Maximising energy efficiency in residential design by Geoff Clark
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Maximising energy efficiency in residential design by Geoff Clark

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Maximising energy efficiency in residential design

Geoff Clark, Troppo Architects

Informed materials specification and thermal performance in timber frame designs can increase housing star ratings and lower operational energy costs.

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  • Troppo - since 1980 - worked almost entirely in the tropics. Tropical specificity enables critical of alternative climatesIn the tropics you MUST - in the temperate you MAY
  • Images – to comply with expectationsIn these sketches it is possible to identify performance considerations:Shading – Aspect - orientation – materials - materials disposition – structure – elevation – scale – proportion, bulk - … etcPERFORMANCE is what these sketches are about – explorations of the manner in which particular performance outcomes might be achieved.They are very cursory sketches – but the performance attributes can be readily identified – climatic zone in question SHOULD be evident in the diagrams.More later.
  • There are aspects of building materials and performance that we can STATE as FACT:IINSULATION THERMAL MASS ORIENTATION AND ASPECT
  • PROPORTION COLOUR REFLECTIVITY TRANSLUCENCYThese are physical properties – simple facts – not solutions. They are raw, unprocessed DATA STAR RATINGS prescribe the extent or magnitude of these TYPES of attributes, SUPPOSEDLY to improve building thermal performance.Prescription of numbers – statements of fact unfortunately are of NO REAL VALUE to the serious designer. The attainment of real (energy) efficiency bears little if any relation to STAR RATING… Architecture is NOT the prescription of DATA sets - How do I feel about the BCA? - In the words of Edmund Blackadder – “… I find it soft, strong and thoroughly absorbent”Stating facts about the thermal performance of materials is EASY – and good working knowledge essential. But if that were ARCHITECTURE we would all be out of a job.It is however VERY difficult to make statements of fact about thermal performance of buildings - they are COMPOSITES or COMBINATIONS of a range of performance attributes – they are complex systems when in operation, rendered even more complex by the fickle nature of human beings
  • These THERMAL FACTS - revolve largely around fundamental material properties – the properties that we :Resistance value - resist the transfer of energy or heat – clothes for exampleThermal Mass ability to store heat (or cool) – potential energy, but in heat form if you like – an ice blockTime lag - The delay in heat transfer through a particular material of a particular thickness – regardless of R-valueThe latter three – Emissivity – Absorptivity – Reflectivity – also have an appreciable effect, but are more dependent upon the FINISH than on the MATERIAL itself, and their pairing with the substrate is an important consideration. WHY do we not prescribe these? Syle is choice is what people want?White colorbond roof is cooler than a sliver or zincalume roof – despite a slightly higher reflectivity, the zincalume roof has a significantly lower Emissivity
  • R-VALUE – figures vary…if you require an R-value of between 0.1 and 0.25 in a lining material of approximately 20mm thickness THEN Wood has EXCEPTIONAL INSULATIVE PROPERTIES: Higher than glass Lower than fibreglass insulationFibreglass insulation cheats. - fibre, does not require low R-value. The bulked-up relies on STILL AIR trapped within –to good effect.In a free running tropical house this R-value of wood is in fact very useful - EXCEPTIONAL
  • If low thermal mass is what is required - Wood too shows EXCEPTIONAL thermal mass propertiesThis number appears MODERATE - but thermal mass is volume dependent. Concrete - Is used in large thick slabs, either horizontal or vertical AAC – Is used in relatively large volumes, again, in three planes Fibreglass insulation - Is used In blanket form obviously, between other materials Wood - Is used in thin sheets or slender members – hence VERY low thermal mass Water - AIR - One kJ/m3k
  • IF a low or close to non-existent time lag is required - timber shows exceptional performanceDesirable attribute in the tropics - exploitation of the small windows of reprieveEARTH SHELTERING - delays of 6 months AT 6m.DIURNAL swings will be more significant in HOUSE design than the seasonal shifts, - this is an important point when considering materials performance – BIGGEST IS NOT BEST, optimum is.A long time lag in summer may not be right for winter – design decisions address this sort of variance
  • Thermal mass / density of building materials In most cases DENSITY is GREATER, with the three exceptions in this graph being – Water - AAC – WoodRockwool / Fibreglass Insulation – NO THERMAL MASS OR DENSITYNot on the face of it significant - but these sorts of aberrations can represent opportunities - HKMaterial properties allow the exploitation or mitigation of climatic variables - the designer must utilise these climatic assets and liabilities. Insulation is being pushed too hard – not the be-all and end-all in building performance
  • In addition to materials performance we have another more significant tool at our disposal – the architects primary tool – GEOMETRY (and disposition)WHAT THE NUMBERS DON’T SAY5th Year design at Utas considers – considers WHAT THE NUMBERS DON’T - it considers DISPOSITION as the means of determining performance - a four-room plan is assessed for it’s climatic flexibility, resilience or robustnessOne resistive - three responsive components are the starting point – the fabric of the component parts possess DIFFERENT THERMAL characteristics - they each either exploit or resist DIFFERENT climatic influences – but their geometric characteristics and mutual dispositions are what offer the real opportunitiesThis is an exercise in exploring the ALTERNATIVE approach to the NUMBERS gameIt is to encourage students to apply KNOWLEDGE and UNDERSTANDING to the problem of SHELTER – NOT, if you like SCIENCE (and Technology)4 spaces – 4 different orientations will produce four different internal environmental conditions at any one instant – You can ABSOLUTELY guarantee that one will be better than the other three. How much better depends upon the skill of the designer but THIS solution is embodied in DIFFERENCE, not sameness
  • For a given material or envelope set, simple re-organisation produces performance differencesDISPOSITION and GEOMETRY rather than SPECIFICATION are the means by which performance is improved.Without technological inputs - without energy EXPENDITURES - this sort of redistribution will produce SHELTER if thought through
  • Broader characteristics such as- surface area to volume ratios - may form the basis of the thinking… The broader characteristics will be common to climatic zones – geometric patterns will emergeIn the tropics - Long, thin plans maximise ventilationBut in other zones may also offer: Larger heat losses Potentially larger heat gains assuming access to direct sunlight Either - morning or evening gain Storage of the gained heat Dissipation of the gained heat…All these are characteristics that can be identified in these absurdly simple diagrams.
  • The possibilities for a very basic HOUSE are truly vast – these are just some of the orthogonal optionsWith a minimal materials palette, a very broad range of IE conditions CAN be generated . We could almost certainly each find a comfortable space in even relatively harsh environmental conditions in one of these arrangementsAND this is the next important point – we would have to FIND that space – the one that suited us at the time. COMFORT in STASIS is not in fact a worthy goalThe details of the DESIGN are unimportant at this stage. If we choose to DESIGN for climate, it is relatively easy to do so as long as we are willing to design to THAT purpose and ready to to design-in the DIFFERENCE
  • I am suggesting that design for climate is firstly simple geometry / simple disposition. Our manipulation of the disposition and interrelationships of materials and component parts, of buildings, CAN produce an extraordinarily wide range of performance outcomesfroma finite materials set – This is what enables us to SHELTER.I would like to think that architects might be considered PROBLEM SOLVERS, rather than PROBLEM MAKERS but Whacky Geometry Fixation evidences the latterWe have DATA, and we have DISPOSITION as our primary passive tool set – we are at risk of utilising DATA and failing to acknowledge the importance of DISPOSITION and as a result, far too eagerly turning to TECHNOLOGY or ENERGY to solve the problems that we ourselves generate.R-values, thermal mass, time lags are meaningless without the application of KNOWLEDGE AND UNDERSTANDING – but they can provide SHELTER without energy inputs.When we did not have such ready access to technology and energy we didn’t need it, so why now?
  • Another fifth year exercise – to identify from a very limited component set and a finite rule set, the number of possible FUNCTIONAL permutations and combinations. The exercise reinforces the fact that we make CHOICES…. And that those choices have RAMIFICATIONS that affect the performance outcome.
  • Our knowledge, understanding, and experience, enable us to process infinite fields of information, or DATA for the purpose of producing a prescribed effect – a thermal effect in this case.Adding a basic materials palette to this exercise renders a solution set of permutations and combinations that number in the several millions, BUT there is a clear trend in selected solutions – based on performance outcomesStudent’s experience, knowledge, and understanding, enables them to select WELL from this very large set.If design were about picking a material that has the BIGGEST R-value and applying ENERGY to attain COMFORT, we should all be out of a job – but this feels like where we are headed – ‘exterior decorators… of esky’s’ may soon be our job description.Simple geometric manipulations, coupled with knowledge and understanding, are what have been sheltering the human race since time began and in consideration of this I have to confess to finding it rather difficult to imagine that much of what passes as architecture today in fact IS shelter. Fashion and choice seem to be the 21st century obsession and this may be what we are RESPONDING TO. But if this is the case we need to confess the fact. If we are proposing a dumb, non-functional but aesthetically bizarre box and relying on energy input for the attainment of the code-prescribed temperature or energy outcome – then I think that we fail our profession.
  • In the real world – beyond formal education – when the contrived sets of rules employed in the design studio are removed - the permutations and combinations of material and disposition become literally infinite.The sketches that we undertake are our first breaking down of the INFINITE into processable packages – fundamental geometric dispositions are explored to find functional outcomes
  • These drawings are NOT an exploration of numbers, or raw data, They are NOT drawings of stylistic explorationAnd they are NOT an attempt to determine what the next fashion trend might be. They are an exploration of DISPOSITION…. an exploration of GEOMETRY and RELATIONSHIPS in order to determine an appropriate ‘FORM OF’ end or outcome…
  • A focus on disposition and geometry enables ROBUST outcomes… rather than technologically reliant ones.ROBUST outcomes can accommodate fluctuations, changes, difference, the unexpectedIn this case geometry enables reliable off-grid / gravity-fed systems
  • ROBUST, truly ROBUST design is NOT in the first instance about Maximising Energy Efficiency – but this is what we are told, perhaps BECAUSE we have failed to lead by showcasing ROBUST designEnergy efficiency should be a ramification of broader actions, NOT an applied technological rectification to poor or highly fashion sensitive decisions. An occupant’s desire to BE EXPOSED is perhaps a more worthwhile aspiration and a more useful GOAL for architecture – we have certainly tried the alternative…An unfortunate turn of phrase from the BCA – “…designed to use energy efficiently” does not appear to set the bar particularly high.BLACKADDER
  • A building that is considered ACCOMMODATING and COMFORTABLE is surely preferable to one that is defined by its numeric SCIENTIFIC definition – it’s R-valueCOMFORT itself is of course an extremely complicated SET of data and that set is never identical from one individual to the next… but this is EXACTLY WHY we need ROBUST design, why we need to offer internal and external spaces that COLLECTIVELY provide, not individually.DIVERSITY within design is fundamental to producing ROBUST outcomes
  • Our NEED for UNIVERSAL COMFORT seems to me to be rivalling the automobile for deliterious outcome under the guise of NECESSITY. Human beings are not designed to be UNIVERSALLY COMFORTABLE in the same way that human beings were NOT DESIGNED to be constantly and universally stuffed-to-the-gills…The ramifications of our SO CALLED LIFESTYLE choices have become tragically obvious and the ramifications of our COMFORT FIXATION may well do likewise in time.
  • Both physically and psychologically we require environmental change. We need difference, we need DISCOMFORT if you like. It may seem difficult to agree that we NEED discomfort – but with a COMFORT band as narrow as that which we have come to expect perhaps all discomfort is - is DIFFERENCE.GIVE ME DIFFERENCE!Our buildings fail us if they provide universal ‘COMFORT’ conditions – hospitals provide this - but our buildings must still offer us comfort, or more correctly perhaps REPRIEVE.DIVERSITY of internal environments is what we need - to allow us to make our own decisions about how sheltered we NEED to be at any one time, to move form one space to the next… DWEEBs
  • We need connection to outside - to the place that we are IN - and EXPOSURE is an important part of this connection – to FEEL the place …not just to look at it.A room at 22 degrees and 75% humidity provides COMFORT – but does it have the same appeal as a shady tree, and a light breeze, on a hot afternoon if the activity to be accommodated is - drinking beer
  • How we dispose the elements of our buildings is what enables or disables the enjoyment of these sorts of connections, and is what enables or disables choice.A diversity of spaces – not so much in the volumetric sense but in the sense of diversity of climatic conditions – warmth, cool, light, sound, breeze, stability, dynamism, radiant effects, scent, - are essential to facilitating comfort through diversity and sensory STIMULATION they are essential to reducing energy costs by NOT focusing on heat load equations that require the answer to be ZERO.
  • Depending upon geometry and disposition, TIMBER most definitely offers:Excellent R-ValueSpectacular Thermal MassOutstanding Time Lag…and - Informed materials specification and thermal performance in timber frame designs CAN – MOST DEFINITELY increase housing star ratings…but if STAR RATINGS are our goal, have we had it wrong since time began … up until a decade ago?… have we craved comfort since we first started staggering around on our hind feet…The NUMBERS approach assumes fixed dispositions of materials and component parts and this is NOT what we as designers of buildings, as providers of shelter, as solvers of accommodational problems deal with.
  • It remains our RESPONSIBILITY to appropriately array the elements, and to specify materials that work WITH disposition for best OVERALL effect… and the best OVERALL effect is ABSOLUTELY NOT - SAMENESS – The best overall effect is achieved through DIFFERENCE and DIVERSITY, in every way.

Transcript

  • 1.
  • 2. Inspiring Sustainable Design
    Geoff Clark
    Troppo Architects – Global Award for
    Sustainable Architecture
    Senior Lecturer
    School of Architecture and Design
    University of Tasmania
  • 3. Geoff ClarkInspiring SustainableDesigns
  • 4. Maximising Energy Efficiency in Residential Design
  • 5. Maximising Energy Efficiency in Residential Design
    Things we know: Thermal Facts
    Thicker insulation will reduce the transmission of heat energy compared with thinner insulation
    Thermally massive materials will store more heat than less thermally massive materials
    A longer wall facing the north will achieve greater direct solar gain than a shorter wall
  • 6. Maximising Energy Efficiency in Residential Design
    More square metres of building fabric will lose more heat in winter than less square metres of building fabric
    Darker colours convert light to heat energy more efficiently than lighter colours
    Reflective finishes emit less than matt finishes
    Translucent or transparent materials can allow the ingress of short wave radiation for conversion to heat
  • 7. Maximising Energy Efficiency in Residential Design
    What the numbers say:
    R - Value m2K/W
    Thermal Mass kJ/m3K
    Time Lag Hrs
    Emissivity
    Absorptivity
    Reflectivity
  • 8. Maximising Energy Efficiency in Residential Design
    What the numbers say:
    R - Value m2K/W
    Wood 25mm 0.12 - 0.25
    Concrete 100mm 0.07
    Glass 6mm 0.006
    Still air layer 0.14
    Fibreglass insulation 3.5
  • 9. Maximising Energy Efficiency in Residential Design
    What the numbers say:
    Thermal Mass kJ/m3K
    Concrete 2060
    AAC 550
    Fibreglass insulation 9
    Water 4186
    Wood 904
  • 10. Maximising Energy Efficiency in Residential Design
    What the numbers say:
    Time Lag Thickness Hrs
    Wood 20mm 0.4
    Concrete 200mm 6
    AAC 200mm 7
    Clay 2000mm 1500
  • 11. Maximising Energy Efficiency in Residential Design
    What the numbers say:
  • 12. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 13. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 14. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 15. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 16. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
    Disposition
  • 17. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
    Disposition
  • 18. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
    Disposition
  • 19. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 20. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
    Disposition
  • 21. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 22. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 23. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 24. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 25. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 26. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 27. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 28. Maximising Energy Efficiency in Residential Design
    What the numbers don’t say:
  • 29. Maximising Energy Efficiency in Residential Design
  • 30. Inspiring Sustainable Designs
    Questions?
    Geoff Clark
    Troppo Architects – Global Award for
    Sustainable Architecture
    Senior Lecturer
    School of Architecture and Design
    University of Tasmania