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Jobin Varghese explains how a Hybrid approach offers adaptable air conditioning that will stand the test of time.

Flexibility is increasingly essential for today’s buildings. Take offices, for example. Over the past two years, businesses have been looking for locations that can accommodate a hybrid approach to work – open plan meeting spaces with smaller offices for focused work as well as high-tech video conferencing facilities.

Other sectors such as hotels and educational facilities have also faced significant changes in occupancy patterns and use.

And building occupants are looking for higher levels of comfort and wellbeing than ever before. All in all, it puts pressure on building services design to be adaptable, robust and energy-efficient.

It’s simple to isolate and decommission, providing quick installation to meet changing demands

Jobin Varghese Jobin Varghese Product Manager for VRF and HVRF

Saving time and money

Flexibility is vital even in the early stages of a building’s life cycle, such as a change from Cat-A to Cat-B fit-out in offices. For instance, when leasing a new office, a tenant will add partitions for meeting rooms, break-out areas, and other spaces.

Using a traditional 4-pipe air conditioning system can create significant costs in terms of time and money: The system has to be de-gassed (refrigerant removed) and pipework modified for the new layout.

This process may involve brazing with related hot works permits required. It can mean high costs and delays for the landlord and tenant alike.

Mitsubishi Electric developed its Hybrid VRF (HVRF) system with this challenge in mind.

In the HVRF system, all of the R32 refrigerant is contained in a central Hybrid Branch Controller (HBC). From there, water pipes connect to the indoor units.

The first benefit of this approach is that there is no refrigerant in the occupied spaces, so there is no requirement for leak detection under BS EN378.

Highly flexible

More importantly, the HVRF approach is highly flexible. So, when changing a fit-out from Cat-A to Cat-B, there is no need to de-gas the refrigerant as this is only present in the Hybrid Branch Controller.

The pipework to the indoor units is plastic, as it carries water rather than refrigerant.

There is no need for an F-Gas accredited installer to carry out the work; no hot works are required, and the process is cost-effective and time-efficient to complete.

And later in the building’s life, a Hybrid VRF system makes alterations and updates easier. For example, because of HVRF’s decentralised set-up, it is straightforward to add to a building’s air conditioning requirements in a phased approach.

It’s also simple to isolate and decommission, providing quick and smooth installation to meet changing demands.

Sustainable refrigerants

Sustainability is another critical issue for today’s building services specifiers, so finding energy-efficient solutions is integral to the decision process. It’s also crucial to bear in mind the F Gas requirements for the use of low GWP refrigerants.

Mitsubishi Electric has already adopted R32 refrigerant for its HVRF system, so it meets these requirements ahead of time.

What’s more, because only the HBC contains refrigerant, the amount of R32 is around 30% to 40% less than in a traditional VRF system.

It is not easy to make building services flexible as there are time and cost implications in making changes after initial installation.

However, the Hybrid VRF approach gives designers, installers and clients a more versatile system that will stand the test of time and ensure that the building retains its value as an asset for many years.

Easier application

We have also recently added another element to the HVRF range – a vertical hybrid branch controller.

This development adds to the system's flexibility by allowing the HBC to be installed as a floor-standing unit in a small maintenance cupboard or linen closet in a hotel.

The system is easier to apply in refurbishment projects where a ceiling-mounted HBC might not be suitable.

The CAT-A to CAT-B conversion with a Vertical Hybrid Branch layout will be more straightforward as the recommissioning parts are all easily accessible. This saves time and gives a much more comfortable approach on re-commissioning a hybrid layout during this transition.

Jobin Varghese Product Manager for VRF and HVRF