TY - JOUR A1 - Summ, Thorsten A1 - Ehrenwirth, Mathias A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Pischow, Kaj A1 - Greenough, Richard A1 - Oyinlola, Muyiwa T1 - Effect of argon concentration on thermal efficiency of gas-filled insulating glass flat-plate collectors JF - Applied Thermal Engineering N2 - Insulating glass flat-plate collectors can save cost by being produced quickly and automatically in insulated glass production facilities, and they can be filled with argon to reduce heat loss. During its lifetime, the collector is likely to lose argon because of gradual material degradation of the sealing. However, information on the influence of the argon concentration on the collector efficiency is limited. Therefore, the objective of this research work was to analyse this effect. A theoretical material property calculation of argon-air mixtures was carried out to determine the convective losses with variable argon concentrations. Thermal collector performance was measured experimentally using an outdoor solar tracker test rig. The results strongly suggest, that the influence of argon concentration on both the convective losses and the thermal efficiency is non-linear. The measurements revealed that an argon concentration of 90 % can increase average thermal performance by 6.7 ± 4.8 percentage points. An increase in argon concentration from 0 % to 50 % has almost twice the effect on average thermal efficiency as an increase from 50 % to 90 %. Concluding from these results, an argon leakage threshold of 2.5 percentage points per year is proposed to avoid disproportionate loss of efficiency over time. UR - https://doi.org/10.1016/j.applthermaleng.2023.120657 KW - Insulating glass KW - Flat-plate collector KW - Argon KW - Gas concentration KW - Efficiency measurement KW - Convective heat transfer Y1 - 2023 UR - https://doi.org/10.1016/j.applthermaleng.2023.120657 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-37875 SN - 1873-5606 SN - 1359-4311 VL - 2023 IS - 230, Part A PB - Elsevier CY - Amsterdam ER -