18 May 2017

O.3.1.2 Study of In Situ Performance of the VRF Multi-split Air Conditioner for the Commercial Building

When variable refrigerant flow multi-split air conditioning and heat pump equipment for commercial buildings (VRF system) is selected, a capacity greater than the air conditioning load is often selected. As a result, it is said that it often operates in the low load factor region, and that the catalog performance is not achieved. In this report, a field monitoring result that includes an actual capacity and efficiency is reported. The monitoring instrument, comprising an ultrasonic flowmeter, Coriolis mass flowmeter, thermocouples, pressure sensors, current frequency meter, and a wattmeter, were actually installed in the VRF system (2015 model year, Daikin Industries) at Kanagawa Pref. in Japan. We estimated performance using the compressor curve (CC) method and the refrigerant enthalpy (RE) method. Although the equipment was operating in the low load factor, results show that efficiency between the rating point and a load factor of 20% was higher than the rated efficiency.