Characterizing the IR Reflecting Properties of Pigments for Cool Roofs
Introduction
The sun energy reaches earth as UV visible and Infra-red radiation. UV radiation is an invisible part of electromagnetic spectrum. Only 5 % UV from sun reached the surface is play the major role to the degradation of coating .Visible light wave (295-400 nm) seen by human eyes. Around 50% of the suns energy occurs in this region which gives the perception of colour.45 % of total solar energy is in IR region (700-2500 nm) .The purpose of IR reflecting pigment is to keep the object cooler than using standard pigments. Pigments are organic or inorganic substance which is insoluble in water or organic medium in which they are used as dispersion. Paint is fine dispersion …show more content…
If an object reflect entire visible wavelength region then it is white. If some region of this light are absorbed and other part is reflect then object is colour. Black surface absorb all the visible region and nothing reflect. IR reflective inorganic colours pigments reflect wavelength in IR region with reflect the some portion of visible region. Abosrptivity and reflectivity are independent with each other So that IR reflective pigments having any colour. IR reflecting pigment synthesized by Mixture of metal hydroxide, nitrate, acetate, at very high temperature called as calcinations process. The usage of IR reflectance pigment for roof and construction materials increases because of it’s a good weatherability property. In urbane area roof design is major source of heat absorption from sunlight. The amount of IR reflection depends on roof structure, type and colour of roof coating. Nickel manganese ferrite blacks, iron chromites brown-black, Pigment Blue 28 Pigment Blue 36, Pigment Green 26, Pigment Green 50, Pigment Brown 33, Pigment Brown 24, Pigment Black 12 and Pigment Yellow 53 s are some of the pigment used to provide dark colour with minimized the heat build-up. IR reflecting pigment having high heat stability, it can be used for high heat
Introduction
The sun energy reaches earth as UV visible and Infra-red radiation. UV radiation is an invisible part of electromagnetic spectrum. Only 5 % UV from sun reached the surface is play the major role to the degradation of coating .Visible light wave (295-400 nm) seen by human eyes. Around 50% of the suns energy occurs in this region which gives the perception of colour.45 % of total solar energy is in IR region (700-2500 nm) .The purpose of IR reflecting pigment is to keep the object cooler than using standard pigments. Pigments are organic or inorganic substance which is insoluble in water or organic medium in which they are used as dispersion. Paint is fine dispersion …show more content…
If an object reflect entire visible wavelength region then it is white. If some region of this light are absorbed and other part is reflect then object is colour. Black surface absorb all the visible region and nothing reflect. IR reflective inorganic colours pigments reflect wavelength in IR region with reflect the some portion of visible region. Abosrptivity and reflectivity are independent with each other So that IR reflective pigments having any colour. IR reflecting pigment synthesized by Mixture of metal hydroxide, nitrate, acetate, at very high temperature called as calcinations process. The usage of IR reflectance pigment for roof and construction materials increases because of it’s a good weatherability property. In urbane area roof design is major source of heat absorption from sunlight. The amount of IR reflection depends on roof structure, type and colour of roof coating. Nickel manganese ferrite blacks, iron chromites brown-black, Pigment Blue 28 Pigment Blue 36, Pigment Green 26, Pigment Green 50, Pigment Brown 33, Pigment Brown 24, Pigment Black 12 and Pigment Yellow 53 s are some of the pigment used to provide dark colour with minimized the heat build-up. IR reflecting pigment having high heat stability, it can be used for high heat