Experimental validation and numerical evaluation of a heat-driven direct-coupled Stirling combined cooling and power system

A direct-coupled Stirling combined cooling and power system for waste-heat-driven cooling and power cogeneration has been designed and experimentally tested for the first time. Distinguished by the use of only two pistons, this system offers a more compact and reliable alternative compared to the conventional duplex Stirling combined cooling and power systems. Experimental investigation involving variations in resistance, heating temperature and cooling temperature has been conducted, with a focus on analyzing the output cooling capacity, the electricity power and the exergy efficiency. The experimental results demonstrate a favorable agreement with simulation outcomes. It shows that the variation in resistance influences the motion of the alternator, thereby impacting system performance. A smaller resistance is preferable when the cooling demand is low, leading to a higher exergy efficiency. Conversely, a larger resistance is favored to meet the higher demand of cooling capacity. In an optimal scenario, at the resistance of 100 Ω, the system achieves 92.4 W of cooling power and 35.7 W of electricity power, with the exergy efficiency of 6.2 %, when the heating, ambient and cooling temperatures are 523 K, 308 K and 280 K, respectively. Higher heating temperatures enhance cooling capacity, electricity power and exergy efficiency, while lower cooling temperatures adversely affect system performance. Beyond its simpler structure, the system exhibits flexibility, making it promising for waste-heat-driven cooling and power cogeneration.