Optimum operation of a thermal plant with cogeneration and heat pumps

In this paper, a complex thermal plant is analyzed. The plant under analysis is basically made-up by four gas-fueled engines with heat recovery. Each engine call drive simultaneously an electric generator and the compressor of a heatpump/chiller. The plant is interconnected to the electric utility grid, both to receive additional power and to deliver power in excess. In addition, each heatpump/chiller can be driven electrically, using the electric generator as a motor. For any given amount of power and heat required by the users, a large number of operating conditions are possible. So, tile problem arises of selecting, at any given time, the operation mode that involves the lowest instantaneous cost of operating tile system. This cost call be regarded as the objective function to be minimized in a typical constrained optimization problem. In tile paper, after a short description of the plant, this problem is dealt with. Some examples of tile results provided by the optimization algorithm are provided and commented. Tile economic savings achievable through ail optimized operation are highlighted too.