Magnetorheological fluid is one of the smart materials. There are various excellent features of MR fluids such as adjustable viscosity, fast response time when exposed to magnetic field, ability to work in different temperature gradient, simple interface between electrical power input and mechanical power output, precise controllability of MR fluids makes the MRF technology attractive and feasible for many applications and has also been employed successfully in various applications. Latest application of Magnetorheological fluids are in the field of thermal engineering, MR fluids are used in refrigerators, ovens etc, and the heat transfer techniques of fluids is used to provide heating or cooling. In these appliances if heat transfer is controlled, then there will be automatic decrease in energy consumption..