## 3 Results and Discussion
emissions revealed that both the indirect emissions factor and the heat pump system's power consumption have a remarkable influence on the indirect emissions. When the source of electricity is clean energy, such as nuclear or renewable energies, the indirect emissions factor decreases with the CO\({}_{2}\)-eq. emissions for the generation of each decrease in kWh. This results in a reduction of the indirect CO\({}_{2}\)-eq. emissions of the RACHP systems. Furthermore, the electricity consumption of the RACHP system, which is inversely proportional to the COP of the system, influences the indirect CO\({}_{2}\)-eq. emissions. Hence, the utilization of refrigerants that increase the system's energy efficiency or any modifications in the system's design can decrease the electricity consumption of the RACHP systems and consequently reduce the indirect CO\({}_{2}\)-eq. emissions. The TEWI per kilowatt heating capacity (TEWI/Q) of MTHP and HTHP using the alternative refrigerants is presented in Figures 6 and 7, respectively. In Figure 6, it is observed that for the economies with low carbon intensity values, such as Sweden and Brazil, the TEWI/Q of R134a is higher than its alternative refrigerants. Although the COP of R134a is higher than other selected refrigerants, very low \(\beta\) values in Sweden and Brazil compensate for the lower COP of alternative refrigerants. For economies with relatively higher carbon indexes, such as Canada and Poland, the lower COP of R1234 yf makes this refrigerant the worst case among tested refrigerants. However, it has an ultra-low GWP value. This means that direct emissions are the main contributors to the TEWI/Q in countries such as Canada and Poland, with relatively higher \(\beta\) values. Moreover, R1234 ze(E), as an energy-efficient case with an ultra-low GWP value, is almost the best refrigerant in terms of TEWI/Q in all tested countries, except in Poland, where R134a showed the minimum emissions. This is due to a much higher \(\beta\) value in Poland than the other selected countries, which dominate the role of electricity consumption and consequently indirect emissions on TEWI/Q. Comparing the TEWI/Q of the alternative refrigerants to R245 fa (Figure 7), the results illustrate that R1336 mzz(Z) achieves the lowest environmental impact in all selected countries. Due to the much higher COP of the system using R1336 mzz(Z) and its ultra-low-GWP value. Similar to R1336 mzz(Z), it was also found that R1233 zd(E) and R1234 ze(Z) have lower TEWI/Q compared to R245 fa due to their higher COP and lower GWP values. In a country such as Sweden, with a relatively small \(\beta\) value, the TEWI/Q of R245 fa is notably higher than the alternative refrigerants, which means the HTHP system can benefit from utilizing alternative refrigerants. In Poland, where there is a relatively higher \(\beta\) value than other selected countries, R600 presents a slight TEWI/Q increase compared to R245 fa as it exhibits lower COP compared to other tested refrigerants. It is important to note that irrespective of the type of refrigerants, the value of the TEWI/Q is strongly affected by the \(\beta\) value. For instance, the \(\beta\) value in Poland is more than ten times greater than that in Sweden; and consequently, the TEWI/Q using alternative refrigerants to R245 fa in Poland is on average 65 times higher than in Sweden. Moreover, the analysis results depict countries with low carbon intensity values, such as Sweden and the CO\({}_{2}\)-eq. emissions of RACHP systems using HFCs are much lower than countries with high carbon-intensity values, even if low-GWP refrigerants are employed in RACHP systems in those countries. This is since the contribution of indirect emissions to the TEWI is much higher than that of the direct emissions of the RACHP systems. The results confirmed that the TEWI/Q values of R134a and R245 fa in Sweden are much lower than the TEWI/Q of the alternative refrigerants in other selected countries.