Optimization of a District Heating energy supply system under a cost-effectiveness perspective

Abstract

The necessity to reduce greenhouse gas (GHG) emissions is a world global challenge that is reflected in numerous international, agreements, national and local regulations. Build-ings stand out as one of the sectors that require a significant amount of energy, hence building efficiency optimization and incorporation of renewable energy sources (RES) is a constant tendency aimed at leading to the creation of concepts, such as nearly Zero Emission Buildings (nZEB). In this respect, the potential for reducing energy consumption in the building stock evolving towards districts scale, which can play a significant role in the energy transition of the stock, as its tackle larger scale of projects. To this end, along with passive energy efficiency measures (EEM) district heating (DH) is one of the options for the reduction of energy consumption and emissions from heat production. The thesis concerns optimization of the district heating network under the cost-effec-tivity analysis of centralized energy supply systems (ESS) in conjunction with passive EEM, and RES for the Otxarkoaga neighbourhood in Bilbao. For this purpose, based on a simplified model (131 buildings) of the neighbourhood created in the Design Builder program the set of ESS scenarios for the DH network has been designed, described, and simulated. Following that, simulation output has been analysed by energy demand and ESS consumption within a set of applied EEM at the district level. In total 60 combina-tions have been considered. Also, the DH network topology was proposed, and distribu-tion heat losses were characterized. Finally, the economic study of considered ESS tech-nologies of DH network analyzed under the cost-effectiveness perspective and compara-tive characteristics of the district to individual building renovation is carried out. The study showed that centralised heating could be cost-effective for a considered neighbourhood within some technologies. The biomass boiler ESS can have renovation combination with the lowest investment in 10,000 € per building, and geothermal solution, being highly investment, can reach the lowest energy consumption.