Hi Paul
On (23 Sep 96) Paul Tortora wrote to All...
 PT>  I'm currently working with a group of fellow students on the
 PT> preliminary design of a solar powered 1kW power supply, and was 
ondering
 PT> if anyone could offer opinions/experience on this type of product.
I don't have experience on such a large outfit as that. But I maybe can give
useful input-
Definition required: 1kW peak output at strongest sunlight? Or 1kW average
over a defined period? You must get the task accurately defined. The capital
cost and complexity is VERY sensitive to this.
Is winter output defined?
Battery storage is surely required. What peak output to be allowed? One
battery, or more for redundancy/ security?
Inverters are made in the range 50 watts to way over 1 kW. Is one sufficient?
The AC side duty cycle would have a profound influence on what inverters to
best match requirements. It would be foolish to keep a 1kW inverter running
all night at a very light load.
 PT> I would also know what a customer demands of a 1kW power supply
 PT> (reliability,
 PT> what kind of power demands are put on the thing in the course of a day,
 PT> etc.)
This is best advised by your Utility advisers. You need to decide what
appliances to permit. Compressor type airconditioning- NO. Electric iron,
toaster, vac cleaner- YES.  Kitchen frig- YES. Cooker, electric hot
water- NO. And so on.
 PT> We're designing this thing to be a really remote power supply, for use 
n
 PT> locations where power lines are not available.
In that case you MUST provide a gas engine standby generator for those bleak
winter periods when the sunlight fails to support the tired battery.
An important design input, has to be the talent of the family who will live 
n
the house. Will they be naive, helpless technically? Or can they be relied on
to understand problems and find solutions.
I would be thinking along the lines of two batteries and two power circuits,
lets call these Priority 1 and Non essential.
Priority 1 would feed an efficient lamp in every room, the radio, TV, phone
or other essential communications, burglar alarm, fire detection, elec 
ontrol
power if needed by any GAS appliances, electric blankets if it's a cold
district, and the water pump if there is no gravity feed from water storage.
Non essential would be everything else including decorative lamps, hifi,
outdoor flood lighting, washer, iron, toaster, powered garage door.
A second [mini] frig could be a good idea for crisis use. Put the beer and
eggs in the big frig that is non essential but put the fragile milk, fresh
meat etc in the mini frig and treat it as Priority 1.
Associate the gas generator with the Priority 1 system but allow an
intelligent user to elect certain changeover switching for main frig or
whatever. Hope to see your Report in due course!   Cheers.....ALEC
... ........I have no answers, only questions [Galileo]
--- PPoint 1.92
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