development of a solar cavity receiver with a short term storage system

Abstract The technological progress carried out in the development of high-temperature materials has led to the design of new concentrated solar power plants, like Dish-Micro Gas Turbines (Dish-MGTs). This study proposes a novel cavity receiver for small-scale Dish-MGT plants with a phase-change material storage system integrated inside the receiver container. Such a storage system provides a proper thermal inertia to the component, to level the effects of short-term solar radiation fluctuations which can reduce plant performance and, in the worst cases, damage seriously the MGT. In the paper, results related to CFD steady-state and transient (charge and discharge storage phases) analyses are presented and discussed

Design of power-blocks for medium-scale supercritical carbon dioxide plants

For power production, the emerging technologies of supercritical carbon dioxide (S-CO2) cycles show potential advantages if compared to conventional plants. The current bottleneck in exploiting such cycles is the development of novel components such as turbomachines and heat-exchangers. This paper focuses on the layout arrangement and machinery design of a novel power block for a 10 to 15 MW supercritical carbon dioxide plant. The applied design procedure involves 0D and 1D models implemented using an in-house Fortran code, and 3D computational fluid dynamics (CFD) analyses using ANSYS-CFX. Novel configurations of the power block were designed, starting with the same primary thermal source. At nominal conditions, expected overall output powers from 13.2 to 16.2 MW were found. Finally, some qualitative considerations were included in the discussion to compare the analysed arrangements

Energy and exergy analysis of fuel cells: a review

In this paper, the fundamental overview of theoretical and practical aspects of thermodynamics analysis for mainly used fuel cells (FCs) are presented. The FC converts the chemical energy of fuel (normally hydrogen) directly into electrical energy resulting heat and liquid water as a waste products. In first part, governing equation of mass, energy, entropy and exergy are presented according to first law of thermodynamics (FLT) and second law of thermodynamics (SLT), more specifically energy and exergy analysis are covered for fuel cell system. Basic criteria of energy and exergy analysis of flowing and non-flowing system, energy and exergy efficiencies, analysis procedure and models of reference environment are discussed in detail. In the second part, electrochemical reactions and thermodynamics modeling of proton exchange membrane or polymer electrolyte membrane fuel cell (PEMFC), solid oxide fuel cell (SOFC), and molten carbonate fuel cell (MCFC) are presented

The dynamic impact of renewable energy sources on environmental economic growth: evidence from selected Asian economies

The linkage between renewable energy resources and environmental influences on economic growth among selected Asian economies play a vital role in sustainable economic development. This study encompasses the panel data sets for eight selected Asian countries, and the period starts from 1990 to 2018. This research relies on the panel vector error correction model (PVECM) for data estimation. The overall findings indicate that biomass, geothermal, and wind power sources of energy have a positive and significant impact on the economic advancement of Asian economies. Besides that, as opposed to the other two renewable energy sources, windpower has a greater impact on economic development. Furthermore, the empirical findings of current research have significant implications towards selected Asian countries’ energy policy related to both private and public sector enterprises as it helps in identifying the industrial sectors which have greater contribution towards the economy and their energy requirements in long term

Thermal process enhancement of HNCPCM filled heat sink: Effect of hybrid nanoparticles ratio and shape

The present study based on the numerical investigation of a hybrid nanocomposite phase change material (HNCPCM) filled heat sink for passive cooling of electronic devices. The combination of graphene oxide (GO) and silver (Ag) hybrid nanoparticles are added inside the RT-28HC to enhance thermal performance. The volume fraction ratios of Ag:GO are varied from 0:0, 0:4, 1:3, 2:2, 3:1 and 4:0. Four different shape factor values of 3.7, 4.9, 5.7 and 16.1 of Ag-GO are varied. The transient simulations are carried out to solve the governing equations using the finite volume method scheme. The results depicted that employing HNCPCM has better heat transfer enhancement compared to the pure PCM because of the addition of nanoparticles. The results showed that adding the Ag-GO inside the RT-28HC improved the thermal conductivity and uniformity in the melting process compared to the RT-28HC based heat sink. With the addition of Ag-GO, melting time of HNCPCM filled heat sink is reduced and heat transfer rate in increased. The optimum ratio of 1:3 of Ag:GO nanoparticles and shape factor value of 16.1 show the higher thermal conductivity of 0.348 W/m.K, 12.93% reduction in melting time, 8.65% enhancement in heat storage capacity and rate of heat transfer

Transient simulation of finned heat sinks embedded with PCM for electronics cooling

This paper reports the two-dimensional (2D) transient numerical simulation of a phase change material (PCM) based finned heat sink to investigate the heat transfer performance for passive cooling of electronic devices. The finned heat sinks of 2 mm and 3 mm fin thickness are employed with a constant fin volume fraction of 9%, acting as thermal conductivity enhancer (TCE). The n-eicosane is employed as a PCM inside the heat sink to store the heat generated from the electronic device applied at the heat sink base. Transient numerical simulations are performed using finite-volume-method and conjugate heat transfer and melting/solidification phenomenon are investigated by applying various power levels. The numerical results show that the employed PCM with low temperature keeps the heat sink base temperature in lower limits and uniform melting is observed inside the finned heat sink. With the increase of heating power level, the PCM melting time is decreased for fin thickness heat sinks. By increasing the power level from 4 to 6 W, for the case of 3 mm fin thickness, the melting time increases by 6.63%, 3.59% and 1.90% by 3 mm fin thickness heat sink, compared to the 2 mm fin thickness heat sink. The developed equations of liquid fraction and modified Nusselt number are obtained as function of modified Fourier number, Stefan number, and Rayleigh number which provide guidelines for generalizing the thermal performance of PCM based finned heat sinks

In-vitro Antagonistic Potential of Different Fungi Against Fusarium oxysporum f. sp. Capsici

The current research was conducted in Lab. to assess an antagonistic effect of various fungi against Fusarium oxysporum f. sp. capsici. In the present research, each treatment (Trichoderma viride, T. harzianum and T. Koningii) with three concentrations viz.

Charge and discharge analyses of a PCM storage system integrated in a high-temperature solar receiver

Solar Dish Micro Gas Turbine (MGT) systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures with concentrated solar radiations, which strongly vary with time. This paper deals with the design and the analysis of a novel solar receiver integrated with a short-term storage system based on Phase Change Materials to prevent sudden variations in the maximum temperature of the MGT working fluid. Particularly, the charge and discharge behavior of the storage system was analyzed by means of Computational Fluid Dynamic methods to evaluate the potentiality of the concept and the component capabilities. Achieved results were highly satisfactory: the novel solar receiver has a good thermal inertia and can prevent relevant fluctuations in the working fluid temperature for 20-30 min

High-temperature solar receiver integrated with a short-term storage system

Small-Scale Concentrated Solar Power Plants could have a potential market for off-grid applications in rural contexts with limited access to the electrical grid and favorable environmental characteristics. Some Small-Scale plants have already been developed, like the 25-30 kWe Dish-Stirling engine. Other ones are under development as, for example, plants based on Parabolic Trough Collectors coupled with Organic Rankine Cycles. Furthermore, the technological progress achieved in the development of new small high-temperature solar receiver, makes possible the development of interesting systems based on Micro Gas Turbines coupled with Dish collectors. Such systems could have several advantages in terms of costs, reliability and availability if compared with Dish-Stirling plants. In addition, Dish-Micro Gas Turbine systems are expected to have higher performance than Solar Organic Rankine Cycle plants. The present work focuses the attention on some challenging aspects related to the design of small high-temperature solar receivers for Dish-Micro Gas Turbine systems. Natural fluctuations in the solar radiation can reduce system performance and damage seriously the Micro Gas Turbine. To stabilize the system operation, the solar receiver has to assure a proper thermal inertia. Therefore, a solar receiver integrated with a short-term storage system based on high-temperature phase-change materials is proposed in this paper. Steady-state and transient analyses (for thermal storage charge and discharge phases) have been carried out using the commercial CFD code Ansys-Fluent. Results are presented and discussed

An experimental investigation of performance of photovoltaic modules in Pakistan

An outdoor experimental study was carried out to investigate and compare the performance of three commercially available photovoltaic modules (monocrystalline, polycrystalline and single junction amorphous silicon) under the weather of Pakistan for the month of January. Power output efficiency, module efficiency, and performance ratio are calculated for each module and comparison is presented. Results have shown that mono-crystalline and poly-crystalline modules perform better at high irradiance and show poor performance in low irradiance conditions. Amorphous solar module has shown better light absorption characteristic and performs better in low irradiance i.e. in cloudy and diffuse sunshine conditions. Monocrystalline photovoltaic module is found to be more efficient, having module efficiency of 13.5% which is higher than the other two modules. Furthermore the power output of mono-crystalline and poly-crystalline modules has shown a higher decrement at higher module temperatures compared to the amorphous solar module. Because of better performance in low solar irradiance, amorphous solar module has shown monthly average performance ratio of 1.07 which is higher than other photovoltaic modules under study