Experimental performance of heat pump batik dryer with closed-loop airflow system

• A laboratory-scale closed-loop air-source heat pump dryer for batik textile processing was experimentally developed and evaluated. • The system maintained stable drying temperature above 40°C through condenser fan modulation and air recirculation control. • Drying time was reduced by 25% compared to traditional sun drying (30 min vs 40 min) • Experimentally obtained SMER ranged from 1.7–2.2 kg/kWh, within the expected performance envelope of small-scale closed-loop HP dryers. • Latent heat recovery and controlled airflow (1.2–3.6 m/s) enhanced moisture removal and thermal uniformity. • Closed-loop configuration minimized environmental contamination and improved drying consistency. This study experimentally evaluates the thermodynamic and drying performance of a laboratory-scale closed-loop air-source heat pump dryer applied to batik textile processing compared to traditional sun-drying methods used in batik cloth production. Drying is often inconsistent due to unpredictable weather conditions, such as rain or cloud cover. Proper drying is essential for maintaining the quality, color vibrancy, and durability of Batik fabric. To address these issues, a heat pump dryer with a closed-loop airflow system is developed to provide stable drying conditions while minimizing energy consumption. The system integrates vapor-compression refrigeration with controlled air recirculation to enable latent heat recovery and stable low-temperature drying. Experimental parameters, including chamber temperature, relative humidity, evaporator temperature, condenser temperature, and airflow velocity, were monitored. The experimentally obtained Specific Moisture Extraction Rate (SMER) ranged between 1.7–2.2 kg/kWh. The heat pump dryer significantly reduced drying time, completing the process in 30 min compared to 40 min for sun drying. Compared to traditional sun drying, the proposed system reduced drying time by approximately 25% while maintaining stable thermal conditions (>40°C) and minimizing environmental contamination. The results confirm that the prototype operates within the expected thermodynamic performance envelope of small-scale closed-loop heat pump dryers. Heat pump dryers offer a more reliable and weather-independent solution for the batik industry, enhancing production efficiency and fabric consistency. Industrial-scale validation under variable humidity conditions remains necessary.