From: ems@gallant.apple.com (Mike Smith)
Subject: Re: SOLAR efficiency
Date: Sun, 4 Oct 1992 12:21:00 GMT
Organization: Apple Computer Inc, Cupertino, CA

In article <1992Sep30.102738.14004@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>In article <1992Sep28.213033.1123@michael.apple.com> ems@michael.apple.com (E. Michael Smith) writes:

>>My home is a VERY ordinary stucco (boy, can you get stucco! ;-) house.

>>Never underestimate the heat storage capacity of several tons of 
>>stucco, drywall, insulation, wood, tile, composite shingles, ...
>>
>>If we don't turn the A/C on until 7pm, we will still be sweltering
>>at 10pm (and sometimes later...).  If we turn it on at about noon,
>>the house stays comfortable all day long.  Admittedly, this is with
>>a little wall unit, but then again, it is accurate testimony to the
>>expected behaviour of a smallish solar powered system....
>
>Well, on the flip side, my central unit, with a SEER of 10.6 can
>bring my brick house with white roof and tree shading back down to
>68 degrees after a 90 degree day in about 10 minutes, using about
>2 kWh in the process. Meanwhile your window unit has used about
>7 kWh keeping the house cool all day. 

Mighty precient of you to be able to see the duty cycle of my wall
unit in the white space of my posting.  Care to fill in the turn off
times for the two scenarios (start at noon vs start at 7pm).  And
while your at it, tell me the BTU capacity of my wall unit...

While it is fun to pull numbers out of the air, please don't presume
that they have any validity ...

You have as much chance of telling me how many kWh I use as you have
of telling me the species of trees in my yard ...

>>Unless you have NO photographic materials you care about, there
>>is more than ample reason to keep your house at 74 or less all day long.
>>At temps over 85 F, photos degrade at an alarming rate...  Ditto for
>>some other household archives...  I'd rather keep the house cool,
>>while not sucking down a huge peak pulse of kW-hrs when I get home,
>>and have my 'stuff' age well (my old cabernet, especially...).
>
>Keep then in the fridge. That's where I store film. It's a lot cheaper
>to cool a little box than an entire house.

Uh, I prefere to keep my kids portrates on the walls.  They are a
bit large for the fridge and very hard to see by that little light
bulb in the back ...

Photographic materials includes all those prints you have with no 
negatives available ...

>>Solar exactly matches the best way to run my household.  It just costs
>>too much.

>Of course it does..that's the whole point of this exercise, cost 
>minimization with utility maximization. Right now solar electric
>doesn't fit. Passive solar does in many cases. That's why my house
>is surrounded by oaks and maples, why I have a white roof, and why
>I use lots of good insulation including storm windows year round.

And why I have plantings near my house, and insulation, and a light
grey painted finish and ...

>>The house IS a storage system...
>
>But not a very good one.

Quite good enough.  It has a serveral hour lag relative to the sun.
(That is, it takes several hours for the solar heat to reach the 
interior)  Go back and re-read the statement about tons of stucco
and drywall and ...

I can't tell you exact efficiency as a storage system, but you can't
tell me either.  I CAN tell you it works nicely, based on experience.

>When grids are interconnected, the preferred method is through an EHV
>*DC* circuit that isolates the phase response from one grid to another.
...
>>Pardon me, but I was under the impression that Andrew, as big as it
>>was, didn't cause the entire SunBelt to be clouded over!  Are you
>>presuming that there will be NO sales of power from Calif., Ariz., Texas,
>>et.al. to the SouthEast when there is a hurricane?  Also, the last time
>
>Yes I'm presuming exactly that. While intra-regional interties exist,
>inter-regional ties aren't practical on the scale required. The losses
>are too great for transcontinental tie lines without superconductors,
>and the grid management problem would be incredible.

A 1000 or so mile intertie exists in the Pacific Northwest, I think.  I'm
also a bit surprised that in one breath you talk about the DC technology
that is used to prevent grid management problems and in the next
you assert that long interties can't exist due to these ... 

I would also guess that you are defining intra-regioal at about 1000
miles... given the PNW Intertie, but that makes for awfully large
regions ...

-- 

E. Michael Smith  ems@apple.COM

'Whatever you can do, or dream you can, begin it.  Boldness has