This paper presents the development and experimental study of an ammonia water absorption refrigeration prototype for waste heat utilization of diesel engine exhaust. Side cooling rectification and side heating generation are designed to achieve desirable heat matching for better internal heat recovery thus improving the system performance. An active open heat pipe method is applied for taking the exhaust heat to make the heat input stable. The condensation and absorption processes are combined in one unit and cooled by circulated precooled solution. Small diameter tube bundle heat exchangers with large specific surface area are employed for all components. Both the features make the system bulk small. The experimental results show that the operation of the system is reliable with a sharp variation of the exhaust condition. The prototype produces cooling capacity of 33.8 kW and the system thermal COP reaches 0.53 under the test conditions that the temperatures of the cooling water, secondary refrigerant and exhaust inlet are 26.1 °C, −15.2 °C and 567 °C, respectively. The novel design of the prototype is proved to be valid and its concept can be extended to other applications. •Side cooling rectification and side heating generation are designed.•An active open heat pipe technology is used for taking the exhaust heat.•Small channel tube bundle heat exchangers are employed.•The prototype produces cooling capacity of 33.8 kW and thermal COP of 0.53.