The efficiency of generating power and cooling can be enhanced by using cogeneration systems. To simultaneously generate cooling and power, a novel ammonia-water cogeneration system driven by waste heat recovery is presented. In the proposed system, the boiler and condenser work at the non-isothermal and isothermal phase changes, respectively. To evaluate the novel cycle, firstly, for heat source temperature of 473K, the effect of maximum pressure of cycle and ammonia concentration is investigated. Considering the results, increasing ammonia concentration decreases the ratio of net power to cooling capacity while increasing maximum pressure increases the net power to cooling capacity ratio. At various ammonia concentrations and the constant pressure of 25 bar, the maximum exergy efficiency occurs at a concentration of 89%. Also, at a constant concentration of 85% and various maximum pressures, the optimum exergy efficiency occurs at 34 bar. To optimize the proposed system, the selected objective function is the total exergy efficiency. So, by a genetic algorithm, at a heat source temperature of 473K, the concentration and pressure are optimized at the values of 88.28% and 31.1 bar, respectively. Eventually, the optimum values of pressure and concentration for various heat source temperatures are presented in a table.