Keeping up with developments in VRF
David Dunn highlights trends in VRF air conditioning that you need to be keeping up with.
There are sometimes only small but sometimes significant differences in the technological solutions used by the different leading manufacturers to satisfy today’s shared market requirements. This year’s RAC Show should provide a great opportunity to examine them, ask technical questions and make your own judgments. After all, it is normally the case that technology for technology’s sake is of no benefit to anyone, so new products always deserve healthy scepticism. Some market drivers can become so powerful that they squeeze technological responses out of the marketplace before their real commercial significance is understood. Ground source water based technology may yet prove to be one such example — ultimately useful in only a few specialised cases. New technology should be examined in the light of the sorts of project that it is expected to suit, and even then there are often several alternative ways of providing the right solution. Last year’s BSRIA figures show that mainstream VRF technology is still increasing in demand. There have been new developments since the last RAC Show and there are still developments to come. Satisfying increasing customer demand
Some general trends can be identified in the new ranges of most major manufacturers, but there are also differences in the detail of how they approach the same topics. Two of the main trends are the development of equipment for bigger buildings, both taller and more extensive and also to meet the needs of smaller buildings. There is little doubt that VRF is eating into the traditional chiller market at the larger end. At the smaller end, VRF may also be starting to cannibalise the market for larger split systems. A 5-port multi-split has been developed by one manufacturer, but it is hard to see what advantage that brings over the new mini VRF systems. When VRF began, it was seen as being restricted to 25 to 45 kW. Now it has no trouble dealing with 12 kW at one end and 350 kW at the other — and growing. Toshiba’s Mini-SMMS, for example, is one of the three or four small-scale VRF systems on the market offering all the flexibility of larger-scale VRF for homes and small office buildings, which might previously have made do with a couple of multi-split systems. Different manufacturers use different compressor technology. For example, a twin rotary compressor reduces noise and vibration as well as having 97.5% less oil migration compared to a scroll compressor. With the right type of inverter drive, such a compressor will operate at very low speed to produce exceptional efficiencies at very low load conditions typical of the UK. Increases in piping length and increases in vertical separation are just two benefits mini VRF has over multi-splits. This is technological development not for its own sake but to do the job that needs doing. Such piping improvements are being made across the board and make possible larger and larger installations. Other market influences
The latest three key product-selection drivers for designers, owners, and users are changes in the Building Regulations referring to energy performance (Part L), the requirement for energy certification for buildings and regular inspection of air conditioning systems for leaks. Gas leak-detection regimes will soon become a hot topic, and different manufacturers are evolving different approaches. All is unclear until July. when the EC rules on its expectations, but what is certain is that more complex control systems will come increasingly to the fore. Energy certification of smaller air-conditioning products has been with us a while now, and all the premium brands offering Japanese or equipment made in the Far East have ranges dominated by A or AA rated products. Cutting carbon emissions is the coming trend. All of the equipment at the show is worth examining for the contribution it can make. Ask for a comparison with boiler-based HVAC systems. High COPs
Such is the level of the co-efficient of performance (COP) now being achieved on the heating side that heat-pump VRF and split systems are being specified in some installations purely on the strength of their heating efficiency. The ability to cool efficiently too is considered an added bonus. Many air conditioning systems today have a COP of well over three and some products achieve over five, so it is easy to see why this is happening when even the most efficient boilers struggle to achieve 95%. Air-conditioning technology is better seen as part of the solution rather than part of the problem. Better air
Another set of technological developments to look out for relates to the indoor end of VRF systems. Manufacturers are expanding their ranges by increasing the number of indoor units that outdoor units can control and also by extending the types and sizes of indoor unit. Within indoor units, air filtration technology is increasingly becoming a differentiator. The new technologies include the use of nano-particles of different compounds such as ginseng for its energising and deodorising capabilities and silver for its ability to sterilise other particles. More control
The variation in types of indoor unit is part of what is prompting an increase in control options. Complex control arrangements that once needed expensive programming solutions are now easily achieved using BACnet or LonWorks Internet interfaces, but many customers still fail to ask for them. Touch screens are all the rage, but arguably much more useful are Windows-based systems which allow you to easily input building schematics and other graphics to make the operation of the system more user friendly and remote access to allow control of installations from offices at company headquarters so that energy-saving regimes can be implemented and controlled as well as allowing interrogation of the system by the service provider. Full-year programming, building schematics and detailed graphics can be available at a facilities manager’s desk, and VRF equipment can itself send alerts via e-mail, fax, text or pager. Energy monitoring and energy data provision are available from several manufacturers. Added value
Where once products were either indigenous or came from the dominant US factories, the market is now truly global with manufacturing almost everywhere. Competition is therefore enormous and can only be expected to increase. However, the tight European regulatory environment means that the UK marketplace, at least, will require a high proportion of the best-quality equipment. Product differentiation is achieved by the premium brands through quality of product, quality of service, support and training. It will be possible to see the commitment of companies to training via the stands at this show. CPD courses and literature should be available to support engineers in their service to the customer. Concern for quality is also visible via the evidence for training; the best companies will be involved in training today’s engineers in the industry and tomorrow’s as they join it. There are also further positive points to be taken from the increase in regulation. For example, the Carbon Trust’s Enhanced Capital Allowance scheme on behalf of the Government enables equipment owners to claim a valuable tax benefit that helps cash flow as well as the potential to obtain, in effect, an interest-free loan up to £100 000 for four years. Compliance with the RoHS directive by most manufacturers gives a greater degree of safety and security to those working with the equipment. The move to R410A, that is now almost tota,. has increased equipment efficiency significantly. The overall development of a regulated environment is causing more manufacturers to sign up to the reassurance of the Eurovent independent testing and verification scheme. This is something that the best manufacturers have always subscribed to, sometimes to their cost in a cut-throat market. Look out for the labels — they are beginning to mean something. David Dunn is with Toshiba Air Conditioning UK.