This paper reviews and surveys the available hybrid liquid-desiccant air-conditioning system technologies. These technologies are proposed as alternative to the traditional vapor-compression systems because of its advantages in removing air latent load, environment-friendly feature, ability to remove pollutants from the processed air, and ability to reduce electrical energy consumption. This paper first introduces the traditional air-conditioning system: vapor compression, vapor absorption, and evaporative cooling. In addition, the principles of liquid desiccants and liquid-desiccant dehumidification systems and the hybrid liquid-desiccant classifications are discussed. Next, combination of the liquid-desiccant systems with vapor compression, vapor absorption, and direct and indirect evaporative cooling units are outlined. Finally, conclusions and some important suggestions are presented based on the collected information.

Survey of hybrid liquid desiccant air conditioning systems

Experimental evidence of a new regime for boiling of water at subatmospheric pressure

A review of reverse cycle machines thermodynamics is proposed. It is shown how starting from equilibrium thermodynamics at the beginning, a new appraisal was proposed since 1980, and developed until now. Particular emphasis is put on vapour compression reverse machines (mainly refrigerating machines and heat pumps), but also on three or quadrithermal configurations, that appear as the most promising alternative to vapour compression machines today. However other machines alternatives are considered shortly. The main features of this review are: the usefulness of thermodynamics to develop more significant upperbounds for various optimization criterions concerning reverse cycle machines and their possible interrelation. The importance of irreversibilities in characterization of reverse cycle machines is enlighten too. Complementary studies are proposed in the field of exergoeconomy and environmental concern.

Thermodynamics applied to reverse cycle machines, a review

Survey of liquid desiccant dehumidification system based on integrated vapor compression technology for building applications

Visualization and experimental analysis of Geyser boiling phenomena in two-phase thermosyphons

Subatmospheric pressure boiling on a single nucleation site in narrow vertical spaces

A novel Carnot-type cycle is proposed to reach high performances for sub-critical and trans-critical applications. Two natural fluids, ammonia and carbon dioxide each one corresponding to one of the application, were chosen. Compared to conventional cycles, the Carnot-type cycle leads to COP increase by 4–70% depending on the application. For the most suitable case (CO 2 ), a simpler design resulting from a trade-off between complexity and performances still exhibits high performances (92.5% of COP Carnot vs. 95.4% for Carnot-type cycle). Compared to conventional one, this simpler design appears to be more sensitive to the expander efficiency but still achieves higher performances: 80% vs. 50% of COP Carnot . The impact of the compression cooling efficiency was explored too. With a temperature pinch equal to 20 K, the performances are still better than those of the conventional one (+21% of COP) despite a decrease by 24% of the COP.

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Cyril Toublanc

Papers

Experimental evidence of a new regime for boiling of water at subatmospheric pressure

Subatmospheric pressure boiling on a single nucleation site in narrow vertical spaces

Analysis of a novel refrigeration Carnot-type cycle based on isothermal vapour compression

Experimental study of water pool boiling at very low pressure on a vertical or horizontal heated surface

Investigation of properties and compatibilities of POE oils/R-290 mixtures