Heat Exchanger for 1 BBL Brewery

My brewery is in a constant state of upgrade, and I plan to keep upgrading it right on to 1bbl. So, with that in mind, I'm looking at building a two vessel brewery for now. I want to use 2 kegs, and do 10 gal all grain batches. Recently I've started to appreciate the two vessel systems I've seen where the HLT and the BK are the same vessel. And then a HERMS coil is used for maintaining mash temp and chilling by pumping ice water through. What I'm wondering, is if I can design the HLT coil right, so that I can use it to maintain mash temps on a 55 gallon MT. If I run a 1/2 ID coil through the HLT, will I be able to maintain a 55 gallon MT temp with it?

My system is 35 gallons. I can maintain mash temps with my HERMS (25 foot, 1/2" OD coil) but I can't raise the mash temp very effectively at all. My system used to be a 15 gallon system and I could make the mash temp whatever I wanted in very short order. When I doubled the size of my system, I lost that capability. Providing that the heat source in your HLT is adequate, then the ability to raise your mash temp is directly proportional to the HERMS flow and indirectly proportional to the thermal mass of your mash. In my system, I doubled the thermal mass of the mash without changing the HERMS flow.

You SHOULD be able to maintain your temps....insulation is key in this setup. I wouldn't worry about raising the temp too much...you're using modified grain so it's less important. I wonder how breweries do it....does the thermal mass maintain the temp long enough? Or do they run the wort through a modified RIMS?

I hear that thermal mass helps a lot... I also wonder if I would be better with a RIMS vs a HERMS for the size. At 1 bbl I'd like to get an instant hot water heater for my strike water, but who knows..

Large breweries do not recirculate. Thermal mass makes a huge difference in terms of heat loss in 1 hour. I have been thinking about doing away with the herms and measure the mash temp over one hour to see what I get...