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I'm trying to design a cold air blower system to cool something periodically - can't attach peltiers directly, and can't use a condenser like a fridge etc, the system needs to be small, and dry ideally also. Basically it has to be this way.

I'm using off-the-shelf heatsinks that are like hollow aluminium profile bars and have strapped a few fans to these. It's not working well though - besides simulation, can anyone give me any advice on how to design an efficient cooling system? i.e. how would I work out what my heatsinks need to look like, and what fans to use, etc.? And how would I work out the sort of maximum efficiency I could hope for from such a system? Many thanks

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  • $\begingroup$ Do yo care about actual efficiency or performance? Peltiers are not efficient, and frankly don't perform very well either. Your design is basically the only way to do it, getting better performance means a lot more of these in parallel. $\endgroup$
    – Tiger Guy
    Nov 21, 2022 at 18:38
  • $\begingroup$ @TigerGuy Yes, efficiency and performance is the entire point of making it. Its not the general arrangement of peltiers and heatsinks etc., its how to optimise it to work as well as it can - if someone wanted to do something similar 50 years ago, before thermal simulation packages existed, how would they have done it? Just tried iteratively changing fans and heatsinks until they got bored? There must be an intelligent way to solve this that avoids simulation? $\endgroup$ Nov 22, 2022 at 19:37

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The design you present in your diagram is nearly identical (fan orientation excepted) to the configuration of a Peltier-cooled picnic cooler manufactured by Coleman™. The hot side of the heatsink is mounted under the surface of the cooler, with appropriate vent slots cut into the skin. Ambient air is pulled into one opening, heated by the device and ejected from the other side.

The cooling side is similar, with a protrusion in the cabinet area, also with a fan and dual vent openings.

The specifications for this device state a 40°F delta and my experience validates that figure. In a 70°F hotel room, the water within the cooler would begin to freeze overnight. In a 90°F vehicle, drawing tremendous current from the battery, the beverages were of acceptable temperature.

I'm sure that part of this system involves as much insulation as practical. Larger area of the Peltier chips or a greater number of them will provide greater cooling, at the cost of increased power consumption.

I did not perform efficiency calculations, but one can measure voltage and current on the input side to determine power draw. You would have to have a reference source for cooling with which to compare the collected data.

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