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Cutting heat transfer, energy consumption

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Rising energy costs has increased the need for energy efficient solutions in the building sector which accounts for 33% of electricity consumption in India. Innovative building envelope systems can effectively cut through the modes of heat transfer transmitted by way of conduction, convection and radiation.

Heat transfer takes place from the roof or from the western and southern walls of the building due to the higher incidence of solar radiation. Depending on the properties of the roof material and construction, the absorbed heat in the roof is conducted inside the building. This process is governed by the solar reflectance and emissivity properties of roof materials (on the over deck part) and the thermal conductivity of the materials used in the roof (in the under deck par

The application of radiant barrier results in up to 40% reduction in heat flux from the exterior of the building to the interior resulting in a lot less temperature differentials for the thermal non-conductive layers to work against.

According to test results, if an additional thermal resistance of Radd = 6.0hr/sqft °F/Btu is added to the wall system having the ordinary house paint on its outer surface, the higher heat flux being conducted into the building, namely, 5.24 Btu/hr sqft would be reduced to the lower heat flux value of 3.57 Btu/hr sqft for the wall painted with paint having additives with insulating properties.

A specialised insulating paint additive has been developed in conjunction with NASA and is a propriety ceramic material that is used to create a highly efficient radiant barrier. The ceramic microspheres are inert, non-toxic and are 93% vacuum and have been designed at the outset itself as an additive and can be mixed with any ordinary paint or coating, thereby creating an effective radiant barrier paint / coating.

The insulating paint additive powder (ceramic microspheres) has to be added in the ratio of 1:4 by volume to any paint or coating, mixed well and then applied as per the paint manufacturer’s specification. Insulating Exterior paint results and benefits vary with each application due to differences in geographic location, type of construction, exposure and dwelling usage.

Reduced thermal stress on the building due to lower surface temperatures will result in lower expansion and contraction joint stresses resulting in reduced crack formation on the over deck roof areas. The under-deck insulation will then be subject to lesser temperature differentials thereby increasing the effective life and use of the insulation. Reduced load on the cooling equipment will have a similar benefit on the life of cooling equipment.

Thermal Barrier insulating additive for paint and roof coatings can improve the effective insulation value and energy efficiency of exterior surfaces such as walls and roofs equal or close to R-6 insulation value. Exterior walls and roofs painted with Thermal Barrier insulating additive for paint have shown to contribute to energy savings of upto20% and more in some cases

It has been further noted that conventional insulation materials like fiberglass, cellulose, rock wool, XPS, EPS and Styrofoam, no matter how thick, have almost no ability to block radiant heat energy which can account for as much as 93% of summer heat gain and up to 75% winter heat loss in conventional structures. Thermal Barrier insulating additive for paint blocks radiant heat and is a simple and affordable solution to high energy costs.

As per the ECBC guidelines – an ideal exterior surface coating of a building in hot climate and under indoor cooling would have reflectance near one and absorptance near zero and emissivity near one to radiate asborbed heat back to the sky.

Building Protection Systems (BPS) has ventured into the thermal insulation business by taking on the distribution of Insuladd, a NASA technology spin off product. “This could be used very effectively for buildings which have a huge requirement for air conditioning. It can reduce energy bills by about 12-24% in addition to being compliant with all the IGBC green rating requirements,” said Aditya Kaura, Director, -BPS. The product is also equally effective in non-AC buildings for internal thermal comfort of occupants.

SRI of 102 and 107 for roof and wall systems respectively, has been tested by CEPT, Ahmedebad and roof surface temperature reduction by 15-25oC has been tested by TERI, Bangalore. A versatile solution, Insuladd can be added to any external paint and applied to any paintable surface like concrete, metal, plastics, etc. Refurbishments are also possible where it can be used for re-painting of existing walls of buildings being refurbished.

The life of the application of the product depends on the life of the paint. Since the roof is a horizontal surface, it needs to be cleaned regularly with a hard broom and water stagnation should not be there as this could lead to algae growth on the surface. Surface should be cleaned thoroughly before application so there is good bonding between the paint and the surface. After five years, it will be required to recoated with a single coat of paint.

“We have completed sales covering approximately 800,000sqft area with customers such as Infosys (Mysore, Hyderabad, Bangalore, Chennai locations), HSBC (Hyderabad), L&T (Gujarat), Cognizant (Coimbatore), Titan Industries (Hosur), Century Developers (Bangalore), BCIL (Bangalore), JP Morgan Chase (Bangalore) and are presently in discussions with clients such as a cold storage in Delhi, and a large educational institution in Delhi,” said R.N. Kaura, Director,BPS.

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