Thermoelectric generators (TEGs) are solid state devices that convert thermal energy into electrical energy. Using the nighttime sky, or deep space, with an effective temperature of 4°K as a cold sink, the TEG module presented here can produce electrical power at night. The “hot” junction is supplied energy by the ambient air temperature or some other warm temperature source. The cold junction of the TEG is insulated from the surroundings by a vacuum cell, called a Vacuum Pod™ improving its overall effectiveness.
Studies have shown that with particular TEG module designs, a temperature differential across the TEG can be achieved that will produce an estimated 10mW/cm2. This is comparable to the energy available from photovoltaic cells in the noontime sun. Therefore a prototype Nighttime Solar Cell™ is being built and will be tested to determine the effectiveness of the cold junction insulator as well as the influence of other system parameters.
The prototype TEG module is being built with off-the-shelf components to reduce cost and emphasize the availability of standard materials. The prototype is currently in the manufacturing stage.
The theoretical results of the model presented here indicate that the vacuum cell is a very effective addition for the efficient production of electrical energy for TEG modules in a terrestrial application.