Describe how you might recover heat from a) a process exhaust gas stream [e.g. from an oven] and,b) a process warm water stream [e.g. from a commercial dishwasher].Discuss any aspects of the streams that may influence your choice of heat recovery system.Need some help / hint etc... Thanks :)
In both cases, you could cool the exhaust gas or the warm water by running it thru a heat exchanger. This would extract the heat (or some of it) and would heat up something else. In the case of the oven, you could use this reclaimed heat to preheat the air feeding the combustion if it is a gas oven or you could use it to preheat the material going into the oven. You could use the reclaimed heat to preheat the water that goes into the water heater that supplies hot water to the dishwasher. There is technology for converting heat directly into electricity (thermo-electric materials) but these material are pretty expensive and not very efficient. Depending on the temperatures involved, you could boil water to make steam and generate electricity. Factors to consider: the temperature, the specific heat of the material, any potential phase changes (boiling or condensation or freezing or melting), any potential hazardous, toxic, or corrosive materials, the cost
