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Natural Ventilation for Glass Facades

IQ Radiant Glass® glazing option for operable vents by Jansen VISS or Schüco AWS 102

Schüco AWS 102 vent compatible with IQ Radiant Glass
Open Vent Schüco AWS 102 All-glass façade window

HVAC systems, including heating, ventilation, and air conditioning, usually account for over 33% of total energy consumption in tall office buildings. More than half of this energy is used to counter the heat gains from occupants, lighting, and electronics. To prioritize sustainability, it's essential to enhance energy efficiency. One way to do this is by adopting hybrid HVAC systems that incorporate natural ventilation. However, in colder climates, natural ventilation may not be suitable for specific locations. Fortunately, IQ Radiant Glass is a practical solution to this problem.

Efficient energy management in buildings can be achieved through building automation and smart systems. A crucial aspect of this is the integrated control and coordination of a building's heating, ventilation (including natural ventilation). The HVAC system must be designed to support this feature. To enhance thermal comfort and optimize air quality, heating glass vents can be utilized to complement the use of natural ventilation.

Our primary goal is to enhance occupant comfort by energizing the operable vents in our building systems. However, fixed openings can also benefit from heating glass glazing. The combination of fresh air and radiant heat improves indoor air quality and human comfort. The IQ Radiant Heating Glass system possesses unique capabilities to provide targeted thermal comfort to occupants without overheating or dehydrating the air.

This technology can generate zonal heat by allowing individual glass pieces to be controlled by the building's smart control system. It operates only when required, providing thermal comfort to occupants and warming up other surfaces within the specific area where the active radiant heating glass is installed. During winter, the operable vents can be opened for natural ventilation without compromising on thermal comfort, reducing the load on heat pumps and air circulators.

For example, Installing IQ Radiant Glass in KönigStahl/Jansen Steel VISS Parallel Vent Windows, and similar systems, can achieve significant energy savings and improve overall thermal comfort. This approach can be expanded beyond operable vents to include other areas of the building, further optimizing energy efficiency and thermal comfort. Traditionally, heating and air-conditioning design strategies have focused on achieving a specific indoor temperature based on a given design air temperature. This approach fails to differentiate between convective energy and radiant energy exchange, leading to inaccurate representation of occupant thermal comfort.

The use of radiant heating glass technology eliminates thermal asymmetry discomfort by emitting long-wave radiation that provides thermal comfort to occupants at lower interior air temperatures. It's important to note that every building and location is unique, and the goal is to incorporate such systems into HVAC design to facilitate natural ventilation, enhance thermal comfort, and achieve energy savings. At its core, our approach aims to energize the operable vents while also integrating other technologies, like radiant heating glass, to improve building performance, occupant comfort, and sustainability.

The basic strategy has been known for some time:

In 2008, a test conducted at KSU by the International Quality and Research Group (IQRG) studied the effectiveness of different heating systems in a building environment. The study compared the use of radiant glass with forced air using natural gas. The results showed that using radiant glass had numerous benefits, including: - It reduced the interior air movement noise level to zero as radiant heat does not require fans and ductwork to deliver heat. - The radiant delivery system caused no air movement, thus eliminating the transmission mechanism for pollens and air-borne particles. - It reduced heating demand, expressed in BTUs by 44% while doubling the area of thermal comfort. - There was no transmission loss through the ductwork using radiant heated glass. - Condensation, a major cause of mold, did not form on radiant glass. - An ancillary benefit of Radiant Window systems is no condensation forms on the glass. These findings indicate that the use of radiant glass can significantly improve the indoor air quality and reduce the energy demands of a building.


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