| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1732489 | Energy | 2014 | 18 Pages |
•Space heating and hot water supply analysis of a small city in Japan is conducted.•Geothermal and waste source based district heating system is modelled.•LowEx and SPECO methods are combined for analysis from single user perspective.•District heating system has lower exergy efficiency of 4.2% against 5.4%.•Due to thermo-economic synergy district heating system has lower unit exergy cost.
In this study an exergy and exergoeconomic evaluation of a heat supply system paradigm of Japan and a district heating system (DHS) is conducted from a single user perspective, providing cost-based information on the systems inefficiencies and improvement potential. A heat supply system of a case city is used as a paradigm for Japan and a DHS is modelled according to standard practice for the same city, integrating geothermal heat and local waste sources. The local resources can supply 21% of the design load and natural gas is used for supplying the rest. For the analysis a pre-design exergy analysis tool combined with the specific exergy cost method is applied. The DHS and Japanese paradigm system have exergy efficiency of 4.2% and 5.4% respectively. Due to thermo-economic synergy effect however, the DHS has lower unit exergy cost of space heating and domestic hot water of 508 $/GJ and 273 $/GJ compared to 686 $/GJ and 726 $/GJ of the Japanese paradigm system. The DHS has considerable performance improvement potential through reduced operation temperatures and effective use of combustion sources through co-generation. The unit exergy cost difference leaves margin for capital investment cost increase for decreasing exergy consumption of the DHS.
