Phases and Heat Exchange

Phases and Heat Exchange

                               INTRODUCTION                 RESEARCH                EXPERIMENTS                                

Energy can be transferred from one medium to another using a heat exchanger.

A heat exchanger can be as simple as two concentric pipes as shown below:

How quickly heat passes from one fluid to the other is controlled by the rate of heat exchange. This rate is dependent on a number of factors, including;

• the temperature difference of the fluids,

• the boundary through which heat is being transferred,

• the specific heat capacity of the fluids,

• the area over which the fluids come into contact.

Phase changes theoretically occur at specific temperature and pressure combinations for different materials. However, in practice it's not just these variables that affect whether or not a substance will change phase. A substance can be below its theoretical freezing temperature, but still stay liquid, given the right conditions. This is known as a "supercooled" substance.

                                                 From pg 238 in Cengel...