Doing research now for the purchase of LED lights for hydroponics. One important consideration is heat sink for the light. as it adds to the cost quite abit.

I just found spent the last 3 hours reading everything about heat sinks. 

Did you know that.... 


The scientific analysis of aluminium vs copper as a heat sink, 
copper has a conductivity of about 9 watts/inch degree C; Aluminum, about 5 watts/inch degree C.
In other words, copper conducts heat almost twice as much as aluminium.

But... that does not mean that copper is better than aluminium, there is still something called thermal schematic from heat sink to air and then the temperature gradient of the design.   0,o  

Meaning... the design can actually make the cheaper aluminium become as efficient as copper. Or copper can be worst as a heatsink depending on the design.

Aluminium has much lower anisotropic values (1.22) compared to copper (3.16). This results in lower vibrational entropy which microscopically (quantumly) means much lower thermal capacity leading to lower heat storage levels than that of copper. So, yes! while copper tends to conduct and accelerates heat diffusion much faster than aluminium  copper's higher vibrational entropy stores heat energy longer while it is being transformed from thermal to vibrational entropy back to thermal, and that is why its release speed of heat is significantly lower than that of copper. so while for cooling heat diffusion is faster in copper, heat release is lower in copper and higher in aluminium  For heating, not quite so! while for coils inside the warmer medium (condenser is now inside the room) heat is dissipated faster by aluminium coils, which is what we need to get warm, evaporator coils outside in colder temperatures need to be copper so that they absorb heat faster, and store heat longer. 

In short....(i found this very good article that puts it in layman terms... 

Copper and aluminum are both effective materials for heat sink construction, but they have different requirements. If you want to know why, consider a great chef's kitchen.

Aluminum sure can move heat, if it has been done right. It very efficiently absorbs and transfers heat to it's environment and things that interact with it. This works great for bacon in the morning, and even for boiling water, but isn't so good for a large, thick filet mignon. That cold slab of beef sucks the heat right out of the aluminum, and there isn't any left to keep up the cooking. Many people who buy aluminum cookware have a lot of trouble doing steaks properly for this very reason. Aluminum has a low thermal capacity, and a very high thermal conductivity.

As such, aluminum just wicks heat away with little concern for anything else. It won't wick as much as copper, but it sure will move it quickly; Dumping it's capacity as soon as any heat leaves the sink, and quickly soaking up more.

Copper moves heat as well, even if it hasn't been done all that well. Copper very efficiently absorbs and transfers heat as does aluminum. It does it faster, as well. That said, copper has an incredibly high thermal capacity. That big fat steak just can't suck up all the heat that copper will hold on to, and this is where copper and aluminum differ in requirements. Copper won't readily dump all the heat energy it picks up, because it holds so much of it before it changes temperature to any great degree.

That leaves us with a problem. Copper needs help. Somehow, you have to remove all that heat from the copper, as it will just hold on to it otherwise. A copper heat sink can work much better than an aluminum one, but you have to either have loads of pipes and lots of fins and airflow, or you need peltier/water cooling with excellent transfer to help it out.

The thermal capacity of copper, when compared to an aluminum heat sink of the same design, completely removes the benefit of using copper in the first place without help. As a matter of fact, a poorly designed copper sink can be much worse than an aluminum model.

The best way to use the materials is being tried nowadays, and that is combining them. As with most good things, they work better together than apart.

WHEWWWW..... this is heavy... but now i know that its not necessary to spend much more for copper as long as i find someone who knows what to do with aluminium.  :D