View source for PEX

=Specs=
*'''Pressure drop, bend radius''' - [https://www.pexuniverse.com/pex-tubing-technical-specs]
=Sourcing=
*1/2", 600' for $120. [https://smile.amazon.com/Happybuy-Oxygen-Barrier-PEX-Tubing/dp/B0711Z2Y9Y/ref=sr_1_18?dchild=1&keywords=1%2F2%22%2Bx%2B300%2BFt%2BOxygen%2BO2%2BBarrier%2BPEX%2Bpiping%2B-%2BGenuine%2BPEX%2BGUY%2Bpiping&qid=1627766649&s=hi&sr=1-18&th=1]

=Calculations=
*Internal volume - 6 gal [https://smile.amazon.com/Happybuy-Oxygen-Barrier-PEX-Tubing/dp/B0711Z2Y9Y/ref=sr_1_18?dchild=1&keywords=1%2F2%22%2Bx%2B300%2BFt%2BOxygen%2BO2%2BBarrier%2BPEX%2Bpiping%2B-%2BGenuine%2BPEX%2BGUY%2Bpiping&qid=1627766649&s=hi&sr=1-18&th=1]. 1 gal per 100 feet.

=Lessons Learned=
*Large bed of sand to store heat, or even pulverized, dry soil - is sufficient to store large amounts of heat. Even for seasonal storage.
*It is easier than having to maintain a large pool of water.
*Specific heat of water - 1 cal/gram/C vs rock at 0.2 cal/gram/C. Need 5x rock to water. But [[Void Ratio]] may be 50%, so one would need 10x the sand compared to water.
*Insulated basement with sand would be ideal.