[ilyagr]

Yeah, I think this makes sense. If you connect many of my heat exchangers in series, the temperature gradient increases; only the middle one will work at the average of the inside and outside temperature (the example of 3 in a row makes sense to me). At the limit, it becomes what you described.

Thanks!

[vanderZwan]

The mechanism described is called a countercurrent exchange. One fun detail is that it's quite commonly found in biological systems in nature too!

https://en.wikipedia.org/wiki/Countercurrent_exchange

[open_erv2]

It's actually a regenerative heat exchanger: https://en.wikipedia.org/wiki/Regenerative_heat_exchanger.

[lsaferite]

The person you are replying to was discussing "exchanging heat across a continuous length along opposing flows", which is countercurrent exchange. Regenerative exchange is, at least to my understanding, more of a cyclical store and release process.

[vanderZwan]

Yes, which is what OpenERV is. I can understand why they might have thought I was talking about their system, my wording was a bit ambiguous there. So it doesn't hurt that they cleared that up :)