Archive for December, 2009
Power surges
Power surges is one of the most destructive of electrical power disturbances. Power surges are sudden spikes in voltage. They are usually brief, lasting only millionth of a second. Electricity used in homes across the US is in the form of single phase 120 volt, 60 hertz alternating current. The voltage oscillates from 0 to a peak of 169 volts, and most household appliances are designed to operate under this condition.
Power Surge
A power surge is a spike that goes above 169 volts. Power surges cause internal spikes in voltage in your appliances. Heat generated in the electrical arc can cause damage to the appliance. Overtime, the cumulative effects of these damages will cause the appliance to malfunction.
Power surges can come in different sources, the most common ones are from the utility companies during switching from power grids, from household appliances like air conditioner, refrigerators going on and off, and also from lightning. It is estimated that 20 million lightnings strikes the 48 contiguous US states each year. Surges can vary in duration and intensity ranging from several hundred to thousands of volts.
Most of us are aware of the need to protect electronic equipments from power surges using point of use surge protectors like power strips and uninterruptible power supplies. The installation of a power factor correction device like the Power Save 1200 power factor conditioning unit aside from providing power factor correction, has the added benefit of acting as a whole house surge protector, providing 2000 joules of surges protection.
Department of Energy explains power factor
DOE Explains Power Factor
Low power factor is inefficient and expensive. Low power reduces the distribution capacity by increasing the current flow. Correcting power factor enhances the efficiency of the electrical system and lowers electric bills.
To understand power factor, visualize a horse pulling a railroad cart from the side of a railroad track. The horse is pulling the cart at an angle to the direction of travel. The power required to move the cart is the working (real) power, the effort exerted by the horse is the total (apparent) power. Because of the angle of pull, not all the power exerted by the horse is used to move the cart. One can resolve this effort into two components, one that moves the cart along the direction of travel (functional power), and one that moves sideways (nonworking or reactive) power.
Power factor = Real Power ÷ Apparent Power
As an example, let’s say the real power is 100kVA, and the apparent power is 142kVA, then the Power Factor is 100 ÷ 142 = 0.70 or 70%, meaning that only 70% of the effort is doing useful work, while the rest (30%) is wasted.
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Power Save 1200 tested by user for power saving
Power Save 1200
Some of you may be skeptical as to how much a power factor correction unit like the Power Save 1200 attached to your main circuit breaker panel can help you save on electricity and lower your electric bills. John Turtletaub from San Diego installed the Power Save 1200 power factor conditioning unit, and tested its performance. Below is his account regarding the ability of Power Save 1200 to correct the power factor.
“I must admit, I was a bit skeptical about your product (Power Save 1200), as an electrical engineer friend introduced me to Power-Save a few months ago…
While I was testing the unit, I had my friends present. I tested the product on the load side, and I found no difference in the amperage draw to my A/C unit on the circuit conductors directly from the breaker to it. At first, I was disgruntled. After settling down and thinking about what I had just done, I realized my error and clamped my Fluke meter on the mains directly behind the meter registering current drawn at the line side of the load center….and BINGO!!!!
On start up, the A/C unit went up to 91 amps and leveled out at 13 without the Power-Save 1200 on. When the Power Save unit was engaged it was a draw of 35 amps and leveled out at 8.75. That pretty much blew everyone away! After that, I tested everything with a motor load in my house. I was astonished at the significant reduction in amperage.
I have had, in addition, a lot of customers complaining of bad power spikes, sags, and all kinds of irregularities from their utilities which could benefit from the unit.“
Property tax exemption for renewable energy installations
Home improvements like adding a room or upgrading a bathroom or bathroom often mean increased property taxes, as the improvements add value to the property and thus the tax assessment increases. However, with the states and local governments’ emphasis on encouraging home owners to derive part or all of their energy need from renewable sources, most states have made renewable energy installations like home solar power systems, wind and geothermal power installations tax exempt for up to 5 years.
For more information on individual state property tax exemptions, check out this website: www.dsireusa.org
It pays to conserve energy
Home electronic products use energy when they’re off to power features like clock displays and remote controls. According to the Department of Energy, U.S. households spend $100 per year to power devices while they are in this “standby” power mode. Products that have earned the ENERGY STAR use less energy to perform these functions, while providing the same performance and features as conventional models. Using less energy preserves energy resources and helps reduce the risks of global warming while lowering energy bills.
How much shade free space do you need?
Here is the rough sizing requirement for photovoltaic (PV) solar power system:
You need about 100 sq. ft. for each kilowatt (kW) of system capacity for the crystalline PV solar power system and 175 sq. ft. for each kilowatt for the thin film PV products.
For example, a 3 kW system with crystalline modules would require 3 kW x 100 sq. ft. per kW = 300 sq. ft of unshaded area.
A 3 kW system using thin film product (e.g., building-integrated roofing material) would require 3 kW x 175 sq. ft per kW = 525 sq. ft. of rooftop or other space.
Consider these estimates to be minimums for the shading analysis.
Shading and Solar Panel Efficiency
The performance of photovoltaic (PV) solar panels is highly sensitive to shading. The PV array needs to be located where it will direct exposure to sunlight and not be in the shadow of other building elements (e.g. facades and parapets, mechanical/ plumbing elements including vent pipes and flues) or landscape elements like trees.
Solar Panel Array
Full or partial shading of the PV panels impede the production of electricity. It is important to recognize that the solar cell with the lowest amount of light exposure determines the operating current of the portion of the solar power system wired in series. This partial shading effect can be compared to that of the kinking of a garden hose restricting the flow of water. Thus a small amount of shading can disproportionately compromise the efficiency of the entire solar power system.
It may be helpful to perform an analysis of the site and surrounding buildings and landscaping to optimize the space with maximum sun exposure.