> On 2/16/2012 6:08 PM, Jim Wilkins wrote:
>> ..
> We don't do winter weather well. You should see them drive in it, ... from
> a distance!
> Jeff
That happens as far north as Pennsylvania. For New York and above a little
snow is a minor nuisance. We don't take well to the 100F heat with high
humidity when we are downwind of you, though. Luckily it's rare in NH, and
alternates with beautiful cool dry air from Canada. Canadian weather is less
welcome in winter.
My brother tells me the GA and SC highway departments have at least learned
to recognize pictures of snowplow trucks.
Watch the winter temps in Atlanta and Anchorage. Some years they aren't far
apart.
jsw
Here’s climate data for Atlanta, GA. Calculated from NREL’s TMY data
and PvWatts to help with both solar PV and thermal.
Curbie
Climate Data for: Atlanta, GA. Time Zone: -5
Fixed Parameters Units Notes Values
Latitude & Longitude ° 5,11 33.65 -84.43
First & Last Frost Dates Date 5,9 11/03 04/02
Growing Season Days 5,9 215
Elevation Ft. 5,11 1033
e-Rate $ 5,11 0.102
Yearly Parameters Units Notes Values
Average Hours of Full Sun Per Day Hours 8,11,12 4.7
Temperature, Ave, Max, Min °F 8,9 61 97 12
Degree Days, Heating, Cooling, Growing °F 1,2,3,8,9 3073
273 5212
Average Air Pressure mbar 10 981
Average Wind Direction ° 4,10 199
Average Wind Speed mph 10 8.8
Average Rainfall (Estimated) In. 9 72.2
Total AC-kWh kWh 5,11 1732
Ave. Daily Heat, Tilt, North, South, East, West btu/ft2-d
7,8 1612 414 1017 849 840
Monthly Parameters Units Notes Jan Feb Mar Apr
May Jun Jul Aug Sep Oct Nov Dec
Average Temperature °F 8,9 41 44 53 61
70 76 79 77 73 62 51 44
Maximum Temperature °F 8,9 66 72 77 86
88 93 97 91 86 90 73 70
Minimum Temperature °F 8,9 16 12 30 30
54 59 57 61 57 37 27 18
Heating Degree Days °F 1,8 747 582 370 168
16 0 0 0 0 135 406 649
Cooling Degree Days °F 2,8 0 0 0 0
12 55 123 75 8 0 0 0
Growing Degree Days °F 3,9 61 118 214 395
609 754 839 821 692 416 191 102
Average Air Pressure mbar 10 983 981 979 980
978 982 981 981 981 980 982 981
Average Wind Direction ° 4,10 186 202 190 212
203 204 230 197 163 201 178 218
Average Wind Speed mph 10 7.9 8.7 10.9 10.4
9.5 8.9 6.8 6.3 8.2 9.0 7.8 11.3
Average Rainfall (Estimated) In. 9 8.5 10.6 6.3
4.0 5.3 1.9 7.1 2.7 6.0 3.9 5.0 10.9
Total AC-Watts kWh 5,11 116 126 152 171 166
154 156 159 140 158 125 113
Average Daily Heat Tilted btu/ft2-d 6,8 1203 1451
1621 1917 1848 1802 1806 1813 1623 1717 1382
1163
Average Daily Heat North Vertical Surface btu/ft2-d 7,8
236 291 381 478 582 649 598 509 425
328 262 223
Average Daily Heat South Vertical Surface btu/ft2-d 7,8
1123 1210 1113 988 767 685 715 882 999
1339 1257 1127
Average Daily Heat East Vertical Surface btu/ft2-d 7,8
533 693 833 995 1086 1078 1159 1104 814
788 618 487
Average Daily Heat West Vertical Surface btu/ft2-d 7,8
523 679 840 1145 1058 1104 947 933 893
855 603 506
Notes
[1] Number of heating degree days, 66°F base.
[2] Number of cooling degree days, 76°F base.
[3] Number of growing degree days, 50°F base, 86°F cap.
[4] No Wind = 0, East = 90°, South = 180°, West = 270°, North 360°
[5] Ac watts generated per kilowatt of photo-voltaic panels. (as
calculated by PvWatts)
[6] Solar heat generated on a surface, through a glazing, tilted at
latitude. (as calculated by PvWatts)
[7] Solar heat generated on vertical surface (no glazing) per day. (as
calculated by PvWatts)
[8] Helpful for evaluating solar-thermal energy (and domestic heating
and cooling).
[9] Helpful for evaluating bio-energy.
[10] Helpful for evaluating wind energy.
[11] Helpful for evaluating photo-voltaic energy.
[12] Helpful for evaluating solar energy.
>On 2/16/2012 3:07 PM, Curbie wrote:
>> I think on a small scale, you'd be lucky to produce the panels
>> including cells but excluding a lot fussy labor for same cost as
>> buying commercial panels, so not unless you doing something special,
>> like collecting solar for both PV and thermal from the same limited
>> panel area, if cost is your primary driver, I don't think you'll beat
>> buying commercial PV panels.
>That is what I've come to think too. The cost of the incidentals is too
>high.
>>
>> If you are doing both solar PV and thermal, combining the two help the
>> efficiency for PV in the summer when you probably don't need the heat
>> collect from the thermal, but the efficiency for thermal when you need
>> heat in the winter is going to be far less than a dedicated thermal
>> panel.
>>
>> How many hours of full sun energy do you get in coldest month?
>Here is the NREL insolation calculator:
>http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/
>I'm in Atlanta, Ga. Completely overcast and drizzly today. The collector
>is at or slightly above inside ambient and has been off all day. But
>then it is 59F outside!
>My "butler" is in the Solar Cabana reading. That is at 64. On a clear
>cold day that can easily get into the 80's and up and temps in direct
>sun over 100. When the sun goes down though, the temperature plummets.
>Usually the coldest days are the clearest.
>What I would like to do is put the solar hot water online and do staple
>up underfloor radiant with the stored hot water. That way I could be
>nearly all solar heated. Next year, I think...
> Jeff
>>
>> Curbie
>>
>>
>> ..
> We don't do winter weather well. You should see them drive in it, ... from
> a distance!
> Jeff