Posts Tagged ‘energy efficiency’

Windcatchers have been employed for thousands of years to cool buildings in hot climates. The windcatcher is able to chill indoor spaces in the middle of the day in a desert to frigid temperatures.

Windcatchers have been employed for thousands of years to cool buildings in hot climates. The windcatcher is able to chill indoor spaces in the middle of the day in a desert to frigid temperatures.

The following list includes dozens of low tech, low cost ways to cool buildings in hot climates passively without electricity or machinery, i.e., passive cooling or natural cooling. This list is in addition to the 11 or so simple passive cooling techniques that I talked about in my video the other day. Altogether there are over 50 practical methods for cooling your home sustainably. Despite all these wonderful methods, most people – at least in North America – live in poorly insulated boxy houses with costly, wasteful air conditioners. This is one example of “ignorance is not bliss”.
– night cooling: open the windows at night to let in cooler, fresher air.
– roof vents for improved ventilation. This could include a ridge vent and cupola.
– gable vents on gable end walls
– adequately shaded clerestory windows
– smaller windows on the east and west to prevent overheating (if the walls aren’t shaded)
– louvers and vents
– well located doors
– 50-100% more or larger windows on the leeward side than the windward side to help hot air to escape
– earth berming with moist vegetation such as grass
– keeping vegetation moist around the house to help cool the breezes (the yard)
– planting trees to funnel air toward your house
– plant trees that don’t block breezes
– wing wall to direct cool breezes into the home
– building on stilts
– stack effect: multi-story designs can be very effective at encouraging natural convection
– open plan living areas that encourage air circulation
– narrow floorplans
– orientation to catch breezes more effectively
– location: breezy locations near lakes, etc.
– outdoor living areas
– porches/verandas that shade the walls
– shaded, high thermal mass walls such as earthbags, adobe, etc.
– windscoop/windcatcher (with possible addition of a water element)
– evaporative cool wall such as double terra-cotta brick walls (low fired brick) filled with moist sand
Venturi effect
– solar chimney: chimney designed to heat air and draw air from the house
– atrium or sunroom: can act like a solar chimney if properly designed
– basement: upper floors draw cool air upwards from the basement
– cool pantry and rootcellar
– well, open air cistern or underground water canal in the basement
– earth tubes in dry climates where mold is not a problem and digging is fairly easy
– roof insulation and reflective roof insulation
– fly roof (secondary roof over the main roof)
– green roof/living roof
– soffit vents and baffles between rafters to improve roof ventilation
– light roof color that reflects sunlight
– manmade water feature such as a lily pond on the windward side
– awnings (if you don’t have large roof overhangs)
– inner courtyard/open atrium
– pergolas and trellises to shade walls
– minimize sun reflection and re-radiation from surrounding environment: plants versus gravel or pavement
– blinds: close if sunlight is entering window
– avoid skylights unless openable and tinted
– smooth plaster reflects more light than textured plaster

Note: This is just a list of practical cooling strategies. There are plenty of ‘yeah, buts’ you should be aware of to prevent problems. There isn’t time or space here to cover everything. A fair amount of research is required to learn the details so you can optimize the passive cooling design for your home and building site.

Image source: Wiki – Windcatchers (good info on windcatchers)
Good reference with more details: Passive Cooling at House-Energy.com

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Chest fridge that consumes about 0.1 kWh per day or about $5 worth of electricity per year.

Chest fridge that consumes about 0.1 kWh per day or about $5 worth of electricity per year.

I saw this fridge a few years ago on Build it Solar.com. It’s a great site like I keep saying with hundreds of practical projects. Several years later and now I’m asking the same questions as the author below. Why haven’t more people made the switch to this super energy efficient fridge?

“Using vertical doors in refrigeration devices is an act against the Nature of Cold Air. Understanding and cooperating with Nature rather than acting against it leads to much better efficiency.

My chest fridge (Vestfrost freezer turned into a fridge) consumes about 0.1 kWh a day. It works only about 2 minutes per hour. At all other times it is perfectly quiet and consumes no power whatsoever. My wind/solar system batteries and power-demand-sensing inverter simply love it.

It is obvious that a truly energy efficient fridge does not cost any more money than a mediocre one. It actually costs less. It also has amazing food-preserving performance because temperature fluctuations in its interior are naturally minimized.

So – WHY mediocre food-spoiling fridges are being made? WHO makes decisions to manufacture them? Who awards them “stars” and other misleading awards? Why people continue to buy and use energy wasting and food-spoiling devices? Does anyone care about understanding anything?

Nearly every household on Earth has a fridge that totally wastes at least 1 kWh of energy a day (365 kWh a year). How much reduction in greenhouse emissions can we achieve by banning just ONE inefficient household device in just ONE country? How many politicians debating for how many years will it take to achieve such a ban?

Rather than waiting for someone to do something I would like to volunteer to supply modified chest freezers and/or freezer modification kits to environmentally conscious people of Australia. Let’s do something in the right direction right now.”

Source: Mt. Best.net (lots more good info on this site)
You can read the full article here.
How to Convert a Chest Freezer to a Fridge

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Installing window quilts is one of the simplest, easiest ways to save on energy costs. It’s right up there with caulking, weather stripping and adding extra roof insulation in terms of rapid payback. Window quilts would probably pay for themselves in just one or two seasons. With something so simple and obvious you’d think more people would use them, especially those in cold climates. You save energy and improve comfort by greatly reducing drafts. As pointed out in the video, window quilts are especially practical in passive solar homes that have more windows than typical homes.

I’m not promoting any particular brand. It’s the concept that’s important. You could even make your own window quilts. Fabric stores sometimes sell window quilt material. A client of mine is thinking of sewing quilts with recycled ground styrofoam, foam peanut packaging or bubble wrap insulation, possibly with Velcro around the edges. Use rot resistant fabric for durability and make sure the edges are sealed. Use a design that’s easy to put in place so you don’t grow weary of installing the quilts every day.

Simply adhering plastic film or bubble wrap might be more practical for some. Here’s an experiment from BuilditSolar.com (great site) that shows how bubble wrap on windows can reduce heat loss by about 45%.

Window Quilt.com

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Kelly sent me the following article about government and big industry plans for achieving energy efficiency in buildings. One goal is to achieve zero net energy by 2030. While I agree with the need to slash energy consumption and the overall goal of zero energy buildings, I have almost no confidence these type of plans will be practical and affordable to average homeowners. Housing is already unaffordable for most people. I think we need less government interference, not more. Imagine a giant ‘energy efficiency building bureaucracy’ like the building department involved with every project, and all the associated fees, forms, permits, inspections, regulations, fines, delays, and on and on. No thanks. The know-how to build super efficient buildings is already widely known. Rising energy costs and costs of materials are gradually making the need for energy efficient buildings a no brainer. As costs escalate, people will naturally gravitate to affordable, low impact, low energy buildings like earthbag, adobe, pole building and so on.

Source: The Three Factors Behind a ‘Moon Shot’ for Building Energy Efficiency

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