Recovery of Short Circuit Current of 3J Solar Cells by Current Injection at Low Temperature
InGaP/GaAs/Ge triple-junction (3J) solar cells designed for space applications were irradiated with 10 MeV protons at 3times1013 /cm2 at 210 K. Current at 0.25 A/cm2 was injected into the irradiated 3J solar cells after irradiation at 210 K to avoid the thermal annealing effects. The short circuit current (Isc) recovered with increasing current injection time, and the recovery saturated at current injection times above 1000 sec. The saturated Isc was 98% of the initial value. The defect annealing rate (A) was estimated to be between 0.003 and 0.01/s from the fitting of the current injection time dependence of the recovery of I sc
Deep-level defects introduced by 1 MeV electron radiation in AlInGaP for multijunction space solar cells
Presented in this paper are 1 MeV electron irradiation effects on wide-band-gap (1.97 eV) (Al0.08Ga0.92)0.52In0.48P diodes and solar cells. The carrier removal rate estimated in p-AlInGaP with electron fluence is about 1cm−1, which is lower than that in InP and GaAs. From high-temperature deep-level transient spectroscopy measurements, a deep-level defect center such as majority-carrier (hole) trap H2 (Eν+0.90±0.05eV) was observed. The changes in carrier concentrations (Δp) and trap densities as a function of electron fluence were compared, and as a result the total introduction rate, 0.39cm−1, of majority-carrier trap centers (H1 and H2) is different from the carrier removal rate, 1cm−1, in p-AlInGaP. From the minority-carrier injection annealing (100mA∕cm2), the annealing activation energy of H2 defect is ΔE=0.60eV, which is likely to be associated with a vacancy-phosphorus Frenkel pair (Vp‐Pi). The recovery of defect concentration and carrier concentration in the irradiated p-AlInGaP by injection relat...
Full-scale measurements of SO2 gas phase concentrations and slurry compositions in a wet flue gas desulphurisation spray absorber
Abstract Two measurement campaigns were carried out at ENERGI E2's Asnaes Power plant, unit 5. The unit has a capacity of 620 MW e and is equipped with a wet flue gas desulphurisation (FGD) plant employing a counter-current spray absorber with five spray levels. In the first campaign, the power plant was firing Orimulsion ® with 2.85 wt% S resulting in a flue gas concentration of SO 2 exceeding 2000 ppmv. In the second campaign, the fuel applied was a low-S blended coal and the SO 2 concentration in the raw gas was around 400 ppmv. A novel probe for in situ sampling of gas phase concentrations in wet FGD spray absorbers was developed and applied for measuring axial profiles of the SO 2 gas phase concentrations in the absorber. The expected decrease in SO 2 concentrations along the height of the absorber was found in the spray section (from height 26.5 to 36.2 m) whereas the SO 2 concentration above the holding tank and below the gas inlet was quite low probably due to long local residence times in the region. Horizontal variations, due to somewhat different flow conditions near the column wall were investigated and the SO 2 concentrations were found to be higher near the wall. Measurements at different gross loads showed that the SO 2 gas phase concentration at a given position inside the absorber was roughly linearly related to the L/G ratio in the measuring interval. Turning off one of the lower spray levels, while burning coal with low S content, did not lower the overall removal efficiency of the absorber. However, the SO 2 gas phase concentration inside the lower part of the absorber was increased by a factor of 2–3. Measurements of slurry pH at different positions showed a decrease of approximately 0.5 units from the upper to the lower part of the absorber. The full-scale measurements provide a detailed set of experimental data for validation of mathematical models of a wet FGD spray absorber.