Trigeneration systems use waste heat from prime movers to generate heating and cooling along with power. They are more efficient, less polluting & more economical than conventional systems. In this paper, in addition to the electricity generated from the engine genset waste heat from engine exhaust was used for heating and space cooling purpose. In this work, for space cooling, four units of Electrolux vapor absorption system, each with a capacity of 51 liters and heat input of 95 Watts, were used. Exhaust gas from the engine was the source of thermal energy to provide heat to the four generators of the VA system. A cabin (3’X5’X6’) made of ply wood was fabricated as a space for cooling. The test results show that a temperature drop of 6.5°C was obtained in cabin at full engine load about 6 hours after system start up. In this trigeneration or combined cooling heating and power (CCHP) mode, cooling water after extracting heat from engine block was designed to pass through the heat exchanger, where the other fluid was exhaust gas coming out from VA system generators. For the optimization of trigeneration system in CCHP mode, different VA units were operated one by one to obtain the best energy output in terms of space cooling and water heating. The test results show that in this size of set-up, using 3 units of VA system (i.e. approx. 150litres) generates an optimized trigeneration system. However, if more cooling effect is desired, then all four units of VA system should be put into operation, though sacrificing some output in terms of water heating.