Recorded Watt Hrs Harvested per Day per nominal watt



Diary of the spanish solar pilot and test facility - first entry December 2008

Recently (November 2008) we have had the time and updated monitoring equipment to start recording some solid solar data.
Solar electricity design is normally based on various "rules of thumb" and the designers experience. In this competitive world we think we should "go back to basics" and redesign our standard packages. This will enable us to price more keenly and will be much more factually based as opposed to estimations, and more specific to Southern Spain.

Solar energy input data, starting with the month of November 2008
Daily Power consumptions of a typical rural solar household in Spain in 2009
Optimum system design for a typical rural solar household
Test System 1 Description


Solar Energy Input Data

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Daily Power consumptions of a typical rural solar household in Spain in 2009

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Watts continuous Hours on per day Estimated watt days
Summer Winter Summer Winter
Daily Draws
inverter 25 24 24 600 600
Internet modem and router 25 24 24 600 600
hands free telephone 5 24 24 120 120
Mobile Phone and camera chargers 5 1 1 5 5
PC 80 8 8 640 640
Flat screen TV with 20" LCD display 50 6 6 300 300
Sat box 15 24 24 360 360
Waste water treatment air pump 50 24 24 1200 1200
A grade fridge (without auto defrost) 150 12 6 1800 900
lights (low energy) 50 3 12 150 600
 
Intermittent items averaged to daily consumption
Washing machine - cold wash - 2 days in 7
(averaged for watt days)
200 2 2 400 400
(When running peak is 700 and this is used for peak power) 700
Watt days total 6175 5725
Peak total when running 1155
Potential peak if all "switch on" together
(3 X running power)
3465
Design safety factor and system loss (X 1.1) Watt days 3812 6793 6298


Optimal system design, using standard equipment and rounding

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Inverter (potential peak watts at "switch on") 3800 watts peak
Panels (Winter watt days / 4.5) 1400 Watts minimum 1400
Regulator MPPT feeding 24 volt batteries - amps 60 amps minimum 58
Batteries - 1 day storage - amphours at 33% discharge 940 amphours 795
Batteries - 2 day storage - amphours at 33% discharge 1500 amphours 1590


Test System 1 Description

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3 Sharp 165 watt 24 volt panels are roof mounted. In spring and autumn, they will be angled at our latitude degrees to the horizontal, in summer they will be mounted at our latitidue minus 15 degrees, and in winter they will be mounted at our latitude plus 15 degrees to the horizontal.
They are currently in their spring position of latitude Deg
They are wired in series to give a nominal 72 volts
That output is converted by a T80 MPPT controller made by Apollo. Data is mirrored on a remote panel above my desk. This unit reports amps into the batteries as well as amps out to the inverter/charger. The system is forced to the bulk charging condition by always running below the full charge level. Thus the data reflects all power that is available from the panels.
The batteries are 12 X 12 volt Varta batteries of 230 ampere hour capacity. They are 3 to 5 years old batteries which we have taken in part exchange for new batteries sold to customers in those days. Those batteries are however perfectly adequate for the pilot unit, and have still some years life left in them.
The inverter is a Studer 4400-24 with capability of producing 230 Volt AC 50 Hz power at 4000 watts continuous. It is also a charger drawing current from the grid. An automatic fast action relay is triggered by the auxiliary circuit of the inverter when battery volts fall to a low level, and stopped when the batteries are again charged.




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