Heat exchanger performance modeling using ice slurry as secondary refrigerant

Ice slurry is a biphasic secondary refrigerant that theoretically allows important energy savings in secondary refrigerant distribution loop compared to single phase refrigerants. However, an accurate evaluation of these energy savings requires the knowledge of the thermal and rheological performance of the refrigerant.Based on the experimental model developed by the authors, a theoretical analysis of heat exchangers performance is presented in this work in order to calculate the potential energy savings associated to its use. The influence of ice concentration, mass flow rate, heat exchanger length and cooled fluid temperature over pumping power and heat transfer rate is studied. The ratio between heat transfer rate and pumping power is used as the evaluation parameter, which allows us to find the most favorable operation conditions for ice slurry flow.Results for ice slurry are compared to those obtained for carrier fluid at same inlet temperature to assess the improvement obtained.

► This work assesses the improvement obtained using ice slurry in heat exchangers.
► Ice slurry direct use has been compared to indirect (chilled carrier fluid) use.
► Pumping power and heat transfer rate have been analyzed varying operation conditions.
► Optimal ice concentration depends on the operation conditions and tube type.
► Optimal ice concentration increases as the heat exchanger length increases.