R-32 (Difluoromethane HFC32), as used in the new Adveco FPi32 range of Air Source Heat Pumps (ASHP), is an HFC refrigerant used as the preferred replacement for R410A refrigerant. Not only is the new refrigerant environmentally friendly, it also enables high performance to save energy, as well as making the heat pumps easy to install, control and maintain.
Safer for the Environment
A hydrofluorocarbon (HFC) refrigerant, R-32 belongs to the family of fluorinated gases, controlled by the F-gas regulation, and developed to replace refrigerant which can deplete and damage the ozone layer. Whilst all HFCs remain greenhouse gasses, R-32 which offers zero potential for ozone depletion and is non-toxic, has a much lower Global Warming Potential (GWP) than R-410A which has been typically used as the refrigerant of choice in ASHPs. GWP is a means for measuring the impact on the atmosphere of one kilo of released HFC compared to a single kilo of carbon. A kilo of released R410A would do 2,090 times the damage of a kilo of carbon. With a GWP of 675, R-32 is considerably more environmentally friendly. R-32 reduces Adveco FPi ASHP’s GWP by 80%.
Offering a similar boiling temperature to R410A but with better energy efficiency, R-32 based systems have smaller charge requirements, typically requiring far less refrigerant – in the case of the FPi, refrigerant required is reduced by almost a kilo compared to R410A models – which means smaller exchangers and components so units can be more compact. For the Adveco R32 range, the 12kW variant now takes up no more space than the 6 or 9kW models, replacing the dual fan for a single fan and substantially reducing the size from the previous FPi-13 model that it replaces. This also helps reduce the noise generated by a unit, with FPi32s operating at 52-53 dB(A) compared to prior models that would have operated at 56-59 dB(A). With improved efficiency also comes lower operational cost.
Safe for Installers
One other environmental gain comes from the relative ease of recycling compared to R410A, as R32 is a single component refrigerant it is easier to handle and recover. All fluorinated refrigerants, including R32, will decompose, creating toxic by-products (hydrogen fluoride and carbon dioxide) when burnt. Classified in international standard ISO 817:2014, R-32 is classified as A2L, where class A signifies that the toxicity of a refrigerant has not been identified at concentrations less than or equal to 400 ppm. Class 2L indicates the refrigerant is lower or mildly flammable. This lower flammability for R32 means that should an accidental release of R32 refrigerant occur, ignition is difficult, even if attempts are intentional. The velocity of released gas is deemed too high at the point of release to allow for ignition, and when velocity is low enough concentration will be too low to ignite. All F-Gas qualified engineers should have few issues handling R-32, but the safe management of any installation should always be a must. It is mandatory to comply with safety requirements from local building safety codes with regard to the installation and operation of heat pump equipment containing A2L mildly flammable refrigerants. As a monobloc unit, the Adveco FPi32 comes pre-charged with R32 refrigerant from the factory making it safe and easy to install and Adveco’s trained engineers are on hand for all warranty-based servicing.
Thermal decomposition of R-32 would require a leak into an enclosed space, with a close to floor level open flame. The production of hydrogen fluoride under test conditions that replicate such an unlikely scenario is no more than seen with non-flammable refrigerants such R410A. Hydrogen fluoride has an extremely pungent odour which is easily detected by smell at concentrations lower than levels expected to cause irritation or be harmful. This gives an occupant in the room plenty of time to make a safe exit. If the concentration is high enough, any refrigerant gas classified in ISO 817, including R32 could initiate some form of adverse health effect. R-32 would require the highest concentration level to cause any adverse health effect. When compared to other Class A Lower Chronic Toxicity refrigerants R-32 has the highest (therefore the safest) Acute Toxicity Exposure Limit (ATEL) of 220,000 ppm.
Retrofitting R410A units with R-32?
The one advantage for heat pumps using R410A was its’ non-flammable nature. This means that R-32 cannot be used to retrofit pre-existing heat pumps, such as the Adveco FPi-9 & 13. As older units are not designated for use with A2L class mildly flammable refrigerant, there is a potential for damage to the Air Source Heat Pumps, property or injury to a user.
Better ASHP Systems
The advantages of R-32 in terms of energy efficiency, safety and especially the much lower Global Warming Potential makes ASHP systems based around R-32 refrigerant highly attractive. Its use provides an immediate way of reducing a building’s energy consumption and operational costs. Perfect for commercial hybrid hot water (DHW) systems that combine either a gas or electric water heater and controls, with FPi32 ASHPs help reduce emissions to meet new carbon targets without compromising reliability or performance.