Daikin claims new benchmark with VRV IV+


10 April 2019
Daikin is claiming a new benchmark for seasonal efficiency with the UK launch of its VRV IV+ heat pump, featuring a new compressor said to deliver a 15% increase in efficiency.
Five years ago, Daikin’s VRV IV system reached new levels of seasonal efficiency and comfort, which have since been introduced throughout the VRV IV heat pump, heat recovery, cold climate and water-cooled models. Offering an integrated solution for multiple applications, the company reports that more than 220,000 units have been sold since its launch.
daikin air conditioning VRV heat pump seasonal efficiency
Figure 1
daikin air conditioning VRV heat pump seasonal efficiency
Figure 2
With the launch of the new VRV IV+ heat pump, Daikin says it has has once again raised the bar.  Existing VRV IV features such as Variable Refrigerant Temperature (VRT) and continuous heating during defrost are matched by a redesigned compressor, which is optimised to ensure high performance at part loads - the main operation mode throughout the year.

The new compressor also addresses a key issue that can occur during low load operation, which is that refrigerant leaks can occur from the high-pressure side to the low-pressure side in the compression chamber, resulting in loss of efficiency. (Figure 1). This has been resolved with the inclusion of a back-pressure control port that sends a small amount of high-pressure refrigerant from the compression chamber to the back of the scroll (Figure 2). This optimal separation of lower and higher-pressure sides within the compression chamber boosts seasonal efficiency to a new standard, delivering a 15% increase in efficiency.
Since January 2018, when the Ecodesign Directive on Energy Related Products (ErP) came into force for commercial air heating and cooling products (ENER LOT21), legislation sets minimum efficiency performance targets for cooling and heating products based on their actual year-round performance and not just on a single test result at peak load. The calculation method applied to determine a system’s seasonal efficiency, rather than its nominal efficiency, is set in EN 14825. 
Daikin says the launch of the VRV IV+ series continues to build on its strategy of delivering systems that are efficient in real-life situations. 
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