This is a peltier element used usually to cool a CPU and I got this from Thermal Enterprises on eBay is a 50x50x3.6mm and advertised as model CP1-12726 400W (Qcmax is 243.5W) max 15.4V at 26A internal resistance of 0.48ohm .There are also two aluminum heatsink glued to each side of the peltier element using thermal glue and in this experiment I use tap hot water at about 50C degree so a delta T of about 20C voltage output was 0.65V and I got a max of 1.3V for 40C temperature difference betwin hot and cold side.