DIY Chiller

[Killerwhale]

Hi guys,

Any mechanical student outthere thinking of DIY a chiller? Basically, the concept of heat transfer is simple and to improve the efficiency for larger tank is also possible. The problem is assembly of chiller. This is the main obstacle that I encountered. If we can form a grp of DIY team to do this project, the problem of getting a cheaper chiller will be eliminated.

So just want to survey around, who is keen to carry out this project.[]

[Killerwhale]

Hi guys,

Any mechanical student outthere thinking of DIY a chiller? Basically, the concept of heat transfer is simple and to improve the efficiency for larger tank is also possible. The problem is assembly of chiller. This is the main obstacle that I encountered. If we can form a grp of DIY team to do this project, the problem of getting a cheaper chiller will be eliminated.

So just want to survey around, who is keen to carry out this project.[]

[Killerwhale]

Hi guys,

Any mechanical student outthere thinking of DIY a chiller? Basically, the concept of heat transfer is simple and to improve the efficiency for larger tank is also possible. The problem is assembly of chiller. This is the main obstacle that I encountered. If we can form a grp of DIY team to do this project, the problem of getting a cheaper chiller will be eliminated.

So just want to survey around, who is keen to carry out this project.[]

[Killerwhale]

Hi guys,

Any mechanical student outthere thinking of DIY a chiller? Basically, the concept of heat transfer is simple and to improve the efficiency for larger tank is also possible. The problem is assembly of chiller. This is the main obstacle that I encountered. If we can form a grp of DIY team to do this project, the problem of getting a cheaper chiller will be eliminated.

So just want to survey around, who is keen to carry out this project.[]

[wangzx]

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On 10/8/2002 11:56:33 PM

Hi guys,

Any mechanical student outthere thinking of DIY a chiller? Basically, the concept of heat transfer is simple and to improve the efficiency for larger tank is also possible. The problem is assembly of chiller. This is the main obstacle that I encountered. If we can form a grp of DIY team to do this project, the problem of getting a cheaper chiller will be eliminated.

So just want to survey around, who is keen to carry out this project.[]
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When you said transfer heat, are your referring thermal technology or compressor? Just like to find out more.

[bclee]

First, we have to determine the method of heat transfer.

1. Convection
Simply by blowing air across an array of pipes or heat sink or something like that.

2. Compressor/refrigerant
Compressing and liquidifying of refrigerant and releasing it through a trottling valve(correct term?) vaporising it thus absorbing heat.

3. Evaporation
Something like a cooling tower. Water is trikled down with forced convection evaporating the water, and creating a cooling effect.

Option 1 will be the simplest but least efficient. 2 & 3 will need more elaborate setups.

BC

[wangzx]

option 1 is just like the teco - micro chiller or edio chiller technology used. In simple terms, using rev. current to pull down the temp., attach with heatsink w/ fan to transfer away the heat from the contact surface. Just like CPU cooling fan. Well, in actual fact, not so simple lah. Need a lot of cal. to make it work. But is not a bad idea to group technical know how ppl. here to create a chiller.

[setiardi]

Maybe can drill hole for inlet/outlet pipes in those small fridge which cost ard less than $200. Only thing is cannot control temp. Might even freeze ur tank.

[Phang]

What about adding a thermoset into the system... when water reaches a certain temp. off goes the mini refrigerator....

[ZeRoC00l]

Read somewhere tt an american did his own DIY chiller with a fridge.

He used a small mini bar fridge, drilled 2 holes on the side.

Collected a pump to a huge coil of hose in the fridge and back to the tank, but the temp he got was only 27 degrees... lots of electricity wasted.....[]

His tank was a normal 3 feet w/ 4 PL.

[tawauboy]

if not mistaken, think he used something like 40' of piping in the bar fridge.

[bclee]

Maybe to justify the electrical bill, you can store your beer in the fridge.[]

Just by having the pipes running in the fidge may not be so efficient. Heat transfer between air and metal pipes is not so good. If you submerge the pipes in a bath of cold water in the fridge, that may improve the heat transfer.

BTW, I understand that Cu is a no no in marine tanks. I wonder what metal pipes are there besides Cu ones.

BC

[Killerwhale]

Hi guys,

I was busy lately so didn't got much free time to log on. Actually, my ideas are very close to bc & zerocool. Below are just few pointers that I have thought but not in depth.

1. modify a small scale fridge
2. force convention
3. heat sink method
4. venturi effect
5.............etc etc. Got some more to say but my wife is back, so got to log off.

Chat with you guys again. Anything is possible for a team work !

[CoryDorus]

I am in computer line where we seen NB that use solid state forced refrigeration technic. 3 years ago a 3in by 3in matter cost roughly S$10. Now should be cheaper. By rough guessing, believe will need less than 2 pc for even a 4ft tank because the matter work extremely efficient.

1. We can stick solid state refrigeration matter with 1 sided hestsink to 1 leg of an U -steel plate and the other leg immersed in the tank.

Thermostat device can be used to manage the temp. control.

That's it.

[bclee]

I have an idea using the cooling tower method.

It is something like a sump tank. A drip tray is install above the sump. A small pump is used to pump the water up to the drip tray. Water will trickled down back to the sump. A fan or an array of fans will be installed to blow air accross the gap between the drip tray and the sump. This forced evaporation will cause temperature of the water in the sump to drop.

The water in the aquarium can be cooled by running through an array of pipes immersed the sump tank or positioned between the drip tray and the sump.

Or alternatively, water can over flow into the sump tank and pumped back to the aquarium. But this way, you need to top up the water very frequently because the evaporation from the sump will be quite high.

This method is normally used in those central air-con.

BC

[tawauboy]

unless you are using refrigerant or themoelectric devices, i don't see how the tank temperature can be cooled lower than room temperature.
at the end of the day, you may be better of by just having fans blowing across the water surface.

cooling tower for central air conditioning is actually the secondary circuit in the air conditioning system. this water is used to cool a chiller, which compresses a refrigerant, and runs from the chiller to cooling tower and back to chiller. the primary circuit runs from the chiller to the fan coils and back to chiller. this chilled water is normally around 7-8 deg.

[bclee]

Oh! Learnt something new and makes a lot of sense.

But cooling tower can cool below room temperature. It depends on the wet bulb temperature. The theoretical lower limit is the wet bulb temperature. Of course, here in Singapore, the relative humidity is quite high, but the wet bulb is probably still around 23°C. If we can design an effecient system, we can probably lower the temp to somewhere close to the wet bulb.

BC

[tawauboy]

one feasibility study that can be done before starting the design is to get a powerful fan and blow into the tank.
don't care about evaporation.
see what is the lowest temperature achievable.
that will give a rough idea whether a more elaborate design on evaporative cooling is feasible.

[bclee]

I did some cooling tower study during my uni days.

If really effiecient, maybe can get within 3°C of the wet bulb.

Just by blowing air across the water is not so effective. You will not get too much cooling.

You need more surface area. One way is to have a sprinkler to spray fine stream of water when forcing a draft across or counter-flow.

I have thought out a design. Maybe when I have time, I will try it out.

BC

[tawauboy]

do try out your design and inform us the results.

btw, the central air-conditioning have water going to cooling towers at about 40+ deg and after cooling, it will drop to around 30 deg.