SCCER Heat and Electricity Stroage HaE 7 th Symposium HSR Rapperswil, November 6, 2018 Thermal Energy Storage Application Perspectives Technical Challenges in the Component Development Paul Gantenbein, Xavier Daguenet-Frick, Mihaela Dudita, Lukas Omlin, Mattia Battaglia, Michel Haller, Daniel Philippen, Daniel Carbonell, Andreas Häberle Institute for Solar Technology SPF – HSR University of Applied Sciences Rapperswil
Content Sensible Heat Storage Stratification / heat and mass transfer Fluid inlet design though CFD 1 Latent Heat Storage Phase change: water Ice / heat transfer Heat exchanger design & Simulation model 2 4.0E+07 Desorber 3.5E+07 Sorption / Thermochemical Heat Storage 0.3 3.0E+07 -0.3 Nu*Pr4.226 [-] Closed – internal heat and mass transfer 2.5E+07 ref 2.0E+07 4 Heat and mass exchanger design 1.5E+07 1.0E+07 5.0E+06 0.0E+00 0 2 4 6 8 10 Re [-] 2 SCCER HaE 7th Symposium
Heat Storage Types & Examples of Materials Materials Sensible heat Latent heat Chemical energy gas - liquid solid - gas solid - liquid solid - solid organics inorganics Eutetics Mixtures Eutetics Mixtures Single Temperature Single Temperature temperature interval temperature interval Paraffins Fatty acids Hydrated salts (alkanes mixtures) Source: A. Abhat: Solar Energy 30 p. 313 (1983) 3 SCCER HaE 7th Symposium
Temperature Distribution in a Sensible Storage Thermal stratification of sensible storage tanks fulfilling application temperature conditions Height H H Diameter D T high D IN Thermocline OUT T low Temperature T Cylindrical tank shapes temperature stratification H=height, D=diameter 𝟒 𝟒 ( 𝒎 𝒕 = ( 𝑵 𝟏 𝝇) 𝑾 𝟏 𝒘 𝟏 ) 𝟓 𝟓 Dimensionless number = 𝟐 𝟐/𝟑 𝛙 = 𝒎 𝒕 /𝒆 𝒈 - deflection relation 𝑾 𝟏 𝒉∆𝝇 (𝑮 𝟏 𝝇) 𝟑 - geometry A & v 0 , r (T), g 𝝇 4 SCCER HaE 7th Symposium
Sensible Storage Type Feed Inlet / Volume Flow / Stratification recommendation v< 0.1 m/s 1800 l/h 900 l/h 2’’, 30°C 2’’, 30°C 5 SCCER HaE 7th Symposium
Sensible Type Temperature stratification Battaglia, M.; Haller, M. Y. Stratification in large thermal storage tanks. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland 6 SCCER HaE 7th Symposium
Sensible Storage Type Fluid feed inlet design fluid velocity v 0 inlet bent horizontal inlet towards the top/bottom of the storage Battaglia, M.; Haller, M. Y. Stratification in large thermal storage tanks. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland 7 SCCER HaE 7th Symposium
Content Sensible Heat Storage Stratification / heat and mass transfer Fluid inlet design though CFD 1 Latent Heat Storage Phase change: water Ice / heat transfer Heat exchanger design & Simulation model 2 4.0E+07 Desorber 3.5E+07 Sorption / Thermochemical Heat Storage 0.3 3.0E+07 -0.3 Nu*Pr4.226 [-] Closed – internal heat and mass transfer 2.5E+07 ref 2.0E+07 4 Heat and mass exchanger design 1.5E+07 1.0E+07 5.0E+06 0.0E+00 0 2 4 6 8 10 Re [-] 8 SCCER HaE 7th Symposium
Latent Heat Storage Using Ice Storage Ice Storage Heat Source or Sink Heat solar collector field Pump A) B) C) Eisspeicher Ambient air Bore hole Ice storage 9 SCCER HaE 7th Symposium
Ice Storage Modul Cylindrical storage shape Plate heat exchanger (hex) Mainly stainless steel Diameter of storage mm 1200 Height of storage mm 1950 m 3 Water content 2.0 Parallel pairs of hex-plates # 4 Distance between plates mm 120 Active surface of hex m 2 22 Latent heat (max.) kWh 129 Maximum icing fraction of mass 70 % Philippen, D.; Battaglia M.; Carbonell D.; Thissen B.; Kunath L.; Validation of an ice storage model and its integration into a solar-ice system. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland 10 SCCER HaE 7th Symposium
Mathematical Model: Ice Storage and Heat Exchanger Model based on a more detailed T amb TRNSYS-model (transcription) Mathematical model implemented into the Polysun simulation software 1 One-node (1) ice storage Multi-node (12) heat exchanger (4 elements in parallel) 1 2 12 Physical model (versus old model which is empirical) T ice 2 plates in series (12 knots) Ice storage can be coupled: − 1 UA tot = 1 1 1 1 a) with ground or + + + b) with a room temperature 𝑉𝐵 𝑗𝑜 𝑉𝐵 𝑥𝑏𝑚𝑚 𝑉𝐵 𝑗𝑑𝑓 𝑉𝐵 𝑝𝑣𝑢 11 SCCER HaE 7th Symposium
Validation of the Ice Storage Model Example: Freezing over 30 hours (steady state growing of ice) 12 SCCER HaE 7th Symposium
Validation of the Ice Storage Model Example: Freezing over 30 hours (steady state growing of ice) Solar Collectors Hot Water Room Heating Heat Pump Combi Storage Hydraulic separator Model implemented in Ice Storage the industry Philippen, D.; Battaglia M.; Carbonell D.; Thissen B.; Kunath L.; Validation of an ice storage model and its integration into a solar-ice system. Eurosun 2018, September 10 – 13, Rapperswil, Switzerland 13 SCCER HaE 7th Symposium
Content Sensible Heat Storage Stratification / heat and mass transfer Fluid inlet design though CFD 1 Latent Heat Storage Phase change: water Ice / heat transfer Heat exchanger design & Simulation model 2 4.0E+07 Desorber 3.5E+07 Sorption / Thermochemical Heat Storage 0.3 3.0E+07 -0.3 Nu*Pr4.226 [-] Closed – internal heat and mass transfer 2.5E+07 ref 2.0E+07 4 Heat and mass exchanger design 1.5E+07 1.0E+07 5.0E+06 0.0E+00 0 2 4 6 8 10 Re [-] 14 SCCER HaE 7th Symposium
Concept & Design Sorbate loop Absorption Storage Experiment Sorbent loop Separation of power and capacity units - Power unit: combined A-D & E-C heat and mass exchangers - Capacity unit: storage tanks Seasonal charging and discharging processes 15 SCCER HaE 7th Symposium
Potential M. Conde Engineering Storage potential of materials solid (crystallization) – liquid LiCl-H 2 O Absorption potential D F in function of load c Eutectic Points 1.40E+06 LiBr-H2O 1.20E+06 NaOH-H2O 1.00E+06 LiCl-H2O D F (J/kg) 8.00E+05 6.00E+05 4.00E+05 2.00E+05 0.00E+00 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 c(H 2 O) (wt.%) “heat of solution” in case of vapour – liquid solution transition. (ex: at 90 wt.% and more water the D h v of water vapour will be released.) Solubility boundary of aqueous solutions of lithium chloride. Polanyi / Dubinin potential adsorption theory 16 SCCER HaE 7th Symposium
Sorption Heat Storage Charging and discharging Falling film - charging: desorption ok A-D tube bundle - discharging: absorption not ok E-C power units predicted exchanges power (W) 4.0E+07 Desorber 3.5E+07 30% 3.0E+07 Nu*Pr 4.226 (-) -30% Nu*Pr 4.226 [-] 2.5E+07 ref 2.0E+07 A-D A-D E-C 1.5E+07 1.0E+07 5.0E+06 0.0E+00 0.0 2.0 4.0 6.0 8.0 10.0 Re (-) Re [-] Condenser maximum flow rate: Heat transfer characteristics: Nu=Nu(Pr, Re) Measured exchanges power (W) 12 l(H 2 O)/min @ T=20 ° C Xavier Daguenet-Frick et al. Renewable Energy 110 (2017) 162-173. 17 SCCER HaE 7th Symposium
Sorption Heat Storage Power unit modification - heat & mass exchange surface wetting wetting agent TRITON ™ QS-1 tube surface structure tube surface anneling / coating - lye residence time in sorbate SiC ceramic foams low wetting better wetting Dudita M., Daguenet-Frick X., and Gantenbein P., EuroSun 2016, Palma (Mallorca) 18 SCCER HaE 7th Symposium
Sorption Heat Storage Power unit modification Lye IN Tube surface geometry Wetting agent gravity Hydrophilic ceramic foam: wetting with concentrated aqueous sorbent. Lye OUT increased residence time of the aqueous sorbent on the tube Excellent wetting of the SiC ceramic foam with concentrated NaOH and LiBr 10 PPI and NaOH 50 wt.% 20 PPI and NaOH 50 wt.% SiC and LiBr 54 wt.% 30 PPI Hydrophilic SiC ceramic foam with pores partially filled by concentrated aqueous sodium hydroxide. Porosity is ranging from 10 to 30 PPI , where PPI = number of pores per inch. 19 SCCER HaE 7th Symposium
Experimental Set-up of the 1 kW Unit Power and capacity units - Combined A-D & E-C heat and mass exchangers – seasonal separation C D - Sorbent and sorbate storage tanks A-D unit E-C unit A-D E-C B A T 60 water tank T 20 T 30 lye tanks (H 2 O) (NaOH-H 2 O) T 20 T 30 T 60 H 2 O loop NaOH/H 2 O loop feed pump feed pump Lab set-up EW 6 20 SCCER HaE 7th Symposium
Operation with Water set in operation – tests performed with water 4000 48 46 Expected power: 1 KW 3500 44 3000 42 40 2500 38 2000 36 34 A-D 1500 32 Temperatur T (°C) 1000 30 Power P (Watt) 28 500 26 0 24 22 -500 20 -1000 18 16 -1500 14 -2000 12 E-C 10 -2500 8 power AD unit power EC unit T inlet AD -3000 6 4 -3500 T outlet AD T outlet EC T inlet EC 2 -4000 0 13:00:00 13:30:00 14:00:00 14:30:00 15:00:00 15:30:00 16:00:00 time (hh:mm:ss) Power and temperatures in the A-D and E-C units 21 SCCER HaE 7th Symposium
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