by Fred Abler
The summer I was 11, my cousin and uncle helped me build a large scale model of a tug-boat. I have always loved Tug boats. Who doesn’t.. they just look Tough!
Fig.1 – FormFonts 3D Model of Mr. Darby Tugboat, by Gabriel Concha.
Both my cousin Dave and my uncle are world class model builders. So we made the custom-designed hull from hand laid-fiberglass (way before carbon fiber). And after weeks of hard work, huffing VOCs from the resin, and repeated wet-sandings of the hull, my Uncle Bud said.. “Hey.. Let’s test it!”
Before I could say “no”, he sprang up like a cat from the back stoop, put the hull keel-up on the concrete patio, and proceeded not just to stand on it. No! He jumped up-and-down-repeatedly on my precious!! I nearly died, until I saw it was unharmed.
This was my first introduction to the strength of composite materials; real multi-channel radio control; negative steering; and small electric motors and batteries. We even used a car’s windshield-wiper motor to equip the Tug with real bow-thrusters. Like I said, world class.
I remember clearly buying my first real battery for the Tug at SEARS. It was a small 9V motorcycle battery, about the size of 5 packs of cigarettes. This was my first real introduction to electric batteries and Direct Current, and DC has since become something of a fascination for me.
(we will return to boats shortly)
— DC now—
Years later, as an architect and home-moaner, I’m increasingly aware of the extent to which Direct Current now confronts me in my everyday life. Anything with a transistor inside it uses DC, electricity that flows only in one direction.
This means that every PC, laptop, iphone, flat panel TV ( all 3 of them) in the house has it’s own in-built converter box, to convert AC from the wall into DC. This is horribly inefficient. But then it’s not just electronics.. there are electric cars, and LED lighting.
The advent of affordable LED lighting is really starting to change the balance of power. To the point I find myself asking, “Do residences even need AC for anymore?”. And for about the past three years, I’ve asked myself:
“Why didn’t I just wire the whole house with DC circuits??”
Just use one big DIEHARD battery (or more likely an AC-to-DC converter) in the garage for everything. Think about it. You’d never have to change those damn smoke-detector batteries ever again!
—– Direct DC —–
I am not alone in my latent appreciation of; efficiency, Direct Current, or even ‘productive laziness’. Researchers at Carnegie Mellon University (CMU) in Pittsburg, Pennsylvania, have recently done some valuable ‘What If’ scenarios on DC-powered LED lighting.
They ran several lighting scenarios on a 48,000 s.f. building using either a central DC power supply, or AC from-the-grid. Using DC on fluorescent lighting did not result in savings. However, with DC-powered LED lighting, CMU researchers found a savings of $24,000 per year.
Of course, if the LED lighting is powered directly from a PV solar array on the building, savings are even greater (no AC-to-DC converters required). It should also be noted that to sell solar PV power back to the grid, an DC-to-AC converter is required. Use the juice …directly, and both converters are obviated.
There are a few drawbacks of course. Permitting DC wiring (the full safety of which is not fully known) and installation costs (higher than AC) all need to be addressed. But these are relatively minor and can be designed-away. What I’ll call Direct DC is coming soon.
——– All On’Board —–
It’s not hard to see a ship as just a floating building. And if you do so, the future of Direct DC is already here. This February, ABB, the huge Swedish-Swiss power and automation technology group, won an order from ship owners to build the first OnBoard DC power grid.
The OnBoard DC grid will provide all power and propulsion systems for the vessel – a 93 meter long 5000 tonne multi-purpose oil-field supply and construction vessel currently being built in Norway. The ship is slated for operation starting the first quarter of 2013.
In traditional propulsion systems, the electric thrusters and propulsion drives are powered by AC converted to multiple DC circuits, and together account for more than 80% of the vessels electrical power use. ABB’s OnBoard DC power system saves energy by distributing power through a single DC circuit.
In Short : The future is electric! Get OnBoard with Direct DC.
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