Monday, March 29, 2010

Rebuild the Nation’s Water Mains and Sewer Systems and City Streets!

Reposted here from another of my blogs:


February 10th, 2010

During a heavy rainstorm the other day, I was surprised to notice the massive amount of water flowing out of a storm drain and back onto the rapidly flooding street. A little later, as I was driving through the small lakes and streams that are normally shoddy city streets, I again began to reflect on the state of the nation’s infrastructure. I started to ponder why more infrastructure projects have not been undertaken to rebuild the nation’s often ancient sewer and water main systems as well as the antique city streets. I understand the rationale to wait until these systems break to begin any repairs or rebuilding efforts. But, maybe the best ‘bang for the buck’ or return on investment would not be to wait until these infrastructure systems demand immediate attention when they fail. Nevertheless, given the fact that the nation can afford to spend probably a billion dollars a day in Iraq and Afghanistan, and given the fact that the nation can afford to give trillions of dollars to our impoverished bankers and financial institutions, I found myself at a loss as to why the nation does not undertake the massive engineering and infrastructure projects required to rebuild the country’s water main and sewer systems before these systems catastrophically fail – with such failure likely only a matter of time. I mean…, we could create a lot of engineering-related jobs by investing more in our nation’s infrastructure.

Adam Trotter, P.E. / AVT


PS. Should such engineering endeavors ever be undertaken by the nation as a whole, we could probably use to replace some of the ancient bridges as well, if not build more bridges to supplement the over-crowded ones that exist now.

Thursday, March 4, 2010

Orange County Tsunami Warning System Offered No Warning? Does the Nation have an Undue Reliance on High-Tech Systems?

March 4th, 2010

As reported today on KCAL TV News, Channel 9 in Los Angeles, the tsunami warning system in place to warn portions of Southern California of incoming tsunamis failed to warn many of the relatively minor tsunami that came ashore as a result of the recent large earthquake in Chile. The system recognized the tsunami but the phone system became flooded and dysfunctional as warning calls went out and therefore the warning calls did not connect to the residents who may have otherwise been in harm’s way and awaiting such a warning.

An assuredly expensive high-tech system failed to perform as expected? Who would ever think such a thing was possible? Given our unequivocal and utter dependence on high-tech systems for every nearly every facet of our lives from pocket change to warning and safety systems, maybe, for times of emergency, we best start keeping a cookie jar full of money buried in the backyard or under the mattress too? Such an emergency plan assumes any of us to be in a position to fund such a cookie jar now-a-days, of course. ‘Cause who knows what other high tech systems that are vital to the nation’s well being may also fail when we need those systems the most.

Adam Trotter / AVT

Wednesday, March 3, 2010

Solar Electric Basics, Solar Photo-Voltaics

March 2nd, 2010


Crystalline Silicon PV Panel:
100 sq.ft. can create 1 kW, efficiency 15% to 22%


Thin film PV (like tiles):
200 sq.ft. can create 1 kW, efficiency 7% to 15%


Monocrystalline (single crystal): 75W, Polycrystalline (multi crystal): 80W,
Amorphous (Thin Film): 43W


PV Output drops with higher temperatures, say above 70 F / 20 C
- Percentage amount of drop with temperature increase is called Temperature Coefficient of Power. This number is less in thin film PV.


Inverter
- converts DC electricity to AC electricity
- should locate in a cool area


PV Panels can last 25+ years – used in space program

Net Metering – Electrical meter sins both ways, net amount is measured. Also, Net Time of Use Metering applies to time of day you are making electricity and when you are taking from the grid


On-grid vs. off-grid (off-grid requires battery)


On-grid requires electric grid. Electric grid goes down, on-grid system goes down too.


However, buying electricity is cheaper at night. Also, the less energy one uses, the less susceptible one will be to higher-charged electric rate upper tiers.


PG&E of California estimates that a proper figure for approximating costs to install PV systems is $9 per Watt installed (note this is per Watt, not kilowatt).

Payback on PV electric systems should be 8 to 18 years, according to PG&E.



Other Factors:

Solar Resource Potential (kWhours / sq. meter / day)
Monitoring Hardware Required?


PV Panel and mounting:

Shading (Trees, Buildings, etc., 2:1, two feet of horizontal distance to every
one foot above panel height of any potential shading element)

Southern Exposure (True south, not magnetic south)

Orientation of Panel (True south by southwest, SSW, is probably best)

Tilt of Panel (depends on your latitude, normal roof pitch is generally okay)

Cleanliness of Panel (dust, etc.)

Solar Window (when sun is best, usually 9 AM to 3 PM)

Adequate Roof Area (100 to 300 sq. ft. of roof area per kW, depending on type of
PV panels installed)

Roof Condition (shingle conditions and weight on roof)

Tracking Systems (to follow the sun through the sky and through the day)

Excessive Wind Loading Possible?



Tools:

Solar Pathfinder
Solmetric SunEye


Incentive calculator (for California):
www.csi-epbb.com

Nationally, 30% Tax rebate on Federal Returns

National Rebate Information for Homeowners:
www.dsireusa.org


California Residential Systems must be OG-300 Certified to qualify for rebates.

California Commercial/Non-Residential/Multifamily Panels (only) must be OG-100 Certified to qualify for rebates.


Compare AC Watts with AC Watts, not AC with DC

Panel DC wattage X number of panels X inverter efficiency = number AC watts

Be suspicious if only given DC output of designed/installed PV system?

Normalize to price per AC watt or price per AC kilowatt



Adam Trotter, P.E. / AVT