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The research to substitute chlorinated fluorocarbons (CFC) has brought to repropose fluids already used in the past and also totally new solutions. Among these, the utilization of air has been proposed since this fluid is devoid of any pollution effect; some authors have pointed out its advantages by means of rather sophisticated cycles. However, it is easy to demonstrate that air can not be a competitor as regards two-phase fluids when the cycle exergy efficiency is a fundamental element. Notwithstanding, there are cases in which other considerations are prevailing, as in the case of airplanes in which air is soundly used. An innovative concept of using aircycle technology for the development of a microclimate-cooling device for military and industrial applications has been recently proposed. For this last case, a thermodynamic analysis is here carried out to state pros and cons of such systems.

Liquid Droplet Radiators (LDR) are among the most novel light weight heat exchangers for space applications. Rejected heat flux over mass ratio up to 1.4 kW/kg can be acheived provided that accurate optimization of the global system is performed. In this work a straightforward calculation procedure is proposed to evaluate the heat rejection performances of an LDR sheet. Thank to its short calculation time, the procedure is suitable to be employed in complex optimization algorithms.