Techno-economic analysis of a Cold District Heating system using sea water energy, based on a study case. Maxime Bollinger Master of Science Thesis KTH Industrial Engineering and Management Energy Technology TRITA-ITM-EX 2018:463 SE-100 44 STOCKHOLM Master of Science Thesis TRITA-ITM-EX 2018:463 Techno-economic analysis of a Cold District Heating system using sea water energy, based on a study case. Maxime Bollinger Approved Examiner Supervisor Björn Laumert Rafael Guedez Commissioner Contact person ENGIE Cofely, France Cédric Maisonneuve Abstract When it comes to energy efficiency for heating and domestic hot water demand, district heating systems are known to be energy efficient due to centralization of the production. More recently, district cooling are in development to meet a growing demand. If district heating and cooling systems using centralized plant are strongly implemented as the dominant design, the purpose of this study is to investigate a variant solution using decentralized production: A Cold District Heating system consists of a network carrying tempered water to customers’ substations, to be used as a heat sink or source by reversible heat pumps for heating and cooling purpose. In this study, a CDH system is designed based on the study case and using literature review insights. Then, a model able to simulate a CDH system is developed so that its behavior can be analyzed. Finally, a cost-estimation methodology is used to perform a techno-economic analysis of the system. Insights from this study concerning key factors for a Cold District Heating system profitability enhancement will be highlighted. Sammanfattning När det gäller energieffektivitet för uppvärmning och efterfrågan på varmtvatten är fjärrvärmesystem kända för sin energieffektivitet på grund av centraliseringen av produktionen. Mer nyligen utvecklas stadskylning för att möta växande efterfrågan. Om fjärrvärme- och kylsystem med centraliserad installation används i stor utsträckning som en dominerande konstruktion är syftet med denna studie att studera en variant med decentraliserad generation: Ett fjärrvärmesystem ska användas som kylfläns eller källa med reversibla värmepumpar för uppvärmning och kylning. I denna studie är ett CDH-system utformat utifrån fallstudien och med hjälp av litteraturrecensioner. Därefter utvecklas en modell som kan simulera ett CDH-system så att dess beteende kan analyseras. Slutligen används en kostnadsberäkningsmetod för att utföra en teknisk-ekonomisk analys av systemet. Lärdomarna från denna studie om de viktigaste faktorerna för att förbättra värmeanläggningens verkningsgrad kommer att markeras. 1 Figure 1: Market shares for heat supply to residential and service sector buildings in Sweden between 1960 and 2014 with respect to heat delivered from various heat sources. (Werner S., 2017) ................................................................................................................................................ 9 Figure 2: Layout of a district heating system using centralized production (ScandAsia, 2016) ... 11 Figure 3: Evolution of the TICPE for HFO in France ................................................................... 12 Figure 4: Examples of substrates which can be anaerobically digested to generate biogas (Abbasi T., 2011) ........................................................................................................................................ 13 Figure 5: Simple layout of a geothermal energy system (27) ....................................................... 14 Figure 6: Schematic diagram of a typical geothermal BHE (Andrew D., 2016) .......................... 15 Figure 7: Schematic of a multi-BHE configuration (Andrew D., 2016) ....................................... 15 Figure 8: General schematic of an open loop (on the left) and a closed-loop (on the right) surface water heat exchange system (Andrew D., 2016) ........................................................................... 16 Figure 9: Cornell University free-cooling diagram ....................................................................... 17 Figure 10: Example of ASHP ........................................................................................................ 18 Figure 11: Comparison of typical chillers efficiency using different prime driver (Tredinnick S., 2016) .............................................................................................................................................. 19 Figure 12: Schemes of a branched network (left) and a meshed network (right) ......................... 20 Figure 13: District heating piping network picture ....................................................................... 21 Figure 14:Layout of the pipe for calculation basis ........................................................................ 22 Figure 15: A typical customer substation ...................................................................................... 23 Figure 16: A CDH system scheme ................................................................................................ 25 Figure 17: General scheme of an adiabatic cooler ........................................................................ 26 Figure 18: Example of a substation scheme for a CDH system .................................................... 27 Figure 19:Layout of a multi-purpose heat pump system (Pellegrini M., 2016) ............................ 27 Figure 20: Location of Sète in the south of France ....................................................................... 29 Figure 21: Yearly distribution of the buildings ............................................................................. 30 Figure 22: Final map for the study case ........................................................................................ 31 Figure 23: Space heating, DHW and cooling demand for the district from 2020 to 2037 ........... 32 Figure 24:Location of the three points of temperature measurements .......................................... 33 Figure 25: Layout basis of the CDH system ................................................................................. 38 Figure 26: Electric power absorbed by circulating pumps as a function of the flow rate of sea water .............................................................................................................................................. 40 Figure 27: Sea water temperature throughout the year at the point of pumping “Bassin Orsetti” 41 Figure 28: Electricity consumption of the adiabatic cooler unit as a function of air temperature 43 Figure 29: Customer’s substation diagram .................................................................................... 44 Figure 30: Efficiency of the heat pump as a function of the cold ring temperature and the outlet temperature .................................................................................................................................... 45 Figure 31: Cold ring flow rate and hot water demand represented for the 22th of January ......... 49 Figure 32: Difference of temperature between the supply temperature and return temperature .. 50 Figure 33 Flow rate as a response to cooling demand throughout the 22th of July ...................... 51 Figure 34:End-users demand and flow rate in the cold ring throughout the 13th of April ............ 51 Figure 35:Difference of temperature between supply and return and end-users demand throughout the 13th of April ........................................................................................................... 52 Figure 36: Heating and cooling demand resulting on a total demand upstream of the cold ring, throughout the 13th of April ........................................................................................................... 52 Figure 37: Balancing Factor .......................................................................................................... 53 Figure 38: Investment distribution for scenario A1 ...................................................................... 54 Figure 39: Investment distribution for scenario A2 ...................................................................... 56 Figure 40: Frequency of cold power demand throughout the year ............................................... 57 Figure 41: Peak power required to the production block for the first five years of the project .... 58 Figure 42: Investment distribution in the scenario C2 .................................................................. 63 2 Table 1:Consumption and peak power per floor area unit for housing and tertiary buildings ..... 32 Table 2:Peak power and consumption of the district in 2037 ....................................................... 32 Table 3: French subsidies for district heating network ................................................................. 34 Table 4: Cost per linear meter for trenches opening and closing and for pipes purchase ............. 38 Table 5: Average sea water temperature and daily fluctuations at the point of pumping ............. 41 Table 6: Water temperature needed on user-side .......................................................................... 45 Table 7: Summary of the pricing model used to calculate the LCoHC ........................................ 47 Table 8: Financial hypothesis used to calculate the NPV ............................................................. 48 Table 9: Results for scenario A1 .................................................................................................