Experimental Investigation of Industrial Scale Wraparound Loop Heat Pipes for Heating Ventilation and Air Conditioning System Application

This study experimentally investigates the thermal performance of wraparound loop heat pipes (WLHP) using R134a as the working fluid and copper tubing with an outer diameter of 8.5 mm. A dedicated experimental apparatus was developed to evaluate thermal resistance under varying heat loads (200–500 W), inclination angles (15° and 30°), and coolant temperatures (5–15 °C) at a constant coolant flow rate of 3.2 L/min. Key performance metrics, including evaporator wall temperature and overall thermal resistance, were analyzed to identify optimal operating conditions. The results reveal that increasing the heat load significantly reduces thermal resistance, reaching a minimum of 0.056 °C/W at 500 W. An inclination angle of 30° improved heat transfer, lowering the evaporator temperature by approximately 5 °C compared to 15°. Moreover, lower coolant temperatures enhanced the temperature gradient between the evaporator and condenser, further improving heat transfer. Principal component analysis (PCA) was employed for dimensionality reduction and identification of the dominant thermal variables affecting system performance. Based on the experimental dataset, a regression model was developed to predict thermal resistance, achieving a coefficient of determination of R2 = 0.96. These findings confirm the WLHP’s potential as an efficient and reliable passive thermal management system for medium- to high-power applications in tropical and industrial environments.