how to make aquarium chiller ?

[ame]

hello
i am an aquarium hobbyist facing a problem of overheating of my aquarium water from two heat sources.1 the climate in tropical india (mumbai) is warm and in summers we have 32 C and above room temperature. 2. the heat generated by metal halide lighting for my aquarium.( to grow aquatic plants)
i need to keep my aquarium temp at 24 C and the volume of water is 400 litres approx.
i request members to guide me in building a chiller to serve my cooling requirements.
please share your expertise to help me.
thanks
ame

[frank]

hello
i am an aquarium hobbyist facing a problem of overheating of my aquarium water from two heat sources.1 the climate in tropical india (mumbai) is warm and in summers we have 32 C and above room temperature. 2. the heat generated by metal halide lighting for my aquarium.( to grow aquatic plants)
i need to keep my aquarium temp at 24 C and the volume of water is 400 litres approx.
i request members to guide me in building a chiller to serve my cooling requirements.
please share your expertise to help me.
thanks
ame

Would it make more sense to maintain the room at 24C with air conditioning so that both the occupants and the fish tank benefit?

[NoNickName]

Would it make more sense to maintain the room at 24C with air conditioning so that both the occupants and the fish tank benefit?

I don't think so. Keeping an aquarium cool would require few dozens of watts, keep an entire room cool would take some hundreds of them.

I would suggest a ventilated peltier cell glued onto one of the glasses. You will be able to keep the aquarium cool with 50 to 200watts with a DC power supply (depending on the size of aquarium.

[star882]

How low is the wet bulb temperature? If it's low enough, you could make an evaporative cooler. Use some copper tubing in the fish tank as a heat exchanger. Connect one end to a water pump in a water bin, and make the other end drip on an evaporative pad above the bin. Use a fan to blow air through the pad, cooling it down.

[Lc_shi]

India is humid area,evaporative cooler is not enough. Electric(peltier) cooling is the first choice.

[Ian_Eb]

Is the tank a marine or fresh water one?

If it is marine, then you will not be able to use copper or aluminium in direct contact with the aquarium water, as it dissolves into the water and will kill the fish. I would be equally careful with freshwater as well.

I believe the commercial units cool a water bath of some sort and then pass the tank water through the cooled water in plastic piping.

This kind of thing i guess. http://www.aqua-medic.de/seawater/en/8/skline/

[Temprite]

Is the tank a marine or fresh water one?

If it is marine, then you will not be able to use copper or aluminium in direct contact with the aquarium water, as it dissolves into the water and will kill the fish. I would be equally careful with freshwater as well.

This is absolutely correct.

I have worked on cooling systems for crayfish tanks before and saw three kinds of evaporators.

1.Titanium chiller heat exchanger vessel.

2.Direct expansion. Titanium tube is placed directly into tank.

3.Copper tube inside a plastic tube with oil poured inside plastic tube.The whole assembly lays on the floor and can be covered with rocks.The down fall of this is the amount of tube that has to be ran.

Regards.

[ame]

hello
thanks guys for all your inputs.first i will give you the details of my setup.
i have a planted (not marine) aquarium of around 400 litres water.my room temp in summer is around 32C,plus the heat added by high wattage of lights above the tank.i would like to have a temp of 24C in the tank.
this is the setup i have planned.i want to build a PHASE CHANGE CHILLER with a 1/2 HP compressor,condensor,fan,and evaporator.
ideally i would like to use titanium tubes for evaporator and flow the aquarium water directly over these tubes.
but i am not getting it here.so i chose aluminium tubes for the evaporator.but aluminium hydroxide too dissolves in fresh water so bare aluminium tubes are ruled out.
from your replies i came to know 1.plastic coating of tubes.and 2. copper tubes cooling oil in plastic tube.
please help me by giving more detailed description of both.
in the first case how do i coat the plastic on the tube?
what grade of plastic is suitable and where do you generally get it? how would the plastic affect heat transfer?
in the second option the oil is what worries me.in case the oil leaks then aquarium will be affected.also what oil is generally used for this purpose?
thanks again to you all.
ame

[ame]

dear friends
let the ideas start pouring.i am waiting for your replies to start work.
thanks
ame

[phil68]

How about a plate-type heat exchanger as made by SWEP for the evap. & an aircooled condensing unit. Fully-stainless construction, compact & no problems with contamination to the fish. I'd use a small water pump & attatch the thermostat phial or controller probe to the inlet of the heat exchanger. Just make sure you have good water connections or you may wake up one day to find the water from the tank all over the floor

[Temprite]

hello
thanks guys for all your inputs.first i will give you the details of my setup.
i have a planted (not marine) aquarium of around 400 litres water.my room temp in summer is around 32C,plus the heat added by high wattage of lights above the tank.i would like to have a temp of 24C in the tank.
this is the setup i have planned.i want to build a PHASE CHANGE CHILLER with a 1/2 HP compressor,condensor,fan,and evaporator.
ideally i would like to use titanium tubes for evaporator and flow the aquarium water directly over these tubes.
but i am not getting it here.so i chose aluminium tubes for the evaporator.but aluminium hydroxide too dissolves in fresh water so bare aluminium tubes are ruled out.
from your replies i came to know 1.plastic coating of tubes.and 2. copper tubes cooling oil in plastic tube.
please help me by giving more detailed description of both.
in the first case how do i coat the plastic on the tube?
what grade of plastic is suitable and where do you generally get it? how would the plastic affect heat transfer?
in the second option the oil is what worries me.in case the oil leaks then aquarium will be affected.also what oil is generally used for this purpose?
thanks again to you all.
ame

The copper tube was 1/2" from memory threaded through some plastic tube similar to what you would use for an underground sprinkler system approx 1".

Vegatable oil was used.

I will try and find more info.

[ame]

hello
guys if the evaporator coils (aluminium ) is covered with a tubing of silicone rubber, then how will the cooling be affected?
i understand the time for cooling will increase but any other issues?
i have no experience in refrigeration so please help.
thanks
ame

[Carlo Hansen]

Hi Ame

I like people who does the thing themself, but i got a link
you should see, it solves your problem for a low cost.

http://www.aquastealth.com/index.asp...ProdID=93&HS=1

Best regards
Carlo Hansen

[ame]

dear carlo hansen
thanks for your input.yes i want to make the unit myself .so i am still looking out for ways to solve the material choice for evaporator tubing .
hope to find a solution soon.
thanks

[romaurie]

I have built quite a few aquarium chillers using "plastic heat shrink" to cover the copper tube. For a 300 liter tank I used a AEZ 4440 comp. [1\3HP] with sized capilliary and 11 meters of 3/8 " copper tubing. The heat shrink is slid over the copper before bending. A small heat gun or low flame can be used to shrink the plastic. The heat shrink is usually available in electrical supply companies. My coil sits in a plastic tub under the aquarium.The water is circulated by pump returning thru a 17liter bio-filter and thru a mechanical filter [ferelon fiber] before returning to the reservoir containing the cooling coil. After 8 years of use the heat shrink showed no signs of degeneration. This system is also safe for marine aquariums.
See "youtube"- "Romaurie-Effect" for a video clip of the set-up.
Romaurie

[krazatchu]

Heat shrink tubing sounds like a great option...

Another option would be to paint/coat the copper tubes with low viscosity epoxy. There are also specific grades of epoxy that excel at heat transfer...

Epoxy coated copper, I believe, is used in practice for the protection of copper in chemically hostile enviroments...

I have never done it myself... Just make sure to mix the epoxy well so it cures completely.

Michael

[tsangep]

To build the evaporator i found the cheapest way is to Powder coat the copper tubes with two layers of powder. It conducts heat very well and is like a titanium tube but cheaper. the powder used needs to be marine grade.

You can use a old room aircon running r22 or refill with LPG or propane and butane . It performs better and is cold and cheap and draws lower amps than r 134 in a similar setup.
for your small tank a 1 horse power room air con with the custom coil should chill it down to atleast 15 deg c if needed.

[piashaw]

I know a few people in the past who used old draft beer chillers which they picked up cheap. I personally wouldn't be too worried about some of the possible poisoning EXCEPT if you have Corals and Clams etc. (which you don't) They are very delicate.

Having said that, when I had my tank, I cooled an insulated container of water with the chiller and then ran plastic pipes through it back into the tank. I found that it cooled the water gradually without giving my corals a temperature shock when the system cycled. I'm not certain how delicate the plants would be to rapid temperature changes.

Also as an aside, if you are putting a chiller directly onto your tank, mix the output with original tank water to reduce temperature shock or if you have a sump, put the output into the sump first.