1. I NVESTIGATION OF ENERGY FLOWS IN THERMALLY ACTIVATED BUILDING CONSTRUCTIONS Part 1: Transferring energy between 2 building zones Nordic PhD Seminar 08 / 12 / 2011 1 Jérôme LE DRÉAU

2. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 2 Transfer between zones Radiant cooling T RANSFERRING ENERGY BETWEEN TWO BUILDING ZONES Heating the North side Winter or cloudy days Summer or sunny days Cooling the South side  Transferring energy between 2 building zones

3. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 3  Presentation of the system: capillary tube mats Wall  Very large-area heat exchangers  Low temperature difference can be used  Small time constant Capillary tube  System used for heating  System used for cooling  Thanks to a smart hydraulic layout, possibility of transferring energy between the 2 rooms Transfer between zones Radiant cooling T RANSFERRING ENERGY BETWEEN TWO BUILDING ZONES

4. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 4  Results: Transfer between zones Radiant cooling T RANSFERRING ENERGY BETWEEN TWO BUILDING ZONES

5. 5 Jérôme LE DRÉAU I NVESTIGATION OF ENERGY FLOWS IN THERMALLY ACTIVATED BUILDING CONSTRUCTIONS Part 2: Cooled radiant walls coupled to the room environment Nordic PhD Seminar 08 / 12 / 2011

6. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 6 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Hypothesis: Cooled radiant walls will remove the heat more efficiently than an air conditioning system. Energy Indoor climate Transfer between zones Radiant cooling The different solutions will be compared, combining the analysis of two parameters:  Energy consumption (quantity & quality of the source)  Comfort in the room (quality of the energy delivered)  Finally how to define efficiency…

7. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 7 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT  Methods used:  Simulations (CFD + simulation of energy systems)  Full-scale experiments Transfer between zones Radiant cooling Contents :  How to evaluate the energy consumption?  How to evaluate the indoor climate?  First results

8. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 8 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT H OW TO EVALUATE THE ENERGY CONSUMPTION ? Transfer between zones Radiant cooling

9. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 9  Cooled radiant panel: C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling Wall  Very large-area heat exchangers  Low temperature difference can be used  Small time constant Capillary tube

10. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 10  Different ventilation types:  Mixing ventilation (different types)  Displacement ventilation C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling

11. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 11  What happens in the room? C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT % Radiant panel  % Radiation  % Convection % Transmission % Ventilation Mini 25% 50% 75% 100% Transfer between zones Radiant cooling Result: heat balance of the room

12. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 12 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Result: energy consumption of the room With or without cooling ACH -> Q fans T inlet Flow rate -> Q pumps T inlet Transfer between zones Radiant cooling Different control strategies: high flow rates OR low inlet temperature

13. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 13 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Source 1: Outdoor air BUILDING Transfer between zones Radiant cooling Result: energy consumption of the building & quality of energy Source 2: Groundwater Source 3: Sky radiation Source 4: … Storage tank

14. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 14 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT H OW TO EVALUATE THE INDOOR CLIMATE ? Transfer between zones Radiant cooling

15. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 15  Air temperature  Radiant temperature  Air velocity C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT EN ISO 7730 PMVA DDITIONAL PARAMETERS  Vertical air temperature gradient  Radiant temperature asymmetry  Surface temperatures  Draught rating I NDOOR A IR Q UALITY Transfer between zones Radiant cooling

16. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 16 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT F IRST RESULTS Transfer between zones Radiant cooling

17. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 17  Model used: C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling  Heating case  Outdoor temperature of -12°C  Construction parts (BR10):  External wall: U=0.15W/m 2.K  Window: U=1.40W/m 2.K  Roof: U=0.10W/m 2.K  Ground: no heat losses  Different ventilation rates (0.5ACH – 3ACH)  100% convective OR 100% radiative (floor)  No air temperature gradient OR Air temperature gradient

18. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 18 C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling Static calculation with heating power kept constant  Results:

19. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK 19  Results: C OOLED RADIANT WALLS COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling ACH Heating power (W) 0.5500 1.5900 21100 31500

20. J ÉRÔME L E D RÉAU JLD @ CIVIL. AAU. DK Thank you for your attention! 20 Jérôme LE DRÉAU PhD fellow Supervisor: Prof. Per HEISELBERG Aalborg University (DK) - Department of Civil Engineering @ jld@civil.aau.dk  +45 50 30 01 37 R ADIANT WALL COUPLED TO THE ROOM ENVIRONMENT Transfer between zones Radiant cooling