Analysis Of Energy Efficiency Of District Heating System With Distributed Variable Speed Pumps

With the global urbanization, development of district heating(DH) system and increased level of heat consumer demand the heating network becomes more scaled and complicated. In that situation designing method used before become obsolete that influence on system stability, reliability as well as efficiency. Nowadays instead of old methods the new approaches in designing and improvement of heating distribution network find an application. The traditional designing method that means choosing the heating system circulation pump according to requirements to overcome the resistance of heat source, piping network and the most disadvantaged heat consumer becomes losing its relevance and is replaced by the more efficient method which proposes to use distributed variable speed pump(DVSP) system. DVSP system allows decreasing the required pressure head of main circulating pump at heat source by implementation the variablе speеd pumps in the ma?n trunk l?ne and/or in the branches of heat consumers. Apart from this, DVSPs replace control valves and are acting as adjustment system. It is important to provide optimal control, since in this way minimal operation costs and potentially significant economic savings can be achieved. In this thesis, the operation of DVSP system in actual conditions is analyzed. Analytic derivation, simulation and engineering-practices verification are adopted as research techniques.At first, the paper provides hydraulic calculation of DH system to determine design parameters of pump stations in the system; based on results the paper compares the district heating with DVSP system with tradition heating system, provides analysis of energy savings that can be achieved and discusses the factors influenced on energy saving ratio.Secondly, DVSP system as adjustment system is considered. Advantages of variable flow control instead of constant flow control in DH system are discussed and value of energy savings is obtained.Finally the DVSP system applicability in actual conditions is discussed. The implementation of single variable speed pump as well as variable speed pumps group is analyzed, pump unit and group efficiency are estimated using characteristic curve based method and specific power consumption based methods.