MCDM 23 A MultiCriteria Decision Support Method for

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

Requirements for Successful Solar Building Design: n Start with a client and design team committed to high performance, and willing to alter the normal design process n Select a design team with a wide range of technical skills n Add an energy engineer and other relevant specialists to the team n Commence with teamwork from the very start of the Pre-design Stage n Define performance goals at the outset and referring to them throughout n Use new methods and tools throughout the process Task 23: Optimization of Solar Energy Use in Large Buildings

MCDM’ 23 seeks to facilitate some of the 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 undervalued or poorly documented) Task 23: Optimization of Solar Energy Use in Large Buildings

Problems in doing tradeoffs: · Criteria have different units (k. Wh, $, 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? 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 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 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 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! 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 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? Task 23: Optimization of Solar Energy Use in Large Buildings

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

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 Task 23: Optimization of Solar Energy Use in Large Buildings

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

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

Example of measurement scale for qualitative criteria Score 10 9 Judgement excellent 8 good 7 6 fair 5 4 marginally acceptable Adaptability Different clients without change Different clients by moving adjustable partitions Different clients by rebuilding nonload bearing partitions Different clients by rebuilding some non-load bearing partitions Different clients by rebuilding mostly non-load bearing partitions Different clients by rebuilding all load bearing partitions Not adaptable to different clients 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 Task 23: Optimization of Solar Energy Use in Large Buildings

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

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

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

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

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

Worksheet Provides documentation of the process Scheme B is not so good ( 5. 6 out of 10 ) Task 23: Optimization of Solar Energy Use in Large Buildings

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

Bar Graphs Function ality Task 23: Optimization of Solar Energy Use in Large Buildings

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 ) Task 23: Optimization of Solar Energy Use in Large Buildings

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