scholarly journals Applications of Thermal Energy Storage in Solar Organic Rankine Cycles: A Comprehensive Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Mohamed Salem ◽  
Morteza Fahim Alavi ◽  
Ibrahim Mahariq ◽  
Oussama Accouche ◽  
Mamdouh El Haj Assad

Organic Rankine Cycles (ORCs) are promising approaches for generating power from medium or low temperature heat sources. In this regard, ORCs can be used to indirectly produce power from solar energy. Due to intermittent nature of solar energy, storage unit should be coupled with solar ORCs to improve the output power and operating hours. In this article, studies on solar ORCs integrated with various types of storage units were reviewed; the main findings of such studies were extracted and provided. Based on the findings, several factors such as the temperature and pressure at the inlet of the turbine, as well as the operating condition affect the performance of solar ORCs with thermal storage unit just like the conventional ORCs. In addition, the optimum size of the storage unit in the solar ORCs was found to depend on the operating condition. From the financial perspective, it can be noted that the storage unit affects the corresponding indicators. Moreover, the improvement rate in the ORCs by applying storage units could be affected by the configuration of the system.

Author(s):  
Mustafa Aktaş ◽  
Meltem Koşan ◽  
Erhan Arslan ◽  
Azim Doğuş Tuncer

The integrated usage of solar energy systems, heat pump applications, and thermal energy storage units is an effective way for heating systems due to their sustainability and stability in operations. In this study, a novel direct solar-assisted heat pump with thermal energy system has been designed which uses the solar collector as the evaporator of the heat pump. Besides, two-dimensional transient numeric analyses have been conducted for the thermal energy storage unit using the ANSYS Fluent 16.2 commercial software package. With this direct system, the heat required for heating systems is supplied from the condenser with the heat received from the solar collector of the working fluid. For an effective and high performance system, the solar collector is designed as a double-pass which provided superheating of the working fluid. It is aimed to store the surplus energy from the solar energy in the thermal energy storage unit and to operate the system continuously and efficiently in both sunny and overcast weather conditions. Furthermore, the system has been analyzed theoretically and the results show that coefficient of performance may improve. As a result, this newly designed system can be successfully applied for thermal applications.


2018 ◽  
Vol 1 (3) ◽  
pp. 34
Author(s):  
Luigi Mongibello ◽  
Nicola Bianco ◽  
Martina Caliano ◽  
Giorgio Graditi

Thermal energy storage systems can be determinant for an effective use of solar energy, as they allow to decouple the thermal energy production by the solar source from thermal loads, and thus allowing solar energy to be exploited also during nighttime and cloudy periods. The current study deals with the modelling and simulation of a cooling thermal energy storage unit consisting of an aluminum container partially filled with a phase change material (PCM). Two unsteady models are implemented and discussed, namely a conduction-based model and a conduction-convection-based one. The equations systems relative to both the models are solved by means of the Comsol Multiphysics finite element solver, and results are presented in terms of temporal variation of temperature in different points inside the PCM, of the volume average liquid fraction, and of the cooling energy stored and released through the aluminum container external surface during the charge and discharge, respectively. Moreover, the numerical results obtained by the implementation of the above different models are compared with experimental ones obtained with a climatic chamber. The comparison between numerical and experimental results indicate that, for the considered cooling energy storage unit, free convection plays a crucial role in the heat transfer inside the liquid PCM and cannot be neglected.


2019 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Abdelrahman Aldik ◽  
Tamer Khatib

In this paper, optimization of Electric Vehicle (EV) batteries and dedicated energy storage unit charging profiles were conducted for the sake of bidding into day-ahead ancillary service markets. The aim of the optimization is to provide the maximum operational profits for both the EV aggregator and dedicated energy storage unit administrator. Ancillary service algorithms were then introduced to simulate the response of the EV batteries and dedicated energy storage units. Results showed that the usage of dedicated energy storage units for bidding into the ancillary services markets is more profitable than the case of operating an EV aggregator.


Author(s):  
I.P. Popov

The paper considers the possibility of equipping engineering vehicles with inertial capacitance energy storage units, which should allow the power plant loads to be evened out, in turn leading to reducing the output power, mass and dimensions of the plant. In a range of engineering vehicles, such as excavators, bulldozers, diesel shunter locomotives and so on, loads are of a substantially irregular character. Peak loads are what determines the output power of power plants. It is evident that the power plant is not fully loaded most of the time. We propose a technological solution for balancing peak loads in engineering vehicles. Since operation modes of engineering vehicles change relatively frequently, it is efficient and advisable to equip them with energy storage units. The storage unit will not only level the power plant load, but also allow the energy to be recuperated during deceleration, which should improve the energy efficiency of the machine. We present the theoretical background required to develop an inertial capacitance energy storage unit, which is implemented as a direct current machine featuring a super flywheel. Employing flywheels in engineering vehicles is feasible due to their total mass requirements being flexible. Another advantage of certain engineering vehicles is their electro-mechanical transmission, the presence of which should minimise the development effort concerning the inertial capacitance energy storage unit discussed in the paper engineering vehicle, energy storage unit, super flywheel, power plant, energy efficiency


Author(s):  
Vikas Chourasia

Finite element analysis was used to simulate the performance of thermal energy storage in a solar cooker which was fabricated by our team. This cooker stores solar energy in materials like sand for future use. It is inexpensive to construct and can be widely used in villages and urban areas. The cooker energy storage unit consists of a cubical solid block which contains sand as a solar-energy storage unit, along with conducting aluminum sheets for uniform heat distribution throughout the block. The block is enclosed in a uniform layer of insulation, except the cavities on the top surface to allow heating of the sand and as well as near the cooking pot. This heated sand can be used at night to heat a cooking pot which is centrally located in the storage box. A paraboloidal concentrator focuses solar radiation through a secondary reflector onto the central zone of the storage block through the cavity in the insulation. The storage is charged for a set period of time and heat is subsequently discharged to a pot during the night time. The effects on cooker performance are compared for various numbers of plates in the storage block. The temperature attained at various stages is studied for various models. This can be used to cook food in a slow manner and can be kept heated until night.


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