Toyota Adds Solar Power To Hybrid

from the what's-wrong-with-wind-power? dept

Toyota, already considered a leader in producing hybrid gas-electric vehicles is apparently preparing to make that hybrid a bit more hybrid: it's going to add solar panels to some models, using the solar energy to power air conditioning. It's not much, but it's a start. I've actually been fascinated with solar vehicles since the fifth grade (yikes) when I convinced some engineers at GM to send me some cheap solar panels to build a tiny solar-powered car (Chrysler ignored my letter, Ford sent a form letter in response). While GM had invested in some prototypes and took part in various solar powered car contests, the technology has never been good enough to do very much at a practical level. Now, how long will it be until Toyota figures out a way to use wind power as well?

Filed Under: hybrid cars, prius, solar power
Companies: toyota

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  1. identicon
    Steven Easton, 8 Jul 2008 @ 5:27pm

    Gasoline – Electric – Solar hybrid

    The car companies caused their own problems. They have been promoting power over economy in their advertisements. The American public bought into the concept and started driving SUV and Pickup trucks. These vehicles get 16 mph instead of 26 mph for economy cars. This caused a high demand for gasoline and low supplies and therefore higher prices for gasoline. The fuel shortage and the higher gasoline prices have woke up the public. Many car manufactures are 2 to 5 years behind on fuel economy cars. When the public goes to trade in their gas guzzler, they will buy a fuel efficient hybrid.

    For hybrids, when you slow down or break, the energy is stored in a battery. And when you take off, the energy in the battery is used to get you back up to speed. It is like bouncing on a pogo stick (spring). Each time you bounce you loose a little of the energy but you get 90% of the height back. For cars, the stop and go traffic is where conventional cars use most of their fuel. Also up and down hills requires extra fuel. Regenerative breaking is not a new concept; elevators have been using it for 40+ years.

    Adding solar to the gasoline – electric hybrid cars makes since. Hybrid cars already have the batteries, electric motors and computer controls. I calculate that the Honda Insight would get 17 more miles to the gallon by adding solar cells that could deliver 6 kilo watts per day assuming you drive 55 miles per day. That is what a hair drier would use in 6 hours. That’s the same amount of energy in 1 half of a gallon of gasoline. It is also what the MIT solar race car captured a few years ago. Gasoline fuel is 5 times more expensive then grid electricity, making solar cells easier to justify on cars than houses.

    Photovoltaic cells produce energy continuously as long as the sun is shining. Battery types matter. Some have to be fully drained before recharging, similar to a cell phone. For this type of battery, the computer must control which battery can be charged. Solar cell voltage varies too based on the amount of sun light received. Capacitors must be used to build up the voltage before delivering it to the battery. One day of chargeable battery capacity reserved for the solar cells.

    Mazda is using solar cells to drive a fan which keeps the car cool when parked. The price of solar cells is dropping and the amount of power per square foot is going up. SPR-220 panel produces 29 watts per square foot per hour. A 6 foot by 5 foot panel mounted on and SUV’s roof would provide 6000 watts of power on a peak day. That is 60 gallons per year if every day was peek. In Oklahoma there is a 75% annual solar rating. Photovoltaic cells are approaching 7 dollar per watt so 1000 watts would be $700. The payout at $3.00 per gallon of gasoline is 66 years. If the solar cell cost goes down to $1.00 per watt like computer prices have dropped, it will become a no brainer to make hybrid gas electric and solar energy cars. Solar panels can also be mounted on the roof, hood, sides and trunk and glued on like vinyl roofs. Transparent solar cells can be mounted on windows to tint the glass.

    The Chevrolet Silverado has smaller batteries that are made of led acid. There are lots of solar battery chargers for 12 volt lead acid batteries. You could mount a 500w solar collector on a fiberglass bed cover for $4500 (plus the price of the bed cover). This could boost the fuel usage from 19 mpg to 19.5.

    Cons: Hybrids that could plug into the electric grid would make it harder to justify.
    7/6/2006 Steven Easton

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