Comparison of the energy performance of novel dual-temperature cooling systems: From field testing to simulations

Abstract

Air conditioners (AC) face the challenge of low energy efficiency in field operation. Considering that the performance of dual-temperature systems remains unexplored, especially in different climate zones, an AC with a flat heat pipe and different temperature controls was tested in an experimental chamber. The energy efficiency increased by 14% compared to that of an AC with a dehumidification mode. Furthermore, three novel systems that optimize the dual-temperature cooling process are proposed. These include an AC with a twin-cylinder compressor, AC with medium/low-pressure ejectors, and AC with high/low-pressure ejectors. The performance of these ACs was analyzed under different conditions. The maximum EER of the four ACs was 9.13, 9.91, 9.54, and 10.68, respectively, for an evaporation temperature of 10 °C and different condensation temperatures and part-load ratios. The nominal EER of the three dual-temperature systems increased by 9.4, 6.8, and 19.7%, respectively, with respect to the conventional system. The seasonal energy efficiency ratio of the three dual-temperature systems increased by approximately 5.8–18.8%, 6.3–19.9%, 6.0–18.8%, and 3.9–17.6% in four different climate zones, respectively. Our results indicate that the twin-cylinder compressor system has the highest potential for applications in high-efficiency cooling systems.