While traditional mechanical Heating Ventilation and Air Conditioning (HVAC) systems are still widely used in Australia, contemporary concerns for improving the environmental performance and “liveability” of buildings has led to an increased interest in alternatives like natural ventilation and mixed-mode systems.

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:

WINDOWS

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 byBreezway

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.

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 louvre windows is that they pivot from the top rather than the centre, enabling the installation of internal insect screens.

AIR CONDITIONERS

The Iceberg by Brivis Climate Systems

The Brivis Iceberg is an upgrade from the evaporative coolers of the past. The majority of the Brivis Iceberg is installed out-of-sight in your roof-space (so long as you have sufficient clearance in the roof space) and doesn’t require constant maintenance of the cooling pads and water chambers.

Some other added bonuses to consider is that, unlike refrigerated cooling, the Iceberg won’t drum up a massive electricity bill if the doors and windows are left open during the day. Brivis also claim that the cost to install their Iceberg system is around half that of ducted refrigerated cooling and when compared to similar capacity refrigerated systems, is around 90 per cent cheaper to run.

The Silenceair by Silenceair International

The Silenceair building ventilation system allows you to open your home to natural fresh air, without the noise. The Silenceair wall vents are designed to fit into new or existing walls and offer an alternative to windows in facilitating fresh air ventilation into interior spaces.

At the core of all Silenceair products are special arrangements of open-ended tubes called 'acoustic attenuators'. These tubes allow air to pass freely, but channel and redirect sound waves in such a way that the waves cancel themselves out, significantly reducing the passage of noise through the ventilation passage.

They also help reduce the build-up of moisture and the growth of unhealthy mould and bacteria and help flush toxins from furniture and other chemicals out of the building.

In extremely windy or cold conditions, or when you’d prefer mechanical cooling of the home, the sliding cover on the inside of the vent can be manually closed to reduce airflow.

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Inverted Ducted Systems by Toshiba Air Conditioning

Toshiba Air Conditioning Australia's Inverter Ducted systems provide rapid heat and cool functions which increases power temporarily to achieve desired temperature before returning to normal power.

On/off functions, temperature ranges and noise output can also be automated with Toshiba’s controller devices.

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Braemar Superstealth by Seeley International

The Braemar SuperStealth is the latest evaporative cooler from Seeley International. It has a high efficiency axial inverter fan which offers the quietest cooling in the Braemar range. This latest technology uses far less energy per kilowatt of cooling than previous axial units, and according to the manufacturer offers savings to consumers when compared to refrigerated air conditioning.

crv4_19as_actron_esp_platinum_plus_7-5_hp_4-00_17-00_19-00__c__3-75_19-00_20-00__h__ducted_single_phase_air_conditioner_indoor_outdoor_unit.jpg ESP Platinum Plus by Actron Air

The ESP Platinum Plus received an AIRAH Award in 2014 for Excellence in Sustainability and is marketing on providing comfortable air conditioning with lower running costs. It uses Energy Smart Zoning and Variable Fan Technology to automatically adjust airflow to certain parts of the building and can be plugged into the BMS for remote on/off control.

Testing and energy modelling have shown that the ESP Platinum Plus can save up to 75 per cent electricity compared to conventional fixed speed systems and up to 50 per cent compared to conventional inverter systems on the market.

Nathan Johnson

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