The study of energy-saving strategy for direct expansion air conditioning system

Abstract Most air conditioning, energy-saving research has focused on the chiller system, the most effective energy-saving procedure of its kind would be the use of forced downtime or load shedding control methods. However, the use of forced downtime control methods on direct expansion systems, while saving energy, would be at the expense of increasing room temperature, leading to the discomfort of the inhabitants. This research focused on the direct expansion system and used periodic downtime control methods to execute energy-saving procedures, thus providing reasonable temperature control and saving energy at the same time. According to the results, by reducing the periodic downtime, we can improve unstable temperature problems; i.e. operating for 15 min and downtime for 5 min, provided the optimal energy-saving efficiency, saving 21.66% of energy. However, the percentage of high room temperatures during this downtime period was 40.43%, this meant that if we wanted to save energy, we would have to sacrifice comfort; if we wanted more comfort, then we have to select an operating mode that was secondary to operating for 10 min and downtime for 5 min. We also discovered that if the air conditioner manufacturer modified the embedded program and adjusted the limit for upper temperatures of the settings upward by 1 °C, users would save 7.22% of energy; this was a procedure that was more direct and effective than any other energy-saving requisition.