Readers find sentences easier to understand if subjects are short and the longer, more complex information is located after the main verb, so your decision on how to express the verb does not depend on your preference for the active or the passive per se but on the position of the verb in the sentence.
| The effect of the temperature lift between low and intermediate temperature levels on COP for the double lift cycles working with TFE-TEGDME is illustrated in Figure 8. |
| Figure 8 illustrates the effect of the temperature lift between low and intermediate temperature levels on COP for the double lift cycles working with TFE-TEGDME. |