HOW TO OPTIMISE ENERGY STORAGE IN BUILDINGS?

Transcription

1 HOW TO OPTIMISE ENERGY STORAGE IN BUILDINGS? Which applications for phase change materials? 27/09/2017 Gilles Baudoin Research assistant (UCL-Architecture et Climat) 1

2 Phase Change Materials PCM In Building Applications To Optimise Thermal Mass 2

3 Phase Change Materials PCM 3

4 Why is an ice cube more efficient to cool my glass than 0 C liquid water? 0 C 20 C 0 C 17 C 7 C 4

5 Temperature: an indicator of sensible and latent heat 80 C 0 C 335 kj 335 kj Stored Heat[kJ/kg] Equivalent Energy Reservoir 5

6 Unlike ice cube, latent reservoir of 0 C liquid water is already filled 20 C 0 C 0 C 20 C 0 C 6

7 Equilibrium is achieved at 17 C with 0 C liquid water 17 C 20 C 0 C 0 C 17 C 0 C 7

8 Equilibrium is achieved at 7 C with the ice cube 7 C 20 C 0 C 0 C 0 C 7 C 8

9 Main characteristics and differences between real PCMs and ideal PCMs T Heat Capacity [J/K] ΔT f T f Latent Heat E l [J/g] Latent Heat Sensible Heat E 9

10 Phase Change Materials PCM In Building Applications 10

11 Phase Change Materials for building applications Latent Heat E l [kj/l] Comfort Temperature range Melting Temperature T f 1. Kalnæs, S.E. and B.P. Jelle, Phase change materials and products for building applications: A state-of-the-art review and future research opportunities. Energy and Buildings, : p

12 Is it something new? Telkes M. (1949) Storing solar heat in chemicals - A report on the Dover house 12

13 PCM for building applications: an historical perspective P. Schossig (2005) point of view Kosny (2014) point of view 1949 ± 1980 ± /09/2017 Immersion Micro-encapsulation Macro-encapsulation Shape-Stabilized PCMs 13

14 P. Schossig (2005) point of view: limitation of previous works PCMs that are not encapsulated may interact with the building structure and change the properties of the matrix materials, or leakage may be a problem over the lifetime of many years. Macro- capsules have the disadvantage that they have to be protected against destruction while the building is used (no drilled holes or nails in the walls/ceiling).( ) Another problem with macro-capsules is the decreasing heat transfer rate during the solidification process when PCMs like paraffins are used, with poor heat transfer coefficients in the solid state. This may prevent the system from discharging completely overnight. Due to these limitations, none of the PCM products had a big market impact. 14

15 Classification of PCMs integration in building Ressources Systems Envelope Occupant comfort PCMs 1. System applications 2. Passive applications 3. Active applications 15

16 Technical specifications for PCMs selection 1. Soares, N., et al., Review of passive PCM latent heat thermal energy storage systems towards buildings energy efficiency. Energy and Buildings, : p

17 Commercial PCM products for passive applications Energain ENRG Blanket Knauf SSPCM Macroencapsulation Microencapsulation 17

18 Phase Change Materials PCM In Building Applications To Optimise Thermal Mass 18

19 Thermal mass and water reservoir analogy Stored Energy [Joules] Stored Water [L] T Water Height [m] Heat Capacity [Joules/K] Reservoir Area [L/m] 19

20 Thermal mass in the «building system» Energy NR Solar gains Internal gains Intermittent Renewable Energy Heating System Tc Inside T int ΔT T ext Outside Cooling System Transmission Ex/infiltration Hygienic ventilation Energy NR Intensive ventilation 20

21 PCMs change thermal mass shape T Heavyweight Lightweight PCM tuning 21

22 Levers for action to optimise thermal mass Latent Heat Air Furniture Envelope Active < 24h Active > 24h Melting temperature Tc Latent Heat Used (24h) 2 PCMS with different T f Heat capacity Heat capacity used (24 h) Activation 22

23 Classical PCM use to increase thermal mass in lightweight buildings «Lightweight» Building PCM PCM Envelope + = T confort 23

24 Case study: effect of thermal mass optimisation on cooling loads in a south-oriented office Scenarios for cooling Gains Thermal mass variation without PCM Loss Thermal mass variation with PCM 1 m2 PCM/m2 floor 24

25 Effect of different scenarios on the annual cooling energy (kwh/m2 an) I Gains Heating System Tc T int ΔT Inside T ext Outside Cooling System I Loss 25

26 Effect of different scenarios on the annual cooling energy (kwh/m2 an) S0 Heavyweight S1 = S0 + Heat Recovery Gains S2 = S1 + Solar protection Tc T int ΔT Passive S3 = S2 + Diurnal Free Cooling Intérieur Loss T ext Extérieur 15 S4 = S3 + Night Free Cooling 7 I Cooling System Day Night 26

27 Effect of thermal mass on the annual cooling energy (kwh/m2 an) S0 Heavyweight S1 = S0 + Heat Recovery 1 Gains S2 = S1 + Solar Protection 2 Tc T int ΔT Passive S3 = S2 + Diurnal Free Cooling S4 = S3 + Night Free Cooling Intérieur Loss T ext Extérieur 7 I Cooling System Day Night 27

28 Effect of thermal mass + PCM on the annual cooling energy (kwh/m2 an) 1 m2 exchange surface/ m2 floor PCM effect: E l 110 J/g; T f 23; ΔT f 1 0,53 cm PCMs wallboard Gains Tc T int ΔT ΔE c 1.17 ; 17% ΔE c 2.46 ; 24% Intérieur T ext Extérieur S4H S4L Loss ,3 m2/m2 floor Exchange Surface I Cooling System Day Night 28

29 Cooling loads evolution (kwh/m2 an) in different scenarios S0 Lourd 35,03 S1 Lourd (Echangeur de chaleur) 33,71 S2 Lourd (Protection solaire) 24,50 S3 Lourd (Ventilation 2V/h diurne) S4a Lourd (Ventilation 2V/h nocturne Tset 21) 7,03 14,59 Lambda ΔE c 0.1 S4a Lourd + 1m2 /m2 S4a Lourd + 1m2 PCM/m2 S4a Léger S4a Léger + 1m2/m2 S4a Léger + 1m2 PCM/m2 S4a Léger + 1,3m2 PCM/m2 6,86 5,69 10,32 10,29 7,83 7,03 ΔE c 1.17 ; 17% ΔE c 2.46 ; 24% Exchance surface ΔE c 0.4 PCM quantity 4 ep: ΔE c surf: ΔE c 2.4 S4b (Ventilation 2V/h nocturne Tset 15) 4,62 1 m2 exchange surface/ m2 floor E l 110 J/g; T f 23; ΔT f ,53 cm PCMs wallboard

30 PCM in Building Applications STOCC to Optimise Thermal Mass Gilles Baudoin Architecture et Climat - UCL 30

31 Appendix 1: Ecooling in function of T f, E cooling (kwh/m2an) 7,00 6,00 Energain Without pannel ΔT f and E l Optimum T f 23 C 5,00 4,00 3,00 2,00 1,00 ΔT f, E cooling (1,3,6,10) E l, E cooling (110,220 (limite paraffine),550 (limite sels hydratés),1100 (cas extrême) 0, Melting Temperature T f 1 m2 exchange surface/ m2 floor E l 110 J/g; T f 23; ΔT f 1 0,53 cm PCMs wallboard

32 Appendix 2: Ecooling in function of PCM quantity: increasing of width and number of panels PCM E cooling (kwh/m2an) x * the initial surface/width Ep var S var Lambda variable PCM PCM PCM

33 Appendix 3: cooling loads in the southoriented office 33