CAS Newsletter March 2010
IN THIS ISSUE
There are 3 main ways that heat energy is transferred from one substance to another – convection, conduction and radiation. Thermal insulators retard these processes.
R-Value: A construction industry measure of a materials ability to resist thermal energy transfer.
Space Age Insulator
Aerogel is an extreme insulator. Shown here, a thin slice of Aerogel stops wax crayons melting even though the blowtorch is pointing directly at it. Called a gel because of the way it is manufactured it presents itself as a light almost transparent solid with extremely high melting points, incredible R-values and ultra-low weight. It is reasonably strong. Strength, transparency and other mechanical properties are strongly affected by the manufacturing process. These insulators were used on the Mars Rover. An 18mm layer of aerogel will be sufficient to protect astronauts from temperatures as low as -130C. A sheet of Aerogel as a replacement for glass in a window provides 10-20 times the insulating power. “You could take a two- or three-bedroom house, insulate it with Aerogel and you could heat the house with a candle. But eventually the house would become too hot” – Dr Peter Tsou, Nasa JPL.
R-Values: 14 to +100
Weight : 3 times the weight of air.
Melting : 1200 °C (Silica Aerogel)
Starting to be used for skylightsAirGlass is a variant, similar to Aerogel ,used for window applications as an energy saver and as windows in firewalls.
Engineering Units – Watch Out you can easily be ripped off.
The metric units are m².K/W
1 R value (USA) = 0.17611 m².K/W (SI Units)
Aerogel Brand Names
These products are still expensive and some are hazardous to handle (nano particle dust).
Spaceloft = thin aerogel blanket/sheet made by Aspen Aerogels.
Common Insulators for Home and Commercial Buildings
Completely useless at stopping air and moisture flow. Must be accompanies by air movement barrier. Installation quality sensitive.
Less sensitive to Installation quality. Check for cavities (how ?) Higher density means its better at stopping energy loss due to convection. Minimum wall cavity dimensions and non-self supporting limit applications.
Similar to blown fiberglass. Densities are a little lower and R-value is lower. Made from flammable materials so must be treated.
R-value is stable in adverse weather conditions. Stable, self supporting. More expensive. Excellent at convective, conductive and radiation heat loss.
Studs – A huge waste of energy
The problem is that metal studs conduct heat many times faster than wood, serving as a sort of heat-loss superhighway. To prevent excessive heat loss, the studs must be properly insulated and sealed into the walls. The most commonly used and recommended solution is an exterior layer of rigid insulation sheathing to break that thermal bridge. But not all builders who use steel framing are addressing the alternative stud’s shortcomings.
More About Aerogel
Source=NASA Comet Sample Return Mission web page. http://stardust.jpl.nasa.gov
What makes aerogel so special?
The fact that typical aerogels are between 95 and 99.5 percent porous gives them their unusual characteristics. Because of this highly porous quality they are characterized by extremely high surface area, high thermal and acoustical resistivity, low dielectric constant, and low refractive index. There are other materials that exhibit each of these properties, however, only aerogel exhibits all of these properties at the same time.
Is aerogel such a good insulator because the air within is trapped and immobile? And, is this why it doesn’t melt?
Heat is transferred in three ways: convection, conduction, and radiation. Aerogel is a good thermal insulator for convective heat transfer because the air is severely limited in the distance that it can move and thus transport heat energy. The pores of a typical 20 mg/cc silica aerogel are roughly 0.00000001 meters in diameter. Aerogel is a good conductive insulator because the silica molecules are not as well “connected” as those in a metal (a good thermal conductor). Silica aerogel is a poor radiative insulator because infrared radiation (which transfers heat) passes right through silica aerogel. For this reason, carbon was added to the MER aerogel to stop infrared radiation from passing through it. This is also why one feels the heat from a flame. Air is a poor convective transporter of heat, but infrared radiation passes right through air, from the flame to your hand.
Windows Vista and Windows 7 only support the private edition of HyperTerminal. Windows 7 does not even ship with HyperTerminal. The private edition is NOT FREE for commercial use. Its license requires you purchase the application if used commercially, with the cost of the application being US$59.99, as listed on Hilgraeve’s website.
If you’re looking for a free and solid application to use for your serial COM connections, try PuTTY. It’s free for commercial and private use, and takes up a mere 444KB of disk space.
The latest PuTTY version can be downloaded here:
To use PuTTY for your serial COM connections, follow these steps:
8. Select the Open button to start the session.
Your connection should now be fully functional.
If you find yourself using PuTTY quite extensively, you could save settings to different profiles for fast future usage. To create a profile for your settings:
On your next PuTTY session, you can load your profile by selecting it from the list and clicking the Load button.
Logging is also a great feature that PuTTY provides. It lets you output your entire session to a log file. To enable logging, follow these steps before you open your connection:
According to the U.S. Department of Energy(DOE [http://www.energy.gov/]), lighting represents 40% of the average commercial building’s electric bill. While there are many different energy-efficient lighting solutions available with as much as a 45% return on investment. The initial cost of changing out the older lighting system is often cited as the main reason not to upgrade. Only 20% of existing commercial buildings feature some degree of upgraded lighting technology, while 80% continue to operate lighting systems installed before 1986. The Energy Efficient Commercial Buildings Tax Deduction (CBTD) was created to enhance the financial attractiveness of investment in the most energy-efficient lighting and other building technologies.
This special tax deduction allows building owners to write off the complete cost of upgrading a building’s indoor lighting, HVAC/hot water and building envelope in the year the new equipment is placed in service, capped at $1.80/sq.ft. Alternately, the owner could upgrade one of these three systems to earn the CBTD capped at $0.60/sq.ft. In short, with the CBTD, the cost of new lighting or other building systems can be claimed in a single tax year instead of amortized over a period of years.
What is the difference between a tax deduction and a tax credit?
Answer: The Commercial Building Tax Deduction is a tax deduction, not a tax credit. A tax credit is a direct dollar-for-dollar reduction of tax liability. A tax deduction is a cost subtracted from adjusted gross income when calculating taxable income; therefore, tax liability is not reduced dollar for dollar, but in proportion to the taxpayer’s tax bracket.
Many lighting projects result in tax deductions. Under current law, the cost of the new lighting must be capitalized and depreciated over time. Under the lighting rules in the CBTD, the owner can write off the entire expense of the new lighting, capped at $0.60/sq.ft., in the taxable year that the lighting is placed in service. So it is an accelerated tax deduction.Source: http://www.lightingtaxdeduction.org/CommercialBuildingsL1Q1.html
Answer: The Commercial Buildings Deduction can be applied to any interior lighting project in any building that is within the scope of ASHRAE/IES Standard 90.1-2001 and is located in the United States, including privately and publicly owned buildings.
This includes public buildings, schools and rental housing. Rental housing must be within the scope of Standard 90.1-2001 and four stories or higher.
Religious buildings are covered by Standard 90.1-2001 but do not qualify for the deduction; they do not pay taxes, but they are not government buildings.
More information can be found here
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