slug and inertia

Not the slug in question

A little background information will may make this post funny for you…

The system of measurement that we in the US use is sometimes called Imperial units (Imperial as in British Empire), but it goes down hill from there. As an example of this,  US ounces are not and have never been the same as the Canadian (Imperial) ounce.  The fluid measurement system then goes on to make cups (8 ounces), pints (16 ounces, but 20 in an Imperial pints), gallons (128 ounces, or 160 in an Imperial gallons).  It’s all commonplace to us locals, but maybe, just maybe this helps explain our national distrust of numbers (apparently mortgage rate resets are particularly vexing).   Hmm.. maybe we could work out a system in which all units are related by multiples of 10, there are no multiple versions of measurements (ounce, pint, gallon, bushel, barrel, acre-foot, acre-foot ??). How about that metric system.

So, on to the slug. As the metric system has the kilogram as its unit of mass, we have the pound. Oops. Pounds are units of weight.

What is our unit of mass?  Yes, you guessed it. The slug.  Yes, and this is what makes high school physics so exciting. Knowing that your buddy has a mass of 5 slugs.

So here are the factoids:

1 Slug on earth gravity weighs 32.2 Pounds.

1 Kilogram on earth gravity weights 9.81 Newtons.

Why does the US have so much inertia when it comes to changing to the logical metric system ?  I don’t know, but physical inertia derives from mass, and our mass unit is a slug.

References:

Wikipedia

http://www.diracdelta.co.uk/science/source/s/l/slug/source.html

NASA criticised for sticking to imperial units

town names

Wisdom, Montana 1942

(Photo by John Vachon. Prints and Photographs Division, Library of Congress)

I don’t know why this town did not grow and thrive. They were clearly years ahead of their time.  Putting your town’s name for air travellers to see is, in my opinion, the most important thing a town government can do.  How many times have you looked out the window of an airplane,  noting a beautiful vista, only to never find out what city you were flying over ?

Sound Reduction part 4 – Ducted Models

The final step on our journey of sound reduction brings us to ducted AirScape models. As you already know the ducted design of the 2.5 WHF, 2.5e WHF, 4.4e WHF, 4.5 WHF, and the Kohilo 2.8 allow for maximum airflow with a minimum of noise. Improper installation of these models can increase their sound levels. We touched on this subject earlier in the blog “4.5 Installation – Maximize Airflow, Minimize Noise.” There are a few things you need to consider when installing a ducted model.

90 DEGREE BEND –  The 90 degree bend should be as smooth as possible to maintain the 20″ diameter of the ductwork. Kinking the ductwork will increase the sound level and reduce airflow because the air does not have a smooth path to the fan.

EXTENSION –  It is important to extend the ductwork as far as possible away from the damper box. This needs to be done without distorting the 90 degree bend in the ductwork. Extending the ductwork fully moves the sound source (the fan) to the farthest point from the living space.

D-RINGS –  The 2.5, 2.5e, and 4.4e fans have D-rings which are used to hang the fan from the attic rafters. Only 4 of the 8 D-rings are used in the installation. The unused D-rings should be taped down to avoid excess rattling.

PART 1 / PART 2 / PART 3 / PART 4

Sound Reduction part 3 – Raised Frame w/ Ductboard

The next logical step for sound reduction is to combine the raised frame concept and add the duct board mentioned in part 1. In the following steps we’ll show you how to do this type of install.

STEP 1:  First we created two frames with inside dimensions of 14.5″x22.5″ using 2×4’s.

STEP 2:  Next we made a box using the two frames from step 1 and 3/8″ plywood. For this example we made our raised frame 17″ tall using (2) 25.5″ x 17″ and (2) 18.25″x17″ pieces of plywood. The vertical clearance of your attic will determine how tall of a box you can create. The picture shown is with one side removed.

STEP 3:  Position the box over the framed opening and secure. Caulk all of the seams and gaps of the newly constructed raised frame. Attach the provided gasket to the upper frame of the box. Line the box between the 2×4 frames with duct board. In this example we used (2) 24″x10.75″ and (2) 16″x10.75″ sections of duct board. We decided to go with a friction fit, but adhesive or screws with flat washers would work as well.

STEP 4:  Position the unit on top of the raised frame (1.7 shown). Secure using the provided screws. From the living space caulk all the gaps between the unit and the framing. You can now follow the remaining steps in the installation and operation manual to finish your install.

PART 1 / PART 2 / PART 3

New Rebates!

We are excited to find that a few utility companies outside of California are now offering rebates for whole house fans. It’s nice to see some forward thinking by these companies. After all, energy savings can come from more than just replacing appliances or installing new windows.

Fort Collins Utility in Colorado is now offering a $250 rebate for the installation of a whole house fan

Pennsylvania is the first East Coast state with utilities offering rebates on whole house fans. PECO and Duquesne Light offer $90 and $130 rebates respectively

If you are a builder in Utah you can receive a $200 rebate on a WHF from Rocky Mountain Power when building a new energy efficient home

The table below lists all of the rebates that we are aware of for whole house fans and solar attic fans (your solar attic fan already qualifies for a 30% federal tax credit). Please refer to the utility rebate website for specific details on qualifications, $$$, and application forms.

STATE UTILITY WHF* SAF*
CA LOS ANGELES DEPARTMENT OF WATER & POWER $200
CA LODI ELECTRIC UTILITY $100 $40
CA RIVERSIDE PUBLIC UTILITIES $200
CA SILICON VALLEY POWER $200 $100
CA GLENDALE WATER & POWER $100-$125
CA BURBANK WATER & POWER $50-$100 $200
CA ANAHEIM PUBLIC UTILITIES $100 $30
CA PASADENA WATER & POWER $100
CA SOUTHERN CALIFORNIA EDISON $50
CA SAN DIEGO GAS & ELECTRIC $50
CA REDDING ELECTRIC UTILITY $150
CA TURLOCK IRRIGATION DISTRICT WATER & POWER $75
CA SACRAMENTO MUNICIPAL UTILITY DISTRICT $100
CA MODESTO IRRIGATION DISTRICT WATER & POWER $100 $50-$100
CO BOULDER COUNTY $500
CO FORT COLLINS UTILITIES $250
PA DUQUESNE LIGHT $130
PA PECO $90
TX GUADALUPE VALLEY ELECTRIC COOPERATIVE $50
UT ROCKY MOUNTAIN POWER $200
*Please refer to utility for rebate details

Trains and coal strange bedfellows

We love railroads. Who can’t love their efficiency. BUT… They like coal. They really like coal. According to this report 44% of railroad car traffic is coal. And coal is dirty. It’s dirty in terms of carbon emissions. It’s dirty (but can be cleaned) in terms of particulate emissions. It’s not all that wonderful in terms of mercury dispersal either.

So, which way do you think railroads will lobby (they are corporate “citizens” after all).  Will they throw their weight towards laws which reward efficiency => win for rail transportation. Or will they throw their weight behind more coal burning => still good for railroads.?