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Daikin VRVIII air conditioning / heat recovery improvements




Daikin Europe’s new VRVIII heat recovery system complements the VRVIII heat pump/cooling only models introduced in 2006 plus the more recent mini VRVIII-S and replaces the earlier VRVII heat recovery system.

New features

Among its most important design features is the ability to connect up to 64 indoor units (40 for VRVII) to a single outdoor unit in increments of 2HP up to 48HP. Outdoor unit modules can be configured on a combined ‘multi’ basis between 18 and 48HP with a single heat exchanger as well as in a ‘stand alone’ format from 8 to 16HP with two heat exchangers that is currently the largest single unit on the market. VRVIII HR also offers up to 200% overall increase in unit diversity ratio for a single outdoor module system and 160 to 130% on double or triple multi modules. Operating range is wide at -50C to 430C in cooling and -200C to 15.50C in heating and the system supports no less than 14 different format indoor fan coil units.  

Unlike contemporary VRF systems, which cease operating during defrost and oil return, alternate defrosting of the heat exchangers on VRVIII HR multi module outdoor units or the dual outdoor coil of single modules allows continuous heating to be supplied from the indoor units throughout these cycles thereby avoiding the transmission of cold draughts of air into the room area.  

Leakage prevention is ensured by the use of brazed joints in place of flanged and flared connections before the shut off valves as well as by brazed pressure sensors and electronic gauges instead of sensors and gauge ports. There is also on average, 10% less refrigerant charge compared to a similar VRVII system.

The new VRVIII heat recovery system complements the VRVIII heat pump and cooling only models introduced in 2006. This new system represents a significant step forward in addressing both existing and forthcoming environmental regulations. In addition to its heat recovery facility, it also offers many design, installation and maintenance friendly refinements.

Energy efficiency

VRVIII Heat Recovery takes full account of Building Regulations Part ‘L’ energy efficiency requirements. It returns significantly higher efficiencies than VRVII with an enviable 14% average increase in efficiency across the range, with the most efficient units reaching a 20% increase in efficiency. COPs and EERs of up to 4.3 and 4.1 respectively are obtained at 100% connection. This exceeds the criteria set for ECA qualification.

Increased comfort.....through continuous heating

The new VRVIII Heat Recovery system improves on delivered heating capacity compared to other systems on the market, through changes in operation during defrost. As each system comprises at least 2 heat exchangers in the outdoor unit, the system will defrost these alternatively. This results in continuous heating at the indoor unit even during the defrost cycle. Where other VRF systems stop operating, VRVIII continues in heating to maintain comfort.

Wide range of indoor units

VRV air conditioning brings summer freshness and winter warmth to offices, hotels, department stores and many other commercial premises. It enhances the indoor environment and creates a basis for increased business prosperity and whatever the air conditioning requirement, a Daikin indoor unit will provide the answer. VRV air conditioning can be supplied via 13 different indoor unit models in a total of 75 variations, including the new low-height round flow cassette. The maximum number of indoor units connectable to one system has increased across the range with up to 64 being connectable to the largest outdoor unit.

Extended piping length

VRVIII offers an extended piping length of 165m (190m equivalent piping length) with a total system piping length of 1,000m. When the outdoor unit is located above the indoor unit, the standard height difference is 50m. This can be extended to 90m as an option. In case the outdoor unit is located below the indoor unit, the height difference is 90m as standard. After the first branch the longest piping length is now a maximum of 90m.

Higher External Static Pressure

Due to the increased External Static Pressure in VRVIII Heat Recovery to 78.4 Pa, it is now possible to install condensing units within the building when external space is restricted.

Installer benefit "Automatic charge function"


With VRVIII however, these 2 steps are omitted since VRVIII unit can be charged with the necessary amount of refrigerant automatically via a push button on the PCB. Automatic charging will cease once the appropriate amount of refrigerant has been transferred.

Conventional way:

1. manual calculation of additional refrigerant charging volume

2. manual charging the unit with additional refrigerant

Automatic test

When refrigerant charging has ceased, pushing the test operation button on the PCB will initiate a check on the wiring, shut off valves, sensors and refrigerant volume. This test ceases automatically when completed.

Self diagnostic function

This function operated via push button on the PCB, speeds up troubleshooting and is used for start-up and maintenance.


Tel: +44(0)1234 764128

E-mail: [email protected]




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