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Owing to environmental problems arising from the use of refrigerants, first the ozone depletion and later the global warming, various refrigerants have been banned and their phase-out deadlines established through some international protocols, the Montreal and Kyoto Protocols being two of the most famous of such agreements. This paper intends to make a characterization of the most currently used refrigerants in the Portuguese food industry, through a sample of 148 companies gathered in a nationwide survey. It also aims to analyse not only the environmental impacts of these refrigerants, but also the restrictions that these companies may incur according to the EU Regulation No. 517/2014, such as maintenance and service bans or cap and phase-down on the supply. Finally, according to other research and tests reports, some possible replacements for two of the most commonly used refrigerants (R404A and R22) which are being phased down, are summarized. According to the research, there are some satisfactory mid-term and long-term alternatives available for R22 and R404A that have much lower GWP, allowing systems to achieve higher efficiencies and in turn, lower environmental impacts during their service life.

Buildings are responsible for a large sharing of energy consumption worldwide. Among all energy services in buildings, heating, ventilation and air conditioning systems not only account for a significant part of energy consumption but they are also highly influential on indoor climate and occupants’ satisfaction in consequence. In this paper, four demand-controlled ventilation strategies based on occupancy schedule period, occupancy level and indoor concentration of CO 2 in an office room have been studied. The indoor air quality as well as the energy consumption levels associated to each demand-controlled ventilation strategy were assessed through simulations performed using EnergyPlus . The results showed the best suited ventilation strategies for the office room that can provide acceptable level of indoor air quality with the least energy use. Furthermore, three sensitivity analyses were performed in order to assess the influence of changing different criteria on the energy consumption and indoor air quality.