An exploratory study of a liquid desiccant waterfall system for the Malaysian humid climate

Abstract

An exploratory study of a liquid desiccant waterfall (LDW) system was conducted as a means of achieving air dehumidification of an internal air environment. The aim is to explore an alternative technology which can reduce energy consumption, while still achieving acceptable thermal comfort conditions and achieving specific advantages when compared with conventional air conditioning systems. Some of these advantages include the pleasing aesthetics and appearance of a waterfall feature, the efficient functionality behind desiccant dehumidication technologies of the LDW system. This study and research proposed a system which harnesses hygroscopic salt of lithium chloride (desiccant) in its liquid form (45% concentration). This naturally attracts and absorbs moisture from an internal environment. Having absorbed the moist indoor air into the system, the lithium chloride then converts into a diluted form (30% concentration) and this requires the solution to be reactivated. A further advantage of the LDW system is explored representing significant potential in saving energy through the harvesting of solar thermal energy in order to expel moisture out of the system, as well as to efficiently reactivate the saline solution of lithium chloride to undertake its the cyclic nature of new dehumidification processes. To further quantify the amount of moisture to be absorbed by the LDW system and to some extent verify this exploratory study, a case study of a hypothetical space of an open plan office building in Kuala Lumpur city was proposed. The study then calculates the total amount of moisture to be eliminated by the LWD system (as specified by the common standard) was 25.4 kg/hr based on standards of thermal comfort for an office environment. Life cycle costs and energy savings were estimated. The results demonstrate and suggest a high prospect in creating an attractive financial return-on investment (ROI) including energy savings. When design optimally, this technology or system can save up to 92% of energy consumption and offer an investment rate of return of 34% per year. This was considered an attractive investment because it could offer reasonable payback period of 3 years.