never payed for a stick of wood in my life.[/quote] And to add to that, I've never paid for a gym membership in my life either.[/quote] That was great! That may be coming back in style. There is a food service distributor in our area that built a new ware house for frozen foods. The chiller units are all natural gas fired and the coolant is similar to ammonia. Where I work at they are building a huge chiller to hit temps of -40 to be used in an inline process. It will be natural gas fired also. I am not sure what the coolant will be but it has one heck of an endothermic condensation process. The product is traveling in a 2 inch SS line at 80 gallons per minute. It starts out at 104 degrees F when it hits the pasteurization system at 290 degrees F then drops to -40 F. All this happens in less than 240 seconds for the entire process and at 2500 – 3000 psi.