Just throwing some ideas around while I'm designing my eHERMS system. While debating whether to use 3/8 or 1/2 tubing, I came across people using chillzillas for HERMS duties. They all seemed to have thermal loss issues however since the chiller is usually mounted a bit away on the brewstand. To INCREASE efficiency over a regular HERMS coil, could you immerse the chillzilla (or any all copper CFC) in the HLT/HERMS tank, run your wort through the outside of the chiller where water usually flows, and pump your HLT water through the inside counter to the wort flow(this also prevents hot water stratification in the HLT). This way, you have hot water both inside and outside of your wort and less chance of creating a stale laminar flow in a HERMS coil. I havent done any calculations on this, but I assume it would be very efficient given the nature of ALOT of contact between the wort and hot water. Aside from the cost, would this be a decent idea? Anyone beat me to it and already treid it?