Reasons why you CANNOT use Peltier for air conditioning

Either you will like this video or not, I decided to summarize a few ideas on this topic. In this video, I am trying to show, why Peltier-based air cooling/air conditioning is a bad idea. These devices are not efficient for cooling, because they cannot cool in the same way as the compressor-based coolers do. It will cost you a lot of work and money to make a Peltier-based AC which is comparable to the compressor-based air conditioners. I am not saying that the task is impossible, but it is not worth doing it. Peltiers are not made for this type of cooling.

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[yusifsuleiman]

Very good explanation. Only that remember some people don't even have access to electricity(national grid) or electricity power supply is not constant, the only alternative is to use solar or other methods, and since Peltier is DC, it can easily be connected to batteries with solar pv, without considering much of energy consumptions especially if you get rid of using 3.5kva or 5kva inverter to handle the conventional AC.

[tanjiannan]

Nice calculation. But it's better to modify your title of this video. You said it clearly, it isn't we CANNOT, it's just not worth it from an energy efficiency perspective. However, it's hard to deny that there are still user cases where TEC has advantages over transitional measures.

[katherinek.henkel]

I respect all these equations, BUT..., I have a fact. I have a house in 320 Sqf inside a ship container, So I setup a split unit 12k btu's and works awesome, but I'm off-grid, so I started trying economic systems. I setup 2 outside boxes insulated with 5 peltier each box with a fan blowing air to inside container with a very nice quiet fan, I'm 2 years without turn my split ac on. Each box with 5 peltier + 2 small fan + 1 medium fan is working with 1 12v/100ah battery. My house still cold sometimes I need turn off. Soooo, for me without calc, math equations I have a nice and economic way for AC with 10 peltiers.

[inso]

It is indeed very inefficient for home use, but it works great when sleeping in a tent in the summer.

I use a water cooled system I made using 2 peltier modules with one 120 mm fan and an air radiator on the cold side and two 120 mm fans hooked up to a water radiator and a water block on the warm side, there's also a water pump, everything is connected with 8 mm hoses. It's powerd by a li-ion battery I made with 18650 cells. I simply place the warm side outside the tent and it provides cold air throughout the night.

[JohnS-erjh]

this stuff is above my knowledge base. maybe for air conditioning it might not work, but it WORKS for a mini refrigerator. i bought one for $38 and it works great, it also has a 12 volt adapter plug for using in a vehicle.

[wayneo]

Finally a great explanation on how to read a performance curve chart, my thanks.

[AustinAirCo]

Great video that does a good job explaining the problems when dealing with HVAC. Watts x 3.412 = BTU's a btu is a measurement of heat capacity to remove from a structure. This BTU equation was really the only thing you left out, the load of the structure requires the AC whatever it is to be sized to handle the load. The load isn't the same for every structure. We look for (in USA) a 20F drop across the coil also known as the delta. AC is more or less designed to drop air temp inside from 20F from outside. Desert areas of the climate are different for obvious reasons. Earlier AC's would run a coil temperature of 40F, now the coil temp in some cases may reach the high 40'sF. It's impractical to drop temp below 37F for air conditioning because it's too cold. If sized properly too cold would give you complaints *it's too cold*

A typical room of 120 sq feet may require 9000 BTU or more depending on various factors. That's just one room. The larger the structure the more you need, especially if you live in a climate that requires cooling and it's not just considered a luxury that you use a couple months of the year. The larger traditional compressor & refrigerant designed AC systems for residential max out at near 60, 000 BTU's (5 tons of AC as 12, 000 BTU's = 1 ton of air conditioning.)

I had someone contact me due to some click bait article claiming some major breakthough would solve the AC refrigerant problem. I would rather have a click bait title that proves something rather than just feeding the beast telling people what they want to hear. *Great Job, leave the title of this video as it is*

[drampadreg]

Interesting, if I knew this earlier my A/C wouldn't work! But I use them to chill water and antifreeze in a reservoir, then pump that through the radiators from an old air conditioner and it works brilliantly. Behind the radiator is a centrifugal fan, and the reservoir seems to stay very cold through the day. I must have done it wrong. It also makes a great chiller/heater for my hydroponic reservoir which I keep covered just for humidity reasons. Guess it depends on how you use it, but I remember the old bottle coolers for pop in stores that were filled with water, then paper labels and plastic bottles came along and they faded out of existence. But the idea is still good, and peltier chips are great for those as long as you can vent out the heat efficiently, the faster the better. Cheaper on the hydro bill too, no pun intended.

[kevinthompson]

First of all, thank you for this immerse video.
I found some issues with your work. Please have mercy if I understood you wrong.

1. The temperaturedifference between the hot side and the roomtemp is a dynamic thing. When you start the system, dT is much lower as 10 hours later, when the object of your desire is colder than before.
For my project, I created a linear function for Qc.

2. Peltier-Modules are very inefficient when you let them work at max voltage. If you take a 12715, you should run it at around 6V. Hot side temperature will decrease because you have to transport less heatenergy.

3. Maybe I didn't notice, but you forgot, that the transported heat through the Peltier (Qc) has to be transported through your cooler too. In your example it would mean that the cooler has to transport 225W (P) + 100W (Qc).

4. The maximum dT is defined by how much heatenergy is flowing back in the object that has to be cooled down and Qc.
You can't just say that you want a 30K dT and thats it.

Your video is really good to understand how peltier-modules work, thank you very much for that. But it has its little imperfections.
Please correct me if I'm wrong

[aoxilus]

I disagree, in some cases like in most cars, they generate lots of amps from the alternator allowing you to connect Stereo and amplifier systems that consume 1000 watts many times, using a Peltier for AC even when not as efficient is convenient in this situation.

[herok]

Hello, just one curious question. Can we somehow squeeze out some efficiency using clever control system techniques??

[isidoromaich]

Nicely explained. Peltier technology haven't improved so much since the first devices, let's see in the future, perhaps if someone develop new ideas.
Analysis like this helps a lot to clarify the present situation and maybe motivate someone to break this limits

[phili]

Thankyou for posting this. Hopefully the countless people who claim to have built air conditioning units with Peltiers on Youtube will view this first. You are correct, you need at least 2kw of cooling power to cool the average room.

[ronaldhaduca]

It depends on the design. If you want icy cold peltiers.the peltier's hot side cools on water, make a container that will fit exactly on window type aircon slot on your window with full of water, put a hole that fits the peltiers hot side sink on water, (so no need for radiators or waterpumps). then attach large heat sink on coldside, only 6 peltiers will be powered up and the 12v turbo fan, then make a large tube that the air will pass only throught the heat sinks then attach turbo fan to suck up the air through the tube. No need for cooling fans for the peltiers just pure water. Then put on a room that the water side part is out of the room and the peltier cold tube is In the room. Like window type aircon. I already tested it and runs smoothly and also cold. On a 3x5 sqm room. For larger room make it doubled.

[sebydocky]

Hi, thanks you for all these informations. Was clear in my mind that replacing ac air conditionning with such approach was a crazy/inefficient idea.... but I think in my personal case can be an option. Let's me explain more: I am living solar offgrid. In summer, I got potentially plenty of power (not produced since I have no enough loads for). I got also a system collecting some fresh water extracted from my 20m depht well going to the roof (in a close loop circuit) and thx to a water-air exchanger I can breath in all rooms something around 20 C. I was thinking to decrease this Tc=20C with some peltier modules which can be modulated (in intensity) via a offgrod solar power diverter. (that I have).. For some technical reason I can only use some existing 2.5mm wires to power the peltier module... this is why I was thinking to 24V peltier

[rickycraftyt]

what about if you isolate the exterior and the interior? exemple you put it in a window and isolate both sides? will it work?

[krazypeople]

Peltier devices alone are incredibly inefficient, however they can be used rather effectively in an indirect evaporative cooler. Using evaporation to cool down water that's then pumped through a radiator, adding a TEC to the loop would further cool down the water at the cost of double the energy consumption. Is it an AC? No, but it can drop ambient temperature by 30F in a small room. Anything larger than that would be unfeasible as increasing the amount of TEC's in the loop decreases the coefficient of performance well below that of an AC unit.

[dapenguin]

Hello I am just bored on my lunch break with a question. I have a black car with no AC and it gets super hot in the summer. I thought I could make one of these and stick it in the glove box, which is directly below the vent where my car intakes interior air. I do not expect it to blow ice cold like normal AC, not even close, but would it help a little?

[aldososa]

Would cooling an insulated doghouse be a suitable application for a peltier "AC"? Moving 500 W at a 30 degree F temperature difference?

[jjantonio]

Im making peltier aircon..as of now its 60% done..im an hvac tech ill try to apply my knowledge in it..will post the result after testing