This paper presents the field study results of a novel hot water-powered liquid desiccant dehumidification system, which has been installed in a demonstration building in Beijing, China, as part ofan independent dehumidification air-conditioning system. The hot water is supplied by the urban heating network, which is powered by a heat and power cogeneration (CHP) plant. The working principles of the system, both in summer and in winter, are illustrated in detail. The performance of the system has been measured, showing that the average energy efficiency of the outdoor air processor is 1.83, the average regeneration efficiency 0.82, and the average energy efficiency of the entire liquid desiccant dehumidification system 1.50, which is competitive compared to a conventional electrical refrigeration system. The outdoor processors work in winter as total heat recovery units with efficiency being around 0.5.