It might sound like a good idea, and it might even be a good idea - but don't go there.
To get enough heat transfer all your vessels are going to need to be jacketed, pressure rated and made to extremely high standards - and come at a gold plated price.
If you were serious about this idea you wouldn't be using Glycol just pressurised hot water - it has much better heat carrying capacity - the problem is that if you get a leak in a high pressure hot water circuit, it would be like taking the lid off a working pressure cooker, you get instant flash boiling and what could easily be a steam explosion, sort of thing I would rather watch from a distance than up close and personal injury...
Low pressure steam would be much safer and more manageable, tho that's not without its risks to, this type of heating is better left for the biger brewers I mean 10HL and above, for smaller plants it isn't worth the investment, maintenance and risk.
Mark