Experimental Investigation of the Hydraulic and Thermal Performance of a Phase Change Material Slurry in the Heat Exchangers

The application of phase change material slurry to the refrigeration and air conditioning system opens a new way for energy saving and reduction of the quantity of refrigerant in the system involved because it can serve as both the energy storage and the transportation media in the secondary loop, which is responsible for distributing the cooling power. In the present study, the experimental investigations of the forced flow and heat transfer characteristics of tetrabutylammonium bromide (TBAB) clathrate hydrate slurry (CHS) in both the plate heat exchanger (PHE) and the double-tube heat exchanger (DHE) are carried out. It is found out that the pressure drop in the PHE is about 3.0–50.0 kPa at the flow rate of 2.5–13.0 L/min $(0.15–0.78m3∕h)$and is about 1.0–27.0 kPa at the flow rate of 3.0–14.0 L/min $(0.18–0.84m3∕h)$ in the DHE, which is nearly 2 times of that of the chilled water. The overall heat transfer coefficient is in the range of 2500–5000 $W/(m2K)$ for TBAB CHS in the PHE and is about $1500–3500W/(m2K)$ in the DHE, which are both higher than that of TBAB aqueous solution flow because of the involvement of the phase change of TBAB CHS.