S R C C Alternatives to H F s in the efrigeration and Air Conditioning Sector ection 01 31 Th e only market segments where ODS have been replaced widely by non-HFC alternatives are domestic appliances and some “plug-in” display cases that have changed from R-12 to isobutane (R-600a). In markets where flammability and toxicity have been considered difficult and/or costly to handle safely the transition has been to HFCs. As new technologies are developed and mature and more technicians receive training and become familiar with non-HFC alternatives, these “not-in-kind” alternatives can be expected to increase their market share. As the HFCs are not compatible with traditional refrigeration oils the introduction of HFC normally requires a change to ester-oils (e.g. PAG-oils are used with R-134a in the automotive sector). There is a special range of HFC refrigerants called “drop-in” or “service-blends” that are tailored to allow the use of HFCs with traditional mineral oils by adding a component to address oil transport characteristics (see service blends below). In most R-22 applications the two dominating HFC alternatives for new installations are R-407C and R-410A. The former is closest to R-22 in terms of capacity and pressure. Provided the change to an ester oil has been made, R-407C gives a similar capacity and performance as R-22 but presents a special characteristic. As it is a zeotropic blend – i.e. it has a gliding temperature during condensation and evaporation (glide) - it is less suitable for some applications. R-410A was introduced later and it requires redesign to handle the higher pressure but has an advantage of higher capacity and insignificant glide. R-407C has lost a significant part of its initial markets to R-410A, but is still the preferred solution in several segments such as small- and medium-sized chillers and water/brine heat-pumps. R-410A, on the other hand, has taken most of the market in smaller air conditioning systems of unitary and split type. In commercial applications that traditionally used R-12 and R-502, R-22 is normally replaced by R-404A/R-507. In some traditional R-22 segments such as larger chillers R-134a has taken a significant market share. systems is much higher than that of the HCFCs systems they are replacing. In many sectors there are requirements on minimum efficiencies expressed as Seasonal Energy Efficiencies, for example. In some markets, the government offers tax exemptions or subsidies to high energy efficiency solutions. In most applications the energy consumption will be the major contributor to global warming from a RAC system. TEWI (see Abbreviations and definitions) as well as the Life Cycle Analysis (LCA) of cost and environmental impact are important factors to consider when comparing different alternatives. The most common HFC alternatives in new applications and retrofits with change of oil to a polyol ester oil are: Split and unitary air conditioning units R R-407C and R-410A Heat pumps R R-134a, R-407C and R-410A Display cases and small systems R R-134a and R-404A/R-507 Chillers, air conditioning R R-134a, R-407C and R-410A Chillers, commercial R R-134a and R-404A/R-507 Central system commercial R R-404A/R-507 Industrial R R-404A and R-507 Out of the HFC refrigerants listed above only R-410A requires components designed for significantly higher pressure. Service blends intended for use in existing systems are listed in the next section. T he introduction of “good practice” and functional re-use schemes is essential to achieve minimal emission and high energy efficiency.