1. Task 23: Optimization of Solar Energy Use in Large Buildings MCDM’23 A Multi-Criteria Decision Support Method for Whole Building Solar Design

2. Task 23: Optimization of Solar Energy Use in Large Buildings MCDM-23 was developed within International Energy Agency Solar Heating and Cooling Task 23 “Optimization of Solar Energy Use in Large Buildings”

3. Task 23: Optimization of Solar Energy Use in Large Buildings Requirements for Successful Solar Building Design: nSelect a design team with a wide range of technical skills nAdd an energy engineer and other relevant specialists to the team nCommence with teamwork from the very start of the Pre-design Stage nUse new methods and tools throughout the process nDefine performance goals at the outset and referring to them throughout nStart with a client and design team committed to high per- formance, and willing to alter the normal design process

4. Task 23: Optimization of Solar Energy Use in Large Buildings  Application and integration of knowledge and judgements from a range of experts from different disciplines  “Balanced” specification and integration of design criteria that are incommensurate and may be conflicting (e.g. economics vs. environment, aesthetics, etc.)  “Balanced” integration of both quantitative and qualitative performance criteria (qualitative criteria tend to be under- valued or poorly documented) MCDM’23 seeks to facilitate some of the challenges of integrated design:

5. Task 23: Optimization of Solar Energy Use in Large Buildings Problems in doing tradeoffs:  Criteria have different units (kWh, $, kg of SO 2, percent satisfied, score on a scale of ten, etc.)  Some are quantitative, some are qualitative  For some, smaller is better (resource use), for others, bigger is better (quality issues) How to picture diverse criteria together so we can decide between alternatives?

6. Task 23: Optimization of Solar Energy Use in Large Buildings MCDM-23 is a structured approach to:  Make judgements and values explicit to promote learning and cooperation across disciplines and to reach a common understanding of the overall design problem  Handle values and judgements alongside quantitative assessments in order to clearly see the overall goodness of the design  Help organize and select relevant information and to focus on the most important issues

7. Task 23: Optimization of Solar Energy Use in Large Buildings WHO should use MCDM’23?  In the building design process: All members of the design team, including the client  In a design competition: The competition organizers and the judging committee  A person needs to be appointed to organize the work with the method and to take care of the mechanics of aggregating the information

8. Task 23: Optimization of Solar Energy Use in Large Buildings WHEN should MCDM’23 be used?  For selecting and specifying design criteria in the pre-design phase, and for prioritizing among design criteria  For evaluating alternative design strategies and solutions at various stages in the design process

9. Task 23: Optimization of Solar Energy Use in Large Buildings WHAT is MCDM’23? A method and tool based on CRITERIA, WEIGHTS AND SCORES that is a means to encourage the members of the design team to make their knowledge, values and judgements EXPLICIT - so that the other members (and the outside world) can better understand, learn and interact!

10. Task 23: Optimization of Solar Energy Use in Large Buildings STEPS in MCDM’23 Step 1: Select and describe main criteria and sub-criteria Step 2: Develop measurement scales for sub-criteria Step 3: Weight the main criteria and sub-criteria Generate alternative solutions Step 4: Predict performance Step 5: Aggregate scores Step 6: Analyze results and make decisions

11. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 1 DESCRIBE, SELECT, AND STRUCTURE CRITERIA  Top-down approach: Start with overall objectives, then go into details  Bottom-up approach: Test the criteria on relevant alternatives (cases)  Start out wide (use check lists), then narrow in  Document the reason why a criterion is important:  Irreversible consequences?  Wide ranging consequences?  Far from fulfilling national goals?

12. Task 23: Optimization of Solar Energy Use in Large Buildings main goal (optimal housing area) Main criteria (e.g: resource use, functionality, comfort) Sub-criteria (e.g. energy use) Indicators (e.g. kWh/m 2 ) Lower-level criteria explain the concrete meaning of upper-level criteria Helps sorting out redundancies and double counting Allows keeping the overview as well as going into the details Advantages of a hierarchical structure: STEP 1 DESCRIBE, SELECT, AND STRUCTURE CRITERIA

13. Task 23: Optimization of Solar Energy Use in Large Buildings Example of criteria set for main criterion Resource Use Sub-criteriaSub-sub-criteriaIndicators EnergyNet use of energyMJ/m ² /person LandNet area of land usedm ² /occupant Change in ecological valuejudgement WaterNet consumption of waterm ³ /year/person MaterialsRetention of existing building% of floor area Use of recycled materials% of cost Re-useable materials% of cost Re-cyclable materials% of cost

14. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 2 DEVELOP MEASUREMENT SCALES FOR SUB-CRITERIA ScoreJudgement 10excellent 9 8good 7 6fair 5 4marginally acceptable

15. Task 23: Optimization of Solar Energy Use in Large Buildings Example of measurement scale for quantitative criteria Annual Electric Use

16. Task 23: Optimization of Solar Energy Use in Large Buildings Example of measurement scale for qualitative criteria ScoreJudgement Adaptability 10excellentDifferent clients without change 9Different clients by moving adjustable partitions 8goodDifferent clients by rebuilding non- load bearing partitions 7Different clients by rebuilding some non-load bearing partitions 6fairDifferent clients by rebuilding mostly non-load bearing partitions 5Different clients by rebuilding all load bearing partitions 4marginally acceptableNot adaptable to different clients

17. Task 23: Optimization of Solar Energy Use in Large Buildings The value of creating scales  Generates a concrete discussion about how the building should perform  The process of setting end-points leads to an active search for alternative options: “Can we not do better than that?”  Facilitates interpretation of criteria: the same words may have different meanings for different individuals  Helps define the general nature and context of the problem - may lead to restructuring of the model  Allows each member of the team to express his or her own expertise to the group as a whole

18. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 3 WEIGHT THE MAIN CRITERIA AND SUB-CRITERIA GradeRelative importance (compared with the most important criteria) 10 Of equal importance 9 8 Somewhat less important 7 6 Significantly less important 5 4 Much less important

19. Task 23: Optimization of Solar Energy Use in Large Buildings Pie chart button displays graphic Example of weighing using the tool

20. Task 23: Optimization of Solar Energy Use in Large Buildings The value of weighting  Make values and hidden judgements explicit to the group as a whole  Generates discussion and visualizes different viewpoints  May lead to a redefinition of the scales  Helps focusing on the most important issues

21. Task 23: Optimization of Solar Energy Use in Large Buildings GENERATE ALTERNATIVE SOLUTIONS …………

22. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 4 PREDICT PERFORMANCE using  computer simulations  databases  rules of thumb  experience  expert judgement

23. Task 23: Optimization of Solar Energy Use in Large Buildings Enter the number in the program Click the button to plot the value on the value graph

24. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 5 AGGREGATE SCORES

25. Task 23: Optimization of Solar Energy Use in Large Buildings STEP 6 ANALYZE RESULTS AND MAKE DECISIONS After entering all the values for all the schemes, there are four results options: 1) Worksheet for each scheme 2) Star diagram for each scheme 3) Summary bar graph showing all schemes 4) Summary table showing all schemes Tables can be exported as comma-delimited files. Diagrams can be copied to the clipboard. Both can be printed.

26. Task 23: Optimization of Solar Energy Use in Large Buildings Provides documentation of the process Scheme B is not so good ( 5.6 out of 10 ) Worksheet

27. Task 23: Optimization of Solar Energy Use in Large Buildings Star Charts Functionality

28. Task 23: Optimization of Solar Energy Use in Large Buildings Bar Graphs Functional ity

29. Task 23: Optimization of Solar Energy Use in Large Buildings Scheme A is the best ( 8.98 out of 10 ) This table was generated automatically in MCDM-23, copied directly from the screen, and pasted into this presentation. It can also be exported as a csv file. Summary Table

30. Task 23: Optimization of Solar Energy Use in Large Buildings MCDM’23 is a means to organize the multi-criteria design work and to understand and learn about what’s important NOT to produce the “right answer”! CONCLUSION