Dynamic Character Study on Cool Thermal Energy Storage Process of Storage Tank for Air-Conditioning System

2012 ◽  
Vol 433-440 ◽  
pp. 1052-1056
Author(s):  
Xiao Yan Li ◽  
Yan Yan Wu ◽  
Zhi Fen Cen
Keyword(s):  
Energy Storage ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Tank ◽  
Air Conditioning ◽  
Heat Transfer Fluid ◽  
Inlet Temperature ◽  
Air Conditioning System ◽  
Appreciable Change

Mathematical model of the storage tank for air-conditioning condition was established, the dynamics character of a new type of PCM in the storage tank was studied., and the model was numerical simulated by the method of heat capacity. Effects of flow rate and inlet temperature of heat transfer fluid (HTF) on charging process of the storage tank were obtained. The results show that no appreciable change in the total cold thermal energy storage is observed for the increase of flow rate, whereas the improvement of the total cold thermal energy storage due to the decrease of inlet temperature is detectable, when cold storage is finished during low peak of electricity, the best inlet temperature of storage tank is at 2°C-3°C.

Experimental Study on Melting Characteristics of Spherical Capsule Packed Bed Latent Heat Storage Material System

2011 ◽  
Vol 217-218 ◽  
pp. 1525-1530
Author(s):  
Hai Ting Cui
Keyword(s):  
Energy Storage ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Transfer Fluid ◽  
Inlet Temperature ◽  
Material System ◽  
Fluid Temperature ◽  
Storage Unit ◽  
Latent Heat Storage

A laboratory equipped with the thermal energy storage unit utilizing the solar heat sources was designed and constructed. The spherical capsules which were filled with the phase change material (PCM) were installed inside the unit. The temperatures at inlet and outlet of the thermal energy storage (TES) unit and at the first through seventh layers of heat transfer fluid (HTF) were measured. Many groups of experimental schemes were designed to evaluate the storage unit’s performance. The effects of inlet fluid temperature and flow rate of HTF on the performance of the storage unit were analyzed. The experimental results showed that, with the inlet temperature and flow rate of HTF increasing, the time required to complete the charge process reduced constantly; the efficiency of thermal energy storage is consequently improved. The results provide the basis for designing, optimizing, and applying the TES unit.

scholarly journals Performance Evaluation of a Small-Scale Latent Heat Thermal Energy Storage Unit for Heating Applications Based on a Nanocomposite Organic PCM

2019 ◽  
Vol 3 (4) ◽  
pp. 88 ◽  
Author(s):  
Maria K. Koukou ◽  
George Dogkas ◽  
Michail Gr. Vrachopoulos ◽  
John Konstantaras ◽  
Christos Pagkalos ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Behavior ◽  
Latent Heat ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Solidification Processes

A small-scale latent heat thermal energy storage (LHTES) unit for heating applications was studied experimentally using an organic phase change material (PCM). The unit comprised of a tank filled with the PCM, a staggered heat exchanger (HE) for transferring heat from and to the PCM, and a water pump to circulate water as a heat transfer fluid (HTF). The performance of the unit using the commercial organic paraffin A44 was studied in order to understand the thermal behavior of the system and the main parameters that influence heat transfer during the PCM melting and solidification processes. The latter will assist the design of a large-scale unit. The effect of flow rate was studied given that it significantly affects charging (melting) and discharging (solidification) processes. In addition, as organic PCMs have low thermal conductivity, the possible improvement of the PCM’s thermal behavior by means of nanoparticle addition was investigated. The obtained results were promising and showed that the use of graphite-based nanoplatelets improves the PCM thermal behavior. Charging was clearly faster and more efficient, while with the appropriate tuning of the HTF flow rate, an efficient discharging was accomplished.

Exergy-Based Optimization of Sub- and Supercritical Thermal Energy Storage Systems

2014 ◽  
Author(s):  
Louis A. Tse ◽  
Reza Baghaei Lakeh ◽  
Richard E. Wirz ◽  
Adrienne S. Lavine
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Energy And Exergy

In this work, energy and exergy analyses are applied to a thermal energy storage system employing a storage medium in the two-phase or supercritical regime. First, a numerical model is developed to investigate the transient thermodynamic and heat transfer characteristics of the storage system by coupling conservation of energy with an equation of state to model the spatial and temporal variations in fluid properties during the entire working cycle of the TES tank. Second, parametric studies are conducted to determine the impact of key variables (such as heat transfer fluid mass flow rate and maximum storage temperature) on both energy and exergy efficiencies. The optimum heat transfer fluid mass flow rate during charging must balance exergy destroyed due to heat transfer and exergy destroyed due to pressure losses, which have competing effects. Similarly, the optimum maximum storage fluid temperature is evaluated to optimize exergetic efficiency. By incorporating exergy-based optimization alongside traditional energy analyses, the results of this study evaluate the optimal values for key parameters in the design and operation of TES systems, as well as highlight opportunities to minimize thermodynamic losses.

Investigation of a High-Temperature Packed-Bed Sensible Heat Thermal Energy Storage System With Large-Sized Elements

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Sarada Kuravi ◽  
Jamie Trahan ◽  
Yogi Goswami ◽  
Chand Jotshi ◽  
Elias Stefanakos ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Energy Storage ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Packed Bed ◽  
Inlet Temperature ◽  
Prototype System ◽  
Sensible Heat

A high-temperature, sensible heat thermal energy storage (TES) system is designed for use in a central receiver concentrating solar power plant. Air is used as the heat transfer fluid and solid bricks made out of a high storage density material are used for storage. Experiments were performed using a laboratory-scale TES prototype system, and the results are presented. The air inlet temperature was varied between 300 °C to 600 °C, and the flow rate was varied from 50 cubic feet per minute (CFM) to 90 CFM. It was found that the charging time decreases with increase in mass flow rate. A 1D packed-bed model was used to simulate the thermal performance of the system and was validated with the experimental results. Unsteady 1D energy conservation equations were formulated for combined convection and conduction heat transfer and solved numerically for charging/discharging cycles. Appropriate heat transfer and pressure drop correlations from prior literature were identified. A parametric study was done by varying the bed dimensions, fluid flow rate, particle diameter, and porosity to evaluate the charging/discharging characteristics, overall thermal efficiency, and capacity ratio of the system.

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