What is GWP?
Global Warming Potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (CO2). GWP is 1 for CO2.
Residential and small commercial heat pump systems in New Zealand have generally moved to R32 refrigerant (GWP 677). Larger commercial VRV/VRF type systems are generally R410A refrigerant (GWP of 2088); R32 is not appropriate at larger refrigerant volumes due to its inclusion of hydrocarbons and flamibility restrictions. Domestic and cabinet refrigerators are moving toward hydrocarbons such as R600A (GWP of 4)
Globally governments are phasing down by both banning and increasing tax on synthetic refrigerants. The tax of refrigerants in NZ is tied to the NZ Emissions Trading Scheme, costs of refrigerants are proportional to their GWP. With the tax rate increasing year on year.
In November 2021 the Ministry for the Environment released a consultation document on emissions reductions. The link to this is below, with relevant sections from about page 110 onwards. Following the consultation period late 2021 and presumed strong opposition from industry groups, the ministry is yet to in-act the document at the time of writing.
The table below shows the Ministry proposed phase out dates. By 2023 the R410A used in VRF systems will be unable to be serviced and by 2024, new equipment will be restricted. By 2029 and 2032 further restrictions are proposed, where a working solution doesnt yet exist.
Transitioning to a low-emissions and climate-resilient future: emissions reduction plan discussion document Table 8 page 113.
A 'drop in' refrigerant is one which can be placed in the same system without modifying that system. There is alot of speculation and development on a 'drop-in' for R410A with a lower GWP to maintain existing VRV/VRF systems and to maintain a new equipment option to market for VRF. R470A with a GWP of 909 has been recently suggested, however this still falls short of the Ministries proposed GWP maximum limit of 750. Other hydrocarbon type options are promoted but these will generally require system modification and or condenser replacement.
If the Ministries proposed plan passes through legislation and a suitable 'drop in' refrigerant doesnt come to market, it has major implications. It will make all current VRF/VRV unable to be installed from 2024, but more importantly no one will be able to import R410a refrigerant to be able to service / repair it from 2023 either. So a system that develops a leak after this time will be at risk of requiring complete replacement.
Mitsubishi Electric have a hybrid VRF system that they introduced in 2014 which replaces refrigerant with water between the system branch box (located at each level) and the indoor air conditioning units. They have updated their hybrid system to utilise R32 refrigerant (GWP 677) which works due to the lower refrigerant volumes.
Mitsubishi Hybrid system indicative schematic from BDT website.
There does not appear to be much in the market in the way of further viable systems with low GWP, but with a climate change emergency happening in New Zealand, expect to see more Ministry pressure and corresponding market responses.