Better humidity control for better indoor air quality
The 'Novel liquid desiccant dehumidification system' (Dehumid) project aimed to develop and test a low-cost, compact and energy-efficient liquid desiccant dehumidification system. Dehumid focused on enhancing system components so that outdoor air delivered to buildings and homes could be preconditioned in the interests of saving energy through reduced compressor size. Other advantages of the envisioned system include improved indoor air quality and comfort, and reduced humidity and excess chiller capacity. Researchers carried out a review and analysis of the literature on existing dehumidification technologies and defined properties of technologically and economically justified dehumidification systems. Team members set the functional specifications of all system components and identified basic control parameters. Besides being important with regard to energy reduction, work on the latter enabled work on the design and supply of a system control product. Although an assessment of lithium bromide (LiBr) and lithium chloride (LiCl) showed the latter to be a better desiccant material, design restrictions related to its aggressive corrosive nature and carryover of droplets shifted design ideas towards the use of non-metal material in the absorber. Thus, project partners designed an absorber from cellulose fibre, integrating the cooling of the desiccant solution into its surface. This offered various advantages by eliminating the problem of corrosion and reducing LiCl droplets carryover. Another advantage is reduction of time spent on maintenance activities. Information gathered from the study and analysis of relevant literature was used to formulate requirements for the proposed system and modelling of its various features. Climatic data required for the design of air conditioning and dehumidification systems were collected, analysed and presented for each country represented by project participants. Other activities included connecting communication modules with a personal computer (PC) and the realisation of an emergency programme in the event of communication failure.
