A major benefits of HVAC, particularly in deep plan and larger office buildings, is that they alleviate many of the problems associated with a naturally ventilated building such as noise, dust, insects, heavy winds, odours and uncomfortable temperatures.
However, there are some studies suggesting that a mixed-mode ventilation system of HVAC and natural ventilation, in combination with good passive design, can provide sufficient indoor air quality to keep occupants happy while reducing their reliance on mechanical air treatment.
Typically a mixed-mode system operates in either of two modes and is best used for a buildings’ perimeter spaces or for narrow planned buildings with good cross ventilation. The first is the natural ventilation mode which uses fresh external air from operable windows or dampers to cool the internal spaces and relies predominantly on the stack effect for hot air to be expelled through high-level exhausts. The second is the mechanical mode and sees the windows closed and the HVAC switched on, and is used only when the external temperatures are too hot or too cold for natural ventilation, or when there are heavy winds or rain.
Control of the operable windows can be manual or automatic and, in keeping with current trends in Australia towards automated buildings, we’re seeing more automated windows systems come to the market that are also compatible with Building Management Systems (BMS).
Some window manufacturers offer built-in automated systems that can be controlled by a BMS and that come with inputs for automated weather stations and sensors that detect smoke, rain, hail, temperature, wind, time and smog. Others advertise that their products can be easily automated with add-on products like actuators and reed switches, and can also incorporated into a BMS.
These products render manual operation from building occupants—one of the most difficult-to-control influences on a building’s environmental impact—unnecessary, as the BMS detects when it is optimal to open and close windows, and to operate the HVAC.
Some of the problems associated with the manually operation of a building’s HVAC and natural ventilation, like occupants leaving windows open with the HVAC on for example, can therefore be avoided with automated mixed-mode air-conditioning.
Below are six automated window systems and five new air conditioning systems that could benefit your mixed-mode ventilation:
Louvre Windows by Safetyline Jalousie
Safetyline Jalousie louvre windows are amongst the safest, strongest, widest, most functional and versatile louvre windows on the market. A unique design feature of Safetyline Jalousie automated louvre windows is that they pivot from the top rather than the centre, enabling the installation of internal insect screens.
Coltite by Colt International Pty limited
Most versions of Coltlite are classed as dual purpose ventilators, providing both day to day and smoke control ventilation. It can also be installed either for low level air inlet or for high level extract. Options include pneumatic, electronic or manual controls and a wide range of louvre types, accessories and finishes.
Schneider Louvre LF550 by EBSA
This louvre window system contains a pivoting aluminium window louvre system with concealed motor and mechanisms that can be fully integrated into the Business Management System and Fire Indicator Panel.
These single glazed frameless louvre windows have an opening pivot of up to 90 degrees, which encourages natural ventilation into the building and when closed the windows are completely water tight with the high quality German manufactured mechanisms hidden in the mullion.
TOPP Automated Window Systems by Kintrol Pty Ltd
Kintrol Australia is the authorised Australian distributor of award winning TOPP automated window systems. Kintrol’s range includes everything from louvres to casement windows all of which can be synchronized to air conditioning, security units and fully home automation like BMS systems.
Altair Powerlouvre Automated Windows by Breezway
Widely used in the residential sector, Breezway’s Altair Powerlouvres incorporates a motor and gearbox concealed within the window frame or within the head section, resulting in an automated louvre window with no visible motors, rods or arms. Control is possible via wall switches, remote control systems, a Breezway app or integration into building management systems.
Reference: https://www.architectureanddesign.com.au/features/features-articles/6-automated-window-systems-and-5-new-air-condition