Best alignment for solar HW

Best alignment for solar hot water


It is best to face the collector panels North, and tilt them  at an angle to the horizontal of Latitude X 0.89 + 24 degrees. This will produce maximum heat in winter. There will be more than enough in summer. 




Which angle?

Orientation - needs to face within 45o of North. It is not very critical near the tropics where collector the angle is low.
There is a lot of conflicting advice, much from respected authorities.
Some say the angle should be: latitude, latitude + 9, +20, and + 30o.  Here we are saying Latitude X 0.89 + 24 degrees
It is not easy to work it out. The best angle is steeper than first appears to catch sunlight from the sun earlier and later in the day when it is lower than the noon position.
For SHW set it to your winter sun angle. There will still be plenty of sunlight in summer. The heating requirement is not as much in summer as the water is warmer and the heat losses less.
PV however is best set at the summer angle.

Tilt above Horizontal



Winter max


Summer max

  deg deg deg
Darwin 12 35 -13
Cairns 17 39 -9
Alice Springs 24 45 -2
Brisbane 27 48 1
Perth 32 52 5
Sydney 34 54 7
Adelaide 35 55 8
Melbourne 38 58 11
Hobart 43 62 15
Solar HW should point to average winter sun. PV to the average summer sun.
For winter, Latitude X 0.89 + 24 degrees.
For summer,  latitude X 0.92 - 24 degrees.
Minus means the panel will point south.

The author of this table claims a 4% improvement over established angles.

Ref: Optimum tilt of solar panels

You would think when we can land a rocket on Mars, we could agree on a simple hot water collector angle.

(I'll have a go at it when I get time. JD)










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