In order to maximise the
direct beam component of the incident radiation involves calculations
depending upon the latitude position of the location of the modules and
the season of collection. In Scotland irradiance falls mainly on south
facing facades and roofs. Therefore to maximise solar energy all installations
should be made facing south ( 30o) in Scotland (or anywhere North of the
The location of Glasgow
is 56o North, so using this in conjunction with the above allows the diagram
below to be drawn, which enables the inclination angles to capture the
maximum direct beam irradiance (during midwinter and midsummer only) to
The calculation of the angles f and d just require the use of simple algebra. Equations 1 and 2 below show the calculations for the optimal angles to capture the maximum direct beam radiation.
In order to capture the maximum direct beam component of the incident radiation during midwinter and midsummer the modules should be aligned at 79.50 and 32.5o respectively.
Any modules will tend not to be inclined at these optimal angles for midwinter and midsummer but inclined at a pre-determined value permanently. In most urban solar installations there is no choice in the inclination angle, or scope for variation during seasonal changes. The determining factor is the slope of the roof. An estimation that the inclination angle of 40o is the average slope of a household will be used. Another factor that is very likely outwith an urban installations control is the size of the array. The installation could be made on the roof of a mansion where a vast area could be utilised, or on the roof of a small one-bedroom house, therefore very limited area. Calculations will be made to show approximately the cost of an installation per m2.