AirScape Engineer's Blog

There are a couple of trends that will affect solar photovoltaic installations:

• Newer electrical rate structures encourage conservation (tiered rates)
• ‘Energy Security’ is a powerful motivator
• Photovoltaic rebates require house efficiency check-ups

We think  solar energy gathering is great. The idea of  getting electricity essentially for  free energy has certainly captivated our imaginations. Even though the cost of photovoltaic panels is dropping very quickly, the investment is still considerable.  Our crystal ball tells us that electrical energy is very, very versatile and will be in demand as electrical cars come on stream and coal fired electrical power plants start to show their ugly side. (coal burning)

As the demand for clean electrical energy increases, its value will certainly not go down.   In fact, if the validity of predicting cheap energy such as the famous line is any guide “too cheap to meter”,then we should get prepared for high prices.

By combining whole house fans solar contractors and  homeowners  can:

• Decrease the initial investment in PV panels
• AND/ OR
• Increase the  Return on Investment for the entire system

This article by Henry Gifford, an energy saving specialist discusses why heat pumps are no panacea.  His points, well made, bring home the messages that building envelope efficiency is critical and the importance of examining the entire energy chain -  from power house to your house.  Not that readers of this blog need reminding, but Henry also points out that over half of this country’s electricity derives from coal burning . (BTW clean coal = oxymoron du jour)

www.energysavingscience.com/

http://www.finehomebuilding.com/departments/taking-issue/heat-pump-schmeat-pump.aspx

We’re happy to announce that the 4.4e WHF is currently in stock and we’re moving product out the door.

What makes this an “e” ?  The motor is an ECM (electronically commutated motor) which when matched up with the efficient blade design gives a great power profile and low noise.

See the details here: http://airscapefans.com/products/Shop/Natural-Cooling/Whole-House-Fans/AirScape-4.4e-WHF

The following graph shows the energy use profile of the 4.4e as compared to the theoretical efficiency of a fan system.

Even though railroads are much more energy efficient and deliver lower transportation costs without federal subsidies, why are trucks the preferred mode of transportation?

I think that the answer lies in the fact that the highway truck combination is effectively open source.  The term open source is commonly used in the software world, but it applies here as well.

The platform is a highway, which just about anybody can use, provided they obey rules for weight, size, and safety of their modules (trucks in this case). This gives a tremendous amount of freedom to truckers and shippers to control their own destiny.  Ask anybody who has used the railroads for shipping and you will see that a rigid central planning department controls how and when your freight arrives.

How about this for an idea. Let’s make the railroads into a regulated monopoly. (It works for electricity, water, and gas BTW). The railroad makes its income by maintaining the infrastructure.

We get a lot of questions about the ‘R value’ of our damper doors, so we felt that it’s worth going over the basics.

The so called ‘R value’ is denominated in  the units of (square-feet x degree x hour/ BTU). Sounds complicated, but all you really need to know is:

Heat Flow  Q (in BTU per hour) = Area x (temperature differential) / R-value

[For you techies, this formula is valid for steady state, and assumes an infinite plane area.]

Let’s do the math for our whole house fan dampers.  We’ll assume VERY cold conditions in the attic (0° F) and 70° F inside.

Bottom line:  There is not much heat loss through a well insulated whole house fan damper door.  The question that you SHOULD be asking is: “How well sealed is the whole house fan damper door?”

Most residential windows will have R values of 1 to 3. Another question that we get all the time is : “What is a BTU ?”

BTU stands for British Thermal Unit.

1 BTU is approximately the energy released by burning 1 paper match.

100,000 BTU’s make up one therm – that’s how you purchase natural gas, and right now that costs about $1.50

A gallon of gas has about 114,000 BTU.