Anyone use a tankless water heater instead of a HLT? I was thinking it might work. Set the temp on the highest setting and use a PID or BCS to turn it off and on.
Pull fresh water through it to get the proper strike temp then use a valve to bring in the wort (using a pump) to recirculate through the tankless heater and back to the mash tun.
It seems like it would sort of be a RIMs system, but one you used to heat the strike water as well. I am assuming if the flow rate was high enough you would avoid scorching of the wort.