Evaporative cooling is basically a passive cooling technique in which a body is cooled by the evaporation of water from its surface.The paper deals with the two-dimensional unsteady mathematical model for a clay pot refrigerator and validated with the experimental results obtained in the environment chamber.The test were conducted at different relative humidity and dry bulb temperature and the test results were utilised to obtain the pot efficiency,the COP and the variation of other parameters with the ambient conditions. The presence of the porous medium as clay and sand were given a special importance for modelling the clay pot. The results were also validated with numerical code developed indigenously for the above case. The effect of ambient conditions on mass transfer coefficient, evaporation loss, hydraulic conductivity of clay and sand etc. were studied and analysed.