Water Chillers and Hydroponics
 

I am curious.. does any one keep their nutrients chilled?

The argument in my brain is that roots grow in soil and it is cool.

I have an opportunity to pursue somenew thermodynamic technology to develop a small solar powered water chiller.. something that would keep a 50 gallon drum maybe 30 degrees below ambient.. cost is TBD but I was thinking of targeting 400$. Does this sound useful to anyone?

Such a device could possibly be a game changer in outdoor hydro???

Thanks if you can share any experience with chillers.

Peace

Hello shillamus,
yes nutrient water temperature is very important. I wrote this article on the subject, Nutrient Solution Temperature is Important. Solar is nice but not that reliable, at least not without a battery bank back up, and most people don't need a solar water chiller either. There are already many water and fish tank chillers on the market at your $400 target, or even under that. Not only is $400 to cool a 50 gallon reservoir simply to expensive for most people, but it's not cost effective either. If you could get that cost down to under $100, as well as be able to cool multiple reservoirs with it, and using no more electricity than current water chillers, it might justify the cost.

Yeah my 400$ is high
 

Thanks G. I need to research the market more. There is some exciting new technology called electrochemical compressors.. a fuel cell that you apply voltage to make a thermodynamic process by using contained hydrogen. Uses 30% less energy than traditional hvac equipment. I think it can be miniaturized to an economical package.

Yes. I agree the price needs to be under 100$.. But getting 50 gallons and multiple reservoirs is a challenge. My system is 18 gallons so I am going to target 20 gallons systems first.

I dream of a stand alone grid free cost effective modular hydroponic system. I do believe that people will have to start supplementing nourishment with homegrown farms more and more in the future. Not to mention there is the yuge cannabis craze to cash in on right now. The folks that made shovels made the most money in the gold rush.

Do you chill outdoor systems? Do you insulate the reservoirs? Can you provide an example of a chiller you use? Do you use any passive cooling from the earth?

Thanks GPS.. You are big help.

Hello shillamus,
Sounds interesting, but lower energy bills are only part of being cost effective. The cost of the parts and equipment is a big factor as well. If it takes more than 2-3 grow cycles to break even in cost to buy and run, it's not really cost effective. In other words if it's going to cost you more to grow yourself than it does to buy at the store it's not cost effective. If your going to spend $400 to grow some tomato plants, you better get more than $400 worth of tomatoes from them in the first couple of grow cycles. If not it's not cost effective.

One thing you should keep in mind is that the size of the reservoir (number of gallons) isn't going to play a big part. Temperature differential and BTU capability is. What I mean by that is it's not the number of gallons the reservoir is, it's how much heat you need to remove from it. What works for one guy in AZ (where I live) to cool a 20 gallon reservoir, may also work for someone in Oregon with a 100 gallon reservoir. Why, because here in AZ the day and night time temperatures are much higher and it takes a lot more heat exchange to accomplish the same thing. One person may have a larger reservoir but not need to cool it as much as someone with a smaller one but needs to cool it a lot more.

If I plan to grow during the summer months, then yes I plan out how I'm going to cool the nutrient solution before I even start growing. I learned the hard way how important the water temp is the very first year I grew hydroponically. Winter months (Nov, Dec, and Jan) I need fish tank heaters to keep the water from getting to cold. During fall (late Sept to early Nov) and spring (Feb and March) I don't have too much issue with water temps. but summer months (April through September) the water temps will get to high If I don't account for it.

Yes, absolutely. Insulation is the single best method to not only preventing heat transfer (the water from heating up, and/or staying cool longer). But it's also the cheapest in cost to do, and cost nothing in electricity to work. I use Styrofoam sheets, bubble wrap insulation, rolled foam, and even pipe insulation on water feed and return lines and the tubing.

If you read the article I wrote and posted earlier, I have listed every method I know of on how to cool the nutrient solution, as well as went into detail about them.

I focus on being cost effective and prefer to stay away from costly and complicated cooling methods. I rely mostly on geothermal energy methods for larger reservoirs (in ground reservoirs and cooling coils). Smaller reservoirs I can usually get away with using insulation and ice. I even used a small (2-3 gallon) Ice chest I found in the trash as a reservoir for a small water culture system that worked great even in direct sunlight and in 110 degree heat. I just added 8-16 ounces of ice every night and the water stayed cold all day long.

I do have plans to build a reverse swamp cooler to use as a water chiller, but haven't gotten around to it yet. It sounds complicated, but it's not and uses very little electricity (pennies a day). The best part about the reverse swamp cooler in it can also be used for multiple reservoirs at the same time. I can make you drawings if your interested in building one.

I assume you mean Geothermal energy, and as I mentioned that is the main method I use for larger reservoirs. In ground reservoir's and cooling coils.

P.S.
There is one cooling method I tried years ago that didn't work the way I did it, but think it will work if I can work out details of the design. That is using liquid nitrogen. I had poured it directly into the reservoir, but it floated on top and all evaporated before cooling the water even one degree. However if you could pump it through metal coils you could get heat transfer without it evaporating. The main issue is being able to find a pump to pump it without freezing up, or at least finding a way to get it to circulate through the coils. You also need a pressure gauge and automatic pressure relief valve for safety. While liquid nitrogen isn't expensive, how long it lasts would determined if using it would be cost effective or not. But the build was more complicated and costly than I wanted to deal with for experimenting.

Thanks G!
 

I will have to find that article you wrote.. do you have a link?

Hello shillamus,
I posted the link to the article in the my first post in this thread. I did have to edit the post because of the automatic "advertising linking" this forum uses. It automatically links certain words the first time their used in a post even if the word is part of a link. When it does that it overrides the intended link. To fix it you'll notice I had to use the word "nutrients" before the link in the post because the word nutrients was part of the link. So by using the word nutrients before the title of the article, I let the a automatic "advertising linking" target the word it wants to without affecting the article link. But here is the link to the article again Nutrient Solution Temperature is Important.

Thanks for getting me there so fast G!.. Reading with much interest...

great article GPS.. Thank you

Shillamus, this one might fit the bill for what you are looking for: http://www.htgsupply.com/products/ac...n-unit-1-10-hp

Your system may push the limits of this chiller to the max, but it is an under $400 solution that could work.

If you can fork out a little more cash this Elemental H20 Chiller is a much higher capacity and would be better for your system: http://www.htgsupply.com/products/el...chiller-1-4-hp

If you want to get into cooling a reservoir, the cheapest way is to bury the container in the ground or at least partly. If you're looking to cool a outdoor reservoir outside, you simply need to coat the outside of the container with a hydrophyllic material, and have a simple soaking mechanism to saturate the material with water.Then just let evaporation do the cooling. Another way is to have a pipe coil inside your reservoir hooked up to a water tap. Then use a solenoid valve that is triggered by a thermostat. As the water runs through the coil, the tank is cooled. The waste water can be run onto trees or to water the grass. These are all cheap solutions.

wouldn't a mini fridge work? if you cut holes in the door inlet/outlet put a coil of copper pipe inside it, that should work imo, the dorm size are cheap.

If you had a container of water that the copper pipe sits in inside the fridge, the cooling affect would be improved. Adjust the water height for more or less cooling.