I recently built another PC, and as Intel insists on including a stock CPU cooler (heatsink + fan), I now have a second CPU cooler that's going unused. I'd rather they not go to waste, I was thinking about instead using them for LED indoor lighting. I would love to replace my CFL lamp with something more efficient, and hopefully dimmable as well.
The coolers are made for 95W and 77W TDP CPUs, and are essentially identical except for some minor differences in the fin design. Each features a copper insert at the base, 28mm in diameter, which is then shrouded in radiating aluminum fins. I've uploaded an image of the two coolers (top of one and bottom of the other, fans are identical).
A few things are holding me back before I order, so I came here seeking advice. They are:
- How should I attach the LEDs to the heatsinks? Obviously they'll have thermal grease between the emitter's base and the copper core of the heatsink, but I'm afraid that that won't be enough to hold it on securely, especially once it gets hot. Perhaps some wire between the fins to tie it down? I don't want to use anything too permanent.
- Will I need active cooling, or can I get away with passive? I currently have a 13W and 26W CFL in my lamp, and though I typically only use the 13W, it's nice to have them both on in some occasions. From my quick googling, it looks like 13W CFLs output around 800 lumens, and the 26W is roughly double with 1600 lumens. So, to get the same output with 2 LEDs, I'd need ~1200 lumens/LED, but I'll take anything close to that (+/- 300 lumens/LED). Will the heatsinks alone be enough for cooling LEDs with that output or will I need to plan on running the fans as well?
- Which LEDs in particular, or perhaps more importantly, where to get them? I've browsed around DealExtreme for some time now, but it appears most of their LEDs are a cool white (I definitely prefer a warmer white, i.e. 3500-5000K), and those that are warmer don't have very high output.
- What to drive the LEDs with? I'm in the US, with 120VAC mains. Ideally I'd like adjustable output (voltage, not PWM) to dim the LEDs, and if I need to drive the fans as well, I'd also need a second (ideally adjustable) output as well. Any commercial products I should look at (including fixed voltage options)? Of course, whatever I drive it with will have to be fairly efficient, or else I'd have to put the regulator on the heatsink instead of the LED .
I'll be sure to update this thread once the build is underway, but right now I just need to figure out what to order.