Piezoelectric cooling

[dada_dave]

I have to admit it does seem pretty good - especially for thin and light devices. Not only does it take up less space than a comparable fan but it has some really nice ancillary benefits like high static pressure and dust resistance. Some really interesting possibilities.

 

[dada_dave]

This company just put the air in Apple’s MacBook Air

MacBook Air head-to-head: original versus AirJet.

www.theverge.com

A balanced look at it from the Verge

 

[Citysnaps]

That's pretty interesting. My wife recently purchased a Toyota Venza hybrid car. A nice feature it has are cooled/heated seats. You can choose three levels of cooling or heating. And they work really well. The seats chill pretty quickly.

When running on battery I hear absolutely nothing (ie an AC compressor), which leads me to believe they're thermoelectrically chilled (or heated). Still, I'm a little skeptical as the surface area of the chilled seat is relatively large. More likely it's a smaller thermoelectric cooler (also called a Peltier device) that chills (or heats) air that's pushed through the seats. Or something like that. Current flowing in one direction causes heating. Reverse the current and you have cooling.

As an aside...long ago when I was working in aerospace/defense we developed channelized wideband 100% probability of intercept receivers to snag signals of interest using accousto-optic techniques (coherent laser light modulated by a Bragg cell, illuminating a linear CCD array for readout). They were about the size of two shoeboxes and used a helium-neon laser.

Another version fit in a micro-min package (around 2"x2") and used a laser diode, which needed to be cooled. We used a tiny thermoelectric cooler and regulator circuit to keep the laser diode at a very narrow temperature range. Thermoelectric coolers/heaters are pretty neat devices.

 

[leman]

I still don't see how this is an interesting technology, at least not in its current version. It just consumes way too much power. What use is a cooler that increases the power consumption of a computer by 20-25%? If sustained performance is desired, one can easily add a single small fan and have the same effect at a lower energy and also a lower financial cost. I also don't understand why they showcase it on a MacBook Air. That machine is not made for sustained performance — by design. It's a very strange way to construct a marketing argument for me.

 

[dada_dave]

I still don't see how this is an interesting technology, at least not in its current version. It just consumes way too much power. What use is a cooler that increases the power consumption of a computer by 20-25%? If sustained performance is desired, one can easily add a single small fan and have the same effect at a lower energy and also a lower financial cost. I also don't understand why they showcase it on a MacBook Air. That machine is not made for sustained performance — by design. It's a very strange way to construct a marketing argument for me.

It is running full blast constantly during the tests. I think an Air designed with fans running at the same cooling capacity might consume a smaller amount of energy to one designed with these coolers but would have to be thicker and heavier to compensate for the fan and noisier.

As for testing with the 15” MacBook Air I can see both sides. They wanted to show off that Air could be capable of sustained loads with their tech in a form factor that a fan would result in even more design compromises than adding one of their coolers. On the other hand, the 15” Air with the M2 actually does okay with just passive cooling and even though piezoelectric cooling is supposedly far quieter than a fan it still isn’t as quiet as nothing at all. And of course as you say the product tier is almost explicitly designed for at most burst workloads and getting decent battery life from the low power it’s able to achieve on most daily tasks. So while older Intel Airs might’ve benefited from active cooling (more on that below) it’s unclear how much the current ones would given what they are designed for. The 13” Air might’ve shown more impressive results but I suspect the 13” is too small to modify the chassis after the fact without designing the internals around the use of the coolers.

Having said that we know PC laptop makers, even for thin and lights, having to suffer with much more power hungry x86 chips, often require fans even for decent performance on day-to-day tasks, to say nothing of handheld consoles like the switch or steam deck. Space and weight are at premium and saving both could make a big difference for such devices. Of course if the energy costs are too high then it isn’t worth it.

For Apple, the most attractive option would be to replace the fans in products like the Macbook Pro (depending on energy consumption) and especially the iMac and mini which would result in impressive space, noise, and weight savings. For currently passively cooled devices it might have a benefit if Apple wanted to improve their sustained performance but I’m unsure that they would given the trade offs.

 

[Citysnaps]

I'm not sure Peltier cooling/heating makes the most sense for laptops that are relatively easy to service/replace. But in many scenarios reliability and inaccessibility for repairs (should fans or AC compressors degrade or fail) and potential costs is more important than efficiency.

Assuming (I'm not 100% convinced yet) Toyota does indeed use Peltier tech in their seat cooling/heating for hybrid cars, it would be interesting understanding the trades.

 

[Yoused]

One advantage to the piezo design is that you could place airflow channels on the hotspots (a SoC does not generate heat uniformly) and run zoned cooling (yeah, I still have a G5). That would probably minimize the power draw. The other thing I was wondering about, if these chips produce so much heat, why not generate some cooling power using themocouples? We have seen the IR images, surely the required watt of power could be drawn off that gradient.