1. Marco Molinari, Ph.D. Department of Automatic Control, KTH
The importance of the design phase in Energy Quality Management: an example of the application of the parametric analysis
Marco Molinari, Ph.D.
Department of Automatic Control, KTH

2. Outline
Background
Energy efficiency targets in the built environment
Tools for analysis: S.E.P.E.
S.E.P.E.in practice: performance improvement with exergy analysis
GSHP improvement through integrated design
Current research
Conclusions

3. Energy use in the world: the need for reduced and more sustainable energy use
32%
87%
No wonder that EU prioritizes reduction of energy use in buildings in its energy policy
Source: IEA 2010
Source: IEA 2011

4. Energy and exergy efficiency
Energy supply type in buildings
Source: Fraunhofer IBP
Source: Mure Odyssey database

5. Can we improve our energy management by means of exergy concepts?
Energy quality (exergy) mismatch between supply and demand indicates potential for energy management improvements
Main hindrances:
Lack of a shared understanding of the advantages of the exergy approach
No standardized exergy analysis calculation tools available
Need for demonstration projects

6. Human Body Exergy Calculation
Examples of available exergy analysis software programs: IEA ECBCS Annex 49
Human Body Exergy Calculation
Cascadia – An Exergetic Approach to Neighbourhood Design
Pre-Design Tool for buildings exergy analysis
DPV Tool
S.E.P.E. – Software for Exergy Performance Assessment
What we mean with exergy analysis
No commercial software programs available – too specific field

7. S.E.P.E. HVAC components Generators Distribution components HPs,
Ducts/pipes
chillers
Fans and pumps
boilers
Emission systems
solar collectors
radiators DH FH
Heat exchangers
air units
controllers
Simplified building envelope

8. Component example: boiler

9. Example of S.E.P.E. HVAC system assembly

10. Improvement of heat pumps COP performance with S.E.P.E.
DHW
T10 T9
Heat Exchanger 1 T4 T5
Reservoir T2 P2
Heat Pump 2
T12= 10°C
Floor Heating System T7 T8 T6
Heat Exchanger 2
Tset= 22°C
Reservoir T1
Heat Exchanger 3 T3 P1
Heat Pump 1
Complex system
For a defined energy (exergy) service (DHW and FH demand) we want to improve the exergy efficiency (i.e. provide less electricity)
Example: how much do temperature T1 and heat exchanger area 2 affect the OVERALL performance of the system?
Does the reduction of the overall exergy loss induce an increase of the COP? (of course we know that this is true but we want to quantify how much)
Reservoir T0

11. Results
Add information on the variation of the overall exergy loss
Connect points with arrows
The same physical system can achieve different performance if the subsystems are not properly matched

12. Building heated area: 8000 m2 Locations: Stockholm and Madrid
How to extend these results to other fields: design of ground source heat pumps
Building heated area: 8000 m2
Locations: Stockholm and Madrid
Parametric study
Building envelope
Walls and roof insulation
Borehole field
Borehole spacing
Number of boreholes
Boreholes ! Why so many?
Env heat out of the ground : what’s the problem? Heat & cost

13. Results: Madrid Results: Stockholm
Multiparameter analysis & optimal configurations

14. Current research at KTH: advanced control strategies in buildings
Integration of a model in the controller; optimized control action based on the model predictions based on the forecast of temperature, radiation and occupancy (internal gains) and the current status.
Further development: MPC – exergy:
Building control
Ground storage

15. Conclusions
Conceptual and calculation tools for energy quality management already exist and are now mature enough to shift from research to applications
The application of exergy concepts can be highly valuable to the improvement of the design of buildings, especially in connection to parametric analysis
Examples of improved design of buildings and buildings components based on exergy principles are needed to show the potential improvements in energy quality management
Advanced controls schemes and exergy can be an innovative match to further decrease the overall energy used in buildings

16. Thank you for your attention!

17. S.E.P.E. systems components layout
Maybe replace pic with a video

18. Exergy VS energy or exergy AND energy?
Energy analysis alone has shortcomings
Energy efficiency does not introduce a unique reference to show how much a system can be improved
We somehow account for the energy quality through primary energy: but how can we improve the building design without taking into account explicitly exergy?
Exergy approach is not a standardized approach
Examples of design and implementation on real buildings are limited
It lacks standard commercial calculation software programs
Average exergy efficiency in built environment is low

19. Parametric analysis