Shelter that communication equipment and on-equipment material are mounted on is transported by airplane, vehicle and has a function such as waterproof and shielding EMI. Maintaining proper inside temperature of shelter is important in order to operate equipment. Accordingly proper cooling capacity of cooling equipment which installed on the shelter is important for equipment and operator. To calculate proper cooling capacity, There are some considerations such as environmental factors and equipment in the shelter. In Korea solar irradiation and outdoor temperature is difference in accordance with geological characteristic. Also electric equipment mounted on the shelter is increased by development of technology. But the capacity of air conditioner is not changed thus there is a problem about operating equipment. In this paper, Compare cooling capacity of shelter when using air conditioner that is not enough cooling capacity and calculate proper cooling capacity to consider geological solar irradiation and outdoor temperature.