Thermal Analysis of a Forced Flow Diffusion Absorption Refrigeration System for Fishing-Boat Exhaust Waste Heat Utilization

Abstract

Ammonia water absorption refrigeration systems are effective in utilizing fishing-boat exhaust waste heat for cryopreservation. However, the liquid level control and the use of a solution pump characterized by small flowrate and high-pressure head result in poor reliability in the traditional system. Besides, the system must necessarily be designed anti-swaying and anti-corrosion. This paper proposes a forced flow diffusion absorption refrigeration system, in which an inherently leak-free canned motor pump and an ejector are employed to provide the driving forces of the gas and liquid loops. The approximate single pressure operation allows for a simple passive liquid sealing control without throttling valves. The system adopts an integrated cooling strategy which allows the system to operate under swaying conditions, and the external seawater cooled heat exchanger avoids internal corrosion and leakage. The thermal analysis shows the system is valid to be operated under wide operating conditions, and the coupled gas and solution circulation ratios determined the performance of the novel system. There is an optimal ammonia mass fraction difference in the gas loop to obtain the optimal COP. The COP reaches 0.4 when the temperatures at the outlets of the generator, evaporator, absorber, and condenser are 160, −15, 35, and 35°C, respectively. The novel system provides a reliable absorption refrigeration system design for fishing-boat applications.

Future Sustainable Maritime Sector: Energy Efficiency Improvement and Environmental Impact Reduction for Fishing Carriers Older than 20 Years in the Fleet Part II

“…Energy efficiency technologies [6][7][8][9] can be adapted to ship systems where there is high potential for cutting costs: air lubrication systems, wind-assisted propulsion [10] such as Flettner rotors, kite and sail propulsion, marine battery systems, or any energy storage systems [11], waste heat recovery systems [12][13][14] or energy recovery systems, exhaust gas cleaning systems [15] according to requirements set by maritime regulations, propeller efficiency retrofit, rudder efficiency retrofit, operated system or equipment auxiliary saving technologies to reduce energy consumption, shaft generators, engine tuning, trim optimization, coating or antifoul evaluation, cold ironing, HVAC&R to improve energy efficiency, and insulation improvements to reduce energy losses.…”