Study of the Efficiency of Heat-Supply Systems with Steam Turbine CHP Plants, Taking into Account Changes in the Temperature of the Delivery Water during Transportation

Abstract

The aim of the work is to study the efficiency of steam turbine CHPPs in heat-supply systems, taking into account changes in the temperature of delivery water during transportation for various initial and extended heating regulation schedules. To achieve this goal, the following tasks were solved: calculation of the dependences of the delivery water cooling in the supply and return pipelines on the air temperature, construction of temperature and flow rate schedules of delivery water adjusted for heat losses during transportation, calculation of energy efficiency indicators for the operation of a model CHPP with various options for correcting schedules of delivery water. The most significant results are the following. Firstly, for the first time the method of the degree-by-degree calculation of heat losses during transportation and their distribution between pipelines of heating networks was used. Secondly, the dependences of the delivery water cooling in these pipelines on the outside air temperature are calculated. Thirdly, it has been established that the specific reference fuel consumption for electricity supply significantly decreases when switching to more efficient temperature schedules for heating regulation, but changes slightly when switching from natural regulation by flow rate to regulation by the temperature of the delivery water. The significance of the obtained results lies in the possibility of their use for an accurate assessment of the efficiency of heat supply systems with different heating control schedules and for determining the feasibility of correcting temperature schedules in order to take into account the cooling of delivery water during transportation.