Requesting information, suggestions, tips and whatnot…
I’m thinking something like this for nutrient temp control when i get around to building the RDWC system early in the new year. My current thoughts on setup are a 60 liter reservoir feeding two (possibly four, it depends on how big the plants get) 20 liter buckets.
My question is, would the temp controlled nutes pumped at 60-180 litres/hour (as per unit specs) be sufficient to keep the solution fresh? Or would i be better off trying to keep the entire res at the set temp and using a bigger pump?
Cool that you are thinking ahead on the components needed to build your system.
A couple of notes: This appears to be a thermoelectric chiller which are somewhat inefficient. What they are giving you for power also appears to be the power at the wall plug.
In refrigeration applications, thermoelectric junctions have about 1/4th the efficiency compared to conventional means (they offer around 10–15% efficiency of the ideal Carnot cycle refrigerator, compared with 40–60% achieved by conventional compression-cycle systems
This would equate to less the a quarter of the 180W as cooling. Or, <45W/hr of actual cooling capacity.
Which make this particular chiller appear a bit underpowered for ~40 gallon system. Of course, it really depends on a variety of factors including the temperature of the environment (with lights on), the desired temperature of the solution, and the time required to pull down the temperature.
I’m thinking it’s a little more suitable being rated at 400L a hour compared to the max 180L/hr thing above? Bear in mind i have no idea what 1/10 hp is compared to 180W o.O
Still throwing ideas around, and it helps. At this rate i might get a grow underway sometime this year lol
1/10 hp should be fine for a 60 L res.
are you planning on using a top off res w/float valve? 60 L, even between only 2 plants, will probably mean very frequent res changes once they get big. a top of res would mitigate that without having to go bigger than 1/10 hp on your chiller
I first got a hailea one (h150) and it was easy to use, relatively quiet, and worked so well I got another hailea one (h500) when I found I needed a larger one. My tank is less than 100l.
It is not so much the size of your rez that counts (although it still counts), more the number of lights putting power into that liquid which you need to remove and airflow.
The better insulated the tank (and buckets) and the fewer lights, the smaller the chiller you need. Conversely, if your system has more lights and more of that heat can enter your nutrient solution, the larger the chiller you will need.
You will also need to think about airflow.
If you pull heat from your solution then dump that heat right on top of your solution you will not lose heat overall from the system, the heat will just flow back into your solution and then you will have a vicious cycle of heating going on and your chiller will just not cope.
What you need to do is you pull cold air in from outside if possible which can refresh the air around your chiller then be exhausted somewhere. Barring this then put the output from your chiller so the exhaust fan from your room takes the heat away.
What you must make sure of is that the waste air does not get recirculated or it will just get too hot and then your chiller will be on 100% of the time and also unable to chill your solution. If this is the situation your solution can end up warmer than if you had no chiller.
I ended up drilling a couple of 22mm holes in the wall and putting the chiller on the other side of it. Keeps the kitchen comfy even in winter.
I have a 1/20th HP chiller so it is half that power. It is a Hailea. I have about 150 litres circulating in a RDWC system in a 4’ x 4’ tent. It has a 600W HPS and although i have no plants in it yet i can tell the chiller is not going to have a problem at all. You will be fine with 1/10th.
Thanks for the replies. I’m going to give it a try, the worse that happens is it’s not powerful enough and i have to talk she who must be obeyed into a upgrade
Now to negotiate with the current owner and get the price a bit lower, because i’m a cheapskate like that lol
One horsepower = 745 watts, so 1/10 hp = 75 watts.
This is an important consideration. If the chiller is inside the grow space, you’re just taking heat from the water and pumping it right back into the grow room - which means more heat in the grow room which means more heat in the water that needs to be removed.
Plus, these things are not 100% efficient, so your going to be putting even more heat into the room than you take out of the water.
Your water may end up cooler, but your grow space will be hotter. You need to plan for that or do the things @MicroDoser suggested to handle that excess heat.
