Energy efficiencies fit for the future

Published:  08 March, 2013

Daikin, VRV, VRF, air conditioning, heat recovery
Heat-recovery VRV — at the heart of an energy-efficient services strategy.

Balancing the requirements for cooling, heating and hot water in a building has never been easier. And simulation software makes it easy to evaluate the best option. Michael Passingham of Daikin UK takes up the story.

Separate systems for heating, cooling, refrigeration and hot water have now been superseded by the latest VRF/VRV systems, which bring these services together into one complete solution. Integration ensures a much more effective result, simplifying operation and maintenance, while reducing energy consumption and carbon emissions. Achieving all these goals delivers climate control fit for a future in which efficiency is paramount.

Upgrading to an integrated solution needn’t be difficult to achieve when refurbishing existing building stock. The latest generation of VRV systems from Daikin UK, for example, offers an easy-to-install solution that is infinitely scalable. Modular in design, VRV IV heat pump and VRV III heat-recovery systems can be added floor by floor as part of a phased refurbishment programme, thus spreading the cost of updates and minimising disruption to occupants.

System operation can also be customised to control differing heating and cooling requirements within different rooms or zones to prevent energy waste. VRV is therefore ideal for buildings with multiple tenants, which may have vacant areas and variable periods of high and low usage.

However, to deliver a versatile system that also optimises energy efficiency, it is vital to analyse right from the start a building’s multiple requirements, usage patterns and varying occupancy levels. This enables engineers to specify a system capable of cooling one area of the building experiencing the highest heat gains and transferring that reclaimed heat to other areas of the building requiring heating or hot water.

For example, a typical office building may require cooling down to 16ºC and heating up to 21ºC, with 200 litres of water storage being required for washrooms and 150 litres of water storage for kitchens. By recovering the heat when all indoor units are in cooling mode, a co-efficient of performance (COP) of 3.97 can be achieved. In milder conditions, when 75% of the indoor units are in cooling mode with 25% in heating mode, the efficiencies rise to COPs of 5.57. But when the system is fully balanced between heating and cooling, efficiencies can increase to as much as 10.07.

Integration of a VRV system with the latest intelligent control systems can increase energy efficiency even further. Smart controls can also monitor energy consumption across a range of equipment, including air conditioning, to pinpoint areas of a building where the most energy savings can be made.

According to Franklin + Andrews, one of the world’s leading construction economists, running costs for VRV heat-recovery systems are up to £6.25/m2 of gross floor area. This compares highly favourably with a 2- or 4-pipe fan coil system, which can cost as much as £8.75/m2 and £10.75/m2 of gross floor area, respectively — a 40 and 72% increase on running costs compared with a VRV heat recovery system.

Of course, cost savings must be matched by savings in CO2 emissions too, as designers strive to meet ever-tougher targets for emissions reductions in the years ahead. Tightening up of Building Regulations means that by 2019, all new buildings must deliver zero carbon emissions from the energy required for heating, cooling, hot water and lighting. These challenging targets will require considerable innovations to improve on current practices.

Many organisations and local authorities use BREEAM as a mandatory design standard to ensure that both new build and existing premises meet the exacting requirements for reducing CO2 emissions. Heat-pump technology can assist specifiers to meet BREEAM requirements by delivering heat into a building in an energy-efficient, controlled way. According to the criteria specified within BREEAM documentation, specific credits can be given for integrated services and building management systems.

To achieve the highest level of credits for integrated system design, Integrated Environmental Solutions (IES) offers a new Daikin Dynamic VRV Systems Sizing Tool within the IES Virtual Environment (IESVE). This new software enables architects and engineers to evaluate easily the best option to lower building energy use, by simulating accurately annual loads, power input and efficiencies delivered by such systems.

All these advances mean that VRV solutions are a wise choice for all those designing and installing heating, air-conditioning and hot-water systems to meet current and future legislation.

HVAC systems account for over 40% of building energy usage, so choosing the latest technologies has never been more important, as bottom-line cost savings help to offset the impact of rising energy costs.

Martin Passingham is product manager.

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