In the present study, a calorimeter was used to experimentally investigate the cooling capacity and COP changes according to the pipe length of a variable capacity A/C system with long pipes. Cooling capacity, COP, and compressor discharge temperature were obtained by changing pipe length and loading duty. And the operation status and cycle change process of the A/C system were investigated using some experimental data and P-h diagrams. In long pipes, the pressure drop increases and the operating load on the compressor increases. Additionally, at the same loading duty, cooling capacity and COP decrease and the compressor discharge temperature increases. As loading duty increases, cooling capacity and compressor power consumption increase. Since the temperature deviation between the experimental value and the correlation equation for the discharge temperature of the long-pipe compressor shows a maximum of 10.5℃(50m, L/D : 20/0), the existing correlation equation needs to be modified.

In this study, the cooling performance of a variable capacity A/C system was experimentally studied. A psychrometric calorimeter was used to obtain performance data of the A/C system using the pulse width modulation method and compare it with the compressor discharge temperature correlation equation. Cooling capacity, COP, and compressor discharge temperature were obtained by changing indoor and outdoor temperatures, refrigerant amount, and loading duty. The following results were obtained by selecting 5 types of refrigerant amount, 3 types of outdoor temperature (fixed indoor temperature), and 2 types of loading duty. As the outdoor temperature increased, cooling capacity and COP according to outdoor conditions decreased. And the higher the loading duty, the greater the cooling capacity, but the COP was minimal. The change in cooling capacity and COP due to the increase in refrigerant amount was not significant. Additionally, the change in compressor discharge temperature is more influenced by the outside temperature than by the loading duty.

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.