Design of a district heating network based on the linear heat density

Abstract

This study aims to develop a design methodology for district heating network based on linear heat density. In the previous study, district heating systems including network were designed by applying mixed integer linear programming (MILP), however, number of demands was small because MILP takes long computational time. In this study, we have designed a district heating network design as a spanning tree problem, and have analyzed it based on Prim’s algorithm. First of all, heat demand was analyzed and heat density maps in target municipals were drawn according to the geographical information of buildings, and the statistical data of the energy consumptions. The target buildings as the demand of district heating systems (DHSs) were selected from the higher heat density area in the drawn heat density maps. In the developed methodology in this study, it is assumed that the heat source is installed in the higher heat demand building. Three heat pipe networks were designed based on linear heat density (LHD case), distance (Distance case), and heat demand (Demand case), and their heat loss and cost were analyzed. As a case study, DHSs in Koriyama city and Akita city were designed and compared. The average pipe diameter and the average linear heat density in the LHD case showed similar trend to experiential curve. The trend in heat loss and pipe cost showed rapid increasing as supplied heat increased in LHD case. It can help to select demand buildings for superior performance of DHS. In the Distance case, the minimum heat loss and cost were obtained when supplied heat were higher, however, there were no clear trend in heat loss and pipe cost because they depended on demand distribution.

Keywords

• district heating system
• network design
• energy density map
• heat supply cost
• co2 reduction