Thermoelectric Auto Air Conditioner / Heater

Picture of Thermoelectric Auto Air Conditioner / Heater

Thermoelectric Auto Air Conditioner / Heater

Ok, I have an old 78 Ford truck with no air and no heater. The heater motor and vents are gone. The only thing left is the heater core. So, I can go to a dealer and pay three times the amount that the truck is worth to have it installed, or pay $1,000 for a kit and do it myself, or just use a fan. I also have seen many videos on YouTube of guys filling up buckets of ice and pumping the cold liquid through copper pipes around a fan to get a cool breeze. As ingenious as that is, I doubt it will work well in a vehicle. Plus, filling the thing up every hour or so would be a real pain.

I even thought about pulling an entire system out of the junk yard and then figuring out how to fit everything, and then having to replace my radiator, charge it up, etc. That was going to cost $400+ and a LOT of work. So, I have come up with the following plan that I have begun building. It is a Thermoelectric Air Conditioning and Heater unit with a total cost of $111.00.

I am sharing this idea and will post progress in hopes that people will comment and provide constructive criticism on my design and help in any problems I run across. Here are some opening thoughts:

The problem with the designs I am seeing on the internet is that you have to continue to fill up / empty the reservoir with either cold water or ice. I have decided to have a liquid coolant cooled and/or heated in a cooler (see Price List with links to parts), then pumped through a heater core and then back to the reservoir.
I am placing the CPU fans in FRONT of the heater core to draw and pull air from it instead of pushing air through it. I have read a lot of ideas and opinions on whether it is better to push, pull or do both. I am going to rely on my high school physics class and base my decision on the principle that it takes less energy to pull than it does to push. Plus, having the fans in front will avoid the resistance from the core fins themselves in a pushing situation and a shroud will be constructed around the entire front of the core into the fan area to maximize the flow of air.
The cooler/heater will need to be on a timer to start cooling or heating before the truck is running, I will also want it to continue to run and keep the coolant cool while I am in the store, or away for a while so when I get back in, I don’t have to wait for the coolant to cool back down again. This is why I am adding an additional battery in parallel and wiring in a battery isolator to prevent my starting battery from draining during this operation and also allowing my alternator to charge both batteries when the truck is running.
I am adding a controller that will control the fan speed and also keep track of the temp outside the truck, inside the cab, and also the temp of the coolant itself.

ACC Car Battery $15.00 Junk Yard
Battery Isolator $20 (used)
Controller $11
Heater Core $0 - used existing
3 CPU Fans $0 - had laying around
Cooler/Heater $30 (used)
Reservoir $0 - Old Container
Pump $15
Coolant $11
Supplies (wire, tubing, etc.) $9
Redstormx12 years ago
Good luck with this. i hope you pull it of. IF you dont you can try buying a 12v portable fridge think there $400 and using the esky ice trick.

I made this system to stop the need of having to fill it up with ice all the time. Ive gotten parts of it down to -4.8 deg . Im redesigning at the moment. Could put a 12v compressor in it if i wanted.

Are you having any trouble with your system yet?
I dont understand your system exactly how its set up but
Where is your hot air going?
Your hot engine will effect the cooling ability of the system ?
lschwartz2 years ago
The diagram is fine, but you use lots of parts, with no info about how are they connected, etc.

Also, IMHO, considering that a lot of uknowledgeable people read the Instructables, authors should never introduce an item, e.g., peltier, with out some minimal info about what it does or is.
ROBBIE7772 years ago
I installed on my pc at the time a thermoelectric liquid cooling CoolIT brand, model: Freezone Elite. This system has been discontinued, has a total cooling power of 250W. Works with 12 volts DC. It consists of 6 posts in two blocks Peltiers each with 3 to cool the liquid refrigerant passes through them thanks to a pump as a closed circuit without a reservoir, this cooling, in this case, the processor pc There a driver circuit, where the system receives energy, and this in see this connected to the PC and is controlled by software. This could be an interesting starting point to take it as an example to help you develop your thermoelectric air conditioning system. Find information about this and you'll an idea of ​​what I say, Greetings !!!!!!
kalo023 years ago
I tried making a similar device for a design project using a rechargeable battery to power a Peltier module to cool my old Volvo before i got in on a hot summer day. I lost a lot of sleep trying to operate the Peltier device as it would slowly draw all the voltage from my battery and my cpu fans. I tried so many different things, i.e different heat sinks, batteries(up to and beyond the Peltier's specifications), wiring etc but it would never work. I'm very interested to see how your project goes and figure out where I went wrong..
jawtig kalo022 years ago
I have an 84 Volvo 240. I cut the hoses to the evap core (on the right side of the center console). I filled up a cooler with some water and ice and used a 500 gph bilge pump to circulate the cold water thru the evap core. A few weeks ago here in Florida I drove on the highway for 5 hours. It took approximately one 10lb bag of ice per hour to get the cabin temp down to around 77 deg. F. It was 90 deg. F. outside.
I too am trying to incorporate a Peltier into the mix. I want to be able to use around 1/2 gallon of water pumped through copper pipes. If I can figure out how to get the water in my container to stay cold by using an Peltier then I can eliminate my need for ice and a 40qt. cooler.
If you have figured anything out please let me know.
trknjim3 years ago
May I suggest using a Large surface heatsink on your peltiers to pipe glycol with a waterpump (as used on HIGH CLOCKING PCs). I developed a small unit which radiates through a flexible piped bladder.. It works very well. I have deemed it " The Poor Man's A/C"! The fluid in my unit chilled to an almost 41 deg.( in My '78 Ford p/u) in a stifling 101 deg truck- less than 10 mins !!! Use your own configuration, but pulls 21 amps.
ironsmiter3 years ago
I think you forgot a MAJOR expense.

A Peltier of a large enough size to cool your truck... is going to be well, let's just say an after-market AC kit will be considerably cheaper.
cbassoc (author)  ironsmiter3 years ago
Thank you for your comment. I completely agree, my theory is using a smaller one just to cool the coolant and then pumping that coolant through the heater core will be more efficient that just using the "air" from it. In my initial tests, I am able to pump the coolant through it for several hours with the coolant retaining 20 degrees under the outside temp. I was only able to retain temp for under an hour until I increased the size of the coolant reservoir. I will keep posting my results. Thanks for commenting.
Audi uses a simmilar setup for the heat, in some of their newer cars.

They have a massive thermos, superinsulated, in which they store hto coolant.
When the car first starts, they use that coolant to bring the engine up to tempature quicker. Also fun for winter, as you can have instant-on heat.