Thermodynamic analysis of liquid desiccants

Ahmed, Saleh; Gandhidasan, P.; Al‐Farayedhi, Abdulghani A.

doi:10.1016/s0038-092x(97)00087-x

Cited by 67 publications

(27 citation statements)

References 12 publications

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“…As reported by [2] and [5], latent loads are always higher than sensible loads, except for desert climates. The high latent load could result in an inefficient dehumidification process with conventional vapour-compression systems [6]. Due to the development of ASHRAE standards 62 [7] and 6 90 [8], the conventional vapour-compression systems have progressively become less efficient in dealing with latent loads present in buildings, causing an oversize of the system when it must deal with high moisture content [2].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and economics of liquid desiccants for heating, ventilation and air-conditioning – An overview

Giampieri

Smallbone

et al. 2018

Applied Energy

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In an effort to minimise electricity consumption and greenhouse gases emissions, the heating, ventilation and airconditioning sector has focused its attention on developing alternative solutions to electricallydriven vapour-compression cooling. Liquid desiccant airconditioning systems represent an energyefficient and more environmentally friendly alternative technology for dehumidification and cooling, particularly in those cases with high latent loads to maintain indoor air quality and comfort conditions. This technology is considered particularly efficient in hot and humid climates. As a matter of fact, the choice of the desiccant solution influences the overall performance of the system. The current paper reviews the working principle of liquid desiccant systems, focusing on the thermodynamic properties of the desiccant solutions and describes an evaluation of the reference thermodynamic properties of different desiccant solutions to identify which thermodynamic, physical, transport property influences the liquid desiccant process and to what extent. The comparison of these thermodynamic properties for the commonly used desiccants is conducted to estimate which fluid could perform most favourably in the system. The economic factors and the effect of different applications and climatic conditions on the system performance are also described. The paper is intended to be the first step in the evaluation of alternative desiccant fluids able to overcome the problems related to the use of the common desiccant solutions, such as crystallization and

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Section: Introductionmentioning

confidence: 99%

Thermodynamics and economics of liquid desiccants for heating, ventilation and air-conditioning – An overview

Giampieri

Smallbone

et al. 2018

Applied Energy

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“…For the selection of a liquid desiccant, several parameters should be considered, such as boiling point elevation, energy storage density, regeneration temperature, thermo-physical property, availability and cost [11].…”

Section: Introductionmentioning

confidence: 99%

Performance assessment of a membrane liquid desiccant dehumidification cooling system based on experimental investigations

Chen

Zhu

Bai

2017

Energy and Buildings

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A membrane-based liquid desiccant dehumidification cooling system is studied in this paper for energy efficient air conditioning with independent temperature and humidity controls. The system mainly consists of a dehumidifier, a regenerator, an evaporative cooler and an air-to-air heat exchanger. Its feasibility in the hot and humid region is assessed with calcium chloride solution, and the influences of operating variables on the dehumidifier, regenerator, evaporative cooler and overall system performances are investigated through experimental work. The experimental results indicate that the inlet air condition greatly affects the dehumidification and regeneration performances. The system regeneration temperature should be controlled appropriately for a high energy efficiency based on the operative solution concentration ratio. It is worth noting that the solution concentration ratio plays a considerable role in the system performance. The higher the solution concentration ratio, the better the dehumidification performance. However simultaneously more thermal input power is required for the solution regeneration, and a crystallization risk in the normal operating temperature range should be noted as well. The system mass balance between the dehumidifier and regenerator is crucial for the system steady operation. Under the investigated steady operating condition, the supply air temperature of 20.4°C and system COP of 0.70 are achieved at a solution concentration ratio of 36%.

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“…Compared with the solid desiccant system, the liquid desiccant system is more economical and flexible in utilization of low-grade energy sources 2 and efficient in providing high quality supply air with independent humidity and temperature controls 3 . Generally, the selection of a liquid desiccant depends on various operating parameters, such as boiling point elevation, energy storage density, regeneration temperature, thermophysical properties, availability and costs 4 . Halide salts are the most common liquid desiccants, such as Lithium Chloride (LiCl), Lithium Bromide (LiBr) and Calcium Chloride (CaCl 2 ).…”

Section: Introductionmentioning

confidence: 99%