
d8648b7d2098a1a24cd53e0010244393.ppt
- Количество слайдов: 21
16469 Low Energy Building Design Conflict and Interaction in Environmental Engineering Design
16469 Low Energy Building Design Conflict and Interaction • design is a complex task, especially in low energy buildings and where there are multiple design objectives • in this situation there is rarely an “optimum” design solution – a good choice according to one criteria may be detrimental when judged against another (conflicting outcomes) • effectively need to undertake multi-criteria analysis and select a “best” design option • requires the generation and assessment of multiple design solutions
16469 Low Energy Building Design Conflict and Interaction Challenge: - generate alternative design solutions: to meet the design objectives while “optimizing” (one or more) performance criteria - need to appraise the different design options and decide on that which best matches the criteria – perhaps an iterative process
16469 Low Energy Building Design: Conflict and Interaction Targets: Design criteria can be usefully expressed in terms of targets – e. g. capital cost, energy consumption
16469 Low Energy Building Design: Conflict and Interaction • There are many examples of conflicting outcomes between different design options: • energy/comfort conflicts -reducing window size: may improve thermal comfort near the window, but will increase heating load in certain circumstances -increasing window size: may lower heating energy consumption but lead to overheating in summer - energy acoustic conflict -increased thermal mass: may reduce overheating problem but cause acoustic problems
16469 Low Energy Building Design: Conflict and Interaction • How to choose between options? • need evidence of how design options will perform – taking account of interactions – simulation • need to find some mechanism of comparing and ranking options according to design criteria – need a method – subjective comparison (table of options) – PAM – iterative approaches
16469 Low Energy Building Design: Conflict and Interaction Subjective comparison: - take into account all design objectives - assess suitability of each design choice against objectives – usually use a matrix - present results via rank-ordering of design options (possibly after applying weighting factors to the evaluation results)
16469 Low Energy Building Design: Conflict and Interaction • Example compare different design options to maximise solar gain and reduce heating load (3 -good 2 -average 1 -bad) design option reduction in heating load reduction in lighting load timing of gain glare risk overheatin g risk capital cost score south facing glazing 2 3 1 1 1 3 11 south facing glazing plus shade 2 3 1 2 2 2 12 trombe wall 3 1 3 3 3 1 14
16469 Low Energy Building Design: Conflict and Interaction Subjective comparison: - advantages: results are easy to understand results – through generating the data to support the assessment may be difficult - disadvantages: - results depend upon comparative criteria - danger of basing results on opinion rather than evidence - subjective – which criteria are more important? How to translate technical result to assessment score? - difficult to compare between very different design outcomes
16469 Low Energy Building Design: Conflict and Interaction • Example – let’s compare different LEBD options for a householder trying to reduce their heat and electricity costs • Get into a group of 3 or 4 and rank the following options based on your existing knowledge ….
16469 Low Energy Building Design: Conflict and Interaction design option PV solar thermal collector micro. CHP double glazing cavity wall insulation loft insulation reduction in heating/ HW costs reduction in electricity costs installatio n cost running costs carbon savings Score
16469 Low Energy Building Design: Conflict and Interaction • my scores … design option reduction in heating/ HW costs reduction in electricity costs installatio n cost running costs carbon savings Score PV 1 2 2 8 solar thermal collector 3 1 2 2 3 10 micro-CHP 2 3 1 1 2 9 double glazing 2 1 2 3 2 10 cavity wall insulation 3 1 2 3 3 12 loft insulation 3 1 3 3 3 13
16469 Low Energy Building Design: Conflict and Interaction • previous example was very subjective … need to remove some of the guess work – need to provide technical evidence to back up scores – need to translate technical outcome to score or (weighting) – how can we do this where there may be a need to appraise many options • modelling and simulation can play a role
16469 Low Energy Building Design: Conflict and Interaction The use of simulation for design option appraisal - virtual design: based on integrated computational tools - multi-factorial tools available: various demand supply systems simulation tools - decision support: iterative appraisal techniques (building energy performance, occupant comfort, renewable supply potential, etc. ) - easily interpreted display: enable designers to quickly identify impacts (PAM)
16469 Low Energy Building Design: Conflict and Interaction • can apply modelling based - multi-criteria analysis at various levels – strategic – country or city level – individual building • and at different levels of detail – appraisal of energy supply technologies (demand supply matching) – appraisal of system performance and different system design options • in the following examples we have a computationally based more methodological (sometimes automated) approach
Digital cities metered energy demand & supply predicted energy database of actual & likely consumption energy model city or region government local authority institutions industry utilities and others database population database analysis support for decision-makers consumption & emissions monitoring; city profiling & property classification; trend analysis & action planning energy/environment information overlaid on maps to support decision-makers at all levels
Supply demand matching supply scenarios demand scenario goodness of fit combinatorial search auxiliary duty cycle supply v. demand surplus or deficit
Virtual design
filtering of data for perfomance appraisal
The Lighthouse Building in Glasgow PV: 0. 7 k. We PV hybrid: 0. 8 k. We & 1. 5 k. Wh DWT: 0. 6 k. We total demand: 68 k. Wh/m 2. yr total RE supply: 98 k. Wh/m 2. yr
16469 Low Energy Building Design: Conflict and Interaction • model for use of simulation in multi-criteria design process: simulation design options appraisal literature review
d8648b7d2098a1a24cd53e0010244393.ppt