Mathematical modelling and simulation of the dehumidifier for the tropical region of Malaysia
In this paper, mathematical model for an adiabatic dehumidifier of liquid desiccant air conditioning system is presented. Regression approach is used to generate the mathematical relation between enthalpy and humidity ratio. Flow-pattern between air & desiccant mainly affects the performance of adiabatic dehumidifier therefore to get proper dehumidification counter-flow configuration is considered as previous studies show that counter-flow direction of air to desiccant has better dehumidification results. For validation, results of present study were compared with those of numerical and analytical results of previous studies, and the agreement was found to be quite satisfactory. The developed mathematical model is then used to study the performance analyses of adiabatic-dehumidifier for the tropical region of Malaysia. Analyses are made for the week having very high range of humidity ratio (18 - 19.5 g/kg). The main concern of the current article is given on moisture removal from the ambient air according to thermal comfort-zone.
A technical review on use of liquid-desiccant dehumidification for air-conditioning application
Liquid-desiccant dehumidification has been proved to be an effective method to extract the moisture of air with relatively less energy consumption, especially compared with conventional vapour compression system. To date, the conventional dehumidification mode with desiccant solution has been improved or replaced by newly emerged energy-saving systems with better performance. This paper gives a detailed account of the general features of the major desiccant dehumidification techniques and configurations of the related systems; meanwhile, attention has been paid to both technological and theoretical development of regenerator, which is an indispensable component of the liquid-desiccant dehumidification system. Moreover, a summary of the experimental and analytical studies to optimize the system performance has been made. Some new hybrid systems that greatly expand the desiccant dehumidification technique in industrial and residential applications, as well as effectively promoting the single system's performance, are also introduced. Finally, future study and application for liquid-desiccant dehumidification techniques are concluded.
Water Quality Aspects of Irrigation and Drainage: Past History and Future Challenges for Civil Engineers
This paper presents a brief history of irrigation and drainage related to ASCE activities on its Jubilee. This paper discusses legislation and policies that affect irrigation and drainage practices, water quality constituents of increasing concern in irrigation and drainage practices, and presents a prognosis on the future of declining freshwater resources available for irrigated agriculture and growing water quality problems in irrigation and drainage. Civil engineers in ASCE’s Irrigation and Drainage Division have compiled an 80-year history of highly meritorious service and accomplishments. In the next millennium, civil engineers will face a formidable challenge in managing and protecting the precious freshwater resources in the U.S.