What is Radiant Energy?

Radiated energy ^[1] refers to the sum of electric field energy and magnetic field energy in electromagnetic waves, also called the energy of electromagnetic waves. Solar radiation hits the earth at the speed of light (c = 3 × 10 ^ 8 meters / second), and it has both the characteristics of particles and waves. In the physical geographic system, the reception and storage of radiant energy are inseparable from these characteristics. For example, green plants carry out photosynthesis, and the absorbed energy is carried out in the form of light quanta. Because of this quantum characteristic of radiant energy, the magnitude of quantum energy depends on wavelength and frequency. As we all know, light has two sets of contradictory theories of electromagnetic waves and quantum energy, and modern theories have confirmed that light is an electrically neutral elementary particle with a static mass of zero, and the vibrational propagation of electrically neutral elementary particles is simply impossible. Both electricity and magnetism are generated, then the above-mentioned explanation of the magnetoelectricity of sunlight is inconsistent with the explanation of the optical quantum described later.

The sun continuously releases energy to the surrounding space in the form of radiation. This energy is called radiant energy ^[2]

The process by which objects emit or transport energy in the form of electromagnetic waves or particles.

Electromagnetic spectrum

Electromagnetic waves are arranged in different order of wavelength, which is called electromagnetic spectrum.

· = 3 × 10 ⁸ ms ^-1

The concept of particles (quantums): Some physical quantities in the micro world cannot change continuously and can only change by integer multiples of a certain minimum unit. These minimum units are called the quantum of this quantity.

If the electron is a quantum, the energy of each quantum is:

E = h ·

h is Planck's constant, h = 6.626 × 10 ^-34 J · s = 6.63 × 10 ^-27 erg · s

1 Joule (J) = 10 ⁷ erg

Radiation flux (F), radiation flux density (E)

Radiant flux : Radiant energy passing through an arbitrary area per unit time.

Unit: J · s ^-1 or W or (mol s ^-1 )

Radiation flux density (E) and unit

Definition: Radiative flux per unit area.

Unit: J · s ^-1 · m ^-2 or W · m-2 or mol m ^-2 s ^-1

Radiation flux density is also called radiant intensity, radiant power, or radiant power.

Luminous flux and unit

Definition: A quantity that characterizes radiant flux and produces a light sensation.

Unit: Lumen (lm)

Luminous flux density and unit

Definition: Luminous flux per unit area.

Unit: lumens / meter ² (lm · m ^-2 )

Illumination and unit

Definition: Accepted luminous flux per unit area.

Unit: lx, transliterated to lux, 1 lx = 1 lm · m ^-2

The ability of an object to absorb, reflect, and transmit radiation is represented by the absorptivity a, the reflectivity r, and the transmittance t, respectively.

According to the principle of conservation of energy:

Gives a + r + t = 1

Definition: objects with a = 1 are black and objects with a = const <1 are gray.

Stephen-Boltzmann's Law

E = T ⁴

= 5.67 × 10 ^-5 Erg. cm ^{-2 .Kelvin -4}

Significance: The radiation intensity E of the black body surface is proportional to the fourth power of its absolute temperature T.

The radiation received by a surface depends on how the surface is directed towards the radiation beam. If the radiation flux of this beam does not change, but the surface area it occupies becomes larger and larger, as the surface area increases, the radiation flux density on this surface becomes smaller and smaller. This can be expressed quantitatively by Lambert's cosine theorem ^[2]

Photosynthesis in plants

Photosynthesis ^[3] , that is, the synthesis of light energy, refers to chloroplast green plants and certain bacteria, under the irradiation of visible light, through light and carbon reactions (formerly known as dark reactions), using photosynthetic pigments, carbon dioxide (Or hydrogen sulfide) and water are biochemical processes that convert organic matter and release oxygen (or hydrogen). There is also an energy conversion process that converts light energy into chemical energy in organic matter.

Photosynthesis is the sum of a series of complex metabolic reactions. It is the basis on which the biological world depends, and it is also an important medium for Earth's carbon-oxygen balance. Photosynthesis can be divided into oxygen-generating photosynthesis (oxygenic photosynthesis) and non-oxygen-generating photosynthesis (anoxygenic photosynthesis). It is a biochemical process in which green plants and some bacteria use chlorophyll to convert carbon dioxide and water into organic matter (mainly starch) under the irradiation of visible light, and release oxygen. For almost all living things in the biological world, this process is the key to their survival, and the carbon and oxygen cycle on the earth, photosynthesis is essential.

Solar photovoltaic

Photovoltaic power generation ^[4] is a technology that directly converts light energy into electricity using the photovoltaic effect of the semiconductor interface. It is mainly composed of solar panel (component), controller and inverter. The main components are composed of electronic components. The solar cells can be packaged and protected after being connected in series to form a large-area solar cell module. A photovoltaic power generation device can be formed by adding a power controller and other components.

solar water heaters

Solar water heater ^[5] is a heating device that converts solar light energy into thermal energy, which heats water from low temperature to high temperature to meet people's hot water use in life and production. Solar water heaters are divided into vacuum tube solar water heaters and flat-plate solar water heaters according to their structural forms. They are mainly vacuum tube solar water heaters, occupying 95% of the domestic market share. The vacuum tube type domestic solar water heater is composed of related parts such as a heat collecting tube, a water storage tank and a bracket. The conversion of solar energy to heat mainly depends on the vacuum heat collecting tube. The vacuum heat collecting tube uses the principle of hot water to rise and cool and sink, so that water generates microcirculation Get needed hot water

Other areas

It can also be used in bore flame image processing, textile dyeing and finishing industry, particle accelerator, heat treatment production, radiation detection and other production activities.