On the performance of district heating systems in urban environment: an emergy approach

The overall results showed that four-pipe ESPEX district heating network with central solar plant is the most suitable solution from the emergy point of view. The second most suitable solution was the two-pipe district heating network with solar plant as the heat production unit. On the other hand, networks with central boiler that used the fuel mixture (bioethanol and fossil fuels) and natural gas had lower environmental performance than the natural gas distribution network with individual boiler in each dwelling.