First of its kind fuel cell tri-generator promises to reduce energy loss, costs and emissions
Phys.org, August 26, 2015. Image credit: Silvia_Hartmann
Almost a half of the world’s primary energy consumption is in the provision of electricity, heating and cooling. Most of this energy comes from centralised power stations where up to 70 % of available energy is wasted. The inefficiency of this model is unacceptably high, leading to considerable CO2 emissions and unnecessarily high running costs. These problems could be addressed if we move from conventional centralised power generation systems to efficient onsite micro-generation technology, and one promising possibility in this line is the solid oxide fuel cell (SOFC).
SOFC technology combines hydrogen and oxygen in an electro-chemical reaction to generate electricity, with the only by-products being water vapour, heat and a modest amount of carbon dioxide. Hydrogen can be supplied from hydrocarbon fuels such as natural gas, which is widely available for domestic and public buildings. For three years, the TRISOFC project team worked to advance this type of technology by developing a low-cost durable low temperature (LT) SOFC tri-generation (cooling, heating and power) prototype.
The TRISOFC’s system boasts a number of unique features that set it apart from anything that has been done before. In particular, the operating temperature of the TRISOFC system is between 500 and 600 degrees Celsius, in comparison to normal SOFCs of 800 to 1000 degrees Celsius. “This is important,” Dr Worall notes, “Because it enables BoP and other temperature dependent components to be manufactured from relatively low cost materials, such as stainless steel, and so potentially it substantially reduces costs of materials and components.” Additionally, the LT-SOFC is based on a single component nanocomposite material, an invention of a team led by Professor Binzhu Zhu of KTH, one of the consortium partners, which is unique in that it can act as an anode, cathode and an electrolyte. Dr Worall adds, “Again, this has the potential to reduce costs and complexity and increase reliability and durability.” Finally, the system has been integrated with an open cycle desiccant dehumidification and cooling system to provide heating, cooling and thermal storage. This has not been used before in fuel cells and it has the advantage of potentially increasing the utilisation of the waste heat (currently 40 % to 50 % of the total energy input is wasted).