Aluminium heatsinks banned from electronics

[cupoftea]

We just won a large project to build offline car parking LED lights.
But the grant says that we must not use any metal heatsinks.
Each lamp is 60W.
So we must use parallel converters etc so as to avoid aluminium heatsinks.
Our enclosures must also be all plastic and totally enclosing.
We cant use fans either.

So is it true that aluminium heatsinks are bad for the environment?...because aluminium takes loads of energy to make, and even if you recycle it
by melting it back down, this again consumes vast quantities of energy.
And lets face it, nobody ever re-uses old heatsinks that are pulled out of dead power supplies.

So is it right? Is there no way we can argue the case to allow us to use aluminium heatsinks, ie we need to proove that alu heatsinks are not bad for the environment.

 

[BradtheRad]

Is there any substitute for conventional heatsinks? Something thermally conductive but not electrically conductive? Graphene?
Is a vendor or agency waiting nearby, hoping to sell you some alternate substance?

 

[ahsrabrifat]

LED efficiency drops significantly with higher temperatures. Aluminium heatsinks improve thermal management, increasing LED lifespan and reducing energy waste. Most LED manufacturers still rely on aluminium heatsinks. Aluminum has a high recycling rate compared to plastics.

For a comprehensive guide on PCB heat sink, you can see here:

Introduction to PCB Heat Sinks | A Comprehensive Guide - The Engineering Projects

In today's tutorial, we will have a look at the detailed Introduction to PCB Heat Sinks, essential for heat removal from PCB boards.

www.theengineeringprojects.com

 

[dick_freebird]

What is the purported reason behind the nonmetallic heat sink demand?

 

[cupoftea]

The reason is that the energy to make the aluminium heatsinks is bad for the environment. Or the energy to smelt alu back down to recycle it also uses an enormous amount of energy.

Aluminium smelting - Wikipedia

en.wikipedia.org

...As can be seen aluminium smelting uses utterly enormous amounts of electrical power....so we have been told to get paralleling SMPS's and stop using aluminium heatsinks....or keep using them and just get thrown off the car park lighting contract.

 

[stenzer]

There are also copper, brass and ceramic heat sinks available, set the filter in the link below.

https://www.digikey.com/en/products/filter/thermal/heat-sinks/219

Is there no way we can argue the case to allow us to use aluminium heatsinks, ie we need to proove that alu heatsinks are not bad for the environment.

Is there a possebility to source used/scrapped ones by a charity recycle project? Which dimension limitations do you have? Required quantity?

You could make the out of some other kind of metal e.g. steel. Yes, I know steel has a lower thermal conductivity. Back in the days I made heat sinks by bending metal (steel) sheets in U-shaped profiles with different widths and stacked them, to get multiple fins.

 

[cupoftea]

Thanks, but i think other metals are just too expensive. And as you know, if a heatsink is used, it needs to be of a shape and size that can reliably sized for availablity for the foreseeable future...rather than some pieces sourced from old units....but i agree that your principle is very very good.

 

[KlausST]

Honestly, that doesn't make sense to me.

Steel is cheaper, but has a higher density and lower thermal conductivity and you have to treat it against oxidation -> more expensive than aluminum

Stainless steel is comparable in price, but has a higher density and lower thermal conductivity and is harder to work with -> more expensive than aluminum

Copper is more expensive, but has a higher density, better thermal conductivity and you have to treat it against oxidation -> more expensive than aluminum

The melting energy of aluminum is short-sighted, because it gives back exactly the same amount of energy when it hardens. You could use that energy to preheat the aluminum before melting. Some kind of energy recycling. For sure you can´t re use 100% of the energy .... but the same is true for every other material.

I mean you produce a lot of beverage cans and other stuff from aluminum and throw them away...in best way you recyle them.

Klaus

 

[cupoftea]

Thanks Klaus

Why is aluminum used so much when it's energy-intensive to mine and refine?

Answer: Well, for one thing, it’s really common. Of course for economic reasons we still talk about ‘reserves’ in terms of high quality ore that’s accessible, and by that standard there’s ‘only’ 32 billion tons out there in the form of bauxite containing about 50% or more of Al2O3. But in reality...

www.quora.com

...i must admit, despite extensive search i cant find out that aluminium gives back loads of energy whilst its hardening...most experts just say vast qtys of electricity to make it.
The below shows alu making energy is 3% of the worlds energy useage.

This means that 621 billion kilowatt hours of electrical energy were used in the production of aluminium. To put that in perspective, the total world production of electrical energy was 20261 billion kilowatt hours, meaning that more than 3% of the world’s entire electrical supply went to extraction of aluminium.

 

[dick_freebird]

Said nonmetallic, not non-aluminum.

It could be a safety thing (conductive), could be
greenie hyperventilating. Perhaps the purpose of
the grant was to spend "agenda money" and
declare an "environmental win" (despite there
being no real battle to be "won").

As if polymers (in this time of microplastic
macrohuffery) would "solve" it, and aside from
metals and plastics, what've you got for materials?

Are silver- and graphite-loaded epoxies up to
job?

Are "heat spreaders" "heat sinks" for purpose
of this political exercise? Could you use a metallic
"heat spreader" and a very thin "heat sink" made
that way? Are metal-matrix composites "metals"?

If it were me I'd take exception to the line item
until provided a credible reason to make an
inferior product.

But I notice you seem to have a habit of taking
on jobs with stupid requirements and not
protesting until too late. Might think about working
on that.

 

[KlausST]

...i must admit, despite extensive search i cant find out that aluminium gives back loads of energy whilst its hardening...most experts just say vast qtys of electricity to make it.
The below shows alu making energy is 3% of the worlds energy useage.

You mix two differnt things:
* energy to "make it" --> this is a chemical process
* energy to "melt it" --> this is a physical process

Klaus

 

[Easy peasy]

heat conductive plastics are far more abusive to the environment at end of life than any metals, Al, Brass, copper, are all highly recyclable ( ~ 100 % ) which is why they pose the least environmental issues.
Perhaps your client should take a refresher course on environmental aspects . . .

 

[cupoftea]

heat conductive plastics are far more abusive to the environment at end of life than any metals

Thanks yes, but we wont use heat-conductive-plastics.
We will just have the electronics run cool by way of two or more paralleled SMPS stages.

Al, Brass, copper, are all highly recyclable

Yes but it doesnt happen....all the fets have to be screwed off them etc, and they have to be unscrewed from the enclosure etc, and this is labour intensive, and so alu heatsinks just end up in landfill....at least this is so in the West.
Also, the energy to smelt Alu back down and re-fashion it is still very high.

 

[danadakk]

The melting energy of aluminum is short-sighted, because it gives back exactly the same amount of energy when it hardens. You could use that energy to preheat the aluminum before melting. Some kind of energy recycling. For sure you can´t re use 100% of the energy .... but the same is true for every other material.

Ah but the process creates increasing entropy, more disorder in the universe.

If we stop using heatsinks we are all gonna die

 

[Vbase]

If your heatsink is a plastic box with large surface and filled with water or oil it may do the job.

--- Updated Feb 9, 2025 ---

We just won a large project to build offline car parking LED lights.
But the grant says that we must not use any metal heatsinks.
Each lamp is 60W.
So we must use parallel converters etc so as to avoid aluminium heatsinks.
Our enclosures must also be all plastic and totally enclosing.
We cant use fans either.

So is it true that aluminium heatsinks are bad for the environment?...because aluminium takes loads of energy to make, and even if you recycle it
by melting it back down, this again consumes vast quantities of energy.
And lets face it, nobody ever re-uses old heatsinks that are pulled out of dead power supplies.

So is it right? Is there no way we can argue the case to allow us to use aluminium heatsinks, ie we need to proove that alu heatsinks are not bad for the environment.

If your heatsink is a plastic box with large surface and filled with water or oil it may do the job.

 

[std_match]

Are the LEDs in the same enclosure? If so, even if you solve the electronics cooling, what about the heat from the LEDs?
Higher temperature means shorter life. Can you afford to spread the heat by using more (but lower power) LEDs -> higher component cost?

 

[Easy peasy]

" Also, the energy to smelt Alu back down and re-fashion it is still very high "

But still about 50x less than making new Aluminium from Bauxite - and no CO2 emissions - recycling is almost mandatory in the EU ( design for recycling standards ) - and widely practiced in China & India - where ever your client is - they need to wake up.

 

[betwixt]

Vbase presents a potentially elegant solution but raises a different set of questions. I will open a new topic for discussion as it isn't directly related to the use of Aluminum.

Brian.

 

[cupoftea]

But still about 50x less than making new Aluminium from Bauxite -

Thanks, but i doubt much of power supply aluminium heatsinks gets recycled.
Most probably goes to landfill.

Having spent many days unscrewing aluminium heatsinks away from plastic enclosures, and
trying to unscrew the FETs etc off them, it a fiddley , labour intensive task. I doubt people
will bother to pay people to do it. The whole unit, with heatsinks inside it, will go to
landfill. Even if it didn't, and it is 50x less energy, that's still a lot of energy.
As we remember, making alu is 3% of the world energy...

Better to use paralleled SMPS stages and avoid alu heatsinks altogether.....maybe not in all power supplies
but perhaps in PSU's that have a high volume of sales.

 

[dick_freebird]

Regardless of that, suspect that the fraction of
aluminum that ends up as heat sinks is a nit
compared to consumer and non-power-
supply-component aluminum consumption.

This however is a religious, not a technical
requirement from all appearances. So what
upside to any debate?