Climate control

It is difficult to open the page of a newspaper or magazine without being confronted with information on the importance of addressing climate change, and not without good reason. Positioning the UK at the forefront of the fight against rising temperatures the Government has put in place challenging targets to reduce CO2 emissions.
The Climate Change Bill sets a target of reducing emissions 60% below 1990 levels by 2050 with a more pressing target of a 20% reduction by 2010. If further evidence were needed of the Government’s commitment to reduce emissions, one need look no further than Alistair Darling’s first budget in March when he announced a review of the 60% emission target to see if 80% could be achievable.
As many will know, these targets have been handed down to the management and construction of the built environment through the Energy Performance of Buildings Directive (EPBD), which details obligations that must be met to increase the investment in, and adoption of, energy efficient technology.
This combination of targets and regulations, together with increasing volatility in energy prices is serving to focus attention on achieving energy efficiencies more than ever before.
As the EPBD explains, air conditioning typically makes a significant contribution to a building’s total energy consumption and, in line with the guidelines its sets out, is one area that has come under focus in achieving energy efficiencies.
Air conditioning also faces a unique challenge in achieving efficiencies from the fact that not only will existing systems need modifying and upgrading, but also because the demand for air conditioning is increasing at the same time. Use of air conditioning is increasing due to a number of factors, not least in a change of seasonal conditions which has seen the UK experience record temperatures in recent years. Added to this are the comfort levels demanded by building users which include intensive building use and higher heat gains from more equipment and occupants, and market pressures because the sale or lease of an air conditioned property yields greater profits than a naturally ventilated building.
So if the demand for air conditioning is increasing and the energy consumption cannot be reduced by reducing the demand on the equipment, it is clear that it is the technology itself that will have to deliver energy savings.
Responding to these needs, Daikin has introduced an updated range to its portfolio, the VRVIII (Variable Refrigerant Volume) system. This latest innovation is based on heat pump technology and a three pipe system that enables all indoor units to be operational in either heating or cooling mode at the same time.
Heat pumps are an integral part of air conditioning technology by transferring heat from one environment to another via refrigerant. In cooling mode, heat pumps transfer the heat in an enclosed area (room, industrial process) to the outside air, resulting in a cooling of the area in question. This makes them ideal for the removal of excess heat from critical building areas such as server rooms, where the need for cooling sensitive IT equipment is essential.
Importantly, heat pumps, also allow this process to be reversed. They can pump heat extracted from the outside air indoors, allowing indoor environments to be heated as well as cooled using the same technology.
The heat recovery system provides even greater savings in energy by allowing heat energy recovered from areas requiring cooling, to be transferred to those areas with a heating demand.
Using the same systems to cool and heat results in lower initial investment and leads to more straightforward operation and maintenance.
It is the efficiency performance of such technology, however, that makes it stand out when looking to reduce energy consumption and CO2 emissions. Heat pumps offer efficiency gains in the order of 3:1 and higher, compared to fossil-fuel based heating systems. Thus for every unit of energy consumed by the heat pump, three or more units of heat are gained.
The efficiency levels of heat pumps also make them significantly more cost effective to operate. Using a heat pump for heating could consume less than a third of the energy of a radiator system, along with giving a more even and controllable temperature.
VRVIII Heat Recovery achieves COPs and EERs of up to 4.3 and 4.1 respectively. Not only does this meet and exceed energy efficiency targets set out by the Government in Part L of the Building Regulations, but it also goes beyond the current criteria set for ECA qualification.
And if the heat recovery feature of the system is utilised during the design stage, even greater efficiencies will be achieved in the annual operation.
The technology of course is one part of the solution. Despite achieving high levels of energy efficiency, the performance of any HVAC system can be compromised if the demands of the end user result in high energy use.
Many building engineers and managers will be all too familiar with optimising the HVAC system to provide energy savings as well as internal comfort only to have this changed by an employee who alters the temperature range because he or she is either too hot or cold. Whilst this person is then comfortable, the problem is that their neighbour just a few desks away complains of being uncomfortable and, in turn, changes the temperature again for their own needs.
This cranking up and down of the thermostat is neither cost effective nor environmentally friendly and in the drive towards energy efficiency needs to be addressed. To combat this problem, the way an air conditioning system operates must also be considered alongside its efficiency ratings.
Daikin’s VRVIII, for example, has two heat exchangers in the outdoor unit which means it continues to operate in defrost mode. Whilst other VRF systems stop operating at this time, VRVIII enables the system to defrost each heat exchanger separately, resulting in continuous heating at the indoor unit, maximising comfort for the end-user.
Moreover, unlike many conventional systems, which operate at the same cooling/heating mode regardless of the varying requirements within the same building, VRVIII provides simultaneous heating and cooling. So, for example, if one zone of a building heats up as a result of solar gain, meaning those occupying the space are too hot, the system will respond by changing the operation mode of the fan coils without affecting other zones of the building
These features reduce the likelihood of occupiers changing the thermostat controls themselves which can compromise the functionality of the air conditioning.
A further important factor in this area is one of air flow. While this might seem like a specific point, the direction of air flow from standard units (typically flowing from four points of a ceiling unit in a north, south, east, west direction) can lead to temperature blind spots in which certain building users do not feel the full benefit of the air conditioning.
To address this, Daikin has developed an industry first, the Roundflow cassette, which features a 360 degree radial air flow pattern, designed to improve comfort levels. By ensuring an even air flow pattern, this further improves internal conditions and reduces the likelihood of building occupiers wanting to make localised temperature alterations.
It is addressing specific requirements such as air flow and reducing the occurrence of temperature fluctuation that will become increasingly important aspects of achieving high levels of comfort and energy efficiency in air conditioning systems.
As the issue of energy efficiency continues to drive both the news and corporate agenda it is imperative that businesses embrace the very real benefits of energy efficient equipment and the potential savings that can be made. As we move into an era where energy monitoring and the issue of energy efficiency are of the utmost importance, the role and benefit of systems such as the Daikin VRV system may finally be realised.

0