... various fluid media:all type of refrigerants(R410a,R407c,R404,R134a,R22,R23,etc),oil,water,water and glycol mixtures. 2,Used ... extremely popular unit for wood burning furnaces, radiant floor systems, refrigerant systems, straight vegetable oil conversions, beer chilling, air conditioning system ... which the desired result is for two fluids (liquid or gas) to exchange heat.