Re: PV: Load Data for 'puter & A/C

[Peter Hoyt <hoytp01@satx.rr.com>]

Hello again.

Thanks for the input I've received so far. Looks like I should plan for 
about a 120 watt draw from the PC.

To provide some more background on this...and to open myself for critical 
analysis by everyone interested, here is what I'm planning to do. If you 
see any major problems, please let me know.

I am getting ready to leave the city and move to my place out in the middle 
of the Texas Hill Country where it is literally 12 miles or more to the 
nearest store of gas station. Presently I telecommute from San Antonio to 
Philadelphia.

I have ordered a new Compaq computer from Radio Shack. The computer is 
equipped with their new two way satellite internet service offered by MSN. 
There is only two computer models that come equipped with this system and 
neither is a more efficient notebook computer. This system is supposed to 
enable me to telecommute from my remote location. Unfortunately, this 
standard desktop computer is necessary if this idea of living out in the 
sticks is going to work because I need to continue my employment.

However, I also plan to use a new 15 inch LCD monitor that incudes a TV 
tuner. That eliminates a normal TV from the system and eliminates my 19" 
standard CRT monitor. Both energy hogs...

In addition to the computer, I also will need to power a SunFrost, 3 CF 
lights and a 600 watt microwave.

My working numbers:

3 CF lights for maybe 5 hours a day     3 lights * 15 watts * 5 hrs     = 
225 watts per day
RF-12 SunFrost                                                  = 350 watts 
per day
600 watt Microwave for 30 minutes a day         .5 * 600        = 300 watts 
per day
Computer for 9 hours a day                      9 * 120                 = 
1080 watts per day
miscl loads                                                             = 
500 watts per day


Conservatively I'm guessing that my daily load will require about 2500 
watts per day.

I'm considering:

a 600 watt array, eventually mounted on a tracker.
a Solar Boost 50 MPPT charge controller
a ProSine 2500 watt inverter (88% peak efficiency)
8 Trojan L-16 wired for 24 volts DC

600 watts of PV * 5.6 hours average exposure = 3360 watts under ideal 
conditions. That doesn't give me much room for error or cloudy days but I'm 
only interested in getting the system started. In another few months I can 
double the PV on the array and by then, I'll actually have the SunFrost on 
hand instead of on order.

I'm sure this plan has a lot of faults and I'd welcome any constructive 
criticism so please feel free to comment or ask any questions you wish.

By the way, Zot, thanks for your input. I visited those sites you offered. 
I especially like the idea of the solid state TEAC Peltier Effect 
PV-powered air conditioner. Do you happen to know if this idea has proved 
itself yet? The wording on the site suggested it was something in the works...

Thanks,

Peter Hoyt
San Antonio, Texas




At 03:44 PM 1/26/01 -0500, you wrote:
>Peter Hoyt wrote:
>>Does anyone out there have any good information on about how much a typical
>>computer, with a 300 watt power supply actually draws under normal use?
>Yeah, Dan Hargrove does.
>           Green PC's of Florida
>           2603 N.E. 17th Terrace
>           Gainesville, FL 32609-3241
><http://www.greenpcs.com/>http://www.greenpcs.com/
>
>Is there some reason you are married to that inefficient power supply 
>transformer in your PC?
>
>Are you planning to accept the inefficiency of your battery bank, then add 
>the inefficiencies of inverter and losses in its wiring and safety 
>equipment, then add the inefficiencies of the power supply transformer, 
>then add the phantom load of the  power supply transformer (because its 
>primary sucks power even when its secondary isn't using any), all of which 
>adds unreliability due to complexity?
>
>Do you really need to condition your low-voltage DC power into 
>medium-voltage AC just so you can feed the windings, bridge, and regulator 
>that condition your medium-voltage AC into low-voltage DC again?
>
>Oh, by the way, if you haven't splurged on an air conditioner yet, check 
>out what my customer says about her completely silent, solid state TEAC 
>Peltier Effect PV-powered air conditioner at:
><http://www.phys.ufl.edu/~liz/hvac.html>http://www.phys.ufl.edu/~liz/hvac.html 
>
>http://www.phys.ufl.edu/~liz/home.html
>Zot

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