metal halides and heat

[BeanAnimal]

The other thing that would be helpful would be to measure how long to takes the tank to go from say 78F to 80F.

If we know the tank volume and the temperature rise and time, we can figure out how many BTUs of cooling (chiller) would actually be needed.

You indicate 500 gallons total.
Let's call it 4500 pounds of water for ease of calculation.

If it take 2 hours for that 4500 pounds of water to raise 1F - then we need to combat ~2250 BTUs/h of heat.
That is roughly 1/5 of a horsepower.

Likewise if it take 1 hour, then that is closer to 1/2 horsepower.

Again - this is calculated "worst case" "worst day of year".

The goal of the chiller may not be to keep the system at ideal steady state (77F let's say) where during an 8 hour photo period it rises 10F above ambient, but rather just keep the swing between 77 and 80 and kick in to prevent 80 from going to 81 or 82, etc.

 

[Troylee]

For what it’s worth out here in Vegas I’ve seen garage setups with chest freezers used as a chiller.. they set it up with a hundred feet or so of tubing and have a pump, pushing it through the coil in the freezer! Much cheaper on the electricity bill and works good without putting off a lot of heat. It’s currently 114° out here today

 

[zheka757]

The other thing that would be helpful would be to measure how long to takes the tank to go from say 78F to 80F.

If we know the tank volume and the temperature rise and time, we can figure out how many BTUs of cooling (chiller) would actually be needed.

You indicate 500 gallons total.
Let's call it 4500 pounds of water for ease of calculation.

If it take 2 hours for that 4500 pounds of water to raise 1F - then we need to combat ~2250 BTUs/h of heat.
That is roughly 1/5 of a horsepower.

Likewise if it take 1 hour, then that is closer to 1/2 horsepower.

Again - this is calculated "worst case" "worst day of year".

The goal of the chiller may not be to keep the system at ideal steady state (77F let's say) where during an 8 hour photo period it rises 10F above ambient, but rather just keep the swing between 77 and 80 and kick in to prevent 80 from going to 81 or 82, etc.

Man, God bless your brain. I guess there is equation for everything. Lol I'm pretty sure I messed it all up already by shifting my photo period and less per day, right now I only run for 6 hours of metal helides l, and they turn off at 3p.m. before I would have them run for 9 hours and turn of at 7p.m.
Right now my tank temp is around 80.5F before lights on, and by noon it will be 82F. Also add to that equation, I leave my a/c at 75 during the day. And 72 during the night. I set it back to 75 just before I go to work.
But fixing water temp will be just that, fixing water temp only. I still have lights that produce alot of heat that put alot of strain on my house A/c

 

[zheka757]

For what it’s worth out here in Vegas I’ve seen garage setups with chest freezers used as a chiller.. they set it up with a hundred feet or so of tubing and have a pump, pushing it through the coil in the freezer! Much cheaper on the electricity bill and works good without putting off a lot of heat. It’s currently 114° out here today

Hey man, that's a great idea! You got me thinking now....

 

[BeanAnimal]

For what it’s worth out here in Vegas I’ve seen garage setups with chest freezers used as a chiller.. they set it up with a hundred feet or so of tubing and have a pump, pushing it through the coil in the freezer! Much cheaper on the electricity bill and works good without putting off a lot of heat. It’s currently 114° out here today

I would argue that is far less efficient than an inline chiller and in fact most freezers (chest or upright) have extremely small compressors in the 500-1500 BTU range. They are not designed for rapid BTU removal and make up for it in insulation and being used to STORE foodstuffs. The reason that a steak or other item placed INTO the freezer, freezes so fast is because of the already frozen thermal mass around it.

For an aquarium, this means having enough thermal mass to cool the water during the "hot" time and then enough time and compressor size to RE FREEZE that mass during the OFF time.

Where this makes sense. If you have an obscene amount of heat to deal with in a short period (say 4 hours) and the other 20 hours can be used for the small compressor to rechill the thermal sink. You lose some efficiency but spread the current draw out of 24 hours instead of point load it into 4 hours. So you have a smaller circuit where you trade efficiency and space. You are basically offsetting the power usage from a 4 hour block to a 24 hour block by means of thermal mass.

 

[Troylee]

I would argue that is far less efficient than an inline chiller and in fact most freezers (chest or upright) have extremely small compressors in the 500-1500 BTU range. They are not designed for rapid BTU removal and make up for it in insulation and being used to STORE foodstuffs. The reason that a steak or other item placed INTO the freezer, freezes so fast is because of the already frozen thermal mass around it.

For an aquarium, this means having enough thermal mass to cool the water during the "hot" time and then enough time and compressor size to RE FREEZE that mass during the OFF time.

Where this makes sense. If you have an obscene amount of heat to deal with in a short period (say 4 hours) and the other 20 hours can be used for the small compressor to rechill the thermal sink. You lose some efficiency but spread the current draw out of 24 hours instead of point load it into 4 hours. So you have a smaller circuit where you trade efficiency and space. You are basically offsetting the power usage from a 4 hour block to a 24 hour block by means of thermal mass.

I never said it was sufficient I just know it works! It’s runs a lot less than a chiller out here in a garage where it’s 120 degrees or better.. typical electricity bill out here right now is $600+ I went solar and I only pay $13 a month so far lol.. I keep my ac at 73° so my halides aren’t a problem ..

 

[BeanAnimal]

I am sure it would work in some situations but the capacity is still rather small. Better than a useless dorm fridge for sure.

The real benefit compared to a traditional aquarium chiller is moving the heat out of the house instead of dumping it back into the room.

 

[Troylee]

I am sure it would work in some situations but the capacity is still rather small. Better than a useless dorm fridge for sure.

The real benefit compared to a traditional aquarium chiller is moving the heat out of the house instead of dumping it back into the room.

Very true!