The present study investigates experimentally the effect of employing a plain/dimpled internal tube liquid-suction heat exchanger (LSHE). The cycle pressure ratio (P_c/P_ev) on the performance of a simple vapour single stage compression refrigeration system using 134a as a working fluid. The LSHE is in vertical position. Through the experiments, the dimples pitch to dimples diameter (λ) is varied in the range of 1≤λ≤4. While the evaporator pressure (P_ev) varied from 1.79 bar to 2.75 bar and condenser (P_c) pressure changed from 13.15 bar to 15.48 bar which gives VCRS pressure ratio between 5.6 and 7.35. The experimental results showed that incorporating a plain or dimpled internal tube LSHE in the system considerably enhances the coefficient of performance (COP). It is evident also that decreasing the dimples pitch ratio augments the COP and the LSHE effectiveness. Furthermore, increasing the pressure ratio considerably improve the COP and the LSHE effectiveness. Finally, empirical correlations are deduced based on the experimental results to calculate the COP and the effectiveness of the LSHE.