Why is the angle of the sun an important factor in insulation?

Why is the angle of the sun an important factor in insulation?

If the Sun is 45° above the horizon, the incoming insolation strikes the Earth’s surface at an angle. This causes the rays to be spread out over a larger surface area reducing the intensity of the radiation. As illustrated, the lower Sun angle (45°) causes the radiation to be received over a much larger surface area.

Which time of day will the sun be at its highest angle of insolation?

At what time of day does maximum insolation normally occur? Its rays travel further through the atmosphere than at noon, when the sun is at its highest point. On a clear day, the greatest amount of solar energy reaches a solar collector around solar noon.

What is the relationship between angle of insolation and temperature?

Angle of Solar Radiation and Temperature The angle of incoming solar radiation influences seasonal temperatures of locations at different latitudes. When the sun’s rays strike Earth’s surface near the equator, the incoming solar radiation is more direct (nearly perpendicular or closer to a 90˚ angle).

Where and when is the daily averaged insolation at the top of the atmosphere the greatest?

Averaged over one day, the maximum solar insolation occurs at the poles at the summer solstice (see Fig. 2.11), while averaged over one year the solar energy received at the top of the atmosphere at the equator is about twice that received at the poles.

How do you calculate solar insolation?

Solar insolation (I) can be calculated using the following formula: I = S cosZ.

How do the angles of the sun’s rays determine intensity of solar radiation?

Rays striking the planet’s surface from directly overhead — that is, at a 90 degree angle measured from the horizon — are the most intense. The smaller the angle, the greater the surface area over which the sun’s rays spread. This effect reduces the sun’s intensity in any one place.

Where do you find highest angle of incidence?

Angle of Incidence Rays striking the planet’s surface from directly overhead — that is, at a 90 degree angle measured from the horizon — are the most intense. At most times and locations, the sun forms an angle with the horizon less than 90 degrees — that is, usually the sun sits lower in the sky.

When during the day is there a lower angle of insolation?

At the Equator, daily insolation varies from about 380 W/m2 to about 430 W/m2 and there are two maximums—each near the time of an equinox, when the Sun is directly overhead at noon. At the solstice, insolation is lower because the Sun’s path is lower in the sky (Figure 2.9).

How do you calculate solar radiation?

The solar declination angle varies from + 23.5 deg on summer solstice to -23.5 deg on winter solstice, and 0 deg on the vernal equinox and autumnal equinox. Solar insolation (I) can be calculated using the following formula: I = S cosZ.

How do you calculate instantaneous solar radiation?

Substituting the expression for solar zenith angle into the insolation formula gives the instantaneous insolation as a function of latitude, season, and time of day:

1. Q=S0(¯dd)2(sinϕsinδ+cosϕcosδcosh)
2. =S02π(¯dd)2∫h0−h0(sinϕsinδ+cosϕcosδcosh) dh.
3. ¯Qday=S0π(¯dd)2(h0sinϕsinδ+cosϕcosδsinh0)

How is the angle of the sun related to insolation?

On sa&i formula we develop the exact mathematical relationship between sun angle and insolation. The angle that sunlight strikes a surface affects how much solar energy is transferred to that surface.

How are the angles of the Sun calculated?

The spreadsheet calculates the sun angles at two different times of day. The first is at solar noon, when the sun reaches its maximum altitude in the sky and irradiates the maximum energy for that day. The second is at the given local time.

How does the angle of the sun affect a horizontal surface?

The solar radiation striking a horizontal surface is affected by the angle of the sun (the solar angle) which is in turn influenced by latitude, season and time of day. This page and its companion-pages, sa&i data and sa&i formula explain and quantify these relationships.

What is the insolation of the sun during June solstice?

During the June solstice day length is 18 hours and 27 minutes and the angle of the Sun reaches a maximum value of 53.5 degrees above the horizon. Minimum values of insolation are received during the December solstice when day length and angle of incidence are at their minimum (see Table 6h-2 and section 6h).