Fig. 4 | Nature Communications

Fig. 4

From: Contactless steam generation and superheating under one sun illumination

Fig. 4

Performance of a laboratory-scale contactless solar evaporation structure. a Measured and modelled steady-state efficiency as a function of the incident solar flux. Each data point corresponds to a single unique experimental run. The steady-state efficiency was determined by dividing the evaporated mass during the quasi-steady phase Δmss by the duration of the quasi-steady phase Δtss. The evaporated mass was determined by measuring change in the mass of water in the basin before and after the experiment Δmbasin. Error bars indicate uncertainty in steady-state efficiency due to the small amount of evaporation in the heat-up phase (see Fig. 3) Δmheat-up, which is attributed partially to evaporation from the basin, and partially to evaporation of residual moisture in the system. For the lower bound, Δmheat-up is attributed solely to basin evaporation, is thus subtracted from Δmbasin to obtain a rigorous lower bound on efficiency. For the upper bound, Δmheat-up is attributed entirely to residual moisture and thus does not need to be subtracted from Δmbasin. The marker location indicates a representative intermediate value where we attribute 50% of Δmheat-up as being due to basin evaporation (see Supplementary Note 11 for details). b Measured and modelled superheated steam temperature during the quasi-steady region as a function of the incident solar flux. The analytical model is described in Supplementary Note 3, and is summarized by Eqs. (5) and (6). The numerical model is described in Supplementary Note 5. For the results labelled “shielded”, a radiation shield was used to boost the steam temperature