Heating and Cooling of Tanks

Indirect Heating and Cooling of Stirred Tank Reactors... 

The temperature in stirred tank reactors may be influenced by chemical or physical reactions within the tank. Cooling or heating devices might be required to control the process temperature. In many endothermic processes heat has to be added to raise and maintain the temperature of the bulk. In other exothermic processes heat is removed to avoid hot spots. Heating and cooling of the process fluid are accomplished by heat transfer between the process fluid and a heating or cooling media that is circulated within a closed heat transfer surface. Different types of heat transfer equipment are used in industrial processes such as jackets, external or internal helical coils, as sketched in Fig. 7.10. Heat transfer from the bulk of the tank to the heat transfer medium can be calculated by the standard heat transfer model ... 

Bayonet Heaters A bayonet-tube element consists of an outer and an inner tube. These elements are inserted into tanks and process vessels for heating and cooling purposes. Often the outer tube is of expensive alloy or nonmetalhc (e.g., glass, impeivdous graphite), while the inner tube is of carbon steel. In glass construction, elements with 50.8- or 76.2-mm (2- or 3-in) glass pipe [with lengths to 2.7 m (9 ft)] are in contact with the external fluid, with an inner tube of metal. 

The initial cost of an ACES is much higher than that for conventional home heating and cooling systems, mainly because of the cost of the storage tank. Energy savings in a house with electric resistance backup can be over 1,000 per year, which gives about a 10- to 15-year payback. 

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