Experimental study on a heat pump-boosted closed-cycle desiccant wheel system in deep mine

Abstract

Deep mine heat damage critically threatens mining safety, whereas traditional cooling systems suffer from high energy consumption and inadequate dehumidification. To address these issues, a heat pump-boosted closed-cycle desiccant wheel system (HP-CDWS) is proposed, which uses water source heat pump (WSHP) and desiccant wheel system to achieve deep cooling and dehumidification of mine airflow. The evaporator provides chilled water for precooling of mine airflow, and the condenser supplies hot water to heat the regeneration air of the desiccant wheel with purge sector (DW-PS). Condensation dehumidification is used to pre-dehumidify the mine airflow, and DW-PS is used for further deep dehumidification to obtain low air humidity ratio. An experimental platform is built and used to test the performance of the HP-CDWS. The results show that increasing the mine airflow inlet temperature from 28 °C to 38 °C boosts the thermal coefficient of performance (TCOP), moisture removal capacity (MRC), and exergy efficiency by 93.3%, 84.0%, and 11.8%, respectively; higher mine airflow inlet relative humidity (70–95%) increases TCOP and MRC by 29% and 27%, respectively, but reduces exergy efficiency by 21.2%; elevating regeneration temperature (50–100 °C) increases MRC by 29% while decreasing TCOP and exergy efficiency by 51.4% and 6.9%, respectively. Compared with traditional systems, the HP-CDWS achieves a 5.2-year payback period and 4.8% lower life cycle cost, proving an energy-efficient and economically viable solution.