Le Chateliers Principle. I learned this theory in Chemistry Class 1974 and I still remember it.
It goes like this:
When ever a Stress is added to a equilibrium System. The System moves in a direction to counteract the Stress.
Heat exchanger system
A coil heater assembly has a housing. The housing has a heated gas inlet and a heated gas outlet. The coil heater assembly has a plurality of coils. The coils are formed of a single tube. The coils are shaped into separate coils with a water inlet and a water outlet. Each of the coils is spiraled around its own unique axis. The axes are parallel with respect to each other. In this manner the heat transfer between the gas and water within the coil heater assembly is maximized.
U.S. PATENT NO. 8,141,199
a device for transferring heat from one medium to another.