In our study

we chose crown daisy

a representative leaf-vegetable vegetable

to study the relative energy saving and the temperature decrease rate experimentally. The vacuum pump was controlled to start at different inlet water temperatures of the condenser pipe. The result shows that it can save energy and the temperature decrease rate is rapid if the vaccum pump starts running when the proportion of the saturation pressure corresponding to condenser pipe inlet water temperature to the saturation pressure corresponding to the experiment object temperature is 0.5.