Evaluation of thermal performance in small-scale air conditioning system with water-cooled thermoelectric module

Abstract Improving the energy efficiency and thermal performance of air-conditioning (AC) systems is an important challenge, particularly for small-scale or localized cooling applications. This study experimentally investigates the performance of a small-scale hybrid AC system integrated with a water-cooled thermoelectric module (TEM). Eight operating conditions were tested by varying the coolant flow rate (2–4 L/min) and applying a 500 W heater to simulate thermal load. Temperature, humidity, and power consumption were monitored continuously for 24 h under each condition. Results showed that higher coolant flow rates improved convective heat transfer and enhanced system performance. The coefficient of performance (COP) increased from 1.13 (no TEC) to 2.19 at 4 L/min without the heater, and from 2.60 to 3.46 with the heater, verified by one-way ANOVA at a 95% confidence level (p < 0.001). The system maintained an indoor temperature around 22.4 °C and a relative humidity of 57–61%, aligning with the ASHRAE comfort zone. These findings demonstrate that coupling a water-cooled TEM with a conventional AC unit can enhance cooling efficiency and thermal comfort under controlled conditions. At the same time, future studies may focus on system scaling and optimization for practical applications.