The ice slurry technology is today well known and one can expect its development in refrigerating systems, especially in district cooling networks. In this case, the cost of the refrigeration energy consumed by the end-user will depend on the measurement of the flow rate and the ice mass fraction. The latter must be reliable, accurate, cheap and settled on both the inlet and the outlet of the delivery. This paper presents theoretical and experimental results obtained with two different devices based on the density measurement of a slurry (static differential pressure and Coriolis Effect). The results obtained are compared to a reference method based on the measurement of the temperature referring to the liquidus equilibrium curve of the solute that is propylene glycol. The advantages and the limits of each measurement method are presented and discussed. It is shown that, if the defined protocol for the static pressure measurement should allow to be free of the knowledge of the initial concentration of the solute, the obtained repetability on the results remain closely related to sampling problems. The results obtained with the Coriolis Effect appear to be accurate and reliable. Meanwhile, this method requires the knowledge of the initial solute concentration and also remains expensive. On the other hand, the same sensor also delivers a flow rate measurement which is the other parameter required to bill the provided refrigerating energy to the end-user.