Ammonia for power

Environment friendly alternatives to halogenated refrigerants—A review

A review of waste heat recovery technologies for maritime applications

Exergoeconomic comparison of TLC (trilateral Rankine cycle), ORC (organic Rankine cycle) and Kalina cycle using a low grade heat source

In 2014, the Directive 517/2014 was introduced by European Parliament to reduce the use of high-GWP greenhouse gases in the European area in order to limit global climate change in accordance with the objectives marked by the EU Research and Innovation programme Horizon 2020. These restrictions affect the large majority of artificial refrigerants among which R134a is included due to its relatively high GWP100 (1301). The widely used of R134a in the refrigeration and air conditioning fields reveals the need to identify new low-GWP alternatives. Accordingly, in this work five low-GWP R134a possible choices have been tested and compared in an identical refrigerating facility equipped with a hermetic compressor, under the same operating conditions. The refrigerants used in this analysis are: R290 and R600a (HCs); R134a and R152a (HFCs), and finally, R1234yf and R1234ze(E) (HFOs). All of them have been assayed without changes in the facility, that is, as direct drop-ins. The results obtained from the experimental tests are presented and commented in this work from the energetic point of view.

Energy performance evaluation of R1234yf, R1234ze(E), R600a, R290 and R152a as low-GWP R134a alternatives.

This paper presents a review of the research on the Kalina cycle, including the description of the Kalina cycle, the comparison of the Rankine and Kalina cycle, energy and exergy analysis on the Kalina cycle, different Kalina systems and their different applications. Moreover, different correlations for calculating thermodynamic properties of ammonia–water mixture are screened and discussed. In the end, some technique concerns on ammonia–water mixture, i.e., stability, environmental impacts, safety and corrosion problem etc are also discussed.

A review of research on the Kalina cycle

Design, modeling and experimental verification of circular Halbach electromagnetic energy harvesting from bearing motion

Application of natural refrigerant propane and propane/isobutane in large capacity chest freezer

Enhanced swing electromagnetic energy harvesting from human motion

Bistable system exhibiting complex dynamic behavior has been viewed as an efficient method to overcome the issue of linear energy harvester only performing well near the resonant frequency. Moreover, performance enhancement strategies of bistable energy harvesters have been extensively discussed mainly for systems with perfectly symmetric potentials. Due to the presence of imperfections as a result of non-uniform manufacturing of the harvesters, eccentricity of the buckling or magnetic force and uneven gravity, the dynamic characteristics and performance enhancement of asymmetric potential energy harvesting remain an open issue. Therefore, this paper investigates the influence mechanism and performance enhancement of a cantilever-based bistable energy harvesting system with asymmetric potentials. Bifurcation diagrams of the dimensionless electromechanical equations are employed to discover the effect of asymmetric potentials on the output response. Based on the numerical results, a performance enhancement method is proposed by compensating the asymmetric potentials with an appropriate bias of the system to decrease the negative impact of asymmetric potentials on bistable energy harvesting. The optimum bias angle is derived and numerical simulations under constant and sweep frequency excitations demonstrate that the performance of the asymmetric potential bistable energy harvesters is enhanced in a certain bias angle range around the optimum value. Two bistable energy harvesters with different asymmetric potential energy functions are investigated in the experiments and results verify the effectiveness of the proposed method for improving the energy harvesting performance.

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Ying Zhang

Papers

A review of research on the Kalina cycle

Design, modeling and experimental verification of circular Halbach electromagnetic energy harvesting from bearing motion

Application of natural refrigerant propane and propane/isobutane in large capacity chest freezer

Enhanced swing electromagnetic energy harvesting from human motion

Nonlinear dynamics and performance enhancement of asymmetric potential bistable energy harvesters