Cooling a resistor load powered at 6 to 10kW

[stube40]

I have some resistors to cool that I presume are going to get rather hot!!

I am using 6x wirewound resistors in parallel to create a 3.75 Ohm load for a 150V source, hence generating 40A and 6kW. Later I may up the voltage to 200 so I need to spec the cooling for a max of 10kW. Each wirewound resistor is 28mm dia and 350mm long.

I was thinking of a open perspex box filled with some oil (maybe olive oil). Then creating a custom lid for the box out of a thermally conductive material that is an electrical insulator. Then mounting the resistors on to the bottom side of the lid on long legs so that they are completely submerged. On the top side of the lid I would put a large heatsink and fan.

The maximum length of time the power will flow through the load is 1 minute, so this will help reduce the overall specs.

If anyone likes this idea then my next challenge is to spec the size of the box, amount of oil and the size of the heatsink and fan. This is the tricky bit obviously and I'm not really sure where to start.

 

[IanP]

Olive oil (cold press – extra virgin) is fantastic for cooking purposes, for cooling resistors consider transformer oil, something like Diala BG or Diala BX (Shell) ..
I read somewhere sometime ago that the volume of cooling substance should be around 10L/kW, but that was probably calculated for 25deg ambient and natural convection ..

Rgds,
IanP

 

[FvM]

I would prefer air cooling at this moderate power level. The problem is of course, if you already have resistors that can't work with
air cooling at this power level. The resistor has to be designed for it.

If you have to go for liquid cooling, you can also consider demineralized water. It's often used in laser systems. I guess you are
a physicist, you should know about these instruments.