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incorporating of water through our hybrid chilled water VRF solution is a great step . We have been able to take all the best elements of chilled water and VRF technology and combine these into one system and we believe this has changed the VRF landscape . While water is known to be an excellent absorber of heat , the further advantage of this technology is that it reduces the amount of copper pipe work by using Pex PVC piping between the BC controller and the indoors , reducing potential copper theft . Leaks are also easy to find and a major benefit is the limiting and elimination of sensors that are now required through the EN 378 standard for occupied spaces ,” adds Ferdinandi .
The EN378 standard : Refrigerating systems and heat pumps : safety and environmental requirements relates to the amount of allowed refrigerant within a confined occupied space . VRF systems , carrying significant amounts of refrigerant , fall within the limit values of the standard .
EN378 further specifies that if the amount of refrigerant exceeds the limit-value , refrigerant sensors must be installed in the space as indicated . These sensors need to be calibrated , tested , and further connected to the building management system ( BMS ) that will then in turn connect to a separate alarm system installed in every room , or facility . This naturally carries a lot more costs , not only in the actual products required , but installation cost too .
“ Something to note , specifically if we take a look at energy efficiencies and new technology , is that we have a lot of solutions in the market , but the problem is everybody is ‘ pushing for maximum energy efficiency . But at the end of the day , there is always the cost factor that clients are not willing to pay for . Yes , energy efficiency will be included in proposals but at the final stages will get dropped due to costs . Energy efficiency is important , but the local market does not seem to have the required appetite , which is actually essential these days ,” says Bester .
Douglas Scott , mechanical engineer at HCM Contractors says , “ The pro points in VRF are definitely that it ’ s great for applications with varying loads , especially systems with full fresh air . Manufacturers , as has already been mentioned , spend a lot of money on R & D and by using their VRF systems , you gain access to this technology .”
According to a statement from Daikin South Africa : “ Daikin follows an application-based strategy and from an environmental point of view we always look mainly towards the Total Equivalent Warming Impact ( TEWI ), which covers both the potential CO₂ emissions in case of leaks and the guaranteed CO₂ emissions from electricity consumption . It is furthermore not just GWP that dictates the impact of a refrigerant on the environment as each refrigerant has different characteristics and charge ( amount of kilograms
© Fourways Airconditioning
VRF systems allow the allocated plant space for buildings to be greatly reduced .
needed to reach a certain capacity ), efficiency , cost of components , technical requirements and complexity of handling can be totally different . Therefore , we have assessed various refrigerants ( R32 , blends , natural refrigerants and HFOs ) based on four criteria ( overall environmental impact , energy efficiency , safety and cost-effectiveness ), and have utilised many of these refrigerants in selected applications . After examining the key properties , Daikin has concluded that R32 is today , for a large part of the direct expansion type cooling and heating equipment – including single package products , the best option .”
INSTALLATION AND MAINTENANCE “ You always have to consider what the cost of maintenance is , and the cheapest solutions are never the right choice and educating the end users in this regard is so important . The consultant and installation team may offer a 12- or 18-month warranty , but after that when maintenance is in the hands of the owner and things go wrong , they need availability of support from suppliers and not to have to replace their entire HVAC system . One thing all suppliers need to consider is that once a warranty period is over , it doesn ’ t matter who was involved in the process – the only thing the end user will see is the name of the brand on the unit in their office not working ,” says Ndelu .
Manufacturers spend a lot of time during development with installation and maintenance in mind . The easier the installation the quicker it is , and the less parts involved in a system means fewer replacement components too . Time means money – and the less time required on site means profitability for the contractor , as well as savings for the client . A simple example is the ability to reduce the amount of electronics that are typically the costly elements . If something does go wrong for the client ,
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