



I started with hot water..100F and turned the power on.



after running for 6 mins...38.8F..it would have froze the water if I left it on



So by comparing numbers to real water chillers...this setup should have the cooling capacity of a 1/4hp 480w real water chiller that cost $600+

The only thing I will need is a relay controlled thermostat that the dehumidy plugs into so I can accurately control the water temperature.

Something like this:
http://www.ebay.com/itm/Titan-Contr...night-thermostat-fan-controller-/261298261997

http://www.ebay.com/itm/CAP-TMP-1-C...troller-hydroponics-temp-sensor-/200933814717

Great idea!
I wonder if I can use the 2 Deh's that I have that were recalled.

Do you use any of the Deh's digital components?

very cool man.......lol

Been doing this with window AC for years 100 bucks for a 1/2 ton chiller! You need to ph the water to around 8 to minimize corrosion.
After 1 year of constant use with this unit.


I added this coaxial heat exchanger



and ended up with this:



They work great.

Also, you don't want to power down your chiller to control temp. You need to attach your thermostat relay to the same wires that are connected to the humidistat. Then your compressor will cycle but the fans will not.

budleydoright said:

Been doing this with window AC for years 100 bucks for a 1/2 ton chiller! You need to ph the water to around 8 to minimize corrosion.
After 1 year of constant use with this unit.

[URL=https://www.icmag.com/ic/picture.php?albumid=20521&pictureid=427094&thumb=1]View Image[/URL]
I added this coaxial heat exchanger

[URL=https://www.icmag.com/ic/picture.php?albumid=20521&pictureid=797405&thumb=1]View Image[/URL]

and ended up with this:

[URL=https://www.icmag.com/ic/picture.php?albumid=20521&pictureid=797404&thumb=1]View Image[/URL]

They work great.

Also, you don't want to power down your chiller to control temp. You need to attach your thermostat relay to the same wires that are connected to the humidistat. Then your compressor will cycle but the fans will not.

Click to expand...

Okay you have to tell me about that coaxial heat exchanger. How did you hook it up? I dont understand. Did you remove the freon and attach all the lines? It looks good, I am very interested how you did that. It looks like you put a schrader valve on the condensation line.

And what do you mean you have to pH the water? The coil sits in the reserv solution, it has to remain in the optimal plant range.

I dont have the resources to remove freon and refill it. So I am going to use the control bucket as a control bucket filled with anti freeze/water. I own a aluminum heat ex-changer so I figure ill drop that in my hydro reserv and pump cooled antifreeze through it from the dehumidy control bucket.

That should work and keep the reserv solution off the evap coil of the dehumidifier.

I dont understand how to hook up a thermostat to the hydrostat or whatever so I figure ill just have the pump controlled by the CAP thermostat outlet and let the dehumidy do its thing.

Damn though, I dig the coaxial heat exchanger. Cant wait to hear how you did it. What you have made is a legit water chiller.

It does require a cut in and freon charge. I have a buddy that's a jack of all trades that did the job for me. Coaxial evaporator was under 100 dollars. I'm thinking about getting a 4 ton AC condensor and making a BIG one.

The water that is touching the heat exchanger should be neutral ph. Of course glycol helps too. You idea is perfect. I like the way you used the water bucket! Great job.

you should make some into a product to sale. you know how many people could use one of those at a good cost. Chillers cost 700- 1000$ for a 1/2 hp. Nice DIY project

Nice, this is something I google once every few months to see if anyone's done something new. How's that specific dehumidifer working out for you in terms of recovering from power off? I wouldn't want to control the humidistat or whatever either without some sort of clear guide (though I can solder and whatnot) but I'd much rather kill the power to it. Only problem would be having it start back up. Most of the DIYs on this sort of thing suggest finding an older dehumidifier that doesn't have digital controls.

I like your setup a lot though, seems easily expandable should you wish to expand the reservoir. Set up a larger insulated water bin a few feet above the dehumidifer and drill a hole in bottom, setting up a stand pipe a few inches from the top. That way if the power fails to the pump then the water from upper reservoir will only flow in to the small built in reservoir until it hits the bottom of that pipe, preventing overflowing. Adding some ball valves on the inlet, output, and upper reservoir stand pipe would allow you to disassemble everything and relocate it to another spot pretty easily. From what I understand, bigger reservoir = less ons/offs.

Care to post a model number of your unit? Would love to replicate this to a T. Also, if you use a wort chiller like you were saying, to separate your nutes from the water, you could definitely run antifreeze (which already boasts anticorrosion properties) but add in a little bottle of Subaru coolant conditioner which many swear by to help even more (in engines at least). I'd love to go water cooled in my new spot, even if air conditioning is potentially cheaper. Could have a chiller 50 feet away from the grow spot and spend $20 on two garden hoses, giving you more flexibility on where the chiller goes.

Well I am glad people are digging this idea. The thing about opening up a dehumidifier is it is so easy. I can post model numbers later after I check it out.

On mine I have a hydrostat and I also have some sort of device (which I believe measures temp) attached to to the condensation coil. I have no idea if I'm correct in thinking so but it only has two leads which could easily bit spliced and extended. I'm unsure what role it plays in keeping the dehumidy turned on but it for sure does something.


All in all though it will only take time to figure it out. The wiring is easy enough, it will just take time to figure out what does what.

A fluke meter would be great.

Still so jealous of the coaxial heat exchanger.


And as far as recovering from power off...right on the front of my LG dehumidy, it says "auto restart" so it cycles the condenser if power is killed. It takes a good 3-5 mins to start working again.

I just found this ad on Craigslist. Look for someone like this!




STARVING HVAC Contractor



License info: XXXXXXXX

I have 5 children and have recently run out of work. My rates are excellent! Please call or text scott at 505-236-3249. Plumbing, hvac and electrical. Quality work. Thank you.

budleydoright said:

I just found this ad on Craigslist. Look for someone like this!




STARVING HVAC Contractor



License info: XXXXXXXX

I have 5 children and have recently run out of work. My rates are excellent! Please call or text scott at 505-236-3249. Plumbing, hvac and electrical. Quality work. Thank you.

Click to expand...

This is excellent. We are kicking around some great ideas in here. I have a brand new A/C I bought last year that I already drained of freon.

I broke a line on it trying to bend the condenser coil and all the freon was released. Sorry earth..........

anyway.......

its brand new, and I kept it for parts thinking I could use the coiling on it for something garden related. I imagine a HVAC guy could solder a schrader valve on and attach a fancy coaxial coil to it in place of the condenser coil.

The only thing I see being the problem is the cost. If it can be done for less then 100 bucks then sure, but any more then that one would have to consider the price of an actual chiller.


So before I consider that route, let me ask a some questions.

Would it be a bad idea if the cooling coil come in direct contact with reserv water? Would heavy corrosion happen? Great heat transfer would be attained with this method but what are the consequences?

Secondly,

How cold does a fluid have to be in order to cool a room? I know it comes down to thermodynamics and given temps and desired temps.

So scenario....its 95 degrees, I want to cool down to 75 degrees. How cold does a liquid need to be traveling through a heat ex changer in that given room to have a cooling effect?

I am really starting to like the idea of a separate cooling reserve with different heat exchanges running off of it. One for the nutrients reserv. and the other mounted in the room with a fan attached to it.

One would kill two birds with one stone by not needing separate cooling devices for the room and nutrient reserv.

The cooling reserv would have to be insulated to avoid condensation I imagine.

You know how rubbermaid containers stack together? You get that pocket of air and gap between the containers when stacked....well you think two stacked together would intern work as a insulating barrier for the cooling reserv?

Green house do it to retain heat/cool by making a dual layer plastic cover around the greenhouse. Same concept I suppose?

Sorry if I am rambling, Im just spitting my ideas out. I have grown quite obsessed with this. Running to home depot now to buy some parts.


(are you ever in a hardware store and notice people with weird shit and think its for a grow room? lol ..like some young hipster punks buying a whole shit load of unusual PVC parts. Or some average joe like myself buying 10 big containers...umm Geewiz, that guy must really need to store some stuff)

I have seen people use Mini freezers/frig. They drill 2 holes in the back of freezer. install 2 compression bulkhead fittings..In side the freezer put 100' of 1/4" tubing attached to the 2 bulkhead fittings one is for water in the other water out. Set the temp to what ever install tubing on the outside on both fittings. put a small pump in your rez attach to tubing. Put the other end in the rez done. Now just test and adjust temp on the freezer/fridge to get the temp stable.

I rewired the dehumidy.

The air conditioner I have that none longer works, I basically took its controls and wired them up on the dehumidy...

was quite easy because the a/c unit has a wiring diagram on it and the small capacitor in both units are the same with all the same wire colors.

It was a matter of unpluging the dihumidy controls and plugging in the a/c controls and following the wire diagram. Now I have a fully functioning thermostat on my demunidy with a simple on off switch just like on a a/c unit.

Ill post pics later.

The evap coil from the a/c also has a shroud and fan attached to it. I figure I can use that has a heat exchanger inside the bloom area and use it just like a hydro innovations ice box.

You can also use heater cores from autozone. Here's one on the back of an Lg dehuey. 30 bucks If I recall correctly.



You will need the larger diameter tubing for water. This worked really well but I needed an additional fan on that isn't installed in this photo.

Bennyweed1 said:

This is excellent. We are kicking around some great ideas in here. I have a brand new A/C I bought last year that I already drained of freon.

I broke a line on it trying to bend the condenser coil and all the freon was released. Sorry earth..........

anyway.......

its brand new, and I kept it for parts thinking I could use the coiling on it for something garden related. I imagine a HVAC guy could solder a schrader valve on and attach a fancy coaxial coil to it in place of the condenser coil.

The only thing I see being the problem is the cost. If it can be done for less then 100 bucks then sure, but any more then that one would have to consider the price of an actual chiller.

Click to expand...

You will pay around that for the coil and at least that for installation. Keep in mind this is a full 1/2 horsepower chiller that is made for constant duty, many small reef units are not for a constant load.

So before I consider that route, let me ask a some questions.

Would it be a bad idea if the cooling coil come in direct contact with reserv water? Would heavy corrosion happen? Great heat transfer would be attained with this method but what are the consequences?

Click to expand...

Yes, copper and mineral salts = plant death. I do have a coil that is made for saltwater (supronickle) but there's no guarantee from the manufacture that it won't leach.

Secondly,

How cold does a fluid have to be in order to cool a room? I know it comes down to thermodynamics and given temps and desired temps.

So scenario....its 95 degrees, I want to cool down to 75 degrees. How cold does a liquid need to be traveling through a heat ex changer in that given room to have a cooling effect?

Click to expand...

I believe the number is 10 degrees below the desired room temp. minimum. Not sure on this though. You do need to be below the dew point to acheive dehumidification.

I am really starting to like the idea of a separate cooling reserve with different heat exchanges running off of it. One for the nutrients reserv. and the other mounted in the room with a fan attached to it.

One would kill two birds with one stone by not needing separate cooling devices for the room and nutrient reserv.

The cooling reserv would have to be insulated to avoid condensation I imagine.

Click to expand...

Do your homework, it can be more expensive and higher maintenence.

You know how rubbermaid containers stack together? You get that pocket of air and gap between the containers when stacked....well you think two stacked together would intern work as a insulating barrier for the cooling reserv?

Click to expand...

You could even put some insulation between them. I built this box, foam lined it and then used a pond liner in it.

Green house do it to retain heat/cool by making a dual layer plastic cover around the greenhouse. Same concept I suppose?

Sorry if I am rambling, Im just spitting my ideas out. I have grown quite obsessed with this. Running to home depot now to buy some parts.


(are you ever in a hardware store and notice people with weird shit and think its for a grow room? lol ..like some young hipster punks buying a whole shit load of unusual PVC parts. Or some average joe like myself buying 10 big containers...umm Geewiz, that guy must really need to store some stuff)

Click to expand...

Click to expand...

Saw two guys buying a cart full of contractor trash bags and another cart of duct tape at lowes just today! At least 100 rolls.

I finally got some free time and finished my little project.

All I did was swap the controls from a new window a/c I had into the dehumidy. I needed a thermostat, not a hydrostat. It was rather easy considering everything between the two used the same capacitor, compressor, and fan. I would imagine they are probably built in the same factory in china.

Anyway.....I tried to take as many pics as I could. Here is what I did.

Here is the window A/C I took apart and used the controls out of



And conveniently it has the warning diagram for its control on a inside panel



Hard to tell what is going on here but this is the dehumidy with the A/C controls all wired in. The bored in the back is completely dead, nothing is going to it...that was for the digital hydrostat controls of the dehumidy.



With the dehumidy mostly buttoned back up and the thermostat wired in with the probe in the cooling tank

And the finished product being test run.



I bought this aluminum heat exchanger about 2 years ago for a liquid cooling project I never completed. It now works perfectly for this.

This is a test run with about 28 gallons of water heated up to 119f





Basically a pump in the cooling tank pumps through the heat exchanger which I will have in my hydro reserv. A closed loop system so my nutrients come in contact with no copper....and aluminum exchnager is very none corrosive.



After 28 mins of running..it brought the 119f water down to 50.9f

water chiller

water chiller

good info
freezer water chillers do work, i chill 150 gal. 3 rez to 70 deg
BUT pumping through 100 ft 1/2 tubing can be a challenge
pumps are big and heat rez to some degree, air in the system will cause problems also,
I have 2 12000 BTU window type A/C units to cool a 12 x 36 room. 12 1000 w lights, air cooled hoods vented from and to outside works ok also BUT
I want the best of both worlds cool water and air, SO i have been looking into walkin coolers, like they use in stores to cool beer and soda
I find them on CL all the time for 750 t0 1000 $ for the mechanicals NOT the insulated box
These things. as I understand it are basic compressor and condensor
mounted out of doors 220 volt,
evaporator-s 120 volt mounted inside 1, 2 3 evaporators with fans are mounted anywhere you want, so add a water chiller onto one of the evap-s thermostats for room and water .... imagine...
has anyone tried this or something similar, commercial equipment repourposed for grow rooms seems to me that the cost of mini-splits
and a water chiller are about twice the cost of what I am suggesting