SPONSOR CPD PROGRAMME Continuing professional development (CPD) is the regular maintenance, improvement and broadening of your knowledge and skills, to maintain professional competence. It is a requirement of CIBSE and other professional bodies. This Journal CPD programme can be used to meet your CPD requirements. Study the module and answer the questions on the final page. Each successfully completed module is equivalent to 1.5 hours of CPD. Modules are also available at www.cibsejournal.com/cpd Moving towards refrigerants with lower global warming potential This module considers the growing use of lower global warming potential refrigerants for chillers, air conditioning and rooftop units Buildings and the construction sectors combined are responsible for 36% of global final energy consumption, and nearly 40% of total direct and indirect CO2 emissions. Energy demand from buildings and the construction of buildings continues to rise, driven by improved access to energy in developing countries, greater ownership, and use of energy-consuming devices, plus rapid growth in global buildings floor area of nearly 3% per year. Some of the fastest-growing end uses are space cooling, with a year-on-year continued rise in global energy intensity per floor area.1 The environmental impact from refrigeration that provides the cooling for HVAC systems results from direct and indirect emissions. Direct emissions occur because of refrigerant escaping from systems that might be a result of faults and breakages, or during maintenance and repair procedures. Indirect emissions result from the generation of power that is consumed by the refrigeration machine. This is likely to release CO2 as well as other environmentally deleterious gases and particulates into the atmosphere from the power-generation plant. The environmental impact will depend on: the thermodynamic effectiveness of the refrigerant; the efficiencies of the refrigeration system and the associated systems; the energy losses in the power-distribution systems; and the primary energy source at the power plant. So, for example, if the primary energy source was deemed as renewable, this impact may be reduced. The unknowns of a future supply scenario, however as well as the benefits of lower operating costs should always favour systems that require less power to operate, subject to an appropriate life-cycle analysis. There was a step-change in the popular understanding of the impact of refrigeration on the global environment following the discovery of the Antarctic ozone hole in late 1985, which was linked to direct emissions. This highlighted the need for stronger measures to reduce the production and consumption of a number of chemicals, including commonly used refrigerants that were, principally, the halogenated hydrocarbons, which encompass the chlorofluorocarbons (CFCs), such as R12, and the hydrochlorofluorocarbons (HCFCs), such as R22. This culminated in the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer. This was subsequently adjusted to accelerate the phaseout schedules, and amended to introduce other kinds of control measures and to add new controlled substances to the list. Using 2010 data, the US Department of Energy (DoE) estimates that the equivalent CO2 emissions from the cooling component of air conditioning were as shown in Figure 1, with approximately 25% (or 175 million tonnes CO2e) the result of direct emissions. For some perspective, the total UK emissions relating to all activities in 2018 were2 451.5 million tonnes CO2e. The direct emissions may be managed through operational procedures to minimise leakage and by employing systems that require reduced refrigerant charges. New technologies may assist in reducing environmental impact. This might include enhanced heat exchangers and smart leak detection, more robust manufacturing processes, superior design, and alternative refrigerants. Indirect emissions may be reduced by using more efficient or alternative refrigerating machines, by using otherwise wasted energy to drive the refrigeration system, or by using www.cibsejournal.com September 2020 63 CIBSE September 2020 p63-66 CPD 167 v2.indd 63 21/08/2020 15:28