A heuristically based "optimal control" strategy for integrated boilers is developed, and the methodology of generating the control profiles is illustrated with examples. The optimal control profiles are assumed to consist of bang-bang (on-off) and unsaturated portions. A one-dimensional numerical search is executed to determine the switching times. By studying the behaviour of state-space trajectories, it is shown that the heuristic profiles are indeed "optimal". Further comparisons with results obtained from numerical optimisation techniques also suggest that the heuristic control profiles are near optimal.

KEYWORDS: optimisers, boilers, space heating, water heating, domestic, controls, comparing.