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
Back to Top| 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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