Introduction: How to Cool Your Dog (Chihuahua Modding With Thermoelectric Cooling)
As a native Texan, I started sweating last month when summer started and haven't stopped since. It's not surprising since our weekly averages are 100+ degrees and sometimes with high humidity as well. I can't imagine how my outside dogs would fare without their ice water and shade considering they have fur coats. Because of that, I'll start with a few reminders and then show you how to build a back-mounted, Peltier-based cooling gadget(the thing on my dog's back in the picture) for your lovely pupper. It is similar to this.
Also, if you like the tips and the dog cooler don't forget to vote for me in the Pet Contest! With that taken care of, Let's begin!
Step 1: Tips: Shade, Wind, Ice!
Like the cute hat on my sweet pet above, shade is a very important factor to keep in mind for keeping your pets cool. Make sure that your furry friends have access to shade during the WHOLE day. Be careful with doghouses as some of them trap heat and turn into small convection ovens.
A fresh patch of shaded grass is wonderful for your pets on a hot day as it protects them from the sun and allows the wind to cool them down. As many of us in the South know, a small breeze on a hot summer day goes a long way. A good rule of thumb when picking a location for your pet is if you are uncomfortable, your pet will be, too.
Add a few ice cubes to your pet's water dish to give them a refreshing drink. I like using bigger pieces of ice as they take longer to melt and keep the water colder for longer.
Now, let's get on with the real tutorial!
Step 2: Materials and Tools
-Heat sink with fan
-Thermocouple or thermometer
Notes: I ordered the thermal paste, peltiers, and aluminum cooling block separately. I already had the heat sink and fan. I also cut up an old phone charger for the USB cable. I recently found this kit on Amazon that has everything you need minus the thermometer and USB connection. Really though, the thermometer is only for you to see how cold it gets anyways.
Step 3: Peltier Module Assembly
Cover one side of the aluminum block with thermal pads and stick the Peltier module on that side. Make sure the black text describing the module is facing you. It also works if you accidentally stick it on backwards, you just have to flip the polarity. I like to keep the text uncovered for reference. I included the aluminum block because I didn't want the heat sink to make direct contact with my dog's fur and I also wanted to leave it open for liquid-cooling in the future.
Step 4: Stick the Block to the Heat Sink
Do the same for the other side of the aluminum block and stick it to the heat sink. If you're using paste, make sure you don't use too much. If you're using pads, be careful while placing them and make sure they're flat. I used a fan, heatsink combo from an old desktop I had that no longer worked. If you're using the kit you'll need to attach the fan to the heatsink with screws at this point. Now, if you decide to go with liquid cooling just flip the Peltier block combo so that the Peltier is on the heatsink. Simply switch the polarity so that the Peltier cools the block instead of heating it, attach your tubing, and enjoy.
Step 5: Wiring
The wiring for this is pretty simple. Grab your USB cable and cut the other end off. Locate the black and red(sometimes white and red) wires. Red(+) and black(-) wires will also come out of both the Peltier module and the fan. Connect all three of the red wires with a wire nut and do the same for the black ones. Plug it in to make sure everything is working. The fan on the heatsink should be spinning and the side of the Peltier you can touch should be cool. Use your temperature measuring device to make sure your gadget is safe for your furry family member to wear. They have fur so 75-80 degrees should be cool enough to help them without causing cold burns. Keep it running for about an hour to make sure it won't overheat. Mine will not overheat because of my specific setup, but if you are using the kit or a different heatsink I cannot tell you how long it will last.
Please be careful as an overheating Peltier can cause burns. Only let your pet wear it when absolutely sure it is safe. When you are sure it is safe simply hook this up to a powerbank(1 Amp of current is enough to get it going, but more current = cooler temperatures), attach it to your pet with a ribbon, collar, string and watch you pet enjoy its new found coolness.
Step 6: How It Works
As I explained before in my 5 Minute USB Wrist Cooler Instructable, Peltier modules, or thermoelectric coolers (TECs), pump heat from one side to the other with the direction depending on the polarity. This means that you can flip the polarity to make the originally cool side hot and vice-versa. The module is attached to the aluminum block with thermal paste or thermal pads to get rid of any bumps or inconsistencies on the surfaces of the two items to maximize the area of contact through which the heat can dissipate. My wrist cooler doesn't have a fan, only a heat sink. This is called Passive Cooling as it depends on the environment to cool itself. This build, however, uses Active Cooling. It is considered active cooling instead of passive cooling because we are using a fan to blow air onto the heatsink to cool it down. We are taking the cooling into our own hands and not depending on the environment.
Summary: The Peltier pushes heat from one side to the other. The cool side touches our pet's fur, while the hot side pushes the heat onto an aluminum block and then a heatsink. A fan then cools our heatsink constantly so that our pet is safe from burns due to the Peltier overheating.
If you have any questions or suggestions let me know in the comments below. Have fun!
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