Comparison with Conventional Energy Supply Systems

Comparison with Conventional Energy Supply Systems 

A few selected examples of smaller scale conventional electrical power generators based upon internal combustion engine technology will be discussed below. 

One is the DACHS combined heat and power system developed by the German company SenerTec. The device has an electrical power output of 5.5 kWei, a thermal power output of 12.5 kWth, a high electrical efficiency of 25%, while the thermal efficiency is about 65%. The overall efficiency is therefore high at 90%. It has a size of 1.06-m length, 0.72-m width and 1-m height, a weight of 5 20 kg and noise emissions of less than 56 dB. Possible fuels are natural gas, liquefied petroleum gas, bio-diesel and diesel. 

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Comparison with Conventional Energy Supply Systems... 

The bulk polymerization of styrene at two different power levels - 300 and 500 W - conducted in a multimode microwave cavity was investigated by Chia et al. [38]. The reactions were run in 2-ml sample vials of 10 mm diameter, in which 23.0 mg of AIBN was placed together with 455 mg of styrene. The conversion profiles of the microwave polymerization were significantly different from that of the thermal cure at the same temperature of 80 °C. The thermal cure was characteristic of a gradual gel effect at 30-50% conversion while, with the microwave cure at 300 W and 500 W, a sharp and large gel effect was recorded at conversions 20-69% and 20-65%, respectively (Fig. 5). Moreover, the comparison of thermal and microwave polymerization under similar conditions showed a reaction rate enhancement of 190% for 500 W and 120% for 300 W. Similar to the microwave polymerization of MMA [35], the limiting conversion of styrene decreased from 72% for conventional thermal conditions down to 69 % at 300 W and 65 % at 500 W of microwave irradiation power. Finally, it was stated that comparison of kinetic results of microwave induced reactions should consider the temperature as well as the power of micro-wave irradiation due to different energy supplied to the reaction system [38]. 

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