Tramway air conditioning system assisted by solar panels in a desert climate

In the hot region of southern Algeria, the tramway is a new means of urban transportation but weather conditions necessitate in-depth studies to ensure acceptable comfort for passengers. In this case, thermal comfort becomes a principal criterion for tramway cabin design. This comfort largely depends on improving the temperature distribution inside the cabin. The analysis for this study of internal temperature behaviour was examined by Ansys code. The internal and external heat gains were evaluated and a numerical simulation conducted to examine airflow thermal and dynamic fields for different conditions. In March 2018, an experimental campaign was carried out for temperature measurement and maintenance operation control. The temperature simulation data was validated against the experimental one. For the cooling circuit, two inlet openings and one outlet opening were designed at the internal surface roof to ensure good air replacement in each wagon module. The results showed that the cooling need required a powerful air conditioning system with a maximal capacity of about 18 kW to reach the thermal comfort of 25 °C in July. The maintenance investigation indicated some cooling system failures due to voltage fall of the electricity grid in summer. A reduced number of photovoltaic-thermal systems were designed to assist the heating and the electrical feed with monocrystalline photovoltaic modules. The tramway roof had sufficient area to install horizontal solar panels. The obtained results showed that the integration of PVT panels for the air conditioning system could provide significant energy to assist both heating and cooling tram systems. .