Enhancing efficiencies

A constant stream of evolving legislation is designed to reduce carbon emissions in commercial buildings. Yet further, pending EU legislation means that air conditioning equipment will have to meet even more stringent standards.

It is quite understandable that consultants and engineers might feel snowed under by what many will view as a constant bombardment of changing carbon reduction legislation. What with EPCs, DECs and Energy Performance in Buildings legislation, as well as the latest changes to Building Regulations Part L and the CRC Energy Efficiency Scheme, there is a continual raft of changing rules and regulations that needs to be understood and addressed in the battle to reduce the energy used in, and the carbon produced by, our buildings.

Now there is yet more legislation afoot – namely a draft Energy using Product (EuP) directive from the European Commission – which means air conditioning equipment will soon need to demonstrate seasonal efficiency on energy labels.

However, rather than viewing this new legislation with a feeling of foreboding, it is possible to turn legislative requirements into a positive opportunity to increase efficiencies and reduce costs. By looking at air conditioning efficiencies from the outset and embracing this new legislation, there is a real opportunity for engineers to add value to a building’s performance.

Real life performance

One such area of improvement is how real life performance of an air conditioning system might vary from its predicted performance. Generally this is expressed in terms of nominal performance, however, this can hide the significant differences that exist between rated and actual performance. By assessing and then improving real life performance, huge increases in efficiency are possible.

With the proposed new EuP legislation, seasonal efficiency ratings will be required for all air conditioning equipment, meaning that performance will be calculated and expressed according to its seasonal efficiency rating over the year. This seasonal efficiency rating will eventually appear on a new energy label, giving users a better idea of anticipated real life performance. Once the new regulations come into force, all new units purchased after that date that are unable to meet EuP requirements, will be banned.

The key with all of this legislation is to stay one step ahead. By planning for the regulation changes early on, it is possible to make savings in running costs now. With this in mind, we have already launched technology to address this legislation. Our new Sky Air Seasonal Inverter, designed using Eco-design principles, has optimised inverter control for improved energy performance all year round – delivering higher annual seasonal efficiencies than the latest super inverters and offering major improvements over contemporary non inverter systems.

This new seasonal inverter energy rating takes into account multiple cooling and heating temperatures, as well as the unit operation at partial load instead of just at full capacity. It will also consider the power consumed by equipment in auxiliary mode when the compressor is off.

As well as improving seasonal efficiencies, there are many other ways in which energy efficiency can be improved, not least of which are monitoring efficiency remotely or by the use of intelligent systems.

Remote monitoring

Let’s look at remote monitoring first. The operating efficiency of an air conditioning system not only has an impact on emissions and energy consumption; it also affects the reliability, cost of maintenance and the life expectancy of the system. If air conditioning systems can be kept running at an optimum level, they are longer lasting and cheaper to run while producing fewer carbon emissions.

Remote monitoring involves gathering and analyzing data from a particular system, usually by the air conditioning provider via specialist equipment using an internet connection. Such a service should provide a malfunction prediction service by constant monitoring and analysis of data from the equipment so that any abnormalities can be picked up at an early stage – before the malfunction occurs. In this way, failures can be prevented and possible down time reduced to an absolute minimum. Ideally this service will also flag up certain operational issues such as blocked or contaminated air filters or heat exchangers so that performance and efficiency can be improved. This optimisation will also result in an increased lifespan of the equipment.

The very best remote monitoring will also offer an energy saving function. For example, the Daikin Network Service System (DNSS EcoSave) is designed to adjust remotely the operating parameters (such as outdoor unit evaporating temperatures) of Daikin air conditioners to ensure optimum energy efficiency. Energy saving is obtained by averaging the data of three local weather stations remotely (local to the specific site). This information is combined with the data that is collected from the air conditioners through the DNSS EcoSave service. Judgements are then made according to this information and, if energy saving measures are possible, they will be made remotely. This system will also account for occupancy levels and variations in installation (piping lengths etc) when calculating energy saving potential.

If a building is looking to achieve really impressive energy efficiencies then the use of heat recovery in balanced mode within a VRV system can also be employed. This intelligent approach to heat recovery can deliver exceptional COPs of up to nine or even ten. Yet while heat recovery is already being embraced in other areas of the world, it is still not widely realised in the UK market that a heat recovery system operating in a balanced mode can increase energy efficiency levels massively.

Make an impact

By looking at energy efficiency from the earliest design stage, heat recovery in balance mode can have a huge impact on levels of efficiency. Achieving balanced mode operation might involve cooling one area of the building, which is experiencing the highest heat gains and transferring that reclaimed heat to other areas of the building that require heating or, indeed, hot water. To do so, the indoor units need to be arranged in order to maximise the occasions when this balanced operation can take place, with the heat recovery system diverting recovered heat to wherever it is needed, thus contributing significantly to the goal of zero heat rejection.

However, to achieve these industry beating COPs, it is vital to analyse right from the start a building’s multiple requirements, usage patterns and varying occupancy levels, in order to design a fully integrated system that optimises energy efficiency and heat recovery. So the role of the consultant engineer or systems designer is pivotal in designing in efficiency savings from the word go. By embracing, rather than dreading, changes in legislation, it is possible to stay one step ahead and make a real difference to the bottom line.

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