Simulation and Optimization of a Solar Driven Air Conditioning System for Indian Cities Conventional air-conditioners need high grade energy i.e. electricity, which in India, is primarily produced from fossil fuels. In spite of several emission restraints exercised by many countries under Kyoto protocol, energy consumption and pollution levels are higher than ever. Therefore, an assessment from the ecological point of view needs to be implemented as the greenhouse gases effect remains a threat to the environment. India is a booming economy with not enough installed power to supply the growing demand. This shortage of electricity results in frequent power cuts, even in the metropolitan cities. In summers, the cooling load of buildings increases due to high ambient temperature. It is during the same time that available solar is at its peak. These are some of the motivations behind usage of solar energy for air conditioning of buildings. Solar cooling technology provides an important contribution to both economical and ecological energy supply. The aim of this study was to simulate and optimize a solar based absorption system for Indian conditions. Four cities were selected such that they have different incident solar radiation and climatic region. Since Meteonorm data files are not available for all locations, the availability of city’s data file was also considered during selection. Meteonorm files are used to simulate the ambient conditions for a location in TRNSYS simulations. Energistic SunTrac27 was selected as the solar collector for this study based on efficiency comparisons. Standard configuration for the building and comfort conditions was setup based on ASHRAE standards. The cooling loads were estimated with the standard configuration for selected cities. The parametric analysis was conducted to study the impact each of infiltration, ventilation, comfort conditions, heat gains, and other simulation conditions on the cooling load. It was observed that the months which have highest ambient temperature for the selected cities also happen to be the ones with the highest cooling loads. This was because even if solar radiation was not the only parameter affecting the cooling load, it was certainly the only variable for an office premises where other parameters are fixed, like number of people, working hours, lighting, usage of appliances etc. The cooling loads were simulated hourly and saved in an output file. This file was used for simulating the load component in the TRNSYS model of solar absorption cycle. Solar based absorption cycle was simulated using TRNSYS. Inputs to collector model was provided from datasheet of SunTrac27, whereas the inputs to absorption chiller model were