Hidraulički proračun složenih mreža sistema daljinskog grejanja

Abstract

Poznavanje raspodele protoka i pritiska u mreži sistema daljinskog grejanja u različitim pogonskim uslovima i u celom opsegu snaga proizvodnje i potrošnje toplote, neophodan je uslov za efikasan transport i distribuciju toplote od izvora do potrošača. Mreže sistema daljinskog grejanja imaju prstenastu konfiguraciju i njihov hidraulički proračun je moguć samo ukoliko se istovremeno sprovodi za sve deonice mreže. U radu je prikazana numerička metoda za hidraulički proračun sistema daljinskog grejanja koja se može primeniti na složene mreže proizvoljne konfiguracije. Metoda je zasnovana na linearizovanim bilansima promene pritisaka u okviru prstenova mreže i iterativnom rešavanju korigovanih protoka. Za razliku od standardne metode Hardy Cross, u ovde prikazanom postupku se pri formiranju bilansa promene pritiska za određeni prsten ne zanemaruje uticaj korekcija protoka susednih prstenova. Razvijena metoda omogućava brze i efikasne hidrauličke proračune na računaru i najsloženijih mreža koje se mogu javiti u inženjerskoj praksi. Primena metode je prikazana za jednu konfiguraciju toplovodne mreže koja uključuje toplanu, toplotne podstanice, pumpe i razvodne i povratne cevovode.

Information about flow rates and pressure distribution within district heating system under different operational conditions and m the whole range of heat production and consumption loads is the only prerequisite for efficient transport and distribution of heat from a source to consumers. District heating system networks are composed of pipeline loops and their hydraulic calculation is possible if one simultaneously solves all system segments. This paper presents a numerical method for hydraulic calculations of district heating networks that is applicable to complex networks of different configurations. The method is based on the linearized balance of pressure changes along network closed loops and iterative solution of corrected flow rates. Compared with the standard Hardy Cross method, procedure here applied does not neglect the flow rate corrections of neighboring loops in the pressure change balance of observed loop. The developed method enables fast and efficient hydraulic computer calculations even for the most complex networks that appear m engineering practice. The method application is demonstrated for a typical configuration of district heating system network that includes heat production plant, heat consumer substations, pumps and supply and return pipelines.