Lugubris
New member
Hello, In this thread I will show you how I made a tank sized air conditioner to keep my salamanders cool in the summer using the same technology as wine chillers. It is an affordable, and relatively easy do-it-yourself project applicable to those who are unable to keep their terrestrial setups cool enough with just fans. I meant to post this before the start of summer, but between two moves and extra work, I have been low on spare time
Note: This project is designed for a 10 gallon tank not facing temperatures in excess of 80 degrees. If your tank is larger or is in a hotter place, you probably need more peltier devices (and also another 6 amp power adaptor for it, and two more heatsinks and fans), or at the very least more insulation.
Parts:
-LSE0111B1260 12volt 6 amp AC to DC adaptor ~$5-10
-12 Volt 500mA AC to DC adaptor (wall wort) ~$0-5
-TEC1-12706 Peltier (Thermoelectric) Device ~$10
-1-2 inch Insulated Sheathing (amount needed depends on your setup) ~$10-20
-Alligator Clips, Small ~$5
-Nails ~$0-3
-2 CPU Heatsinks ~$3-5 each
-2 CPU Fans ~$3-5 each if not included with heatsinks
-Thermal heatsink compound $5-10
-Wire 12-20 Gauge ~$0-5
-Cable ties/zip ties 6 inch or more $3
-500mA potentiometer ~$3
-Sponge $1
-Foil $1
-Tape (preferably duct tape)
Total Price ~$49-94, but probably less if you buy used parts or recycle things you already have. For me it was about $35
Where to get parts:
-Power adaptors, online. The 500mA one can often be bought recycled or borrowed from some other home device (old message machines, phones ect...) the current is not that important as long as it is more than 300mA, look at the writing on it to find out what voltage and current it provides. Be aware that sometimes the voltage specifications lie so it is best to check it with a voltage meter if you own one.
-Peltier Device, online
-Insulated Sheathing, hardware store
-Alligator Clips, online or hardware store
-Nails, Hardware store if not already owned
- CPU fans and heatsinks, online or recycled computer part store
-Heatsink compound, electronics store or online
-Wire, hardware store if not already owned
-Cable ties/zip ties, hardware store or online
-Potentiometer, electronic store or online
Parts considerations:
-Larger heatsinks are better
-Any AC to DC power adapter that supplies 12V 6A will probably work
-Thicker insulated sheathing will work better
-Try to get a fan that matches or attaches to your heatsink on at least one side, better yet get one that comes with a heatsink or vice-versa.
-Heatsinks that are the same size will make everything easier
Tools:
-Pliers
-Wire cutter
-Wire stripper
-Wood saw or hack saw blade
-Volt meter/multimeter. (optional)
Caution: The power adaptor provides 12 volts at 6 amps which is more than enough to provide a painful shock or start fires. The peltier device can also cause burns. Do not attempt this project without adult supervision. Do not attempt this project around water. Do not work on any part of the project while anything is plugged in. I am not responsible for personal injury or property damage caused by any attempt on this project.
The project:
Pictures are at the bottom.
1. The first step is to apply the thermal heatsink compound to both sides of the peltier device. You may want to wear gloves and lay down newspaper because this part can be messy. Also, be careful not to damage the peltier device (set it down on soft surfaces), they are somewhat delicate, especially the corners. Attach one fan to the heatsink with included mountings or with cable ties.
2. Next place two cable ties parallel to each other about 1cm in from each end of the heatsink, but not touching any fan blades. Then you place a heatsink with the flat part facing up on top of the cable ties, and place the peltier device in the middle of the heatsink cold side down, place the other heatsink with the fan flat side down on top of the peltier device. Carefully connect the cable ties around both heatsinks, tightening each side incrementally so as not to damage the peltier device. You are now done with the 'cooling unit'.
3. Cut the insulated sheathing with the wood saw or hack saw blade (do this outside, its messy), one piece to cover every side of your tank, with the top and bottom pieces being 1 inch longer in each direction. The back and front pieces should be an extra inch long in the horizontal direction only. Cut a rectangular hole in the piece that will be used for the top to the exact size of the heatsinks, put it 1/3 to 1/4 of the distance from a short side and equidistant from a long sides (see pictures below). Use cable ties or nails to attach the other fan hanging vertically the short side of the rectangular opening that is closest to the edge of the top. Place the cooling unit in the opening with the heatsinks on each side protruding equidistant. Have all of the wires come out on the side that has the fan, this will be the top.
4. Place a preferably empty tank on the insulated sheathing that will go under the tank, and use a pencil or pen to draw the perimeter on the sheet. Remove the tank and use nails and/or tape to attach the back, left, and right insulated sheathing to the bottom piece. Be aware that if you use duct tape, it will damage the insulated sheathing if you attempt to remove it.
5. Place the tank back on the bottom insulated sheathing. Place the top piece of insulated sheathing on top of the tank with the fan side up. Note where top contacts the edge of the tank, remove the top and put nails where the top contacts the front and back corner on the side that is closer to the cooling unit, with the head of the nails protruding about 1-2mm depending on the tank size and number of critters. Put the top back on the tank.
Note on fan wires: some CPU fans have 3 wires, buy you only need two. Usually the ones you need will be red or yellow and black. If not, light colors usually mean positive and dark colors usually mean negative. You can use trial and error to find the correct fan polarity (the red or positive must be attached to another positive) but having a voltage meter will make this much easier, if you don't own one maybe you can borrow one from a friend.
6. Cut the circular plug off of the 500mA power adaptor and use the wire strippers to expose the copper. Use an alligator clip or tape to attach a wire from the power supply to far left or right contact of the potentiometer with another alligator clip. Attach a wire from the lower fan to the centre contact of the potentiometer. Attach the other wire from the lower fan to the opposite wire from the power adaptor and attach the wires from the top fan to the respective power adaptor wires. Check for short circuits. You can try to plug in the adaptor to check your wiring, the top fan should spin up, the bottom fan will spin faster the farther the potentiometer knob is turned from the unused contact.
7. Use wire cutters to cut the round plug from the end of the 6 amp power adaptor. Then use the wire stripper to remove the outer wire covering then each inner wire covering. Attach a nail to one of the wires from the power adaptor. It will act as a resistor of sorts. Use alligator clips to attach the peltier device to the respective wires of the power adaptor. Check for short circuits, then plug in the power adaptor and feel the heatsinks to ensure that the top is hot. If it is cold simply reverse the wiring.
8. Cut the sponge to the size of the heatsink, larger is okay. Put a foil dish around the lower part of the sponge. Use cable ties to secure this to the bottom of the lower heatsink. This will collect any condensation on the unit, which you don't want getting into your enclosure.
You are now done with the project. Test it by placing a thermometer inside the enclosure. Put the lid on and use the potentiometer to get the lower fan running at a slow speed. It should be covered up on every side. Plug in/power on everything, make sure both fans are operating, make sure the top side is hot. Put the front insulated sheathing into place. Do something for an hour then come back and check the temperature. It should be between 50 and 70 degrees depending on the ambient temperature, how much insulation you have, and the speed of the lower fan (it may take some experimentation to find the right speed, I find that faster is not necessarily better).
Here are some pictures of a finished unit.
For the more electronically inclined, here is a very (very) rough schematic.
When you use the unit, stay by it for the first minute of operation to ensure that the top heatsink is hot, or you have an oven instead of a wine chiller. Also check to see how hot the nail is on the 6 amp power adaptor (unplug it first). If it is really hot (hurts to touch it), try moving the alligator clip closer to the wire. If it is not hot at all, move the alligator clip slightly further from the wire. I have not found it to get hot enough to melt things, but not all nails are the same. The purpose of this nail is to stop the power supply from burning out. You could also try a 7.5 amp car fuse after the nail for more security, I haven't gotten around to trying this yet. For even more security you could also include a 100 or more volt diode attached to one of the wires. Once again I have not found this necessary. I have operated my unit many times (in a prototype stage too) and it has worked without fail. It can keep the enclosure at 67 degrees when my room is 80 degrees (yes it gets that hot, broken AC), and I'm sure that with some patches on my prototype insulation and fine tuning of the lower fan it could work even better.
I hope to find time to create a thermostat for this unit soon, but I can't promise anything. Also, I am working on an alternative (and easier) cooling unit using a different technology. I will try to get more pictures up.
Troubleshooting:
P: The fans will not work
A: Check your wiring, use a voltage meter to check the voltage of the power supply. Replace the power supply. Replace the fans.
P: Only the lower fan does not work
A: Turn the knob of the potentiometer all the way left, then all the way right. If it does not work on either side replace the potentiometer. Check your wiring. Replace the power supply. Replace the fan. If the potentiometer fails multiple times you are not getting one that is large enough (500mA should suffice).
P: The peltier device wont work
A: Use a voltage meter to check the voltage of the power supply. Replace the power supply. Replace the peltier unit.
FAQ:
Q: Can't I just use one 12V 6A power supply and skip the 500mA one?
A: Technically yes, but this will make things way more complicated. You will need a 30 ohm 70 Watt resistor before the upper fan. And a 70 Watt rheostat before the lower fan instead of the potentiometer. Both are expensive, hard to find, and will require their own heat management.
Q: With the front insulated sheathing in place I can't see my pets! Or it can kill my plants! Is it necessary?
A: You do not need the front insulated sheathing if the temperature is not too extreme (less than 74 degrees I find), or if your tank is acrylic instead of glass. You can also make the front piece shorter to let some light in. But usually, yes it is necessary.
Q: You can buy a used wine chiller for about $50 online. Why not do that?
A: Because my way is more fun! Also, usually the peltier devices in the used units sold online are either burnt out or close to it. They last about 2 years or more. It is a reasonable alternative if you don't have the time or expertise to try this project.
Q: How do they get air?
A: If you set it up correctly, the nails should elevate half of the top off on one side of the tank about 1-2mm on the same side as the lower fan. If this is not the case, check step 5 of the instructions again.
Note: This project is designed for a 10 gallon tank not facing temperatures in excess of 80 degrees. If your tank is larger or is in a hotter place, you probably need more peltier devices (and also another 6 amp power adaptor for it, and two more heatsinks and fans), or at the very least more insulation.
Parts:
-LSE0111B1260 12volt 6 amp AC to DC adaptor ~$5-10
-12 Volt 500mA AC to DC adaptor (wall wort) ~$0-5
-TEC1-12706 Peltier (Thermoelectric) Device ~$10
-1-2 inch Insulated Sheathing (amount needed depends on your setup) ~$10-20
-Alligator Clips, Small ~$5
-Nails ~$0-3
-2 CPU Heatsinks ~$3-5 each
-2 CPU Fans ~$3-5 each if not included with heatsinks
-Thermal heatsink compound $5-10
-Wire 12-20 Gauge ~$0-5
-Cable ties/zip ties 6 inch or more $3
-500mA potentiometer ~$3
-Sponge $1
-Foil $1
-Tape (preferably duct tape)
Total Price ~$49-94, but probably less if you buy used parts or recycle things you already have. For me it was about $35
Where to get parts:
-Power adaptors, online. The 500mA one can often be bought recycled or borrowed from some other home device (old message machines, phones ect...) the current is not that important as long as it is more than 300mA, look at the writing on it to find out what voltage and current it provides. Be aware that sometimes the voltage specifications lie so it is best to check it with a voltage meter if you own one.
-Peltier Device, online
-Insulated Sheathing, hardware store
-Alligator Clips, online or hardware store
-Nails, Hardware store if not already owned
- CPU fans and heatsinks, online or recycled computer part store
-Heatsink compound, electronics store or online
-Wire, hardware store if not already owned
-Cable ties/zip ties, hardware store or online
-Potentiometer, electronic store or online
Parts considerations:
-Larger heatsinks are better
-Any AC to DC power adapter that supplies 12V 6A will probably work
-Thicker insulated sheathing will work better
-Try to get a fan that matches or attaches to your heatsink on at least one side, better yet get one that comes with a heatsink or vice-versa.
-Heatsinks that are the same size will make everything easier
Tools:
-Pliers
-Wire cutter
-Wire stripper
-Wood saw or hack saw blade
-Volt meter/multimeter. (optional)
Caution: The power adaptor provides 12 volts at 6 amps which is more than enough to provide a painful shock or start fires. The peltier device can also cause burns. Do not attempt this project without adult supervision. Do not attempt this project around water. Do not work on any part of the project while anything is plugged in. I am not responsible for personal injury or property damage caused by any attempt on this project.
The project:
Pictures are at the bottom.
1. The first step is to apply the thermal heatsink compound to both sides of the peltier device. You may want to wear gloves and lay down newspaper because this part can be messy. Also, be careful not to damage the peltier device (set it down on soft surfaces), they are somewhat delicate, especially the corners. Attach one fan to the heatsink with included mountings or with cable ties.
2. Next place two cable ties parallel to each other about 1cm in from each end of the heatsink, but not touching any fan blades. Then you place a heatsink with the flat part facing up on top of the cable ties, and place the peltier device in the middle of the heatsink cold side down, place the other heatsink with the fan flat side down on top of the peltier device. Carefully connect the cable ties around both heatsinks, tightening each side incrementally so as not to damage the peltier device. You are now done with the 'cooling unit'.
3. Cut the insulated sheathing with the wood saw or hack saw blade (do this outside, its messy), one piece to cover every side of your tank, with the top and bottom pieces being 1 inch longer in each direction. The back and front pieces should be an extra inch long in the horizontal direction only. Cut a rectangular hole in the piece that will be used for the top to the exact size of the heatsinks, put it 1/3 to 1/4 of the distance from a short side and equidistant from a long sides (see pictures below). Use cable ties or nails to attach the other fan hanging vertically the short side of the rectangular opening that is closest to the edge of the top. Place the cooling unit in the opening with the heatsinks on each side protruding equidistant. Have all of the wires come out on the side that has the fan, this will be the top.
4. Place a preferably empty tank on the insulated sheathing that will go under the tank, and use a pencil or pen to draw the perimeter on the sheet. Remove the tank and use nails and/or tape to attach the back, left, and right insulated sheathing to the bottom piece. Be aware that if you use duct tape, it will damage the insulated sheathing if you attempt to remove it.
5. Place the tank back on the bottom insulated sheathing. Place the top piece of insulated sheathing on top of the tank with the fan side up. Note where top contacts the edge of the tank, remove the top and put nails where the top contacts the front and back corner on the side that is closer to the cooling unit, with the head of the nails protruding about 1-2mm depending on the tank size and number of critters. Put the top back on the tank.
Note on fan wires: some CPU fans have 3 wires, buy you only need two. Usually the ones you need will be red or yellow and black. If not, light colors usually mean positive and dark colors usually mean negative. You can use trial and error to find the correct fan polarity (the red or positive must be attached to another positive) but having a voltage meter will make this much easier, if you don't own one maybe you can borrow one from a friend.
6. Cut the circular plug off of the 500mA power adaptor and use the wire strippers to expose the copper. Use an alligator clip or tape to attach a wire from the power supply to far left or right contact of the potentiometer with another alligator clip. Attach a wire from the lower fan to the centre contact of the potentiometer. Attach the other wire from the lower fan to the opposite wire from the power adaptor and attach the wires from the top fan to the respective power adaptor wires. Check for short circuits. You can try to plug in the adaptor to check your wiring, the top fan should spin up, the bottom fan will spin faster the farther the potentiometer knob is turned from the unused contact.
7. Use wire cutters to cut the round plug from the end of the 6 amp power adaptor. Then use the wire stripper to remove the outer wire covering then each inner wire covering. Attach a nail to one of the wires from the power adaptor. It will act as a resistor of sorts. Use alligator clips to attach the peltier device to the respective wires of the power adaptor. Check for short circuits, then plug in the power adaptor and feel the heatsinks to ensure that the top is hot. If it is cold simply reverse the wiring.
8. Cut the sponge to the size of the heatsink, larger is okay. Put a foil dish around the lower part of the sponge. Use cable ties to secure this to the bottom of the lower heatsink. This will collect any condensation on the unit, which you don't want getting into your enclosure.
You are now done with the project. Test it by placing a thermometer inside the enclosure. Put the lid on and use the potentiometer to get the lower fan running at a slow speed. It should be covered up on every side. Plug in/power on everything, make sure both fans are operating, make sure the top side is hot. Put the front insulated sheathing into place. Do something for an hour then come back and check the temperature. It should be between 50 and 70 degrees depending on the ambient temperature, how much insulation you have, and the speed of the lower fan (it may take some experimentation to find the right speed, I find that faster is not necessarily better).
Here are some pictures of a finished unit.
For the more electronically inclined, here is a very (very) rough schematic.
When you use the unit, stay by it for the first minute of operation to ensure that the top heatsink is hot, or you have an oven instead of a wine chiller. Also check to see how hot the nail is on the 6 amp power adaptor (unplug it first). If it is really hot (hurts to touch it), try moving the alligator clip closer to the wire. If it is not hot at all, move the alligator clip slightly further from the wire. I have not found it to get hot enough to melt things, but not all nails are the same. The purpose of this nail is to stop the power supply from burning out. You could also try a 7.5 amp car fuse after the nail for more security, I haven't gotten around to trying this yet. For even more security you could also include a 100 or more volt diode attached to one of the wires. Once again I have not found this necessary. I have operated my unit many times (in a prototype stage too) and it has worked without fail. It can keep the enclosure at 67 degrees when my room is 80 degrees (yes it gets that hot, broken AC), and I'm sure that with some patches on my prototype insulation and fine tuning of the lower fan it could work even better.
I hope to find time to create a thermostat for this unit soon, but I can't promise anything. Also, I am working on an alternative (and easier) cooling unit using a different technology. I will try to get more pictures up.
Troubleshooting:
P: The fans will not work
A: Check your wiring, use a voltage meter to check the voltage of the power supply. Replace the power supply. Replace the fans.
P: Only the lower fan does not work
A: Turn the knob of the potentiometer all the way left, then all the way right. If it does not work on either side replace the potentiometer. Check your wiring. Replace the power supply. Replace the fan. If the potentiometer fails multiple times you are not getting one that is large enough (500mA should suffice).
P: The peltier device wont work
A: Use a voltage meter to check the voltage of the power supply. Replace the power supply. Replace the peltier unit.
FAQ:
Q: Can't I just use one 12V 6A power supply and skip the 500mA one?
A: Technically yes, but this will make things way more complicated. You will need a 30 ohm 70 Watt resistor before the upper fan. And a 70 Watt rheostat before the lower fan instead of the potentiometer. Both are expensive, hard to find, and will require their own heat management.
Q: With the front insulated sheathing in place I can't see my pets! Or it can kill my plants! Is it necessary?
A: You do not need the front insulated sheathing if the temperature is not too extreme (less than 74 degrees I find), or if your tank is acrylic instead of glass. You can also make the front piece shorter to let some light in. But usually, yes it is necessary.
Q: You can buy a used wine chiller for about $50 online. Why not do that?
A: Because my way is more fun! Also, usually the peltier devices in the used units sold online are either burnt out or close to it. They last about 2 years or more. It is a reasonable alternative if you don't have the time or expertise to try this project.
Q: How do they get air?
A: If you set it up correctly, the nails should elevate half of the top off on one side of the tank about 1-2mm on the same side as the lower fan. If this is not the case, check step 5 of the instructions again.
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