The current refrigerant of choice for both VRF systems and hydronic systems is currently R410A which is being phased out over the next few years in both Europe and North America. Building owners need to be made aware of the potential consequences when looking at systems for new buildings or replacement systems.
With a VRF system in the building, when the day comes that the system needs to be replaced such as refrigerant not being available, may be a major concern. With a VRF system, the entire system including piping, outdoor units, and fan coils will need to be replaced. With a hydronic system, only the outdoor unit will need to be replaced while piping and fan coils stay in place. One can only imagine the cost of replacing the piping system and fan coils with a VRF system as you will need to patch and replace ceilings and walls throughout the building. There are many hydronic systems still operating after more than 50 years and surely a new refrigerant will be used in the upcoming years so building owners need to choose wisely.
VRF typically uses electric duct heaters or a separate heating system for back up heat or domestic hot water. Water systems use the same piping system by simply installing an inexpensive boiler thus a separate heating system is not required. Electric duct heaters are an option when desired and solar is also a great option for hydronic systems.
VRF systems have large amounts of refrigerant circulation inside the building whereas hydronic systems circulate water. Water is natural and harmless if it leaks, refrigerant is very dangerous when it leaks as it can replace the oxygen in a space and the results may be catastrophic.
Hydronic systems allow the possibility of cooling, heating, simultaneous heating and cooling, heat recovery, and domestic hot water from a single unit. VRF systems do not have all these options from a single package. The Aermec NRP provides simultaneous heating and cooling, heating only, cooling only, and domestic hot water as hot as 149°F from one unit that pipes into the existing system. In most cases no other products will be required to provide the building with all its required heating and cooling needs while providing maximum energy efficiency. No boilers for backup heating or domestic hot water required and the heating and domestic hot water are free whenever there is a need for cooling based on heat recovery.
Hydronic systems allow for radiant heating and cooling as well as fan coil heating and cooling. This results in much greater flexibility in building design and much easier tenant changes when required. Swimming pool heating and dehumidification as well as snow melt are also great options that are available with hydronics.
VRF systems tend to have standalone controls that marry up somewhat with building management systems. Hydronic systems tie in directly to BACNET, LONWORKS, MODBUS etc. Parts for Hydronic heat pumps, chillers etc. are available over the counter at most HVAC wholesaler’s parts for VRF systems are available through the manufacturers only.
Cleanliness, while this is not an often-discussed point it is very important. DX (VRF) systems need proper airflow or the coils freeze up like all DX systems. Fan coils or water systems do not freeze up when filters are not properly maintained but do lose efficiency which allows time for maintenance to respond and keep the clients happy. With a DX system, the system stops working and it becomes an emergency which can create higher maintenance costs as well as unhappy clients.
Aermec North America
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