DESIGN
POWER: SIC
Evaluating SiC efficiency and payback in warm and cold climates Silicon carbide (SiC) is transforming the efficiency and performance of heat pump and air conditioning systems in both hot and cold climates, increasing overall system efficiency while reducing energy consumption and lifetime system costs. I n this article, we explore how two Figure 1. Seasonal inverter efficiency in systems with SiC vs Si-IGBT
European cities with differing climates can benefit from designing heating and cooling systems with silicon carbide power devices instead of traditional Si-IGBTs (insulated gate bipolar transistors). First let’s explore how some common residential heat pump systems (10-15kW three-phase inverter) perform in Istanbul’s warm climate versus Oslo’s cold climate. Figure 1 illustrates seasonal inverter efficiency in systems with silicon carbide vs Si IGBT and reveal efficiency improvements from 2% in the cold climate of Oslo to upwards of 4% in Istanbul. At first glance, the efficiency improvements may seem counterintuitive. The graphs presented indicate that while the efficiency gain with SiC in colder climates is lower than in warmer climates, the overall actual energy savings are greater in colder regions.
By Pranjal Srivastva & Sarah Magargee, Wolfspeed
This phenomenon can be attributed to the load dynamics of heat pumps. In warmer climates like Istanbul, the heat pump operates at lower loads, meaning that while the efficiency improvement is significant – around 4% – the overall energy demand is lower (Figure 2). Consequently, the total energy savings achieved with SiC inverters are not as pronounced. In colder climates, the load on heat pumps is considerably higher. Although the efficiency improvement of SiC over IGBT is about 2% – lower than the 4% seen in warmer climates – the higher energy demand in colder regions results in substantial overall energy savings. This underscores the importance of considering both efficiency and load when evaluating the performance of heat pump systems. The high/low load differential and impact on efficiency and energy savings can be seen in a similarly high-power system optimised
Figure 2. Load dynamics impact annual savings
20 ELECTRONICSPECIFIER.COM
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