The choice of air conditioning ceiling cassette is an important part of the energy efficiency equation but need not come at the expense of interior design, says Martin Passingham

MODERN CLIMATE control systems are designed to meet ever-tightening carbon reduction legislation and ensure occupants are kept comfortable at all times, while also keeping running costs to a minimum. But gone are the days when a ceiling cassette was just a functional unit to be tolerated in an otherwise stylish interior.

Selecting the correct ceiling cassette is an important part of system design and there is a wide variety available. Most importantly these are energy efficient solutions that do not compromise comfort levels but they are also easy to install, flexible and stylish.

For example, the fully flat cassette from Daikin UK is the first commercial indoor unit developed specifically for the European market. Delivering comfort and seasonal energy efficiency (up to A+), it is designed to blend seamlessly with modern commercial building interiors. The fully flat cassette fits completely within a standard European ceiling tile, enabling lights, speakers and sprinklers to be installed in adjoining panels.

To enhance efficiency and to improve comfort levels, ceiling cassettes can incorporate presence sensors to adjust the setpoint or switch on and off, dependent on occupancy. Presence sensors have been shown to improve energy efficiency by up to 27 per cent over a three-hour period. Sensors can also direct air flow depending on where people are in the room, ensuring no draughts. A 'floor' sensor in a cassette can detect the temperature difference between the floor and the ceiling and redirect the air flow to ensure even temperature distribution. For refurbishment projects, it is important to ensure both ease of installation and to select a system that can incorporate future layout changes. Older buildings provide greater challenges for installers as the buildings were not originally designed for today's HVAC systems. It is therefore worth investigating whether the cassette has been designed to be fitted into narrow ceiling voids often found in older buildings.

During refurbishment, temporary or permanent barriers are often erected, which can leave the cassette close to a wall or in a corner, resulting in imbalances in air flow. It is therefore important to choose a cassette that can accommodate changing layouts and individually open or close louvres to restore optimal efficiency and to save on energy costs.

Sound levels are also important to a comfortable working environment and should not be overlooked. Some of the quietest models on the market now operate at 25dBA sound pressure levels. Air quality is another factor, so a good cassette will have advanced filters to remove dust particles, ensuring the air is clean. The system should also be able to reduce humidity levels, without varying room temperature.

Tests have shown the energy efficiency of a ceiling cassette can be related directly to how often they are cleaned. Sometimes it is not always possible to access and clean cassettes regularly enough for them to operate at the optimum efficiency levels. That is where self-cleaning cassettes offer a significant advantage.

Daikin UK's Self Cleaning Roundflow Cassettes save energy and help to meet latest energy efficiency legislation through a daily auto-cleaning function that optimises air flow. The self-cleaning filter cleans itself automatically once a day, resulting in no accumulation of dust on the indoor unit. This increases efficiency, reducing running and maintenance costs, as well improving comfort levels through consistent air flow distribution.

During a year-long trial at a Wolverhampton betting shop, a Self-Cleaning Roundflow Cassette cut energy consumption and running costs by 49 per cent over a unit without the self-cleaning function. The self-cleaning system also saved two tonnes of carbon dioxide over the year, compared with a standard roundflow system. These figures resulted in the rapid payback period for the self-cleaning system - under a year.

These ceiling cassettes also blend with interior décor as they are integrated into the ceiling with only the decoration panel visible. The trial at Wolverhampton also showed that the self-cleaning filter prevented grime accumulating around the decorative panel, saving further maintenance costs in cleaning and tile replacement.

The latest climate control systems offer a wide choice of ceiling cassettes, offering specifiers, installers, building owners and businesses flexible and stylish solutions. They offer high levels of energy efficiency, reducing energy consumption, carbon emissions and energy bills, while delivering optimal comfort levels in hotels, shops, offices and leisure environments.

Modern ceiling cassettes blend seamlessly with any interior décor and incorporate a host of new innovations to reduce energy use, including efficient heat exchangers, fan motors and drain pumps; dust filters and dehumidifiers to ensure air quality; as well as presence sensors and individually controlled flaps to direct air flow and ensure comfort levels, even if room layouts change as a result of refurbishment.

// The author is the product manage, DX Daikin UK //