Flexible comfort: how VRF systems are changing the HVAC landscape

By Eamonn Ryan

Known for their energy efficiency and versatility, Variable Refrigerant Flow (VRF) systems have quickly become popular worldwide as a highly effective solution for controlling heating and cooling in large or multi-zone buildings

All Images supplied by Daikin

VRF systems were first developed in Japan in the early 1980s, with the technology making its way to Europe by the late 1980s.

Technology is focused on R32 developments

Daikin is making strides in advancing its Variable Refrigerant Volume (VRV) technology, focusing on the adoption of R32 refrigerant. Developed and introduced by Daikin nine years ago, R32 is rapidly replacing R410a (in South Africa too, though at a slower pace) due to its lower global warming potential (GWP). For decades, VRV systems have utilised the high-GWP refrigerants.

Current ranges in the South African market mostly use R410a.

For Daikin the current R410a VRV systems supplied are imported pre-charged with a mix including reclaimed refrigerant. This means significant saving in virgin gas being produced each year.
This forms part of Daikin’s ‘LOOP’ programme which aims to recover, reclaim and reuse refrigerants. Daikin’s efforts are done in view of the worldwide direction to reduce the consumption and production of hydrofluorocarbons (HFCs) officialised and formalised in the Kigali Amendment of the Montreal Protocol and also ratified by the South African government.

Nico van Heerden, Daikin consulting sales engineer, says that Daikin’s plans include expanding its VRV range to incorporate R32 across various models. While R410a systems are today’s norm and will remain in use in South Africa over the next few years, the global shift toward R32 is undeniable, with the refrigerant already being offered in several projects in South Africa and further afield in the region. Current VRV 5, R32 range covers the heat-pump, heat-recovery + mini VRV S range which is quite compact and perfect for smallest residential and office applications.

The South African HVAC market is experiencing a growing demand for energy-efficient solutions, driven by rising electricity tariffs and persistent power shortages. Furthermore, the ratification of the Kigali Amendment underscores the global shift towards reducing the use of HFCs. In response, Daikin is broadening its VRV offering to include the R32 line-up, providing cutting-edge advancements in energy efficiency and more environmentally friendly refrigerants.

However, the VRV 5 R32 range is not merely a transition for the South African market but an additional tool in Daikin’s portfolio. “It enables us to fulfil our commitment to delivering the highest energy efficiency with the lowest environmental impact. That said, without significant regulatory changes, Daikin does not foresee an immediate market-wide shift to R32. In specific cases, the R410a range remains a highly viable option. For example, the Daikin replacement VRV line-up based on R410a facilitates retrofitting of older R22 systems by reusing existing piping and certain indoor unit models. This approach significantly reduces installation costs and time while supporting sustainability objectives,” says Van Heerden.

He says Daikin offers the full range of R32 products, including heat recovery systems. However, he cites the key challenge facing the transition to green refrigerants within the industry in South Africa as being the shortage of skilled technicians. “Many technicians in the HVAC field are not adequately trained, and some are less invested in the trades, contributing to inconsistent workmanship. Daikin has recognised the importance of addressing this gap and has invested in training programmes to upskill technicians and ensure proper installation and maintenance of its advanced systems,” says Van Heerden. “Despite these hurdles, our innovation in refrigerants like R32, R290, and CO2 reflects our strong forward-thinking strategy towards R&D and innovation.”

With electrical cost increasing between 15% to 20% plus on a yearly basis, Daikin continues to innovate with features like Variable Refrigerant Temperature (VRT) technology, which allows systems to adjust refrigerant temperatures based on ambient conditions, leading to significant energy savings. This technology, combined with Daikin’s proprietary inverters and compressors, helps minimise energy consumption while maintaining performance.

“The residential sector in South Africa, particularly in cities like Cape Town, is seeing growth, especially with the influx of new developments and security estates. While hotel and large commercial developments remain a strong market segment, residential projects are expected to drive substantial growth over the next five to ten years. Daikin’s ability to provide tailored solutions for both large and small-scale installations, as well as our support for green building initiatives, positions us to capitalise on the growing demand for sustainable HVAC solutions.”

Has Daikin solved the CO₂ VRF challenge?

“We indeed a plan to introduce our first step towards a next generation VRV system with CO2 around April 2025, Eurovent certified. This system will support specific customers looking for ultra low GWP solutions. Our VRV 5 R-32 range will cater to the majority of the market as today it still has the best balance between lower GWP refrigerant and high efficiency. This is not the first time the company has explored the idea of CO2-based VRF solutions.”

With the announcement of a CO2 VRF system, this does not mean that the R-32 systems are an intermediate solution. For the foreseeable future R-32 remains the mainstream solution. It has the best balance between lower GWP refrigerant, high efficiency and cost effectiveness and it complies with the new F-gas regulation until at least 2032.Yet on the longer term, Van Heerden says: “We want to be ready with alternatives when the carbon intensity of the electricity grid drops, as then the CO2 units may be the best placed solution. This will still require

considerable time to be developed. So, we are starting now with a limited capacity range and models to gain experience to bring more systems in future.”

At the recent Chillventa exhibition, Daikin Europe acknowledged the impending phase-out and quota restrictions of high-GWP refrigerants, underscoring the need for lower-GWP solutions. The company identified CO2 as “a promising long-term option” for medium- and large-scale commercial systems and described it as “the next logical step” for VRV technology. Daikin emphasised the importance of collaboration with manufacturers, engineers and installers to advance the next generation of direct expansion systems.

Gas engine VRF systems: where to from here?

Patrick Burke (FSAIRAC) of RPM Consulting Engineers, says: “Following the numerous warnings concerning the future longterm supply of Liquid Natural Gas (LNG) in South Africa, the
general interest in this type of potential energy source had grown considerably with articles now appearing regularly in several leading business news publications.

“While it is difficult at this stage to see the wheat from the chaff, it would seem that the main factor governing the current negative sentiment is the recent decision by Sasol to retain its LNG production for its own consumption, thus preventing local users and suppliers from procuring previously freely available stocks.

“Given the legitimate concerns for future local LNG supplies, one can fully understand their decision to conserve production for their own use (due to their plans to displace coal to support its decarbonisation). However, relying on imported stock will no doubt result in higher costs and as such, could well prove uneconomical for current local suppliers and users of LNG to operate going forward. It would seem that the local liquid natural gas supply industry is indeed under severe threat, with the Industrial Gas Users Association of South Africa warning of a gas supply ‘day zero’,” says Burke.

However, he notes that in the longer term the future of LNG appears a little more encouraging. The exploration of future gas and oil fields in our southern African region continues unabated, with the general consensus that new untapped fields exist off both the east and west coasts. “The big question is: How economical will it prove to produce? Only time will tell, I suppose.”

He says that at the HVAC&R Japan exhibition in 2016, it is reported that one leading manufacturer unveiled a so called ‘hybrid’ VRF system, that connected to a gas-engine VRF system and an electric VRF system to the same refrigerant circuit, thus allowing one product to operate on two energy sources. “The hybrid can switch its energy source to take advantage of the available unit costs of both electricity and natural gas, as applicable. In my opinion, this could well be a possible answer to South Africa’s unique energy supply situation (in the event of both potential energy solutions becoming more difficult to source) thereby providing a semblance of choice for the end-user.

“In any event, as previously stated, only time will prove this to be possible, as all indications are that new local gas fields will only be operational from 2030,” says Burke.

Project Two: Plot C396, Abu Dhabi, UAE.© RACA Journal

AHI Carriers’ innovations lead the way towards sustainable HVAC solutions

In a presentation last year by AHI Carriers at a supplier event titled ‘Feel the Change’, a bold vision for the future of HVAC technology was unveiled, emphasising a shift towards more environmentally friendly products and solutions. Harris Prousalogou, product and solutions development manager at AHI Carrier Fzs, presented a number of project case studies whereby Toshiba products and methodologies had resulted in radically enhanced energy efficiency and reduced environmental impact within the built environment. The following relates to a VRF installation.

Project two: Plot C396, Abu Dhabi, UAE

Following the success of their first project in Abu Dhabi, AHI Carrier embarked on another project, this time optimising HVAC solutions for a multi-floor residential building comprising 131 apartments. This project, also located in the UAE, showcases a different design approach aimed at maximising energy efficiency and sustainability though the requirements were the same: heating, cooling and water reduction.

Patrick Burke (FSAIRAC) of RPM Consulting Engineers. © RACA Journal

The initial design for the building utilised Toshiba’s VRF heat pump systems for space conditioning of the apartments and the common grounds; FAHUs with DX coils and VRF CDUs for the air treatment of the apartments and the common grounds; along with conventional electric water heaters for domestic hot water in the apartments.

AHI Carrier was called in to enhance the system’s efficiency by integrating advanced technologies and sustainable practices.

AHI Carrier proposed a comprehensive solution that included Toshiba VRF systems for space conditioning of the apartments and the common grounds; air to water heat pumps and FAHUs for air treatment; heating unit interfaces utilising heat captured by solar panels and the air-to-water heat pump for sanitary hot water during cooling cycles to supplement hot water requirements, ensuring efficient energy use throughout the year.

This resulted in annual power savings of 73.7% compared to the standard solution in SHW on energy consumption and GHG emissions, for a return on investment of 6.7 years.

Harris Prousalogou, product and solutions development manager at AHI Carrier Fzs. © RACA Journal

To further enhance sustainability, AHI Carriers incorporated passive solar systems atop the building’s water storage tanks. Space limitations meant only 150m2 was available for solar panels, and simulations showed it would deliver only 20-23% towards the building’s hot water needs through solar energy, which was insufficient, which is why it went for the water reclamation heat pumps.

The system design includes intricate piping systems that facilitate heat reclamation from the heat pumps and solar panels into the storage tanks. This stored energy is then distributed via manifolds to the heating liquid phases throughout the building. This holistic approach not only maximises energy efficiency but also minimises operational costs and environmental impact.

Toshiba’s standalone VRF system. © RACA Journal

AHI Carrier navigated local regulatory challenges by utilising available technologies from Cairo and Riyadh, as specific products like the SHRM were not yet certified for use in the UAE. This adaptive approach underscores their flexibility and expertise in tailoring solutions to meet regional regulatory requirements while maintaining high standards of performance and efficiency.

Central to the project’s success is the implementation of a Building Management System (BMS) that monitors and controls all HVAC components, including chillers, heat pumps, VRF systems and hot water production units. This centralised oversight ensures optimal system performance and responsiveness to varying environmental conditions.

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