Solar Collector Tilt

Posted by admin | | Sunday 15 February 2009 8:49 pm

Solar Hot Water System – Solar Collector Angle

Deciding on the proper angle and direction for installing your solar collectors is of just as much importance as properly sizing your solar collectors.  If the angle and direction of your collectors is not correct for your location, then your system will quickly lose efficiency and the ROI will dramatically diminish.

Basically, you want your solar collectors to receive as much direct sunlight as possible each day of the year.  Simply stated, the first rule of deciding the angle and direction of your solar collector is:

  • In the Northern Hemisphere:  Your collector should face South
  • In the Southern Hemisphere:  Your collector should face North

Solar Hot Water Systems - Solar Water Heater Sizing Guide Help

Of similar importance is determining the proper angle to mount your solar collectors at.  The general rule of thumb for determining the angle of your collector is:

  • The angle of your solar collector should roughly equal the latitude of your location plus  10-15 degrees.
  • Denver, CO has a latitude of 40 degrees North – the collector should face True South, at 55 degrees
  • Chicago, IL, has a latitude of 42 degrees North – the collector should True South at 57 degrees

Please note – if your roof is within +/- 15 degrees of the recommended angle for your collector, then you are fine with mounting the solar collectors flush to the roof.  Since Evacuated Tubes gather solar energy from 360 degrees around, the added cost and work of installing the collectors on a tilt mount in this case is not warranted as the increase in efficiency would not be significant enough.

Seasonal Changes in Heat Output –

  • In the winter, you will get proper performance because the solar collector is more in line with the Sun that is lower in the Winter sky.
  • In the Summer, you will get slightly less performance because the solar collector is angled more away from the sun as it is higher in the sky – this allows you to get enough solar hot water output for your needs without the need to worry about excessive heat.