Energy efficiency is secondary, that can be mitigated by solar power plus some thermal mass inside. That is actually most efficient use of solar from my pow.
Their bane is hydrogen partial pressure dropping due to it leaking through the metal of the tubes. That .. is problematic. OTOH it'll last for like 20 years before you'd need to replenish.
Their bane is hydrogen partial pressure dropping due to it leaking through the metal of the tubes. That .. is problematic. OTOH it'll last for like 20 years before you'd need to replenish.