# Icing Mitigation by MEMS-Fabricated Surface Dielectric Barrier Discharge
## 5 SDBD Efficiency  
Previous publications and our results demonstrate a significant anti-icing effect of SDBDs. However, the application prospects of the phenomenon are strongly dependent on the efficiency compared to other technologies. The power consumption of the SDBDs and the parameters used in the current study are compared to the literature data in Table 2. Note that it is important to compare the power normalized to the surface area and only few data is available so far. [PERSON] et al. [54] conducted electro-thermal anti-icing experiments on a composite aircraft component. A hybrid anti-icing system combining thermoelectric and hydrophobic coatings was investigated by [PERSON] et al. [55]. [PERSON] et al. [22] reported on an anti-icing system with 1 mm thick ABS-shell SDBDs with 35 um thick copper electrodes arranged in a stripe and a grid-like geometry. Their operation voltage was 17.8 kV\({}_{\text{pp}}\) (stripes) and 19.1 kV\({}_{\text{pp}}\) (grid) at a frequency of about 11 kHz. They showed that the DBD plasma generated by the two investigated geometries can prevent ice accretion on the leading edge. The zirconia SDBD (\(\epsilon_{r}=28.3\)) has a similar discharge power consumption compared to the SDBDs of [PERSON] et al. [22], see Table 2. However, the glass and PCB SDBD seems to be more efficient since a visible anti-icing effect was achieved at a much lower power consumption. Partly it can be attributed to the dielectric losses, but probably the zirconia SDBD was operated with too much power. An additional power dissipation required to generate the high-voltage should be accounted for when comparing SDBDs to heating technology. For this purpose, the system power consumption \(P_{sys}\) (Chroma output power) was measured before the voltage transformer. Table 2 indicates that our transformer losses are comparable to the one of [PERSON] et al. [22]. The system power consumption of the SDBDs is significantly lower than for the heating devices presented by [PERSON] et al. [54] and [PERSON] et al. [55]. The total plugin-power measured before the waveform generator for the FR-4 SDBD was 160 W (95 kW m\({}^{-2}\)). The laboratory power supply is designed for generation of a stable sinusoidal waveform of different frequencies up to 1 kHz, which can be applied to SDBDs of different geometries. Therefore, it is not optimized for a maximum power efficiency at fixed SDBD operation parameters, discharge geometry and load of the discharge. However, the SDBD plugin power density is comparable with the system power density of the heating devices pointing out the high potential of SDBD anti-icing systems. It can be noted that the electrical power consumed by the plasma for a freely expanding SDBD scales cubic with the applied voltage [43] and quadratic with the dielectric losses [56]. However, when the discharge occupies the whole surface area, the further power increase is linear. The contribution of the dielectric losses to the system power is larger, if the SDBD operates at voltages higher than required for the discharge expansion. Excessive heating of the bulk dielectric alters the working principle of the SDBD to that of an heating device severely limiting the efficiency. The voltage required for the discharge expansion over the whole area depends on the SDBD geometry and the ambient pressure. This observation provides an extra opportunity for the optimization of the SDBD efficiency. Additionally, we would like to emphasize the observed gradient of icing. Electrodes located further downstream already benefit from a partial deicing of the previous ones. Thus, the SDBD efficiency can be optimized by varying the discharge power density over the aerodynamic component. The highest power density should be at the leading edge and it can be reduced along the wing camber. Two strategies can be applied for the variation of the power density. The first one is to vary the density of the SDBD segments. Technically, this seems to be the simplest solution.