Performance of a highly efficient exhausted heat recovery hot water system in hotel kitchens

Proposes an exhausted heat recovery hot water system based on the fact of a large amount of exhausted heat from hotel kitchens released without utilization and the domestic hot water demand at the same time. Presents the composition and operation mechanism of the system. Simulates the annual total amount of exhausted heat and indoor temperature of kitchens by TRNSYS software, and establishes the mathematical models of the main components by Matlab software. Under the condition of constant initial and final water temperature, simulates and measures the heating coefficient of performance (COP) and exhausted heat utilization coefficient (E) of the system under different operating conditions such as indoor temperature, influent water flow rate and hot water consumption. The results show that the annual exhausted heat amount of kitchens with the area of 60, 150, 250 m2 are about 53.72, 107.70, 222.37 MJ, respectively, which is necessary for recovery. When the indoor temperature is in the range of 18 to 26 ℃, the average heating COP of the system is 3.47. When the hot water consumption is 600 to 900 L/d, the E of this system is 0.61 to 0.77. With the increase of influent water flow rate, the E increases gradually, while the growth rate decreases gradually. The influent water flow rate of 2.0 to 2.5 kg/s is preferred.