TEAP report on continued provision of information on energy efficient and low-global-warming-potential technologies
Parties to the Montreal Protocol requested the Technology and Economic Assessment Panel (TEAP) to prepare a report [1] on energy efficient and lower-global-warming-potential technologies and on measures to enhance and maintain energy efficiency during hydrofluorocarbon transition in equipment. The key messages cover a wide range of issues discussed in the detailed report, which provides an update on available medium and low GWP refrigerants, including HFC-32, HFC/HFO blends and HFOs/HCFOs, for a range of applications. Here are extracts of some of the key messages.
Energy Use
A large proportion of RACHP (refrigeration air-conditioning and heat pumps) GHG emissions are related to the energy used. The ratio of “indirect” energy-related emissions to “direct” refrigerant emissions varies between countries depending on factors such as the carbon intensity of power generation, the leakage rate from different RACHP applications, and the GWP of the refrigerants used. The relative importance of direct and indirect GHG emissions can also vary considerably across the wide range of different RACHP technologies and applications.
In all sectors it is now possible to significantly enhance energy efficiency. The overall energy benefits from HFC phasedown depend on the RACHP application, sector and the HFC alternatives used. Incentives would encourage and support transition in the RACHP sector and enhanced energy efficiency benefits would be realised. There is excellent potential to synchronise the reduction in energy-related emissions with the phasing down of the use and emissions of HFCs, for example by integrating with energy efficiency standards and labelling policy.
Heat Pumps
Using heat pumps in place of fossil-fuels for space, water and process heating will be essential for heating decarbonisation. The avoided fossil fuel emissions from the use of heat pumps will massively outweigh any direct and indirect emissions from the heat pumps. Heat pumps are available with low and medium GWP refrigerants with energy efficiency measures implemented for the refrigeration cycle, the selection of ancillary components and the integration of heat pumps with the building controls.
Refrigerant characteristics
Refrigerant characteristics play an important role in the design of RACHP equipment in specific relation to maintaining or enhancing energy efficiency. The two main factors which influence the material cost of equipment are refrigerant thermodynamic characteristics (pressure, density, cycle COP etc.) and refrigerant safety characteristics (e.g., flammability/toxicity/pressure). Other factors may also play a role, such as material compatibility.
Flammability and/or toxicity characteristics may limit the acceptable amount of refrigerant for safety reasons and thus limit the cooling or heating capacity and/or energy efficiency that can be achieved. Reducing the refrigerant charge may be possible using different technologies such as microchannel heat exchangers but these can also bring technical and application challenges.
Operating and maintaining equipment
Ensuring that new RACHP equipment is as efficient as possible, and that existing equipment is operated and maintained for high efficiency makes a very cost-effective contribution to the path to net zero GHG emissions. Energy efficiency (EE) degradation is affected by the severity of use and operating conditions, as well as corrosive environments. Improper installation and maintenance accentuate the loss of EE, and high quality and frequent planned maintenance minimise the loss of EE. Refrigerant leakage impacts EE. Reducing leakage continues to be a service priority for optimised systems using low-GWP refrigerants with reduced refrigerant charge. End-user environmental awareness is driving them to demand lower CO2-eq emissions from the operation of their systems. Preventive and eventually predictive maintenance are becoming a priority for both operators and service providers.
Banks of high GWP HFCs
Continued use of high GWP HFCs will result in an accumulation of a large stock of high GWP HFCs in RACHP equipment in A5 parties. This increasing stock of equipment containing high GWP HFCs has the potential to delay by 20-30 years (the lifetime of RACHP equipment in developing countries) the climate benefits through reduced direct emissions. In addition, if the high GWP HFCs were contained within inefficient RACHP equipment, this would create excess energy demand (indirect emissions) over the same period. There is a significant lack of reliable data on refrigerant banks and equipment stocks by sector which is needed optimise the outputs of modelling. Better data would improve modelling at national and regional levels.
Reference
[1] May 2022 TEAP Report, Decision XXXIII/5: Continued provision of information on energy-efficient and low-global-warming-potential technologies, available at Technology and Economic Assessment Panel (TEAP) | Ozone Secretariat (unep.org)