Secondary Loop System with PCM under Different Climatic Conditions

Transcription

1 Secondary Loop System with PCM under Different Climatic Conditions Nicholas Lemke, Julia Lemke, Jürgen Köhler Institut für Thermodynamik Technische Universität Braunschweig

2 1. Fundamentals 2. Experimental Investigations 3. Simulation Virtual Test Drive 4. Summary 2

3 1. Fundamentals 2. Experimental Investigations 3. Simulation Virtual Test Drive 4. Summary 3

4 Project Background and Partners TIFFE Thermal Systems Integration For Fuel Economy Konsortium Centro Ricerce Fiat SCPA (Projektkoordination), Turin Denso Thermal Systems S.p.A., Turin Ford-Werke GmbH, Köln Institut für Thermodynamik, Technische Universität Braunschweig Maflow BRS S.R.L., Mailand Sintef Energi AS, Trondheim 4

5 Secondary Loop Systems Combination of the refrigeration cycle with one/two water/glycol cycles Ref. cycle Passanger compartment Ambient 5

6 Secondary Loop Systems Combination of the refrigeration cycle with one/two water/glycol cycles CRU: Compact Refrigeration Unit LT- Secondary Loop CRU HT- Secondary Loop Passanger compartment Ambient Water/ Glycol Refrigerant Water/ Glycol 7

7 Secondary Loop Systems CRU with Seconday Loop System - Disadvantages Decrease of efficiency due to additional heat transfers+ irreversibilities Additional constructional effort (pumps, heat exchangers, ) CRU with Secondary Loop System - Advantages Enables application of flammable/toxic/ refrigerants Exchangeability of the MAC-System as a compact unit Lower internal volume lower refrigerant charge (reduction to 5-15%) Reduced tubing (lower pressure drop) Additional storage effect additional comfort, Easier integration in car energy management system 8

8 Phase Change Materials PCM in the secondary loop system Utilization of latent heat temperature Phase change temperature sensible sensible sensible h enthalpy PCM: Additional cold storage within secondary loop (e.g. for start-stop) 9

9 Phase Change Materials - PCM PCM key specifications: Mechanical, chemical and thermal long-term stability (compatible with water-glycol!) Cycle stability, reproducible phase change No / low sub cooling necessary (no hysteresis) temperature High energy- and power density Low cost at least in large scale production Suitable temperatures of phase change! subcooling time 10

10 Enthalpy of phase change [MJ/m³] Phase Change Materials - PCM Carbonates Fluorides Sugar alcohols Salthydrates Hydroxides Chlorides Water Clathrates Eutectic water-salt solutions Nitrates Paraffins Fatty acids Polyethylene glycoles T PC,Evap 0 C (frost) ~10 C (smell) T PC,Cond 40 C 45 C [Mehling] Temperature of phase change [ C] 11

11 1. Fundamentals 2. Experimental Investigations 3. Simulation Virtual Test Drive 4. Summary 12

12 Two ways to integrate PCM in the secondary loop system: Micro-encapsulated PCM: PCM coated with protective shell, implemented in carrier fluid (pumpable emulsion: PCS) Macro-encapsulated PCM: PCM without protective coating macroencapsulated in a container with carrier fluid flowing around [Borreguero] 200 m Container Microencaps. PCM Macroencaps. PCM 13

13 Two paraffin-based samples have been experimentally analyzed: Sample 1: Micro-encapsulated paraffin PCM with a protective polystyrene shell. ~200 m (PCS), dimensionally stable, T PC ~42 C Sample 2: Paraffin PCM for macro-encapsulation, coatless. ~5mm (container), dimensionally stable due to additives, T PC ~6 C 200 m 5 mm Sample 1: Microencaps. PCM Sample 2: PCM destinated for macro-encapsulation 14

14 Sample 1: Micro-encapsulated polystyrene coated paraffin Measurement results: Phase change effect: Mechanical stability: (abrasiveness!) used new 15

15 Sample 2: PCM dedicated for macro-encapsulation - material properties DSC Differential Scanning Calorimetry Cooling down Heating-up Heating/cooling rate: 5K/min (influence of thermal conduction inside the macroscopic structure!) h PC 108 kj/kg -1,5 C T PC,cooling 6 C 9,5 C T PC,manufactor T PC,heating 16

16 Sample 2: PCM dedicated for macro-encapsulation test rig construction Main function: Heat rejection (realized by process thermostat) Main function: Investigation of PCM container with possibility of heat supply (realized by heating cartridge) 17

17 Sample 2: PCM dedicated for macro-encapsulation test rig construction 18

18 Temperature [ C] Sample 2: PCM dedicated for macro-encapsulation measurement results Phase Change heating-up 0-5 Phase Change cooling down Measurement time [s]

19 Temperature [ C] Temperature [ C] Sample 2: PCM dedicated for macro-encapsulation measurement results Fluid temperature, extrapolated (system w/o phase change) Fluid temperatur, measured (system with phase change) max =6 C AC off -2 Heating-up: 270W const Measurement time [s] Time [s] Dt Additional cooling time due to PCM latent heat: 50s (additional water would also increase the time) 21

20 Temperature [ C] Sample 2: PCM dedicated for macro-encapsulation measurement results Fluid Fluidtemperatur, temperature, extrapolated extrapoliert (system without PC) Fluidtemperatur, gemessen measured (system with PC) max =6 C AC off Aufheizung: Heating-up: 270W konst. const. Kühlungs-Zeitgewinn dank PCM: Implemented Ca. 50s PCM quantity: 360g Dt Dt Additional (Anm.: Größere cooling Wassermenge time due würde to increased ebenfalls fluid die Kühldauer quantity: 10s erhöhen) Measurement time [s] 22

21 CRU: Test rig construction Expansion valve Condenser filling/discharge device Evaporator Compressor HT-Sec.Loop Gauge glass LT-Sec.Loop 23

22 1. Fundamentals 2. Experimental Investigations 3. Simulation Virtual Test Drive 4. Summary 24

23 Virtual Test Drive 1 Hour to Munich Car Stops 25

24 Temperature [ C] Virtual Test Drive Ambient Climate on July 21 st (Meteonorm Based Weather) % 20% 30% 40% Finish Enthalpy [kj/kg] Start 70 50% 60% 70% 80% 90% 100% Humidity Ratio x [g/kg] Pressure: bar 26

25 Virtual Test Drive Urban Heat Island Influence of cities on the Planetary Boundary Layer yields an Urban Heat Island (UHI). Urban Heat Island on an hourly base in Bochum (10/2006 to 10/2007) [source: E. Parlow, "The urban heat budget derived from satellite data, ] 28

26 Maximum UHI [K] Virtual Test Drive Urban Heat Island North America Japan Western Europe Number of Citizens [Source: Matzarakis Die thermische Komponente des Stadtklimas ] 29

27 Temperature [ C] Virtual Test Drive Ambient Climate on July 21 st (Meteonorm Based Weather) % 20% 30% 40% Finish Enthalpy [kj/kg] Start 70 50% 60% 70% 80% 90% 100% Humidity Ratio x [g/kg] Pressure: bar 30

28 Temperature [ C] Virtual Test Drive Ambient Climate Effect of Urban Heat Island (UHI) % 20% 30% 40% Finish with UHI Enthalpy [kj/kg] Start 70 50% 60% 70% 80% 90% 100% Humidity Ratio x [g/kg] Pressure: bar 31

29 Simulation using Modelica and TIL Suite Ambient climate data + w and w/o PCM A/C Cycle Secondary Loop IVECO Daily compartment model Modelica / TIL model 32

30 Simulation using Modelica and TIL Suite A/C Cycle PCM Secondary Loop Cabin Model 33

31 Temperature [ C] Virtual Test Drive Simulation Results 40 Passenger Compartment Secondary Loop Air Inlet Time [s] 34

32 Temperature [ C] Virtual Test Drive Simulation Results 40 Passenger Compartment Secondary Loop + 1 Liter H 2 O Air Inlet Time [s] 35

33 Temperature [ C] Virtual Test Drive Simulation Results 40 Passenger Compartment 30 Secondary Loop + 1 Liter H 2 O + 1 Liter PCM (no additional H 2 O) 20 Air Inlet Time [s] 36

34 Temperature [ C] Virtual Test Drive Simulation Results 40 Passenger Compartment 30 Secondary Loop + 1 Liter H 2 O + 1 Liter PCM (no additional H 2 O) 20 Air Inlet PCM Loading Time [s] 37

35 Temperature [ C] Virtual Test Drive Simulation Results 40 Passenger Compartment 30 Secondary Loop + 1 Liter H 2 O + 1 Liter PCM (no additional H 2 O) Air Inlet PCM Unloading Time [s] 38

36 Temperature [ C] Virtual Test Drive Simulation Results 30 Passenger Compartment Secondary Loop + 1 Liter H 2 O + 1 Liter PCM (no additional H 2 O) Air Inlet Time [s]

37 Temperature [ C] Virtual Test Drive Simulation Results 30 Passenger Compartment odour nuisance Secondary Loop + 1 Liter H 2 O + 1 Liter PCM (no additional H 2 O) Air Inlet Time [s]

38 1. Fundamentals 2. Experimental Investigations 3. Simulation Virtual Test Drive 4. Summary 41

39 Summary Automotive secondary loop systems can be improved using phase change material (PCM) Micro-encapsulated paraffin PCM have not been mechanical stable Macro-encapsulated paraffin PCM seem to be a good choice Virtual test drive with PCM showed: - slower cool down performance but - improved cooling performance during stop phase 42

40 Thank you! 43