Search

The use of the two-phase closed thermosyphons (TPCTs) is increasing for many heat transfer applications. This paper reviews the most recent published experimental and theoretical studies on the TPCT. After a description of the TPCT operating principle and the performance characteristics, the heat transfer analysis in condenser and evaporator sections that depends on the complex two-phase process are described. The influence of the affecting parameters on the performance of TPCTs such as the geometry (diameter, shape and length), the inclination angle, the filling ratio (FR), the working fluid, the operating temperature and pressure analyzed by various researchers is discussed. The various operating limits occurring in a thermosyphon includes viscous, sonic, dryout, boiling and flooding are also analyzed. Considering the application of TPCTs, the paper presents a review of experimental tests and applications. This paper can be used as the starting point for the researcher interested in the TPCTs and their renewable energy applications. [ABSTRACT FROM AUTHOR]

The mitigations of global energy demands, climate change and energy related greenhouse gas effects are the most important factors in the modern days. However, renewable energy is one of the alternative sources which has the capacity to mitigate all the above. Among all the renewable energy sources, solar energy is one of the most abundant and the cleanest energy source. Different laboratories of the world have achieved different solar cell efficiencies, which are also discussed in the present paper. This paper presents the global solar PV developments, per capita values, government supportive invectives and policies of the top ten solar power producing countries. This paper also presents the investments of the global solar energy among the countries. Finally, through the study, it is found that these top ten leading countries are following fulfilment of their projections, supportive tariff rates, net metering, green certificates and government incentive policies as their instruments. [ABSTRACT FROM AUTHOR]

Sichuan Province is one of the most important economic inland areas and is characterized by an abundance of renewable energy resources in the form of solar, wind, biomass, and, in particular, hydropower. After the rapid growth of installed hydropower capacity during the past decade, the non-hydro renewable energy resource development is booming in Sichuan Province. This development is bringing about a series of problems as well. In this paper, we give an overview of Sichuan׳s renewable energy development in the past five years, analyze the existing problems, and examine the underlying causes in terms of environment, market, technology, and policy. On that basis, we propose a method for future renewable energy development in Sichuan and suggest that Sichuan׳s government should improve the pricing mechanism and the mandatory share policy for non-hydro renewable energy. Additionally, R&D on the plateau type of wind turbines and the smart micro-grid should be strengthened. Finally, given the mature hydropower industry in Sichuan, the combined operation of wind–hydro and solar–hydro plants is recommended to improve the stability of renewable electricity generation output. [ABSTRACT FROM AUTHOR]

The availability and reliability of renewable energy sources are highly dependent on climate conditions, which may vary due to possible global climatic changes. Long-term energy planning, however, does not normally take into account future threats of climate change on energy security. This paper shows the impacts of drought, as one of the main features of climate change, on the technology of electricity generation and on CO 2 emissions in the Association of Southeast Asian Nations-6 (ASEAN-6). We provide insights into the extent of the vulnerability of electricity generation options to drought. The findings increase awareness for future planning of the energy generation mix and emphasizes on an integrated and collaborative management plan based on drought planning initiatives and measures. [ABSTRACT FROM AUTHOR]

Integrating variable and non-dispatchable renewable power generation into existing power systems will have consequences for their operation and future expansion. These impacts will depend on two factors: (1) the variability of the total renewable power generation on different time scales and (2) the possibilities of accurately forecasting these fluctuations. In this paper, previous research on variability assessment and forecasting of solar, wind, wave and tidal energy resources is reviewed. The aim is to summarize the state of knowledge in each area and to compare the approaches used for the respective resources. For temporal variability, methods and models used for assessing the variability are surveyed, as well as what is known about the variability at individual sites and for larger aggregates of sites. For forecasting, an overview of forecasting methods for the different resources is made, and selected forecasting methods are compared over different time horizons. An important finding is that it is hard to draw strong conclusions from the existing studies due to differences in approaches and presentation of results. There is a need for further, more coherent studies that analyze the variability for the different resources in comparable ways, using data with the same resolution, and for studies that evaluate the smoothing effect and complementarity of combinations of several renewable energy resources. For forecasting, future research should suggest ways to evaluate forecasts from different renewable energy sources in easily comparable ways, using data from the same locations or regions, with the same temporal and spatial resolution, and with comparable metrics for the forecasting errors. [ABSTRACT FROM AUTHOR]