This is a project I've been working on the past couple months. What I wanted to achieve was a stealthy, all-in-one solution. I like the idea of space buckets but I like hydroponics (here DWC) even more, so I combined them into one. I have a GitHub repo for my code: https://github.com/linkcharger/barrel-control.
On the lid there's the heat sink with two COB-LEDs mounted with screws. Thermal grease was added to improve thermal conduction. The chinese LEDs are definitely not driven at 100W (like you could do with Crees or Vero 29s) but kept at about 50-70W. That also makes thermal management easier.
As for the general supply of energy: the 360W driver brings the voltage down from 230/120V down to 30V. From there two small buck converter bring it further down to 5V (microcontroller) and 12V (fans and maybe later LED strip). For the LEDs there's the 150W boost converter to bring the voltage up again to in between 30 and 36V, thus controlling the output power (visible on the amp- and volt-meter).
The chip controls the on-off-times of the LEDs (18/6 and 12/12), regulates the cooling of heatsink and air inside the barrel, and it can also output the sensor values of sink and air temperature as well as humidity. The lights can also be switched on and off manually and of course the user switches from veg to flower.
The lower part of the barrel is filled with 15-20l of nutrient solution. The solution is oxygenated by the aquarium air pump, then the solution is top-fed to the plant 24/7 the first couple of weeks (to promote faster growth). A ball valve allows for easy filling and draining. After that a disk out of thick plastic makes the floor which the mesh pot sits in. On that level there's also the air intake which at the moment creates positive pressure, but once I flower in there it will be fixed to the air outlet to create negative pressure. That air will then be pushed through activated carbon.
The pot is nothing special, I even made it myself out of a regular pot and a dremel. It's filled with small-sized hydroton balls. The bottom, walls, and lid are all painted with a 50/50 mixture out of flat PU-white (sticks to plastic) and BaSO4 (Barium sulfate). This pushes reflection throughout the whole spectrum into the high 90 per cents. Thanks /u/superangryguyfor finding that study.
If you want to build one yourself, here's a parts list: https://www.reddit.com/r/SpaceBuckets/comments/4uoxkn/build_log_i_present_the_hydrobarrel/
(I could also make a kit: get all the parts, wires at correct lengths, maybe already solder some things etc and then send it to you. If you'd like that, message me at /u/linkcharger)