are LED bulbs more greener than CFL

August 17, 2009 · Filed under Green Living · Tagged , , , , , , , , , , ,

cfl-ledElectricity consumed in a commercial building for lighting is 35% of total electricity and it accounts for 12-15% average household energy bill. LED bulbs consumes less watt to operate, long life 30000 to 50000 hrs compared to an incandescent bulb 2000 hrs. Made from non-toxic materials disposal is not an issue. Electricity consumption is one tenth of incandescent bulb and less than half of CFL. No UV and RF radiation, lesser carbon dioxide emission almost half of the CFL. LEDs can withstand high levels of shock and vibration. Its able to convert almost all the energy used into the light output, LEDs generate less than 30% of the heat of traditional lighting technologies . LEDs, being solid state components, are difficult to damage with external shock.

Cost factors and ROI: A typical lighting retrofit project will cost around $.45 per sq ft and will start producing benefits within 24 months. A more involved relighting project runs around $1.20 per sq ft but will yield a higher return on investment in the long term. You can expect a relighting project to pay for itself within 5 years. Annual ROI 108% based on LED lamp equivalent to 20 W incandescent bulb.

Who uses this technology: Shopping center, hotels and resorts, offices, residential apartments, hospital and nursing home, industries and warehouses.
Best uses in new constructions: Walk way lighting, parking, cabinet lighting, can be used on ceiling, embed the wall for decoration, area lighting.
Best uses in existing construction: Retail outlets like jewelers store, bar and restaurant, offices parking lots, entry bays, lobby and conference, walkway and out door lighting.

Comparison of bulbs:

http://www.productdose.com/LightBulb_Comparison.xls

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Magic Of White-Roofs

August 17, 2009 · Filed under greenbuilding · Tagged , , , , , , , , , , ,

whiteroofEverybody is aware with the fact that darker materials absorb more heat from sun than white/light colors, but an interesting data I want to share that black surface in the sun can be 40°C (70°F) hotter than the reflective white surface. This phenomenon occurs in the case of roofs also and heated roof then transfer their heat to surrounded air and contribute to heat island effect, while reflective metallic/ ceramic roof can reflect 65-75 %solar light. According to California energy commissioner “White roofs can cut a building’s energy use by 20% and save consumers money,” and “The potential energy savings in the U.S. is in excess of $1 billion annually.”

White roofs need not necessarily can be achieved by huge investments on metallic roof or ceramic tiles, the flavour of white roof can be realized by inexpensive methods like painting roof with white acrylic paint, titanium dioxide coating or even with limestone talc (In India commly known as choona), and one can have flexibilty by having roof covered with tarpauline sheet in summer or on demand.

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Concept Day Light Window: An amazing window

August 17, 2009 · Filed under Green Living

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Quick TIPS on energy saving: Skylight

August 14, 2009 · Filed under Green Living · Tagged , , , , , , ,

skylight

What is Skylighting?

Skylights is another method often used for day lighting by placing horizontal windows, tube or domes at the roof of buildings. Typically an opening required for skylights to illuminate an area is very less its just 5% of total area. Skylights illuminate more space as compares to vertical windows and distribute the light more evenly in the space.

Why use Skylighting

Skylights and roof windows admit 30% to 50% more light than vertical windows in dormers. A skylight can add daylight and warmth to a room in winter and fresh air in summer. An energy-efficient, properly designed skylight admits enough light for the room and save energy cost by reducing heating and cooling loads. Heat loss in winter and gain in summer due to skylights are negligible as area used for sky lighting is very small.

Some comparison data:

  • One square meter of horizontal roofing using a polycarbonate panel (transmittance 0.5) provides during the 70% brightest hour per year more light that 7 T8 (36 W Fluorescent tubes in luminaries) in Northern Europe and 15 in Southern Europe.
  • One square meter of horizontal roofing using a polycarbonate panel (transmittance 0.5) provides during the 70% brightest hour per year more light that 6 T8 (36 W Fluorescent tubes in luminaries) in Northern Europe and 13 in Southern Europe.

Who Uses Skylighting?

Hotels resorts, offices, residential apartments, schools, gymnasium, art galleries, museum, libraries, religious facilities, airport, production buildings e.g. warehouses or garages.

Where and When to Use Skylighting?

Window skylights are suitable for lighting the space where big area roof is available for installation of window. Tubular skylights are useful where space available for opening are too small for a traditional skylight or places windows can not be placed such as bathrooms, dressing rooms, corridors, staircases, attic or basements. The light tunnel may also be used at night, after installing a light kit.

 

Pluses: Enhanced user’s comfort and electricity savings, less likely to cause UV damage to carpets or furniture. Lesser suffering from Seasonal Affective Disorder (SAD) when there is plentiful daylight, . Tubular skylights reduce absolute heat loss and heat gain because of their small cross-sectional area.

 

Minuses: Poorly constructed or installed skylights may have leak problems and single-paned ones may weep with condensation. Heat loss in winter and heat gain in summer.

References

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Quick TIPS on energy saving: Daylight

August 14, 2009 · Filed under Green Living · Tagged , , , , , , , , , , ,

daylightWhat is Day Lighting?

Day lighting is the controlled admission of natural light into a space through windows to reduce or eliminate the need for electric lighting. Today’s highly energy-efficient windows, as well as advances in lighting design and technology, allow efficient use of windows to reduce the need for artificial lighting during daylight hours without causing heating or cooling problems.

Why Use Day Lighting?

Day lighting has been shown to save from $0.05 to $0.20 per square foot annually. The energy savings from reduced electric lighting through the use of day lighting strategies can directly reduce building cooling energy usage an additional 10 to 20 percent. buildings can lead to annual savings of 35-60% on lighting energy.

The U.S. Department of Energy estimates that electronically tintable window systems are capable of providing up to:

  • 40% savings on energy bills
  • 20% savings on operating costs
  • 24% reduction in peak demand
  • 25% decrease in the size of HVAC systems

Who Uses Day Lighting?

Hotels and resorts, offices, residential apartments, hospital and nursing home, art galleries, museum, libraries, religious facilities, aviation facilities, high-tech or image buildings, atriums and overhead daylight openings.

In the summer, day lighting keeps your house cooler as the heat is kept outside. In winter, the heat from objects that are heated by either sunlight or inside heat sources is bounced back into the home, a process which keeps the entire home warmer.

Where and When to Use Day Lighting?

Solar powered smart window, because of their low DC voltage and power consumption, and the obvious complementary relationship between the amount of sunlight available and the level of tinting required to modulate it.

Pluses: Energy saving, increased user productivity, reduced emission, reduction in cooling up to 32 % annually and heating loads up to 39%, reduced fading due to UV rays, reduce escaped or wasted energy, block glare.

Minuses: The cost of electrochromic windows can be from 2 to 3 times that of a standard window. These costs are expected to decrease significantly when manufacturing techniques have improved and quantities have increased. Liquid crystal glazing adds about $90 per square foot to the glazing. Electrochromic films require an electrical hookup that is not required for other types of solar-control window films and therefore requires unconventional wiring at windows and may require coordination of electrical and carpentry trades.

References

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“LOW BUDGET” Tips on saving in energy bills for buildings

August 14, 2009 · Filed under Green Living · Tagged , , , , , , , , , , , , , , , , , ,

In my previous post ” Tips on saving in energy bills for buildings” I got a nice comment from a reader that most of the tips suggested were practically non-doable in a common housing buildings due to high initial investment and/or longer payback period. That comment intrigued me to elaborate more on tiny-mini low budget tips which any one can apply in her/his house and can save money and earth.
Dimmer switches are the device for controlling brightness of the lights, these switches works very similar to regulator/controller of the fans for controlling speed. A light bulb, on full brightness, can be used for lighting the space for reading and same can be dimmed in night to work as night bulb. Use of dimmer switch saves allot energy, about 25% on dimming on light saves 20% of lighting energy and this smart device pays back in less than an year. Another magical device programmable thermostat pays back its cost in less than an year and provide 20-25% energy saving on heating and cooling. Occupancy and motion sensor turns off lighting in unoccupied space, these sensors can ideally be placed in bathrooms, kids room, hallway, drive way or outdoor. These sensor not only save energy on lighting but also increase the life of bulb and save on maintenance. Energy saving and payback depends upon application but energy saving can be up to 50% for the lighting and pay back period varies from 6 months to 2 year.
I mentioned in my previous post too, windows are the main source for heat gain in summer and heat loss in winters, more we work on heat/gain from windows more we’ll save on energy. Energy saving windows film can reduce heating and cooling energy bills by holding 38% escaping heat in winter and 65% of solar heat in summer and above all blocks 98% of UV-rays which cause fading of furniture. Energy saving windows film returns back its cost from 6 months to 2 years. Curtains and drapes do not only to cover windows for privacy or control day light but they have huge potential in saving heat loss too, these inexpensive curtains can reduce thermal loss up to 25% (Source:Eclipse blackout curtain). In a summer hot day a window loose more heat through a square foot than entire wall and solar gain through the glass accounts for 20% load on A/C, a fabric awning can save up to 65% on south facing windows and up to 77% on west facing windows and reduction 8 F-15F (5C-8C) in internal temperature. Use of swamp (evaporative) cooler is always better option than using air-conditioner for people living in hot, dry place like Phoenix, Arizona or by in large south-west USA or most of the plain area of India, it uses 4-5 times less energy than A/C and initial cost also far below.
A story on energy saving tips can not be complete without mentioning energy star products, CFL and LED lights.

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TIPS ON SAVING ON BUILDING ENERGY BILLS

August 2, 2009 · Filed under Green Living · Tagged , , , , , , , , , , , ,

 

In today and age buildings consume energy from 35-45% of total energy produced.Fossil fuels resources are running down fast, causing fuel prize soaring and access to clean energy has become much more difficult for poor people in developing and underdeveloped countries.
Big chunk of money from every homes goes for fat utility bills, more than 50% of utility purchased get consumed just for heating and cooling. Free, clean, renewable energy can be harness for heating, cooling water heating and even for cooking and reducing money flow from pockets to a large extend. Solar water heaters can save about energy 60-85% of energy and solar heating systems pays back in 4-7 years. Other renewable, clean resources like apartment wind mill, earth-tubes lately catching attention. Apartment wind mill can be used for electrification and earth tube can be used for partly/fully cooling and heating building space.

In “ZEB” (zero energy building/home) net electricity flow and other fossil fuel supply are ZERO, and virtually no $$$ flow from home for the purchase of the energy. ZEB can be electrified using solar-PV or thin film solar system in day time, excess electricity generated(if) can be supplied to power-grid and having meter read “negative” which can be balanced out by electricity consumed in night. Apartment wind mill coupled with solar-PV system can be used for uninterrupted supply of electricity most of the time of the year and may be in night too.ZEBs can have solar water/air heaters or earth-tubes for replacing fossil fuel based heating and cooling system.

Windows are window for heat gain in summer and heat loss from building in winter, properly designed and installed energy efficient, smart,low-e window can prevent 30% heating and cooling energy loss. In summer heat gain be reduced by adopting quick inexpensive tips like use of awning/overhang on south and west facing windows, use of tinted film, curtain and having trees on west and south facing windows for shading.

Daylight is a controlled admission of natural light through windows and skylight into a space to reduce or completely eliminate requirement of artificial light. It is estimated 12% of total energy bring in building use up for lighting, according to U.S.G.B. council’s sustainable technical manual 50-80% of lighting energy used can be saved by properly planned and designed daylights. North side placed skylight can magnificently illuminate the space for more than 70% time of the day. Darker place of the building like bathroom and kitchen, where windows can not be placed for daylight and ventilation,, can be enlighten by solar tubes. Use of CFL and LED bulbs in place of incandesce bulbs can save up to 70% of energy and provide quick return on investment.

Other tiny-mini quickie but important tips for energy=money saving are energy starred products, dimmer, energy efficient fixtures, occupant and motion sensor for kids room and outdoor and possibly green roof.

It has been observed green buildings consume about 40-50% less energy and rely on clean energy renewable energy resources like, solar,wind & geothermal.

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