MCDM’23

1. MCDM’23 A Multi-Criteria Decision Support Method for Whole Building Solar Design

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

3. Requirements forSuccessful Solar Building Design: • Start with a client and design team committed to high per-formance, and willing to alter the normal design process • Select a design team with a wide range of technical skills Integrated Design • Add an energy engineer and other relevant specialists to the team • Commence with teamwork from the very start of the Pre-design Stage • Define performance goals at the outset and referring to them throughout • Use new methods and tools throughout the process

4. MCDM’23 seeks to facilitate some ofthe challenges of integrated design: • 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)

5. Problems in doing tradeoffs: • Criteria have different units (kWh, $, kg of SO2, 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. MCDM-23 isa 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. 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. 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. 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. 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. 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. STEP 1 DESCRIBE, SELECT, AND STRUCTURE CRITERIA Advantages of a hierarchical structure: main goal (optimal housing area) • 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 Main criteria (e.g: resource use, functionality, comfort) Sub-criteria (e.g. energy use) Indicators (e.g. kWh/m2)

13. Example of criteria set for main criterion Resource Use Sub-criteria Sub-sub-criteria Indicators Energy Net use of energy MJ/m²/person Land Net area of land used m²/occupant Change in ecological value judgement Water Net consumption of water m³/year/person Materials Retention of existing building % of floor area Use of recycled materials % of cost Re-useable materials % of cost Re-cyclable materials % of cost

14. STEP 2 DEVELOP MEASUREMENT SCALES FOR SUB-CRITERIA Score Judgement 10 excellent 9 8 good 7 6 fair 5 4 marginally acceptable

15. Example of measurement scalefor quantitative criteria Annual Electric Use

16. Example of measurement scalefor qualitative criteria Adaptability Score Judgement 10 excellent Different clients without change 9 Different clients by moving a d justable partitions 8 good Different clients by rebuilding non- load bearing part i tions 7 Different clients by rebuilding some non-load bearing partitions 6 fair Different clients by rebuilding mostly non-load bearing part i tions 5 Different clients by rebuilding all load bearing partitions 4 marginally accep t able Not adaptable to different cl i ents

17. 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. Grade Relative importance (compared with the most i m portant criteria) Of equal importance 10 9 Somewhat less important 8 7 Significantly less important 6 5 Much less important 4 STEP 3 WEIGHT THE MAIN CRITERIA AND SUB-CRITERIA

19. Example of weighing using the tool Pie chart button displays graphic

20. The value of weighting • Make values and hidden judgementsexplicit to the group as a whole • Generates discussion and visualizesdifferent viewpoints • May lead to a redefinition of the scales • Helps focusing on the mostimportant issues

21. GENERATE ALTERNATIVE SOLUTIONS …………

22. STEP 4 PREDICT PERFORMANCE using • computer simulations • databases • rules of thumb • experience • expert judgement

23. Enter the number in the program Click the button to plot the value on the value graph

24. STEP 5 AGGREGATE SCORES

25. 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. Worksheet Provides documentation of the process Scheme B is not so good ( 5.6 out of 10 )

27. Star Charts Functionality Functionality

28. Bar Graphs Functionality

29. Summary Table 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. Scheme A is the best ( 8.98 out of 10 )

30. CONCLUSION 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”!