There are many reasons why increases in air conditioning efficiencies are absolutely vital to today’s buildings. Legislation and regulations to reduce carbon emissions are the stick to the carrot of reduced running costs and lower fuel bills.
So for building managers, trying to reduce costs and cope with tightening budgets, while complying with the ever increasing raft of legislation coming their way, any technology that can deliver these is to be welcomed.
For the past two decades, variable refrigerant volume technology has produced market-beating efficiencies. Its great advantage is that it varies the refrigerant volume in the air conditioning system to match precisely the building’s requirements.
This allows each area to continually maintain its set temperature while saving money and carbon emissions because it only uses the minimum energy required.
As a result, the efficiencies it delivers - typically of three to five - remain among the highest in the industry.
However, these are by no means the maximum efficiency that can be gained from the very latest VRV systems now available for modern commercial environments such as offices, hospitals, hotels and shops.
In fact, these previously impressive COPs of three to five pale next to the exceptionally high results achievable when employing heat recovery in balanced mode within a VRV system. This intelligent approach to heat recovery can deliver efficiencies of up to nine or even 10. In fact using this system a COP of 10.07 (based on an REYQ10P in mixed mode at nominal conditions) has been proven.
So how does it work? Like conventional heat recovery, balanced mode operation involves cooling an area of the building that is experiencing the highest heat gains and transferring that recovered heat to areas of the building that require heating (or hot water).
It is important that the design process ensures the indoor units are arranged 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 double-digit COPs, it’s 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.
It is key for consultants and engineers to be involved at the earliest possible stages of the design process to help architects and systems designers make the right decisions and incorporate the latest thinking on heat recovery within the building modelling process.
By doing so, project teams and their clients will discover the significant impact that integrated heat recovery solutions can have on cutting energy use.
So for those looking for outstanding energy efficiencies, the use of innovative design from the outset means that it is now a realistic proposition to use VRV technology to achieve dramatically enhanced energy efficiency levels, while helping to reduce carbon emissions at the same time.
John Durbin is engineering department manager at Daikin UK