Abstract: The present invention limits fluid temperature at a point in a fluidic system to below a predetermined temperature by cooling the fluid when needed and without requiring a separate cold fluid source. The present invention “clips” the temperature of the fluid at a point in the system to within a temperature range and prevents overcooling the fluid. When the fluid temperature is below the temperature range, the temperature of the fluid is unchanged as it passes through the apparatus of the present invention. The present invention may operate without external power, can function in any orientation, and works for unpressurized and pressurized systems. The present invention has application in the areas of solar thermal energy systems, fluid tanks, engine oil and coolant systems, transmission fluid systems, hydraulic systems, machining fluid systems, and cutting fluid systems, among others.