Excess heat production of future net zero energy buildings within district heating areas in Denmark

Denmark's long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and net zero energy buildings (NZEBs) has increased. Most buildings in Denmark are connected to electricity grids and around half are connected to district heating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper's objective is to examine how excess heat production from NZEBs influences different types of DH systems. In the analysis three different types of DH systems are analyzed, and three technology development scenarios for each are created. The examination is from a technical perspective and looks into how the overall heat production within DH areas is affected by the NZEBs excess heat production from solar thermal collectors. The main findings are that the excess heat from NZEBs can benefit DH systems by decreasing the production from production units utilizing combustible fuels. In DH areas where the heat demand in summer months is already covered by renewable energy, adding seasonal heat storage is essential to utilize the NZEB production. (C) 2012 Elsevier Ltd. All rights reserved.