The size of the sun's altitude angle at noon:

H = 90'-Latitude difference (Latitude difference refers to the difference between the geographical latitude of a place and the latitude of the direct point of a day). For example, the latitude of a place is 40'n, and the noon sun height of a place from summer to the morning is found. From summer to morning, the latitude of direct sunlight is 23 ′ 26 ′ n, and the latitude difference with A is = 40 ′-23 ′ 26 ′ =16 ′ 34 ′, so H = 90 ′-16 ′ 34 ′ = 73 ′ 26 ′. If you find the height of the sun at noon from winter to Sunday in one place. From winter to morning, the latitude of direct sunlight is 23 ′ 26 ′ s, and the latitude difference with A is = 40 ′+23 ′ 26 ′ = 63 ′ 26 ′, so H = 90 ′-63 ′ 26 ′ = 26 ′ 34 ′. Calculation formula: H = 90-∣ α-β ∣ * α is the latitude of the direct point of the sun, and β is the required latitude (β is positive in summer and negative in winter).

Therefore, the solar altitude angle in Kunming in a year is 90-(2512-23 26') = 8814'.

The solar height from winter solstice is 90-(2512'+23 26') = 4122'

Therefore, in order to make the solar water heater vertical to the sunlight, it should be adjusted within the range of146'-48 38'.

The picture needs to be clicked by the landlord to see clearly.