Better by design
To the point
Since 2005, the Ecodesign Directive has been one of the key enabling mechanisms to drive forward the European Union’s policy designed to reduce the levels of environmentally damaging emissions and to increase the use of renewable energy sources. The Directive establishes a framework to prescribe design principles to apply to energy using products and systems, together with any necessary labelling requirements under the Energy Labelling Directive.
The industries concerned have the initial responsibility of implementation through best practice and other voluntary measures.
During the first three years following the coming in to force of the Directive, nineteen product categories have been the subject of preparatory studies, fourteen of which have been completed and the building services industry played an important and influential part in the consultation process.
The Commission recently confirmed the product groups that will be included in the Working Plan for 2009-2011, and the list includes, amongst others, air conditioners above 12kW, ventilation systems, network, data processing and data storing equipment.
Industries involved will again have a pivotal role during the ensuing consultation process. Consequently, those involved in providing products and systems for the building services industry and the industry itself will be concerned to ensure that their contribution towards the technical, economic and environmental analysis involved in the consultation process is channelled through the relevant representative and consultative bodies.
Although the specific policy aims of the key Directives were set out only a relatively short time ago, manufacturers and providers supplying the building services industry have long been focusing on the energy efficiency of products and systems. The industry has not been slow to appreciate and welcome these design initiatives, understanding their importance in the overall, long term, energy efficiency picture. In the case of air conditioning products, several best practice measures and innovative design features reflect technological improvement enabling greater application of previously existing concepts and the introduction of new technology.
Resulting from initiatives by individual manufacturers or providers, these improvements are currently available for building service professionals for whom energy efficiency is of prime importance.
Free Cooling is a concept that has been understood for many years, based on the principal that the air outside a building is, on occasions, both cool and dry enough to be used to directly cool inside the building, thus obviating the need to use the building’s air conditioning system. However, using traditional methods of assessing the amount of energy available on such occasions could result in creating unwanted moisture in the building. Improved technology has led to the introduction of the integral free cooling circuit with a self-contained control system.
For example, in a free cooling chiller the ambient air, temperature permitting, is used to cool the chilled water supply, utilising compressors, evaporators, condensers, etc, as in a conventional air cooled chiller, but with the addition of an integral dry cooler circuit, thereby reducing power consumption and DX mechanical cooling.
The dry cooler circuit is built into the same mechanical assembly that supports the condenser coils and fans and, where capacity is approximately 300 kW and above, the coil area is generally maximised by sophisticated W formation coil arrangements.
The condenser fans also serve the dry cooler circuits and, using intelligent control routines, can control the compressor head pressure whilst maximising the free cooling operation.
Digital scroll compressor
The compressor is a key component but major consumer of energy within the air conditioning system, as a conventional compressor will power on and off as the level of the cooling capacity varies. However, a more recent innovation, the digital scroll compressor, provides precise thermal management to ensure that the cooling capacity precisely matches the heat load, thereby reducing energy consumption.
Part of the essential heat transfer process is to compress the gas refrigerant to the desired discharge pressure and this is achieved using scroll compressor technology. This technology is based on two spiral scrolls, the upper scroll being stationary whilst the lower scroll orbits, rather than rotates. This creates a series of gas pockets travelling between the two scrolls and these pockets are continually compressed towards the centre of the scrolls, where they are discharged as high-pressure gas. The innovative design of the digital scroll compressor enables the separation of the scrolls to be controlled, which allows continuous modification of the compression cycle to deliver the specific cooling capacity required as the heat load fluctuates.
Correct air distribution is essential and another relatively recent technological advance has been the introduction of Electronically Commutated (EC) motors. The variable speed control the motor offers, when utilised in an air conditioner fan system, enables capacity and load to be closely matched at all times.
The resulting efficiency of the EC Fan leads to a reduction in energy consumption of some 30%, together with a significant lessening of noise and heat emissions. The infinitely variable speed control of the EC Fan extends the working life of moving parts and reduces maintenance costs, making a significant contribution towards overall savings in lifetime costs.
Over the coming months, the Ecodesign principles applying to the products in the Commission’s Working Plan for 2009-211 will be analysed, discussed and formalised. All interested parties, like Emerson Network Power, will be able to take advantage of opportunities given to make their views known through representative and consultative bodies, continuing their contribution towards the achievement of goals that could not be more significant.