In the present work, the performance of different cell designs used for the membrane distillation (MD) process was investigated. Three distinctive cell designs were proposed and compared. A numerical simulation using ANSYS Fluent 19 was used to study the performance of the cells. The effects of changing inlet Reynolds number on pressure drop, salt concentration and velocity contours with in the different cell deigns were investigated. Results show that the pressure drop is minimum across the first design, and the salt concentration decreases as Reynolds number increases. At Reynolds number = 125, the results show an enhanced velocity distribution compared to Reynolds number = 250 and 50. One of the proposed cell designs was then fabricated to study the effect of fluid flow on the performance in a direct contact membrane distillation system. Energy parameters were calculated to evaluate the performance of the cell. An evacuated tube solar collector was used to provide the system with hot water. System thermal efficiency, gained output ratio, and specific energy consumption analysis were performed for the system. The increase in the feed flow rate almost doubled the system thermal efficiency and the gained output ratio was increased from 0.31 to 0.60, while the specific energy consumption decreased from 2064 to 1037 kWh/m3.