Solar district heating for low energy residential areas
This thesis presents studies that aim to investigate the most energy efficient distribution concept for successful implementation of solar district heating technology. An existing solar assisted district heating system is modelled in simulation software and the distribution system is varied in order to find out whether there is a more energy efficient option. Three system concepts are investigated:
1. A Hybrid system using a combination of high-temperature, conventional steel pipe primary culvert, intermediate substations containing solar buffer stores and a low-temperature, EPSPEX secondary culvert with DHW-circulation (so-called GRUDIS).
2. A Conventional distribution system with steel pipes, higher operating temperatures and centralized solar buffer stores.
3. An All GRUDIS system, using only EPSPEX distribution with DHW-circulation, lower operating temperatures and centralized solar buffer stores.
A sensitivity analysis is performed by simulating the three different distribution system for various linear heat densities, with the added objective of detecting any range-bound limitations of the different distribution systems.
Results indicate that both the hybrid and All GRUDIS distribution concept is preferable to conventional DH distribution regardless of the network heat density. The hybrid concept seems preferable in denser district heating networks, but results are inconclusive regarding the best concept for sparser networks.
Preliminary economic considerations show that the initial investment costs may be reduced by changing from a Hybrid to an All GRUDIS distribution concept, although a more detailed analysis is needed to draw conclusions about the most economical solution.
Keywords: District heating, solar thermal, simulation, renewable energy, 4DH.
Chalmers, Arkitektur och samhällsbyggnadsteknik, Installationsteknik
Andersen et al, Technical Study on Heat Distribution Concepts for a small Solar District Heating System, submitted to the Journal of Applied Energy, September 2019.
Chalmers tekniska högskola
SB-L 200, Sven Hultins gata 6
Opponent: Heimo Zinko, ZW Energiteknik AB, Nyköping, Sweden