“…Anand et al [20] considered dual-mode CHPs and found that in this case evolutionary programming was the best to solve the UC problem. Basu et al [21] have in a similar way used genetic algorithms for the UC problem, Takada et al [22] used Particle Swarm Optimization, and Song et al [23] used an Improved Ant Colony Search algorithm. Gopalakrishnan et al [24] used a Branch and Bound Optimization method for economic optimization of combined cycle district heating systems.…”