Charge reduction experimental investigation of CO2 single-phase flow in a horizontal micro-channel with constant heat flux conditions

The use of carbon dioxide as alternative refrigerant in refrigeration plants and heat pumps has been focused recently. Through the specific properties of CO2, the use of very compact heat exchangers is relevant and the technology of micro-channel heat exchangers rises as a suitable solution. The experimental investigation of CO2 flow in a single micro-channel with an inner diameter of 529 μm is planned with an original test section. This test section is initially dedicated for further CO2 two-phase flow analysis. The local heat transfer coefficients are estimated with micro-thermocouples stuck on the micro-channel wall. The pressure drop is also measured. This paper presents the first results in single-phase pressure drop and heat transfer and exhibits promising coming data in two-phase flow pressure drop and heat transfer for mass velocity between 200 kg/m2/s and 1400 kg/m2/s and working saturation temperature between −10 °C and 5 °C. The results stress on the good accuracy of suitable classical laws to predict pressure drop and heat transfer in single-phase flow in micro-channel.