Heat Pumps Today

Info For the full paper visit: www.chemours.com www.acrjournal.uk/heat-pumps 17 W H I T E P A P E R ambient temperatures however, EVI or ELI technology is required to achieve high flow temperature. Without these additional technologies, only 40°C to 45°C would be achievable. Unfortunately, the COP will usually not increase during and due to EVI operation. For renovated buildings at temperate and colder European climate conditions, an additional electrical heater or parallel gas boiler would be necessary to reach the heating capacity and temperature requirements. The behavior of R-454B and R-452B is very similar to that of R-410A and the required compressor technology is also similar, if not identical. When using R-32, high flow temperatures can be achieved, but due to the very high discharge temperature, the maximum requested temperature lift (-25°C to +60°C) cannot be achieved without added measures to prevent compressor overheating. This additional protection is usually detrimental to both the capacity and e“ciency of the system. R-454C can be operated with standard one-stage compressors, foregoing EVI or ELI technologies, and still achieve flow temperatures of up to 75°C, even at very low ambient temperatures. This makes R-454C an ideal choice for: ° Building renovations, as the existing water radiators often require relatively high flow temperatures for optimum functionality. ° Sanitary hot water production, as the additional legionella controls are not needed ° New buildings as the same compressor can be used for hot water production and space heating. 7 Emissions Impact in Various Countries Although there is no combustion in a vapor compression cycle Heat Pump, direct emissions caused by leaking refrigerant can cause GWP. Indirect emissions are also a factor, due to the electrical power consumption of the Heat Pump. Both sources of emissions are addressed in the following chapter. Leakage rates of Heat Pumps (direct emissions) Direct emissions of Heat Pumps can be caused by refrigerant leaks. The decisive factor here is the GWP of the refrigerant and the leakage rate. An analysis of F-Gas logbooks in March 2014 determined that annual leakage rates from Heat Pumps were approximately 3.8% for nondomestic applications and 3.5% for domestic applications (Eunomia, 2014). Based on this annual leakage rate of 3.5%, the direct emissions over the whole life cycle of the system (assuming a 10-year lifecycle) can be set at 35% of the initial refrigerant charge. We will consider the emissions for R-410A (GWP 2088), representing the standard industry reference, and for R-454C (GWP 148) representing a long-term solution. In Heat Pumps with a 5 to 10kW heating capacity, which represent around 60% of the installed market, the refrigerant charge can be estimated to be between 1.8 to 2kg. For Heat Pumps of 10 to 20kW of heating capacity, which represent about 30% of the installed market, the refrigerant charge can be estimated to be about 2.5 to 3kg. As a worst-case scenario, the highest values were used. The lower capacity range (5 to 10kW) is generally representative of new building applications, while the higher capacity (10 to 20kW) represents building renovation applications.