DC wiring for a home

If you had the chance to rewire the electrical cabling for a home, should you make provisions for DC wiring? Here are some tips:

1. Most of your appliances are going to be AC - so converting DC to AC via the inverter should satisfy most of your needs.

2. Some appliances are more efficient when used with DC - especially the ones that take small amounts of power on a continuous basis (e.g. motion sensors) - so it is not worth it to lose the 15% efficiency by running AC power to such appliances (may not matter if the inverter is being used all the time). So it is useful to have one wire dedicated for DC to each room

3. Use 12 gauge wiring for distances up to 35 feet; Use 10 gauge wire for distances up to 60 feet.

4. Since DC plugs/outlets are not standardized, use the standard AC plugs/outlets (the appliance end of the wiring will need to match the power input socket on the appliance).

5. Add 2-3 telephone wires inside your home to be able to monitor the voltage levels of the solar battery packs (in case you want a way to monitor this from a convenient place inside your home - possibly next to your main distribution box)


courtesy: http://www.backwoodssolar.com/reference/home_wiring.htm

Article in the newspaper mentioning cost and subsidy in Chennai

Cost of a 1KW installation is Rs3L with a Rs80,000 subsidy provided by the government. My guess is that the company providing the solar panel solution will be able to help with the govt paperwork...


Panels have a 20-25 year lifespan; batteries have a 3 year lifespan - so you need to keep in mind the recurring investment needed every 3 years for the batteries.



http://www.thehindu.com/todays-paper/tp-features/tp-downtown/article3221485.ece

Tamilnadu department for solar

Here is a link to a dept in the TN govt where they offer subsidized solar installations (possibly only to rural areas)...

http://www.teda.in/index.php?r=site/index&id=7I4r1w2Q2z

solar water heaters

Some basics on solar heating...
http://homepower.com/view/?file=HP107_pg18_Patterson


Venus offers an evacuated tube collector based solar heater in chennai - estimated cost about Rs15-20K...Ideal if you want to feed multiple bathrooms since you can install a compact tankless heater for about Rs 4K...

Tata makes a solar heater that uses the flat-plate collector technology...
http://www.tatabpsolar.com/products_view.php?pr_id=Zing_Solar_Water_Heating

Note that you could pass the solar heated water through a tankless heater to get more oomph during cold/cloudy days...ideally you would want a couple of valves  - one to bypass the solar heater if you need to do repairs to it - and another to bypass the backup tankless heater during seasons when the solar heater is enough to do the heating...

use a combination of DC and AC wiring to conserve power

Courtesy: http://www.backwoodssolar.com/reference/articles.htm

Some appliances like motion sensors, door bells, etc. constantly consume a trickle of power. This issue with this is when you use an inverter to convert the solar DC to AC. Inverters burn up 25-60W of power to produce AC. So even when you think you are not using any appliances, these motion sensors, door bells, etc. are causing the inverter to stay on and waste a lot of power. So the trick is to figure out which appliances to power with AC and which to power with DC....

LED lights are more efficient than Compact Fluorescent Lights (CFL) of same Lumen rating

Courtesy: Moneer H. Azzam, president of SolarOne Solutions

From article: http://www.ledsmagazine.com/features/2/6/7 

Essentially, when you compare an LED light with a CFL of same lumen, the LED is more efficient due to its directionality....

Fluorescents, while providing a cool color temperature at a very efficient lumen per watt (lm/W basis still have fundamental deficiencies. In addition to their bulk and inherent fragility, fluorescents project light poorly, in all directions around the lamp and in almost 180 degrees in the plane of the lamp. Thus their utilization, (the amount of usable light projected) is lower than the technical calculations of efficiency suggest. A reflector can redirect the light around the lamp downward, but there are efficiency costs. Further, as the fluorescent lamp is controlled to direct light downward for ambient lighting, approximately 30% or more of the light is lost. For more demanding task lighting, when even greater control is required, the loss from the fluorescent is approximately 50%.

In contrast, LEDs produce directional beams of light, up to 90% of which is usable for ambient lighting and 70% of which is useable for task lighting (assuming that the lighting design incorporates multiple LED installations to compensate for shadows in a space measuring 4 feet square). The relatively low lumen output ratings of LED lamps are often times compensated for when looking at the foot-candle levels at the illuminated surfaces. In other words, for outdoor lighting applications, SolarOne estimates that an LED lamp rated at 45 lumens per watt will perform equivalently to a fluorescent bulb rated at 75 lumens per watt. This facet of LEDs offer an enormous side benefit to areas with dark-sky mandates

sample pricing for servo voltage stabilizer

I recently spoke to a gentleman who had built a house in Chennai. He mentioned about the challenges he had with the power fluctuations there and how the traditional voltage stabilizers did not work because the voltage sometimes dropped by about 40%!!!!!!! This caused the voltage stabilizer to shut off periodically. So he switched to a servo voltage stabilizer...I am yet to do a survey on the types of stabilizers available - but here is a site with some price quotes...note that most residential power lines are 30KVA...

http://noida-uttarpradesh.olx.in/lowest-price-in-servo-stabilizer-iid-90626031