Hooking Up Emergency Chiller

[mogurnda]

My primary slug colony is in my office, which is usually a good place for it.  However, a few times a year, the facilities people shut off environmental controls, sometimes on purpose and sometimes by accident.  This almost always happens on weekends or holidays, which means I only catch it if I have to be in for some reason that day and find myself in a sweatbox at my desk.  

 

So far, I have not lost any livestock, but it is only a matter of time.  I got an excellent deal on a chiller from a fellow WAMAS member, and would like to hook it up in case of emergency.  It will be controlled by the AC Jr that currently runs things, and I will upgrade to an APEX once I convince IT that it's safe to allow my system to access the internet.  

 

Here is the question: how do I hook it up to minimize energy use during the 98% of the time the chiller is not needed?  Should I continually circulate water through it, and only have the chiller turn on when the temperature gets too hot?  Can I leave the feed pump off when the unit is not in use?  Does anyone else do this kind of thing?

 

 

[Origami]

Dave, the feed pump doesn't need to consume much energy since it's not doing much lifting. Keeping it running affords two things that I can think of: It keeps the lines primed and keeps them filled with oxygenated water (rather than having the water in lines go stagnant, possibly develop sulfides). I think that I used a Maxijet 600 or 900 on a chiller that I had on a nano a few years back. They operate on less than 10W, so they cost about a buck a month to operate.

[mogurnda]

Thanks, Tom.  I suppose you're right that leaving the feed on is smart.  I will probably just hook up a line from the return pump, so it should be even less than a maxijet.  

[Origami]

Thanks, Tom.  I suppose you're right that leaving the feed on is smart.  I will probably just hook up a line from the return pump, so it should be even less than a maxijet.  

I'm not sure if this is exactly true: If you're pumping from a sump, then there's more energy used than if you were pumping in a sort of closed-loop fashion where you don't have much head pressure to overcome. 

[mogurnda]

I'm not sure if this is exactly true: If you're pumping from a sump, then there's more energy used than if you were pumping in a sort of closed-loop fashion where you don't have much head pressure to overcome. 

I'm not sure if I understand this.  I will be pumping from the sump to the chiller either way, so what would be the difference?  To be clear, the system current has 3 tanks and a sump, with a 4th coming on-line soon, so chilling any single tank would not work.

[Origami]

I probably misunderstood you, too. You'll probably dump the water right back into the sump, so there is hardly any lift to overcome. I was picturing it going back into the tank up higher.

 

When I used a chiller on a nano, the maxi jet was in the back compartment of the tank. The exit for the plumbing was about an inch above the water in that compartment, so the maxi jet faced a head pressure of just an inch (and friction, of course). This meant that I could use a smaller pump and get close to full performance out of it.

 

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[mogurnda]

Your post made me rethink the plumbing.  Originally, it was going to loop into and out of the sump, but it seems wasteful to mostly be chilling the sump.  My current plan is to plumb it into the line that goes to the top two tanks, which then flows through one other tank to the sump.  That would deliver more cool water to the tanks that need it, but will add head pressure.  I think it's a good tradeoff.

[Origami]

Your post made me rethink the plumbing.  Originally, it was going to loop into and out of the sump, but it seems wasteful to mostly be chilling the sump.  My current plan is to plumb it into the line that goes to the top two tanks, which then flows through one other tank to the sump.  That would deliver more cool water to the tanks that need it, but will add head pressure.  I think it's a good tradeoff.

Since they're all interconnected, won't it all balance out due to circulation?

[mogurnda]

Since they're all interconnected, won't it all balance out due to circulation?

If I just loop through the sump, then some fraction of the cooled water will be sent back to the chiller.  If I send it to the tanks first, it all goes to where it's needed.  I am not really sure if it makes much of a difference.

[Origami]

If I just loop through the sump, then some fraction of the cooled water will be sent back to the chiller.  If I send it to the tanks first, it all goes to where it's needed.  I am not really sure if it makes much of a difference.

I can't imagine that it makes that much of a difference. It's still taking the same heat out of the system in both cases and, theoretically, at the same rate. So it should take about the same amount of energy and time. 

[mogurnda]

Thanks for the input Tom.  I can ponder while I wait for a few more fittings to arrive.

[Origami]

Pondering is good.... Enjoy.