The refrigerated trucks in the market are mainly equipped with vapor compression systems powered by the diesel engine. Sorption cooling systems for vehicles can reduce the fuel consumption by using exhaust heat recovery. However, under extreme conditions, such as low exhaust gas temperature and high ambient temperature, the conventional single-salt sorbents are not able to complete the sorption-desorption cycles. Owing to the hysteresis phenomenon of the multi-salt sorbent, the desorption temperature can be reduced and the sorption temperature can be increased. Thus, the multi-salt sorbent has better adaptability for low exhaust gas temperature and high ambient temperature, and it will generate cooling power more efficiently when the exhaust gas temperature changes with the engine load.
Recently, Gao, J., et al. from Shanghai Jiao Tong University, proposed a freezing system with novel compact composite multi-salt sorbent of CaCl2 /MnCl2 for refrigerated trucks.
In this system, the modularized sorption bed was designed for the direct heat exchange with the engine exhaust gas and the ambient air intermittently. The characteristics of the freezing system under different working conditions were analyzed. The results showed that for the optimum cycle, the maximum refrigeration capacity in 65 min was higher than 2.4 kW at the heating temperature of 200 °C and an ambient temperature of about 25 °C. The average Specific Cooling Power (SCP) is increased by nearly 100% compared with the existing two-stage sorption freezing system for refrigerated truck. This indicates that the multi-salt sorbent can meet the demands of light refrigerated trucks.
Source: ACCC NEWSLETTER (2020.09; ACCC = Asian Conference on Cold Chain)
Reference: Gao, J., et al.: Performance investigation of a freezing system with novel multi-salt sorbent for refrigerated truck. International Journal of Refrigeration 98, 129-138 (2019). https://doi.org/10.1016/j.ijrefrig.2018.10.024