Background. For modular boiler houses (BMK) of 3–20 MW, the specific power consumption for their own needs reaches 5,5–8,0 % of the generated heat, which is 1,5–2 times higher than its European counterparts due to throttle control of pumps and traction machines. The potential for saving electricity in the country exceeds 2 billion kWh/year and directly reduces the cost of thermal energy. The purpose of the study is to develop and experimentally verify a set of measures to reduce the power consumption of BMK 7,5 MW's own needs by at least 30 % due to introduction of a variable frequency drive and optimized control algorithms.
Materials and methods. Methods of mathematical modeling of thermohydraulic and aerodynamic modes, the theory of controlled electric drive of pumping and fan loads, methods of optimizing energy consumption for own needs of thermal installations, as well as the theory of automatic control with constant pressure drop (DP = const) and excess air coefficient (l-regulation) have been applied. The modeling tools used are the ZuluThermo 10.3 software package (for thermohydraulic calculations), the MATLAB/Simulink environment (modeling an electric drive and a system for its own needs), and original software in Structured Text (IEC 61131-3) for debugging and implementing algorithms into the control panel.
Results. The authors have developed a set of measures for typical Russian block-modular boiler houses, as well as control algorithms for pump and fan equipment. A derived estimate, computer modeling and field tests have been carried out to confirm the effectiveness of the developed algorithms. It has been shown that the proposed solutions will reduce electricity consumption for own needs by 28–34 % and increase the overall efficiency of the boiler room by 4,7–6,2 %. A 34,8 % reduction in electricity consumption, 5,4 % increase in boiler efficiency, annual savings of 680 thousand kWh, payback period of 2,22 years have been achieved.
Conclusions. The proposed technical solutions can be implemented in most existing block-modular boiler houses with a capacity of 3–20 MW, since the design features of the equipment and automation schemes are standardized and unified. The proposed algorithm ensures a sustainable reduction of energy consumption over a wide range of thermal loads, as confirmed by the results of full-scale tests. The developed set of measures is effective, cost-effective, and technologically feasible for autonomous block-modular boiler houses.