MOVE-energy CV glass coating

Today’s business and office buildings are dominated by glass and steel. These materials are excellent for transmitting or transferring heat. In order to improve the energy balance of a building it is advisable to protect the building. In summer the building protection lowers heating by solar radiation and in winter it lessens rapid cooling down of the building.

The following factors determine the heat loading by means of solar radiation:

The direction in which the building faces
The relationship of the window size to the volume of the room
The intensity of the radiation and the duration of the sunshine
The heat storage capacity of the building elements
The starting g-value of the glazing (overall degree of transmittance of the energy)
The heat loads caused by persons and technical devices

The heating of rooms to temperatures outside the comfort zone for people is increased by large window areas. If large window surfaces are facing south, then as early as April the sun’s rays can raise the room temperature to 26°C and higher.

Besides the direction in which the building is facing, the ratio of room volume to window surface influences the amount of heat generated through solar radiation.

The intensity of radiation from the sun

Sunlight radiates solar energy in various wavelength regions. This includes the desired daylight and the undesired heat. Approximately 3% of radiation occurs in the ultraviolet range (UV radiation); some 46% is daylight and about 51% is infrared radiation (IR radiation) meaning heat.

Short-wave UV rays passing through window surfaces into a building convert to long-wave heat radiation that can leave the room only in a throttled manner (greenhouse effect).

The radiation intensity of the sun is strongly dependent on the weather conditions.

Clear blue sky = 1000 W/m²
Sun breaks through = 600 W/m²
Sun as a white disk = 300 W/m²

The storage capacity of the building is strongly determined by the type of construction. Hollow space floors (double floors), suspended ceilings and light separating walls of gypsum baseboard have a low storage capacity.

Although good building insulation will ensure that heat will remain longer in the building in winter, it does the same in summer.

Solar energy entry through glass windows (g-value)

Solar energy entry through glass windows is described by means of the overall energy transmittance (g-value).

The g-value of any sunscreen apparatus should be as small as possible, so that little solar energy enters the building. An arbitrarily low g-value, however, is not desirable because then the room will not receive any daylight. The use of daylight contributes to a good energy balance, because artificial light sources generate heat and use energy. For this reason, a balanced g-value is a sign of good sunscreen apparatus.

The MOVE-energy CV glass coating and energy-saving film has a g-value of 45%. This means that 55% of the solar energy is blocked by the film. In combination with the g-value of the window pane this provides an overall “total g-value”. In a typical insulation glass coated with ME CV glass coating and energy-saving film, a “total g-value” of between 31% and 37% is obtained. With sun protection glazing a reduction of up to 18% can be obtained.

Passive cooling

To raise the room temperature by only 1°C requires an energy expenditure of approximately +6%. This shows clearly the potential of solar radiation as early as March/April, when room temperatures of 26 °C become the norm. With passive cooling this level is only achieved in high summer.

MOVE-energy CV glass coating is a passive form of room cooling that manages without additional electrical energy. Energy consumption and CO₂ emissions are “zero” and there are no operating costs.

Passive cooling can be supported by utilizing night cooling, i.e. the fluctuation in external temperatures between day and night. Here, the building's external accumulators are unloaded at night and are available for reloading the following day. Should both measures – the reduction of radiation inwards and the nightly cooling-off – prove insufficient, an active cooling system is called for.

With an ME CV glass coating on window panes, the rise in room temperature can be minimized while still ensuring optimal utilization of daylight.

MOVE-energy CV glass coating consists of an extremely thin polyester carrier coated with stainless steel grids. The upper layer is of SiO₂ (glass), making it inert and easy to clean. The structure of the grid has been optimally adapted to the wavelength. The grids are very fine and invisible to the human eye.

The functional principle is based on selective reflection of the heat radiation. The vital sunlight will still pass unhindered through the glazing. Only 7% of the infrared part of the sunlight is allowed to pass directly through. In this way the heat radiation of the sun remains outside in summer and the heating warmth in winter remains inside.

Benefit of MOVE-energy

If all glass surfaces are coated, the reduced energy input is maximized. The heating of the building is greatly slowed by the high reflection of the IR radiation. Depending on the proportion of glass and type of glass, the rise in temperature is reduced by up to 9°C.

If the windows are already equipped with an expensive sun protection glazing, the energy entry is even further reduced by MOVE-energy CV glass coating.
Because of the lower starting value the difference will now not be quite so large.
Use of MOVE-energy CV glass coating reduces the cooling load of the air conditioning equipment, thus lowering the overall load even further. An air conditioning installation that is used less has lower material wear and lower servicing costs. In addition, the energy costs and CO₂ emissions of the equipment are reduced.
Fewer cold air currents also add to the occupants' feeling of well-being.

And in winter …..

Because heat losses from a heated room are largely caused by heat radiation through window surfaces, the coating with MOVE-energy CV glass coating can substantially improve the heat damming properties. Depending on the type of glass, usually 50% of this heat radiation can be reflected back into the room. The coating increases the surface temperature of the inside pane and thus improves comfort in the vicinity of the window.