I have made a decent heat pump, with 4 x peltier elements each at 48W. Each element will be switched with a separate relay. I will later install DS18B20 sensors in the heatsinks, embedded in thermal paste. Right now my problem is to choose the best, most workable insulation material. It will be placed as a thermal barrier between the hot and cold chambers, which each have their own airflow running.

I chose PU-foam, which is popularly used for e.g. water heaters. The label says it is a cancer risk, so I was wondering what you lot would recommend as an alternative. PU-foam will harden, and make it impossible to remove my pump for repairs etc.

What's the best practice here?


closed as off-topic by Voltage Spike, Enric Blanco, Wesley Lee, Dmitry Grigoryev, PeterJ May 31 '17 at 15:26

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  • \$\begingroup\$ diy.stackexchange.com has a HVAC tag where you can probably find much information. \$\endgroup\$ – Dampmaskin May 24 '17 at 12:28
  • \$\begingroup\$ Don't eat the PU-foam and you wont get cancer \$\endgroup\$ – Voltage Spike May 24 '17 at 18:02
  • 4
    \$\begingroup\$ I'm voting to close this question as off-topic because has nothing to do with electronics and its a shopping question. \$\endgroup\$ – Voltage Spike May 24 '17 at 18:03
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    \$\begingroup\$ It has to do with housing electronics safely. Don't banish me to the DIY stackexchange. \$\endgroup\$ – user2497 May 24 '17 at 18:05
  • \$\begingroup\$ Please let the question stand for 12 hours more. Then I'll close it myself. \$\endgroup\$ – user2497 May 24 '17 at 18:07

Ok, I want to make something clear. TECs are horribly inefficient for certain applications. You're using 16 Amps for a heat pump! That's a lot of current, and is more than lethal if you don't know what you're doing. Overall, if you are doing a central HVAC project (I assume, as you commented that this question had to do with housing electronics), you're better off using a condenser system as that would be more efficient than your 4 TECs.

Concerning your insulation issue: if you're worried about that California cancer warning label - don't. They have to put that label on there because it's legally bound by Proposition 65. It just means that there are ingredients that are found to cause cancer, but it doesn't mean that are in high enough quantities to actually cause cancer. That said, it also doesn't tell if it is in high enough quantities to cause cancer, so using PPE anyways when dealing with this kind of stuff is a good call. I actually own a organizer bucket that has that Proposition 65 warning for a couple of years now, and as far as I can tell, i'm not dead.

Also, don't worry about repairing TEC units - because you can't. They are either working or broken, there isn't an in-between. :)

  • \$\begingroup\$ I have replacement peltier elements, but if set in PU-foam I can't disassemble the heat pump. Thanks for your advice. What is this condenser system you would choose over a heat pump? \$\endgroup\$ – user2497 May 25 '17 at 18:46
  • \$\begingroup\$ @user2497 A condenser system is the heat pump system used in bigger things like refrigerators and central HVAC units. Ever seen that fan-thing on the side of someone's house? That would be the condenser unit, which removes heat from the compressed freon gas, and makes it cold again for reuse. \$\endgroup\$ – gnimmargorP May 25 '17 at 20:08
  • \$\begingroup\$ I thought using freon was prohibited now. That's an excellent solution. I understand this type of system somewhat. Is it economic to build one? \$\endgroup\$ – user2497 May 25 '17 at 20:15
  • \$\begingroup\$ @user2497 It's currently in the process of being phased-out, but it still isn't finished. On the subject of economics: It depends. Various factors that determine price are, but are not limited to: The size of the system, individual components, utilities, and more. You need to determine if the economics outweigh the time and energy to get this running. This is a decision that really cannot be made on a whim. You need to do research on components, and what the system is actually used for. \$\endgroup\$ – gnimmargorP May 25 '17 at 21:13
  • \$\begingroup\$ What are your thoughts on using cooling fluid for cars instead of freon? \$\endgroup\$ – user2497 May 25 '17 at 21:19

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