| Abstract | This study developed an efficient winter-specific operational method for a single-reversible heat-pump-driven liquid-desiccant (HPLD) system, sized for summer design loads, aiming to achieve optimal year-round energy savings while maintaining thermal comfort. To address seasonal load management challenges, specifically potential inadequacies in handling high building thermal loads encountered during winter operation, two distinct system configurations, each with dedicated control logics, were proposed. In Proposed Case A, the HPLD system handled both building sensible and latent loads with a backup heater providing auxiliary space heating. In Proposed Case B, the HPLD system handled only building latent loads, while a separate parallel heating system handled the remaining building sensible loads. On-site energy performance and thermal comfort outcomes of these approaches were evaluated under typical winter conditions, while including comparisons to a conventional reference system. Proposed Case A achieved the highest thermal comfort satisfaction of 97%; however, its reliance on a low-efficiency heater led to the highest operating energy consumption of 30.4 kWh. In Proposed Case B, efficient indoor humidification and heating resulted in a high thermal comfort satisfaction of 95%, while optimizing energy use at 27.8 kWh. Although the reference system required the least operating energy of 23.6 kWh, it faced trade-offs in temperature and humidity control, yielding the lowest thermal comfort satisfaction of 79%. Consequently, Proposed Case B demonstrated operating-energy savings of 7.40% and 2.41% compared to Proposed Case A and the reference system, respectively, under equivalent thermal comfort achievements. Further compressor adjustments would increase these savings to 28.0% and 24.2%. Therefore, the HPLD system, originally sized for summer design conditions, should operate according to the winter-specific configuration with tailored control logic outlined in Proposed Case B for optimal year-round energy efficiency and thermal comfort. |
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