Meeting heat demands in Dutch existing homes using Low Temperature District Heating

Abstract

Dutch homes use 70% of their total energy consumption for domestic hot water purposes and space heating. Currently, this energy is yielded through the use of natural gas. In order to meet Dutch Climate Agreement goals, which were agreed upon December 2018, Low Temperature District Heating (LTDH) is expected as being the most promising sustainable heat energy system solution for dense populated districts. To produce sustainable heat, Visser & Smit Hanab (V&SH) have developed a geothermal source which extracts heat from shallow surfaces, between 500 and 1250 meters. Currently, this system is only used to provide heat for greenhouses. Greenhouses are in need of heat supply for more than 5000 hours per year. This thesis presents which other technologies are required to make LTDH with Low Temperature Geothermal Heat (LTGH) as main source a success for heating in district areas. For the case, there are 5 LTDH concepts designed to supply heat to the livings with LTGH. The designed LTDH varies in storage methods, supply temperature in the network, and peak heat supply technologies. The used storage methods are Aquifer Thermal Energy Storage (ATES) and a water tank of 250 liters for each living. The used peak heat supply technologies are decentralized heat pumps, electrical heaters, and a biomass boiler. The following LTDH concepts are designed.1a. Collective peak supply 70 ⁰C2a. Decentral peak supply 70 ⁰C1b. Collective peak supply 50 ⁰C2b. Decentral peak supply 50 ⁰C3. Decentralized heat pumps using 30 ⁰C supply temperatureBased on Key Performance Indicators, these LTDH concepts are compared with each other. Throughout a thermodynamic and economic analysis, it appeard that LTDH concept 3, where decentralized heat pumps are used, scores the best on all the KPIs. concept. That is because the central heat pump, of the other concepts, consumes the most electricity of all the technologies in the system and is always on throughout the entire year. The average efficiency, over a year, of an air heat pump is higher than that of the central heat pump at the LTGH. This is because the air heat pump is switched off when there is no heat demand and with an LTDH, there are losses in the network and the ATES.Future research must be done on the electricity consumption of the central heat pump from the LTGH. If the heat pump can consume less electricity, the load on the electricity during cold hours can be reduced and throughout a year CO2 emissions can be reduced. Also, future research must be done on optimizing the LTDH concepts, so that the savings in CO2 emissions and LCOE will improve. In addition, an NPV analysis should be done to determine how the costs are distributed over the stakeholders.