As gravity-fed recirculation evaporator is restricted by its principles

the structure of its flow path couldn’t be the same as that of the direct expansion cooling system. Firstly

in this paper

the flow path optimal principles of gravity-fed recirculation evaporator have been clarified

and two forms of flow path structures have been designed. The first is a flow path structure which is commonly used in the gravity-fed cooling system

and the second is an optimized flow path structure. A gravity-fed recirculation evaporator experiment platform is built based on the above. The evaporator performances before and after the optimization have been compared and analyzed. Results shows that

when the temperature of the insulation body keeps constant

the same circulation ratio and mean temperature difference can be guaranteed at the refrigerant-side of the four branches in parallel since the mean temperature of the air which contacts each of the branches of the optimized evaporator is the same.It is also shown that the optimized evaporation has a better performance

especially under the low-temperature condition. The second (ie. the optimized) evaporator has a greater heat transfer than the first (ie. the common) one based on per unit area

and the cooling capacity increased 60.3% and 44.1% respectively

and the COP increased 16% and 13.87% respectively for the condition of -25 ℃ and -20 ℃.