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From: john larkin <JL@gct.com>
Newsgroups: sci.electronics.design
Subject: Re: dumping a lot of heat
Date: Thu, 05 Dec 2024 06:21:32 -0800
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On Thu, 05 Dec 2024 08:07:35 -0500, legg <legg@nospam.magma.ca> wrote:

>On Wed, 04 Dec 2024 13:29:03 -0800, john larkin <jl@glen--canyon.com>
>wrote:
>
>>I'm thinking about building a biggish rackmount dummy load box. It
>>would simulate series resistance and inductance. Part of the problem
>>is that it will need to dump a lot of heat.
>>
>>We are using copper CPU coolers on PC boards, which are great up to a
>>couple of hundred watts, but I'd like to do a kilowatt or two.
>>
>>https://highlandtechnology.com/Product/P945
>>
>>It would take a heap of expensive extruded heat sinks and fans to get
>>rid of a kilowatt. At 1 K/W, a pretty good heat sink, that's 1000 degC
>>temp rise.
>>
>>A small hair dryer can dump a kilowatt. So some sort of red-hot
>>nichrome coils and a vicious fan might work.
>>
>>I'd prefer to not use water.
>>
>>I wonder if there is some sort of runs-red-hot power resistor.
>
>HVAC heater elements are available, premounted in ductwork.
>
>Typical value 10R xKw. Tap, cut or series/parallel to your heart's 
>content.

Yeah, some commercial heating element would be great.

>
>The components to build similar structures, ceramic insulators, 
>and terminals and coiled resistance wire (of selected tempco)
>are all available off the shelf. Punch your own metalwork.

I'd rather not have to terminate the ends of a red-hot nichrome wire,
if I can buy that already done.
  
Electric clothes dryer elements look interesting. I'll look into duct
heaters too; thanks for that tip.

>
>RL