Products - isolar^® glas

One of the main functions of ISOLAR^® insulating glazing is to provide optimum thermal insulation, thus improving energy efficiency. To be able to analyse the efficiency with which the insulation is performing from an energy point of view, we must observe how solar energy behaves when passing through it. To do this we must define a series of concepts that will allow a better understanding of this analysis.

Energetic radiation

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Energetic radiation is all the energy flow reaching an object. Insulated glazing has three main defined parts: the energy that goes through the glass, the energy it reflects and the energy absorbed by the glass itself.

- Energy transmission (e) is defined as the amount of energy that goes directly through the glass. It is expressed as a percentage of the energy reaching it.

- Reflected energy (r_e) is equivalent to the amount of energy reflected by the glass. It is also expressed as a percentage of the energy reaching it.

- Energy Absorbtion (α_e) or the amount of solar energy absorbed by the glass; this causes an increase in temperature and a transmission of the energy to the exterior and interior.

- The Solar Factor (g) consists of the total energy radiated by the sun into an area, i.e., the sum of the energy transmitted plus the part of the energetic absorption which is irradiated inside by the glass (g = +α_ei )

In the e, r_e and α_e calculations, the sun is taken to be at an angle of 30º above the horizon.

All the information relating to the behaviour of solar energy when it passes through glazing can be determined by the heat transmission ratio (U or K ratio) or the amount of energy, measured in Watts (W) or Kilocalories (Kcal), going through a square metre of glazing (per hour (h) to calculate (K) and by each Kelvin degree (K) or Centigrade (ºC) of difference on each side of the glass.

Light radiation

Energetic radiation is all the energy flow reaching an object

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Another essential property of insulated glazing and of any glass in general is its capacity to filter solar light. Depending on the type of glass, solar light acts in different ways. Light radiation, just like energetic radiation, can also be divided into the amount of light passing through the glazing and the light it reflects.

Light radiation is defined as the flow of visible light we receive from the sun and which is projected onto objects and living beings. When light falls on glazing, it has the following properties:

- Light transmisión (_v) or the amount of visible light passing through the pane. This is expressed as a total of the light falling.

- Light reflection (r_v) or the amount of visible light passing through the pane. This is also expressed as a total of the light falling.