In order to know the heat transfer and fluid flow characteristics of a vertical channel having grooved pattern in one side, we have carried out a numerical analysis using the commercial CFD code. This system may be used as a wall of house to reduce the electricity consumption of an air conditioner. The side wall is heated by radiation of solar energy and is cooled by natural convection of air. This paper describes fluid flow characteristics of inside channel having grooved pattern which are exposed to radiation heat and are cooled by air. We have analyzed the steady state of natural convection in the vertical channel by using Phoenics code (CHAM Limited). From the results obtained in the numerical analysis, it is found that air inside the channel heated by solar energy. This system have a potential to warm the air in a room, however, it is difficult to establish the flow of warmed air from the vertical channel to the room.