Advanced Building Systems Dirk Müller, Azadeh Badakhshani, Alexander Hoh

Transcription

1 Advanced Building Systems Dirk Müller, Azadeh Badakhshani, Alexander Hoh ANNEX 49, , Prof. Dr.-Ing. Dirk Müller EBC Institute for Energy Efficient Buildings and Indoor Climate

2 Exergy balance of a heating system Exergy losses of combustion Hydraulic losses of borehole heat exchanger Heat losses of pipes Exergy losses of heat exchanger Exergy losses of heat delivery Fuel exergy Ex demand Generation Distribution Delivery Energy Demand Auxiliary exergy Auxiliary exergy Annex 49, München Dirk Müller Folie 2

3 Generation and distribution losses Fuel exergy Hot water exergy Exergy of heat losses of pipes Exergy content of heat losses Demand exergy (electricity demand) of pumps Annex 49, München Dirk Müller Folie 3

4 Delivery losses Delivered exergy Demand exergy Annex 49, München Dirk Müller Folie 4

5 Overall system evaluation Annex 49, München Dirk Müller Folie 5

6 Active heat transfer inside of buildings Local Space Zonal Active heat transfer Central Local Time Zonal Central Slide 6

7 Heat Transfer between Zones Heat transfer via thermo active wall systems Direct coupling of rooms/zones by a pump driven water circuit Indirect coupling of rooms/zones by heat pump systems cooling heating Annex 49, München Dirk Müller Folie 7

8 Potentials in Office Spaces Set-up of four test rooms with different orientations Outside temperatures and radiation data from Germany (TRY 4) Medium internal load for office buildings (3 W/m 2, 8: 18:) Constant room temperature of 22 C Annex 49, München Dirk Müller Folie 8

9 Heating and Cooling Demand (Year) Room N Room E Heating Cooling time in month Room S time in month Room W time in month time in month Annex 49, München Dirk Müller Folie 9

10 Heating and Cooling Demand (Winter) 5 Room N Heating 5 Room E time in d time in d 5 Room S 5 Room W Cooling time in d time in d Annex 49, München Dirk Müller Folie 1

11 Heating and Cooling Demand (Transitional Season) 5 Room N 5 Room E time in d time in d 5 Room S 5 Room W time in d time in d Annex 49, München Dirk Müller Folie 11

12 Heating and Cooling Demand (Summer) 2 Room N 2 Room E time in d time in d 2 Room S 2 Room W time in d time in d Annex 49, München Dirk Müller Folie 12

13 Heat Transfer between Zones Ideal Systems transfer power in W/m² Ceiling-Ceiling Ceiling-Floor temperature difference in K Annex 49, München Dirk Müller Folie 13

14 Heat Transfer between Zones Water Systems transfer power in W/m² Ceiling-Ceiling 4 l/(h m²) Ceiling-Floor 4 l/(h m²) Ceiling-Ceiling 5 l/(h m²) Ceiling-Floor 5 l/(h m²) temperature difference in K Annex 49, München Dirk Müller Folie 14

15 Thermal potentials in time Heat recovery potentials in time Variation of internal and external heat loads Yearly changes of the average outside temperature Geothermal systems T room <T outside Daily changes of the outside air temperature Latent heat storage devices T room >T outside Annex 49, München Dirk Müller Folie 15

16 Ambient Air as Heat Sink for Cooling Applications Temperature in C Reference year Berlin, 19 th of August Outside temperature Phase change temperature daytime Annex 49, München Dirk Müller Folie 16

17 PCM System Test Set-up Day time: cooling Annex 49, München Dirk Müller Folie 17

18 Night time: regeneration Slide 18

19 Results Thermal Power in W/kg PCM Annex 49, München Dirk Müller Folie 19

20 Results Thermal Storage Capacity Approx. four times higher than water Annex 49, München Dirk Müller Folie 2

21 Results for the PCM Cooling System Experiment with 1.7 kg/m² without nightly room cooling up to 2.5 K Experiment with 1.7 kg/m² with nightly room cooling up to 4 K Simulation with 8 kg/m² without nightly room cooling up to 4 K Annex 49, München Dirk Müller Folie 21

22 Energy / Exergy Analysis of Heatings Systems Condensing Boiler Air Water Heat Pump Dual Fuel System (Bivalent) Annex 49, München Dirk Müller Folie 22

23 Primery Energy Demand for all Systems Primary Energy Demand in % Insulated Building electr kwh kwh gas 1369 kwh 47% gas 53% electr. Primary Energy Demand in % Non-Insulated Building 3653 kwh kwh 328 kwh electr. gas 7% gas 3% electr. Boiler AWHP Bivalent Boiler AWHP Bivalent Annex 49, München Dirk Müller Folie 23

24 Conclusions The exergy concept offers a better understanding of any kind of heating and cooling system Dynamic exergy calculations shall be used to design better control systems Exergy concepts can fail due to: Fossile fuels are almost pure exergy (but we do not have a perfect fuel cell ) Electrical power is not rated by average efficiency standards ANNEX 49 Dirk Müller Slide 24

25 Thank you for your attention ANNEX 49, , Prof. Dr.-Ing. Dirk Müller EBC Institute for Energy Efficient Buildings and Indoor Climate