Windows provide light, visibility and ventilation, but they are often the weakest element in a building’s envelope from the standpoint energy, security, fire, and severe weather. High-tech windows have a number of advantages, but are not in widespread use, primarily because of cost. Further, even if better windows become available at reasonable costs, they will have shortcomings that well-designed moveable insulation of the kind under development by Synergistic Building Technologies can overcome much more effectively.
Shutters have been used for many centuries all over the world and they aid in the beauty and functionality window systems. The photos show some typical examples of shutters in France. Although these examples of shutters are charming and provide privacy and shade, they must be operated by hand—and they provide very little insulating value.
By their nature, windows can not have the properties of both high solar heat coefficients (SHGCs) that are useful for wintertime passive solar heating and low SHGCs that limit unwanted passive solar gain in the summer. In the northern hemisphere, overhangs are helpful in lessening the effects of summertime solar heating problems on south-facing facades, but not on the east and west. Yet summertime solar gains through west-facing (and even north-facing) glazing in climate zones that require space cooling contribute importantly to peak electricity demands, particularly on hot summer afternoons. They thus fuel the need for new power plants, even when windows in new homes meet current energy code requirements of SHGCs of 0.4 or less. Download Fenestration Report.
Windows with high R values (low U values) are less effective than those with higher U values in climates that have high diurnal temperature swings in the summer, since nighttime cooling in this case will be less effective when nighttime outdoor air temperatures are lower than indoor temperatures.
Optimally, U values and SHGCs of fenestration systems should be variable, allowing adjustment of performance to instantaneous weather circumstances, thereby achieving increased comfort and energy savings. That’s what our shutter systems achieve—and they do it cost effectively. Click here for a discussion of windows and shutters, including details of energy use in Denver's climate, from the Boulder Green Building Journal.
Insulating shutters combine the beauty and charm of shutters with the energy efficiency only excellent moveable insulation can provide. During the winter, they lower night time thermal losses by a factor of up to ten. Further, they control overheating during the summer by selectively blocking direct beam sunshine when appropriate. These systems represent a key step in the direction of achieving genuinely net zero energy-using buildings. This includes super efficient greenhouses
Application to green greenhouses
Two varieties of automated insulating shutters are employed in SBT's high-performance greenhouses. Our shutters are controlled wirelessly with no penetration of the building’s envelope. The shutters are automated to optimize comfort and energy efficiency in all seasons, but may be over-ridden when desired. The shutters can provide excellent insulation on cold nights (think R = 12 fenestration systems!) and shade specific windows when needed on hot days. The result is excellent control of solar light and energy to produce optimal growing environments.
|
