For all who have not heard a good talk on climate change
http://www.ted.com/talks/james_hansen_why_i_must_speak_out_about_climate_change.html
Sunday, 11 March 2012
Wednesday, 7 March 2012
LED certifications
LED Certifications
The electrical performance of the fixture will need to be specified in terms of parameters such
as power factor and leakage current, often arising as a result of local regulations. Whereas
certain certifications may be mandatory, such as RoHS compliance or CE compliance, others
may be the industry norm, for example it may be usual for the product to have a UL listing. It
is incumbent on the end user to be aware of all certifications that are relevant and to ensure at
an early stage that the manufacturer is capable of delivering compliant products. A specialised
fixture manufacturer will be able to work with the end user to ensure that the end product is
properly certified.
Certifications are obtained as a result of product testing by relevant, independent and competent
bodies. The purpose of formal certifications is to ensure that the product meets certain minimum
agreed standards appropriate for the product and its working environment. These standards
cover such things as safety, electrical interference and environmental impact.
It is vital that the fixture manufacturer is aware of what standards and directives must be
met in order to achieve the regulatory compliance. For example, for CE certification the EU
Electromagnetic Compatibility Directive would apply to digital lighting whereas, say, the EU
Pressure Vessel Directive clearly would not. Furthermore, if a particular directive applies to a
product, it must be further established what standards within that directive are appropriate
and what specific tests must be carried out. The certifications required for a given product
are subject to local laws and ultimately it is incumbent on the end user to be aware of all
certifications that are relevant and to ensure at an early stage that the manufacturer is capable
of delivering compliant products.
Other certifications are not legally required, but there may be an industry norm, for example
it may be usual for the product to have a UL listing in a particular category. Again, the fixture
manufacturer will be able to draw on its experience in the field to provide advice on this and
be able to supply the correct product with best practice certifications.
http://www.nualight.com/images/Downloads/Nualight-White-Paper.aspx
The electrical performance of the fixture will need to be specified in terms of parameters such
as power factor and leakage current, often arising as a result of local regulations. Whereas
certain certifications may be mandatory, such as RoHS compliance or CE compliance, others
may be the industry norm, for example it may be usual for the product to have a UL listing. It
is incumbent on the end user to be aware of all certifications that are relevant and to ensure at
an early stage that the manufacturer is capable of delivering compliant products. A specialised
fixture manufacturer will be able to work with the end user to ensure that the end product is
properly certified.
Certifications are obtained as a result of product testing by relevant, independent and competent
bodies. The purpose of formal certifications is to ensure that the product meets certain minimum
agreed standards appropriate for the product and its working environment. These standards
cover such things as safety, electrical interference and environmental impact.
It is vital that the fixture manufacturer is aware of what standards and directives must be
met in order to achieve the regulatory compliance. For example, for CE certification the EU
Electromagnetic Compatibility Directive would apply to digital lighting whereas, say, the EU
Pressure Vessel Directive clearly would not. Furthermore, if a particular directive applies to a
product, it must be further established what standards within that directive are appropriate
and what specific tests must be carried out. The certifications required for a given product
are subject to local laws and ultimately it is incumbent on the end user to be aware of all
certifications that are relevant and to ensure at an early stage that the manufacturer is capable
of delivering compliant products.
Other certifications are not legally required, but there may be an industry norm, for example
it may be usual for the product to have a UL listing in a particular category. Again, the fixture
manufacturer will be able to draw on its experience in the field to provide advice on this and
be able to supply the correct product with best practice certifications.
http://www.nualight.com/images/Downloads/Nualight-White-Paper.aspx
Energy and efficacy of LED lighting
One of the fundamental specifications to consider when evaluating any lighting system is the
power consumption, as it forms a basis of its economic viability. Since there will generally be
some form of power converter (sometimes known as a ballast) between the mains input and
the lighting fixture, the end user must be clear in specifying that wattage will be measured at
the wallplug and not at the fixture. Furthermore, there may be local regulations regarding the
luminous efficacy of the installed system that stipulates a minimum lumens per watt value. In this
case, the end user must be careful in specifying the lumen output of each fixture to confirm that
the standard is met. Simply accepting the figure advertised by the lighting fixture manufacturer
on a datasheet is not advisable and it has been shown that manufacturers commonly exaggerate
the lumen output2. This misrepresentation is not always wilful but can arise through ignorance
of the technology. Typically an errant manufacturer will simply take the LED manufacturer’s
data for a single LED and multiply it by the total number of LEDs to arrive at the lumen output
figure, failing to take into account losses due to lenses, covers, reflectors, side walls, etc. These
can easily cause a 30 to 40% loss in lumen output. Luminous efficacy is dependent on lumen
maintenance, so as the output degrades over time so does the efficacy.
http://www.nualight.com/images/Downloads/Nualight-White-Paper.aspx
power consumption, as it forms a basis of its economic viability. Since there will generally be
some form of power converter (sometimes known as a ballast) between the mains input and
the lighting fixture, the end user must be clear in specifying that wattage will be measured at
the wallplug and not at the fixture. Furthermore, there may be local regulations regarding the
luminous efficacy of the installed system that stipulates a minimum lumens per watt value. In this
case, the end user must be careful in specifying the lumen output of each fixture to confirm that
the standard is met. Simply accepting the figure advertised by the lighting fixture manufacturer
on a datasheet is not advisable and it has been shown that manufacturers commonly exaggerate
the lumen output2. This misrepresentation is not always wilful but can arise through ignorance
of the technology. Typically an errant manufacturer will simply take the LED manufacturer’s
data for a single LED and multiply it by the total number of LEDs to arrive at the lumen output
figure, failing to take into account losses due to lenses, covers, reflectors, side walls, etc. These
can easily cause a 30 to 40% loss in lumen output. Luminous efficacy is dependent on lumen
maintenance, so as the output degrades over time so does the efficacy.
http://www.nualight.com/images/Downloads/Nualight-White-Paper.aspx
Monday, 5 March 2012
Refrigerant for Cars
The European Union (EU) Directive 2006/40/EC (1) prohibits refrigerants with Global Warming Potentials (GWP) greater than 150, starting from 2011
Current automotive refrigerant HFC-134a (GWP = 1,430) will be banned
• in all “new type” vehicle models sold in the EU starting January 1st, 2011
• in all new vehicles sold in the EU after January 1st, 2017
Thursday, 1 March 2012
Why the Global Warming Skeptics Are Wrong
March 22, 2012
William D. Nordhaus
Suppose we were thinking about two policies. Policy A has a small investment in abatement of CO2 emissions. It costs relatively little (say $1 billion) but has substantial benefits (say $10 billion), for a net benefit of $9 billion. Now compare this with a very effective and larger investment, Policy B. This second investment costs more (say $10 billion) but has substantial benefits (say $50 billion), for a net benefit of $40 billion. B is preferable because it has higher net benefits ($40 billion for B as compared with $9 for A), but A has a higher benefit-cost ratio (a ratio of 10 for A as compared with 5 for B). This example shows why we should, in designing the most effective policies, look at benefits minus costs, not benefits divided by costs.
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