An assessment of inverter-driven variable-speed air conditioners: sample performance comparison with a conventional system

The measured seasonal performance of a 17.6 kW single speed air conditioner (SSAC) installed in a high-rise residence in Dhahran, Saudi Arabia, was compared with the simulated performance of a 14.1 kW inverter-driven variable speed system (VSAC) from an energy conservation standpoint. Under the same operating conditions, the VSAC used 24% less energy. Model results also indicate that the VSAC can satisfy building cooling load 100% of the time. Computations show that VSAC will spend 22% of total hours in the low speed mode, thus reducing the energy-savings benefit due to high cyclic losses. Net annual cyclic losses for the SSAC and VSAC were computed as 12% and 3% respectively. VSAC merits and problem areas that need to be addressed to improve performance and reliability are discussed. (from authors' abstract)