A review on present and forthcoming opportunities with natural working fluids in transport refrigeration

There are currently many drivers pushing the transport refrigeration sector towards more sustainable refrigeration systems, being at the same time more efficient and adopting Natural Working Fluids (NWF) in place of synthetics. Due to the variety of involved means of transport, the different and challenging boundary conditions and safety requirements and not last the fact of not being the major user of refrigerants, the refrigeration systems for mobile refrigeration have not always been dedicated the same R&D effort as stationary refrigeration and air conditioning. However, it is now becoming more and more urgent to identify sustainable future proof solutions for the sector. To this extent, transport refrigeration can benefit from the experience gained in other sectors and achieve sustainable solutions in a short time. There are many examples of efficient NWF based systems already out in the market; some others are on the way, also supported by international projects, and others still need some regulatory provisions to become widespread, mainly those involving flammable refrigerants. Innovations in the refrigeration systems need finally to keep the pace and harmonize with the revolution that the transport sector is undergoing towards hybrid and electric vehicles.