Archive for December, 2007

Solar Energy ?

The second part of our solar installation is on it’s way. And it takes the form of several ‘tracking’ photo voltaic panels. For me this is tremendously exciting. Drawing energy from the sun without creating any carbon waste is awesome.




The radiation from the sun travels 93 million miles (149668992 km) to us here on Earth…




That radiation lands on our photovoltaic cells stimulating all those atoms producing electricity…








My problem, however, is where is the sun? To install the base frame correctly, and maximise the panels efficiency, I need it to be pointing to ‘true’ south, or ‘solar’ south, 180*, and here lies the problem.


Just as the Earth’s frozen Arctic and Antarctic have ‘true’ and ‘magnetic’ poles so does the Earth’s position to the Sun. What we have to do is calculate an ‘offset’ called ‘declination’.


Now ‘azimuth’ and ‘bearing’ are terms used to denote direction. The direction you are facing (your bearing) is normally measured in degrees from north (zero). For example if you are facing ‘true’ south your bearing or azimuth angle would be 180*. So, point your compass in the direction your panels are facing. Rotate the compass dial to align the orientating arrow and compass needle ensuring the red parts align then read the degree bearing nearest the travel arrow. Then adjust the panels to face south.


However this only gives you magnetic south. You then have to calculate the degree of ‘declination’.




Thankfully The University of Oregon has an on-line ‘solar position calculator’. Firstly you have to specify date and time followed by ‘Latitude’ (south negative) and ‘Longitude’ (west negative) and your time zone. Here we are Greenwich Mean Time + 1 hour.




They then require barometric pressure, temperature and aspect. i.e azimuth. Once this is all entered into their calculator the program returns solar zenith angle, declination, Julian day, equation of time, hour angle, instantaneous and daily extraterrestrial radiation values and sunrise and sunset times.


Solar position calculator results


(Using solar constant = 1367 W/m2)

Date: 1/1/2008 Time: 12:00:00 Zone: GMT + 1
Lat: 37.76° Long: -2.07° Aspect: 180°
Pressure: 1013.0 mB Temp: 10.0° C  

Declination -23.0310°
Solar zenith angle(no refraction) 63.0794°
Solar zenith angle(with refraction) 63.0477°
Julian day 54466.9583
Equation of time -3.2905 min
Hour angle -17.8928°
Extraterrestrial global horizontal solar irradiance 640.61 W/m2
Extraterrestrial direct normal solar irradiance 1414.91 W/m2
Daily global ETR 4226.4 W/m2
Daily direct normal ETR 13351.6 W/m2
Earth radius factor 1.0351
Sunrise 08:28:28
Sunset 17:54:39



And at this point I should thank my friend Nick for putting his brain power to work on programming this calculator with the right figures.


However, as far as I understand, the solar zenith angle is the vertical winter/summer angle of the sun in the sky and the declination is the solar angle of the sun ‘off’ the north south magnetic line your compass will give you.


So why does the angle of declination change from summer to winter?



Asociacion de Belen

All the churches of Velez Rubio are resplendent with Nativities from associations from all over Spain, and magnificent some of them are too. It is a passionate pursuit here in Spain, people taking great joy and pride in their activity.   nativity-1.jpg 



Ping pong Christmas

We decided on a family Christmas present this year in the form of a Ping Pong table. Consequently I thought I should look at ‘You Tube’ for some inspiration. And boy did I find it…



Producto casero fantástico de nuestros vecinos Juan y Anna


Our lovely neighbours Juan and Anna kindly gave us some of the fruits of their toils in the form of these delicious Morcilla and Chorizo sausage.



Melchior viene temprano!


Two days ago they put up the Christmas lights in Velez Blanco and today school finished with song and dance. And a strange looking red headed Melchior.



Aerogeneradores Juan Bornay

And here is the man himself talking about the product…



Our new wind turbine


There is great excitement at Los Gazquez as our new wind turbine is on it’s way. I installed it’s base today in a cubic meter of concrete. It’s a Bornay ‘Inclin 3000′. It will reside atop a 12m pylon harvesting power from the winter and spring wind and the summer thermal gusts and eddies.




First snow at Los Gazquez


Zero degrees and the first snow of winter at Los Gazquez. It looks like it’s going to be a white Christmas. Today we put up the Christmas tree, lit the fire and prepared the ‘balcony’ for the arrival of Father Christmas next week.



My student Fabio

I think I am entitled to a small claim to fame and one which grows each day as all the financial machinations surrounding the appointment of a new England football coach move forward.

Many years ago, after completing my MA, I was awarded a scholarship to the ‘Academia di Brera’ in Milan. And whilst the disappointing scholarship, which lacked promised funding, proceeded, I needed to supplement my income in some other way. Teaching English seemed the best option.

Lo and behold after a few months experience I was given the ‘star’ student, one Fabio Capello, who it would appear is going to be the next coach of England.


Amazingly he never tired of talking about football.

P.S If you think his English is not so good don’t blame me. Please.



Chris Offili (and turn off the sound track, please!)

If artists required sound with their work they would have used sound, no?



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