TY - JOUR A1 - Kemppainen, Erno A1 - Bagacki, Rory A1 - Schary, Christian A1 - Bao, Fuxi A1 - Dorbandt, Iris A1 - Janke, Stefan A1 - Emery, Quiterie A1 - Stannowski, Bernd A1 - Schlatmann, Rutger A1 - Calnan, Sonya T1 - Dynamic Operation of a Heat Exchanger in a Thermally Integrated Photovoltaic Electrolyzer JF - Energy Technology N2 - The outdoor operation of an up‐scaled thermally photovoltaic electrolyzer (PV EC), constructed using a heat exchanger (HE) made of low‐cost materials, compared to its nonintegrated counterpart to quantify heat transfer and its effects, is studied. Thermal coupling of the PV and EC can reduce the difference between their temperatures, benefitting device performance. Such devices can produce hydrogen at rooftop installations of small‐to‐medium‐sized nonindustrial buildings. The devices are tested outdoors using automated real‐time monitoring. Under ≈880 W m−2 peak irradiance, they produced hydrogen at ≈120 and ≈110 mL min−1 rate with and without HE, respectively, corresponding to about 8.5% and 7.8% solar‐to‐hydrogen efficiencies. During about 700 h of testing, the HE is beneficial at over ≈500 W m−2 due to cyclic device operation. Under lower irradiance levels, pumping previously heated electrolyte through the HE increases the PV and reduces the electrolyte temperature, reducing the device performance. The HE increases the cumulative hydrogen production (≈800 L from both devices), so even relatively modest heat transfer rates can improve the PV EC operation. Improving the HE should further increase the benefits, but additional measures may be needed to maximize the hydrogen production. KW - electrolyzers KW - heat transfer KW - outdoor characterizations KW - photovoltaics KW - solar water splitting KW - thermal integration KW - Wärmeaustauscher KW - Fotovoltaik KW - Wasserstoff Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:523-16903 VL - 11 IS - 2 ER - TY - JOUR A1 - Calnan, Sonya A1 - Aschbrenner, Stefan A1 - Bao, Fuxi A1 - Kemppainen, Erno A1 - Dorbandt, Iris A1 - Schlatmann, Rutger T1 - Prospects for Hermetic Sealing of Scaled-Up Photoelectrochemical Hydrogen Generators for Reliable and Risk Free Operation JF - Energies N2 - Photo-electrochemical (PEC) systems have the potential to contribute to de-carbonation of the global energy supply because solar energy can be directly converted to hydrogen, which can be burnt without the release of greenhouse gases. However, meaningful deployment of PEC technology in the global energy system, even when highly efficient scaled up devices become available, shall only be a reality when their safe and reliable operation can be guaranteed over several years of service life. The first part of this review discusses the importance of hermetic sealing of up scaled PEC device provided by the casing and sealing joints from a reliability and risk perspective. The second part of the review presents a survey of fully functional devices and early stage demonstrators and uses this to establish the extent to which the state of the art in PEC device design address the issue of hermetic sealing. The survey revealed that current material choices and sealing techniques are still unsuitable for scale–up and commercialization. Accordingly, we examined possible synergies with related photovoltaic and electrochemical devices that have been commericalised, and derived therefrom, recommendations for future research routes that could accelerate the development of hermetic seals of PEC devices. KW - photo-electrochemical KW - solar hydrogen generator KW - hermetic sealing KW - reliability KW - safety KW - scale-up Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:523-3878 SN - 1996-1073 VL - 12 IS - 21 PB - MDPI ER -