Heat Load and Cooling Capacity Calculation of Air Conditioning System of Rolling Stock Considering the Environmental Condition of India

The design of the Heating Ventilation and Air Conditioning (HVAC) system has assumed significant importance in the design of rolling stock due to environmental concerns. Countries like India, which have extreme climatic temperature and humidity during summer and monsoon make designing HVAC system complicated. Proper understanding of the environmental requirements for heat load and cooling capacity calculations will help optimise the design of HVAC systems and avoid over-design that increases weight and power consumption. There are limited high speed train manufacturers who have experience in designing HVAC for varying environmental conditions. A country like India, adopting new high-speed rail, may find it challenging to make any significant changes that could affect HVAC weight and power consumption. Therefore, countries newly developing high-speed rail need to consider this aspect carefully and effectively without compromising on proven design and passenger comfort. This study aims to evaluate heat load and cooling capacity, considering factual environmental data. The study includes an examination of three major aspects of HVAC design for rolling stock and its surroundings with each aspect discussed distinctly. (a) Heat load calculation of rolling stock, (b) Determination of the cooling capacity of the system, (c) Passenger comfort criteria. Heat load and cooling capacity mainly depend on the ambient temperature, humidity, and solar radiation gained through conducting material, windows, and fresh air intake for passengers. The present paper illustrates heat load, and cooling capacity calculation in detail considering values/ formulae from ASHARE and then formulating the environmental requirements for Indian conditions by comparing passenger comfort criteria for Indian climatic conditions and cooling requirements. This will be useful for designing and calculating operating criteria for train manufacturers and users for Indian conditions.