Modules for exhaust heat generation at lower than 300 degrees centigrade are available on the market, but Hitachi Chemical opened up the road to a hazardous metal-free module for exhaust heat generation supporting temperatures between 400-500 degrees centigrade. The company has already shipped two kinds of samples supporting two different kinds of temperatures. Because some metals that exhibit high generation efficiency at a high temperature contain antimony and lead that need special care for handling, none of them has been used as a material for a generation module for exhaust heat generation. The new module will be applied to the effective utilization of exhaust heat of industrial forges and vehicles for the reduction of energy consumption.
The company established the prospect for a module that generates 11-12 watts at 450 degrees centigrade on the high temperature side and 20 degrees centigrade on the low temperature side using metals of the magnesium and silicon systems. The module for even higher temperature uses metals of the silicon and germanium systems, and it generates 8.4 watts at 650 degrees centigrade on the higher temperature side and 20 degrees centigrade on the low temperature side. The company plans to increase the generation capacity to 10 watts. For low temperature exhaust heat generation, it uses metals of the bismuth and tellurium systems that contain hazardous substances because there are no suitable materials. It wishes to realize generation capacity of 4 watts at 180 degrees centigrade and 20 degrees centigrade in 2012. Each module is a square of 55 mm by 55 mm with a total of 20 elements connected in series.