Energy microwave-assisted drying

During microwave-assisted drying (Varith et al., 2007 Holtz et al, 2010), the energy consumption comprises of ... 

The electrical consumption can be recorded using a Watt-hour meter. The energy consumption of microwave-assisted drying can be evaluated (Varith et al., 2007 Soysal et al., 2006) by two different efficiency indices, namely specific energy consumption (SEC) ... 

Fig. 9.15 Variation of specific energy consumption and energy efficiency with moisture content during microwave-assisted drying.

When Yan et al. (2010) compared the energy consumptions of different microwave-assisted drying processes (Fig. 9.16), MWVD and MWSD were found to have about 75% less energy consumption than MWFD. Moreover, there was no significant difference in energy consumption between MWVD and MWSD. The difference from MWFD was attributed to the fact that the drying time for MWFD... 

Table 9.2 presents the SEC and drying efficiency values for different microwave-assisted drying processes of food materials, as determined by various research groups. The minimal theoretical value of SEC for a dryer is 2.3 MJ per kg of evaporated water, based on the maximal theoretical specific moisture extraction ratio (SMER) of 1.55 kg per kWh and the latent heat of water evaporation at 100 °C (Holtz et cd., 2009). These results are expected to depend heavily on the scale and design of dryers, as well as on the method used to measure energy consumption (Durance and Wang, 2002). 

Tab. 9.2 Specific energy consumption (SEC) and energy efficiency for microwave-assisted drying...

Fidalgo, B., Domiguez, A., Pis, J.J., Mene ndez, J.A., 2008. Microwave assisted dry reforming of methane. International Journal of Hydrogen Energy 33,4337-4344. 

Subsequent to freeze stabilization, wet books can be thawed and air dried with or without interleaving or they can be vacuum dried in heated chambers (5). The moisture in frozen books can be sublimed by freeze drying (10) or removed by a vacuum/thaw/outgassing process (8), with microwave energy (6, 14), with dielectric energy (6), or by solvent extraction with or without vacuum assistance (5). 

---