David Arnold
Showing posts with label landscaping. Show all posts
Showing posts with label landscaping. Show all posts
Catch and Store Water
Regulations that require the water supply to public buildings to be chlorinated, combined with the relatively low water use of these buildings, made the cost/benefit of plumbing these buildings in to their own tank supply to be marginal. However tanks have been installed to both buildings, at present for outside water use only.
18 000 litre tank at east end of Hall, showing first flush water diverter at left. The first flush of water off the roof washes it, fills this diverter, then cleaner water is allowed to flow into the tank. Diverter empties between rain events. Water from this tank is used to irrigate the entry courtyard garden, and to operate the misting cooling system.
Tanks being delivered. The black t-shirt says "I do whatever the voices in my head tell me to do." : ) Delivering tanks is a good start.
Tanks at early childhood centre. The small tank at right is for the children's use, to fill little buckets for summer play in the sandpit. When it runs out, the children can be prompted to think about where water comes from, how it can run out, etc. Modern house design and reticulated services can leave young people ignorant of where supply comes from, of what is behind the tap or the switch on the wall.
David Arnold
David Arnold
Control Vents and Draughts
Existing Ventilation and Draughts
Many rooms in the community complex building leaked like a sieve. In the 1970's, when this building was constructed, regulations for buildings where public gatherings are held required very high levels of ventilation, including permanently open vents. These regulations were changed in the 1980's, but they left us with a Main Hall and other rooms that were excessively well ventilated. Some of these vents just needed to be covered with insulation and closed off, while others could be useful sometimes.
Ridge Vent in Main Hall
The main hall was built with a permanently open ridge vent that runs the full length of the building - 7m along the top of the stage, and for 18m above the hall.
Trevor Northey setting up for the big fan in Hall, with stage behind. The ridge vent runs right along the top of the space. It is ideally placed in some conditions for releasing excess heat inside, but made it very difficult to warm the space in winter. There are stories of people dancing in their overcoats. The two pairs of double doors to the foyer and courtyard can be seen at left.
As each person's body heat can emit 500W of heat, a hall full of 200 people generates - just from the people - 100kW of heat. In summer this needs to be vented, but in winter the body heat alone can warm the room, provided most of the heat can be retained in the room.
Another aspect of the building design makes the ridge vent potentially very functional, in some conditions. The main entry to the Hall is through the well sited entry courtyard, open only to the south, then through 2 lots of pairs of double doors, through the foyer into the Hall. In some wind conditions, we expect be able to use the ridge vent and open-able high windows to act as a thermal chimney, venting heat and drawing cooler air in from the south courtyard.
Graphic, not of this building, showing the general principle of a 'thermal chimney', using high vents to release hot air, and drawing in cooler air, usually from a shaded area to the south.
View of south entry courtyard, being re-landscaped with new pergola to carry a canopy of grapevines for shading and transpiration cooling. Entry doors to foyer and hall can be seen behind. Misting sprays on this pergola will further cool the air in this space, when cool air is needed for a public event.
Close-able covers for the ridge vent
We needed to a means to control the operation of the ridge vent, so we can close it in winter. Local engineer and inventor Murray Ellis devised a mechanism for this, and will be installing these close-able covers in June 2010 with Trevor Northey.
More thermal chimneys
The roof windows above the kitchen and supper room can vent heat, and on occasion draw cooler air from the entry courtyard space adjacent to those rooms.
Kitchen roof window opened to vent heat, and possibly help to draw cool air into the supper room from the entry courtyard.
Double hung windows are a traditional design that can help to create natural air circulation, with hotter air exiting above and cooler air coming in below.
Tall double hung windows in the Kindergarten, with new flyscreens behind. New heavier safety glass in these windows had made these too heavy for their spring balances, and they were out of use.
Trevor Northey was able to make these windows work again by counterbalancing the top and bottom windows with this little pulley arrangement, so they now work well.
Operating a building space for passive or assisted ventilation
This requires building users to think about opportunities to work with breezes, or a cool air source and high vents, before taking the easy but energy expensive option of putting on an air conditioner if there is one available. With natural ventilation there are benefits of fresh air, already partially filtered by the courtyard space.
Window flyscreens and flywire doors installed at the Community House to encourage use of natural ventilation.
Courtyard air access to supper room
One of many little signs around the building to encourage thoughtful use.
David Arnold
Many rooms in the community complex building leaked like a sieve. In the 1970's, when this building was constructed, regulations for buildings where public gatherings are held required very high levels of ventilation, including permanently open vents. These regulations were changed in the 1980's, but they left us with a Main Hall and other rooms that were excessively well ventilated. Some of these vents just needed to be covered with insulation and closed off, while others could be useful sometimes.
Ridge Vent in Main Hall
The main hall was built with a permanently open ridge vent that runs the full length of the building - 7m along the top of the stage, and for 18m above the hall.
As each person's body heat can emit 500W of heat, a hall full of 200 people generates - just from the people - 100kW of heat. In summer this needs to be vented, but in winter the body heat alone can warm the room, provided most of the heat can be retained in the room.
Another aspect of the building design makes the ridge vent potentially very functional, in some conditions. The main entry to the Hall is through the well sited entry courtyard, open only to the south, then through 2 lots of pairs of double doors, through the foyer into the Hall. In some wind conditions, we expect be able to use the ridge vent and open-able high windows to act as a thermal chimney, venting heat and drawing cooler air in from the south courtyard.
Close-able covers for the ridge vent
We needed to a means to control the operation of the ridge vent, so we can close it in winter. Local engineer and inventor Murray Ellis devised a mechanism for this, and will be installing these close-able covers in June 2010 with Trevor Northey.
More thermal chimneys
The roof windows above the kitchen and supper room can vent heat, and on occasion draw cooler air from the entry courtyard space adjacent to those rooms.
Double hung windows are a traditional design that can help to create natural air circulation, with hotter air exiting above and cooler air coming in below.
Operating a building space for passive or assisted ventilation
This requires building users to think about opportunities to work with breezes, or a cool air source and high vents, before taking the easy but energy expensive option of putting on an air conditioner if there is one available. With natural ventilation there are benefits of fresh air, already partially filtered by the courtyard space.
Courtyard air access to supper room
One of many little signs around the building to encourage thoughtful use.
David Arnold
Deflect Unwanted Heat
Deflect Unwanted Heat
The biggest way that the building deflects unwanted heat is by the solid shade provided by the roof. We have greatly enhanced this deflection of heat by painting the roof with heat reflective paint, and by replacing the old skylights that were effectively a hole in the roof, with the roof windows that have solid canopies and appropriate eaves.
Heat Reflective Paint
Applying heat reflective paint was the single biggest and most cost effective impact we have had on the operation of this building. For approx $14 000 excl. GST, the 1600sq metres of roof over both buildings has been painted. The paint we used, Astec Energy Star white, is said to reflect 89% of heat, and is also very good at releasing heat to the night sky – 89% emissivity.
Kevin Jacka applying heat reflective paint to the roof of the Meeting Room. It is bright up there!
Afternoon on the roof of the Community Complex. The sun is behind the camera, so the light and heat is being reflected away. This roof is mostly flat or low angle, so the glare mainly only effects people walking on the roof, or passing helicopters. For a steeper roof a darker colour of heat reflective paint could be used, to produce less glare. Note also reflective tinting on high windows of Hall, visible to left of picture. It is 3pm on 23rd February, and the sun is just about to start shining onto (before tinting, into) these high windows.
After applying this paint we received many comments from the regular users of the building that it is now appreciably cooler in summer. The cost to supply and apply this paint worked out to about $9.50 /sq metre, including GST. It is expensive as a paint, but can be relatively cheap as a cooling strategy for difficult to insulate roofs.
Most of my direct experience with this paint is with this building, with its very poorly insulated ceiling. However Kevin Jacka, the painter, then went home and painted the metal roof of his own weatherboard house with this paint. His ceiling had about R2.5 insulation. On the summer's day that he put just the primer/undercoat on, his wife came home and said “The house is cooler.” Kevin put the top coat on, and is pleased with the effect. The paint may well be worthwhile applying on roofs where the ceiling is insulated.
However it is a plastic paint and I would like to know more about how it degrades in sunlight before using it on roofs that supply drinking water. I have asked the supplier for more information about this, which they have not as yet provided.
Heat reflective paint is also available for tile roofs, and for walls. Tony Nicholas has used it to very good effect on a west facing wall of his brick house in Hurt St Violet Town. [At Tony's initiative the EcoLiving Project is also encouraging VicTrack to put this paint on the metal shelters on railway platforms.... we'll see how we go with that. I am sure it would be very worthwhile, if they decide to do it.]
Replace skylights with roof windows
see also Use Energy from the Sun The old skylights leaked air, occasionally water until patched up, and definitely leaked heat and cold.
Andrew Otto installing the supper room roof window at midday on December 21, summer solstice. Note the shadow line from the eave extends right to the front of the flashing, well away from allowing sun to enter the room below.
Install apropriate eaves on north windows
There were a number of north facing windows around these buildings that, while being valuable in winter, needed an eave to keep out summer sun.
New canopy/eave installed over north facing window in library courtyard. Shown in May 2010, with warm light entering the library.
Window tinting
Window tinting film can be applied to the inside of existing windows to deflect unwanted heat. This is a compromise solution, because with the deflection of heat comes reduced light passing into the building. A basic purpose of windows is to let in light. However some windows in these buildings, particularly in this case west and south west facing windows, were problematic for letting in summer sun, and we accepted the compromise of reduced light.
Paul Natalizio applying film to a west facing window in the Supper Room. Reduced light from these windows is now more than compensated for by light from the new roof windows. In summer the blinds were kept drawn anyway, because of the sun's heat, so the windows are now more functional than they were.
We used Optitune 15% film, which lets 15% of light in, and rejects 84% of heat. Paul of GV Window Tinting gives a lifetime guarantee on his application of this film for private homes, and a 10 year guarantee for commercial installations. Why the difference? Because the tinted windows must only be cleaned with mild cleaners, and he has found that cleaners of commercial buildings tend to use stronger cleaning products that reduce the life of the film. Sheryl Taylor, the VT Hall Committee, and Strathbogie Shire have all taken note of this. Sheryl only uses mild cleaners at the Hall, anyway.
Mike Larkin preparing wiring for the big fan in the Hall. Note reduced light coming in from the tinted SSW facing windows to right of picture, compared with the NNE facing windows at left. Before the windows at right were tinted, the sun would start shining right into the Hall in the late afternoon, heating it up just before a summer's evening event.
Heat Reflective Blind
Unlike permanently applied tint film, a heat reflective blind can be raised and lowered, giving control over when the effect. It can be raised to allow more indirect light into the room when the sun is not shining in, or to allow winter sunshine in to warm the room. It is more expensive than tinting, but preserves more of the use value of the window.
Sean, Indigo and Steven demonstrate the open-able heat reflective blind installed on a west facing window at Violet Town Community House. This does require someone to think about how the blind works, and actually open it when appropriate – in winter for example to allow the afternoon sun to shine in.
Landscaping for shade
Of course buildings, or badly sited windows, can be also be shaded with vegetation, which is a less energy expensive, and financially cheaper, strategy than high tech window tinting. This works well if well managed. Best if a gardener lives in the building, thinks about how it works, and manages that vegetation to best effect. For this public building we mostly had to accept that the landscape plantings will remain pretty much as they are.
Cutting back the tops of the existing photinia bushes to let winter sun into the Main Hall is one exception. See Use Energy from the Sun. Creating shade for the entry courtyard is another exception. If we can create a leafy shaded space over that courtyard we will deflect heat, create active cooling through transpiration of moisture through the leaves, and create a cool air space from which air can be drawn into the building.
Pergola frame over south facing courtyard garden is to carry four grape vines, which will be guided up the chains hanging from each corner. Shade from the vines will further cool this space. Pergola constructed by Comspread Engineering. Courtyard garden about to be re-landscaped by Graham Jones and Yuta.
Constructing this pergola to carry grape vines and shade this courtyard in summer is an excellent cooling / energy efficiency strategy, but the decision to construct the pergola out of steel is very questionable. I took advice that it should be constructed with galvanised steel for a longer life than timber. On reflection I would prefer to have used very dense Australian hardwood such as Sugar Gum, Ironbark or local Box eucalypt, which in my own and others experience is very durable for outdoor construction.
For any sustainable / energy efficiency project, the embodied energy in the material needs to be taken into account. For the steel, think about the energy cost of digging up the iron ore in Western Australia, digging up the coal in NSW or Queensland, freighting both to port, shipping them to China, freighting these to the steel mill, burning lots of coal to make the steel, then freighting / shipping / freighting the steel back to Violet Town! Compare this with the small energy cost of cutting up a log from within 100 kms, possibly much less, to get durable hardwood timber.
David Arnold
The biggest way that the building deflects unwanted heat is by the solid shade provided by the roof. We have greatly enhanced this deflection of heat by painting the roof with heat reflective paint, and by replacing the old skylights that were effectively a hole in the roof, with the roof windows that have solid canopies and appropriate eaves.
Heat Reflective Paint
Applying heat reflective paint was the single biggest and most cost effective impact we have had on the operation of this building. For approx $14 000 excl. GST, the 1600sq metres of roof over both buildings has been painted. The paint we used, Astec Energy Star white, is said to reflect 89% of heat, and is also very good at releasing heat to the night sky – 89% emissivity.
Afternoon on the roof of the Community Complex. The sun is behind the camera, so the light and heat is being reflected away. This roof is mostly flat or low angle, so the glare mainly only effects people walking on the roof, or passing helicopters. For a steeper roof a darker colour of heat reflective paint could be used, to produce less glare. Note also reflective tinting on high windows of Hall, visible to left of picture. It is 3pm on 23rd February, and the sun is just about to start shining onto (before tinting, into) these high windows.
After applying this paint we received many comments from the regular users of the building that it is now appreciably cooler in summer. The cost to supply and apply this paint worked out to about $9.50 /sq metre, including GST. It is expensive as a paint, but can be relatively cheap as a cooling strategy for difficult to insulate roofs.
Most of my direct experience with this paint is with this building, with its very poorly insulated ceiling. However Kevin Jacka, the painter, then went home and painted the metal roof of his own weatherboard house with this paint. His ceiling had about R2.5 insulation. On the summer's day that he put just the primer/undercoat on, his wife came home and said “The house is cooler.” Kevin put the top coat on, and is pleased with the effect. The paint may well be worthwhile applying on roofs where the ceiling is insulated.
However it is a plastic paint and I would like to know more about how it degrades in sunlight before using it on roofs that supply drinking water. I have asked the supplier for more information about this, which they have not as yet provided.
Heat reflective paint is also available for tile roofs, and for walls. Tony Nicholas has used it to very good effect on a west facing wall of his brick house in Hurt St Violet Town. [At Tony's initiative the EcoLiving Project is also encouraging VicTrack to put this paint on the metal shelters on railway platforms.... we'll see how we go with that. I am sure it would be very worthwhile, if they decide to do it.]
Replace skylights with roof windows
see also Use Energy from the Sun The old skylights leaked air, occasionally water until patched up, and definitely leaked heat and cold.
This old skylight above the kitchen needed to be replaced, and was a hole in the roof letting in heat, cold, and the sun's rays in summer.
Install apropriate eaves on north windows
There were a number of north facing windows around these buildings that, while being valuable in winter, needed an eave to keep out summer sun.
Window tinting
Window tinting film can be applied to the inside of existing windows to deflect unwanted heat. This is a compromise solution, because with the deflection of heat comes reduced light passing into the building. A basic purpose of windows is to let in light. However some windows in these buildings, particularly in this case west and south west facing windows, were problematic for letting in summer sun, and we accepted the compromise of reduced light.
We used Optitune 15% film, which lets 15% of light in, and rejects 84% of heat. Paul of GV Window Tinting gives a lifetime guarantee on his application of this film for private homes, and a 10 year guarantee for commercial installations. Why the difference? Because the tinted windows must only be cleaned with mild cleaners, and he has found that cleaners of commercial buildings tend to use stronger cleaning products that reduce the life of the film. Sheryl Taylor, the VT Hall Committee, and Strathbogie Shire have all taken note of this. Sheryl only uses mild cleaners at the Hall, anyway.
Heat Reflective Blind
Unlike permanently applied tint film, a heat reflective blind can be raised and lowered, giving control over when the effect. It can be raised to allow more indirect light into the room when the sun is not shining in, or to allow winter sunshine in to warm the room. It is more expensive than tinting, but preserves more of the use value of the window.
Landscaping for shade
Of course buildings, or badly sited windows, can be also be shaded with vegetation, which is a less energy expensive, and financially cheaper, strategy than high tech window tinting. This works well if well managed. Best if a gardener lives in the building, thinks about how it works, and manages that vegetation to best effect. For this public building we mostly had to accept that the landscape plantings will remain pretty much as they are.
Cutting back the tops of the existing photinia bushes to let winter sun into the Main Hall is one exception. See Use Energy from the Sun. Creating shade for the entry courtyard is another exception. If we can create a leafy shaded space over that courtyard we will deflect heat, create active cooling through transpiration of moisture through the leaves, and create a cool air space from which air can be drawn into the building.
Constructing this pergola to carry grape vines and shade this courtyard in summer is an excellent cooling / energy efficiency strategy, but the decision to construct the pergola out of steel is very questionable. I took advice that it should be constructed with galvanised steel for a longer life than timber. On reflection I would prefer to have used very dense Australian hardwood such as Sugar Gum, Ironbark or local Box eucalypt, which in my own and others experience is very durable for outdoor construction.
For any sustainable / energy efficiency project, the embodied energy in the material needs to be taken into account. For the steel, think about the energy cost of digging up the iron ore in Western Australia, digging up the coal in NSW or Queensland, freighting both to port, shipping them to China, freighting these to the steel mill, burning lots of coal to make the steel, then freighting / shipping / freighting the steel back to Violet Town! Compare this with the small energy cost of cutting up a log from within 100 kms, possibly much less, to get durable hardwood timber.
David Arnold
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