DYNAMIC MODELLING OF THERMAL GRIDS AND BOREHOLE THERMAL STORAGE

Transcription

1 DYNAMIC MODELLING OF THERMAL GRIDS AND BOREHOLE THERMAL STORAGE Hanne Kauko Karoline Kvalsvik RockStore Workshop, Stockholm

2 Outline 1. Background from previous projects 2. Dynamic modelling of thermal systems 3. Earlier results 4. Tasks in RockStore 2

3 KPN INTERACT ( ) Efficient interaction between energy demand, surplus heat/cool and thermal storage in building complexes. 3

4 Results from INTERACT: Comparison of simulation software for modelling BTES TRNSYS Polysun Modelica IDA ICE Matlab/Simulink +Carnot Earth Energy Designer (EED) IDA ICE 4

5 IPN DSTG ( ) - Development of Smart Thermal Grids 5

6 KPN LTTG+ ( ) - Local low-temperature grids with surplus heat utilization 6

7 Our approach: dynamic modelling using Dymola/Modelica "Dynamic" instead of steady-state: new opportunities and added complexity Necessary realism in systems with energy storage Requires a control strategy and a control system Physical models in Modelica/Dymola Object-oriented, easy reuse of components Flexible, full control of code 7

8 A model of a local thermal grid should include: Loads, pipes and supplier Demand profiles and customer substation Ambient temperature and heat loss Pumps and pressure loss

9 Loads and user profiles Measured demand (various building types) valves Secondary fluids with own pumps Control temperature Radiator in contact with 21 C Heat exchanger models using NTU method Figure taken from: Kauko, Hanne; Kvalsvik, Karoline Husevåg; Rohde, Daniel; Nord, Natasa; Utne, Åmund. (2018) Dynamic modeling of local district heating grids with prosumers: A case study for Norway. Energy. vol. 151.

10 Pipes Ambient temperature Temperature, mass flow and pressure in given Heat loss for twin pipes (Wallenten) Pressure drop, aiming for R-value of 150 Pa/m Length, inner diameter, internal distances, conductivity of insulation and soil Temperature, mass flow and pressure out found

11 Brøset modelled area Figure taken from: Kauko, Hanne; Kvalsvik, Karoline Husevåg; Rohde, Daniel; Nord, Natasa; Utne, Åmund. (2018) Dynamic modeling of local district heating grids with prosumers: A case study for Norway. Energy. vol. 151.

12 Supplier and prosumer Figures taken (and the left modified) from: Kauko, Hanne; Kvalsvik, Karoline Husevåg; Rohde, Daniel; Nord, Natasa; Utne, Åmund. (2018) Dynamic modeling of local district heating grids with prosumers: A case study for Norway. Energy. vol. 151.

13 BTES? Daniel Rohde s Dymola version of a model in Bauer, D., et al. (2011). "Thermal resistance and capacity models for borehole heat exchangers." International Journal of Energy Research 35(4): Hot fluid up Cold fluid down Solar+BTES Conclusion: can supply any amount pure matter of scaling

14 BTES model in Modelica BTES model developed for the BTES park at Ljan school, Oslo Seasonal storage of solar collectors integrated in the school yard 24 x 200m boreholes Heat pump applied in the winter Modelling results validated against measurement data Later the model was modified and tested for seasonal storage of high14temperature heat

15 Charging at HT over summer and discharging over winter Inlet and average outlet temperatures from the BTES park with different borehole depth Temperature [ C] d = 10 m d = 20 m d = 40 m Charging: 180 MWh heat at 90 C and a constant mass flow over the summer (5 months) Discharging: Corresponding to measured heat demand from a apartment block of på 2082 m 2 15 Time [h]

16 Temperature profile on the ground over a year, with a boreholde depth of 20 m 16

17 Models in RockStore? Adjust the model to match BTES parks included as case studies in RockStore and validate the model towards measurement data Integrate the BTES-park model in a model of a local DH-grid? Study the potential of HT-seasonal storage in building areas identified as case studies in RockStore 17

18 Teknologi for et bedre samfunn