Chiller Options?

[xxjt2oxx]

Hey guys!

So I have my in wall 200g running now with a handful of fish, and lo and behold my upstairs AC stopped working throwing the whole house up a few degrees. Parts don’t come until Tuesday, so I guess it was a good time to learn that I’m going to have temp issues if the AC is off for an extended period of time.

It’s an acrylic tank built into the wall between 2 rooms, so I’d like to avoid anything that’s going to cause more evaporation.

That being said, my basement is cold. One of our hot water heaters is a heat pump, so it dumps the cold air back into the surrounding area, which is regularly around 55-60 degrees.

I can add a chiller and plumb it into the basement, but with the cold temps down there I would rather take advantage of that instead of adding another piece of equipment.

I have a few ideas, but wanted to throw the idea out here to see what everybody came up with before I planted a seed with the direction I thought to go in :)

 

[BeanAnimal]

The thermal loop may work, but it is going to take a lot of mass and surface area to do any meaningful heat removal from the tank to the basement. From there where does the heat go? If tank water is in the loop, it can’t stagnate, so control is harder. If freshwater or coolant is in the loop then you need two heat exchangers, one at the tank and one in the basement.

A phase change chiller adds more heat to the basement , but will be predictable and easy.

 

[xxjt2oxx]

The thermal loop may work, but it is going to take a lot of mass and surface area to do any meaningful heat removal from the tank to the basement. From there where does the heat go? If tank water is in the loop, it can’t stagnate, so control is harder. If freshwater or coolant is in the loop then you need two heat exchangers, one at the tank and one in the basement.

A phase change chiller adds more heat to the basement , but will be predictable and easy.

Any heat I dump in the basement will kind of take care of itself - the heat pump hot water heater dumps it's cold side into the surrounding area. There were moisture issues in the basement in the past, and I have a pair of mini splits that run as dehumidifiers which cool the area since the hot side is outside.

Originally I wanted to run a radiator in the basement ceiling below the tank, and control the pump/fan on it based on the tank temp. Coincidentally one of the mini splits is more or less under the tank so it's always cold right there. It seemed super simple, but finding a "reef safe" radiator didn't really seem plausible. My next thought was running a heat exchanger and using a 55 gallon drum I previously used for RODI down there to dump the hot side to. I didn't think about stagnation, but if I put the heat exchanger at the tank, I could circulate tank water 24/7, and control the cold side pump when I needed cooling.

I'm thinking about it now... the tank is in an enclosed wall, so I already have to vent the area to keep it from getting too humid. The basement ceiling under the tank is unfinished, I opened it up to reinforce everything before the tank went in and we haven't closed it back up yet. Maybe simplest solution is to just circulate air up and back down into the basement?

Luckily right now, I'm only 1 degree above my target temp and currently fish only since we just started stocking - there hasn't been any consequence but I want a safety net in case something goes wrong like the situation now.

 

[BeanAnimal]

Why not put a minisplit inthe fishroom and be done with it? Humidity and temp control all in one?

Fill a 55 gallon drum in the basement. Let it come to ambient. (you can measure temp on the way, as s second data point if wish). Heat it from ambient to 2 degrees above using an accurate thermometer. Time how long it takes to come back to ambient. That will be the heat shedding capacity per time that the setup can handle best case if the heat exchanger can keep up and the room stays at ambient.

Now do the same, but with the closed loop pump in the drum to simulate the heat imparted by it.