Leaching considerations with reactive heat sink materials

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To cool a slow-moving hydroponic plant water flow with a nutrient concentration of 1000 ppm and a pH around 6, using aluminum or copper heat sinks is being considered. Concerns about potential contamination from leaching metals into the fluid have been raised. Most coatings that could prevent leaching may reduce thermal conductivity, but the impact might be minimal for this application. It's essential to estimate the required size of the heat sink based on the fluid's flow rate, as water's high specific heat capacity may necessitate a larger or more efficient cooling solution, such as a fan-cooled radiator. Proper evaluation of these factors will help ensure effective cooling without compromising water quality.
shane2
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I need to cool a slow moving small flow of hydroponic plant water, at most 1000 ppm nutrients, with a pH of typically around 6.

I'd like to use aluminum or copper heat sink directly in that fluid stream to drop temp 10 or 20 degrees F down to 50-60F neighborhood.

My concern is I don't want to contaminate my fluids with copper or aluminum reacting to and leaching off into the fluid.

Is that likely an issue and if so, is there any spray coating or other such treatment onto the surface of the heat sink to minimize that happening that does not greatly degrade the materials thermal conductivity?

Thank you for any thoughts.

- Shane
 
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Most coatings will degrade the thermal conductivity by comparison because copper is a very good conductor. The question is will any degradation be significant. I suspect it won't be because your application isn't very critical and the coating can be thin.

Perhaps start by estimating the size of heatsink required. To do that you need to know the flow rate of the fluid you are cooling. Water has a high specific heat capacity so if the flow rate is significant the heatsink required might need to be large or impractically large. Might need something more like a fan cooled radiator.
 
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CWatters, thank you.

- Shane
 
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