Mälardalen University researchers have looked at how waste heat from hydrogen production could be used for the district heating (DH) network of Luleå, in northern Sweden.
For hydrogen production, they considered a proton exchange membrane (PEM) electrolyzer and an alkaline electrolyzer, with installed capacities of 100 MW each. A large-scale heat pump and a heat exchanger were added to the system to integrate the waste heat into the DH network. The system simultaneously provides cooling to the electrolyzer stack, thus reducing the operational costs of the electrolyzer.
“The results showed that 203 060 MWhth can be extracted from the PEM electrolyzer with a waste heat temperature of 79 C, while 171 770 MWhth can be integrated on the DH network annually,” the scientists explained.