Chapter 3 Thermal Management Modeling in Thermo-Chemical Heat Storage Systems 3.1 Different Types of Chemical Reactors In thermal and chemical engineering, chemical reactors are designed vessels where chemical reactions can take place. The design of a chemical reactor deals with multiple aspects of chemical engineering. Chemical engineers design reactors to maximize net present value for the given reaction. Designers ensure that the reaction proceeds with the highest ef ficiency towards the desired output product, producing the highest yield of product while requiring the least amount of money to purchase and operate. Normal operating expenses include energy input, energy removal, raw material costs, labor stuffs, etc. Energy changes can come in the form of heating or cooling, pumping to increase or reduce pressure (under vacuum), frictional pressure loss (such as pressure drop across a 90 °C elbow or an orifice plate), agitation, etc. As described in the previous chapter, the reaction involves hydration and dehydration always followed by thermal exchanges, so the selected reactor should correspond to that need. The number of types of reactors in this field of application is not very large; we denote the packed or fixed bed and the fluidized bed reactors. Small benchtop reactor designs are intended for use in labs (McMahon and Wallace 2003), for example, while large tanks can be used to synthetise chemicals on an industrial scale. The design also includes a variety of features which can be used to control conditions inside the reactor such as evapo-condenser. A quick review on reactor type is described in the following paragraphs. The advantages and disadvantages (Table 3.1) are highlighted, so that a selective comparison becomes easier. In thermochemical processing, a fixed bed is a hollow tube, pipe, or other vessel that is filled with a packing material. The packing can be randomly filled with small objects or else it can be a specifically designed structured packing. Fixed beds may also contain adsorbents such as powders, pellets, granular activated carbon, etc. forming a system of solid particles in contact, surrounded by a fluid (gas or liquid) phase. Therefore it is called packed bed reactor. This type of reactor has a high © Springer International Publishing Switzerland 2016 A. Fopah Lele, A Thermochemical Heat Storage System for Households, Springer Theses, DOI 10.1007/978-3-319-41228-3_3 59