Study on LiBr-H2O Absorption Refrigeration System with Integral Storage

2014 ◽  
Vol 953-954 ◽  
pp. 752-756
Author(s):  
Qi Chao Yang
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Temperature ◽  
Coefficient Of Performance ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Operation Conditions ◽  
Storage Methods ◽  
Absorption Refrigeration System

The absorption thermal energy storage (TES) system stores the energy in the form of potential energy of solution and is a promising technology for efficient energy transformation process. The performance of the absorption refrigeration system with integral storage for cooling applications using LiBr-H2O as working pair under the condition without crystallization was analyzed on the basis of the first law of thermodynamics. Simulation was employed to determine the coefficient of performance (COP) and energy storage density (ESD) of the absorption TES system under different conditions such as the absorption temperature and storage temperature. The results show that the COP of the system is 0.7453 and ESD is 169.853 MJ/m3 under typical operation conditions in summer. A low absorption temperature yields both a higher COP and ESD. The solution heat exchanger could improve the COP of the system while has no effect on ESD. Results also showed that system has a good advantage when compared to other storage methods since it is do no need thermal insulation. The absorption TES may be considered as one of the promising thermal energy storage methods.

scholarly journals Stratification Analysis and Behaviour of a Real Industrial Thermocline Thermal Energy Storage Tank for Cogeneration Purposes

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 120
Author(s):  
Francisco Fernández ◽  
José Díaz ◽  
María Folgueras ◽  
Inés Suárez
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Control Strategies ◽  
Storage System ◽  
Good Control ◽  
Energy Storage System ◽  
Temperature Gradients ◽  
Operation Conditions ◽  
Mean Temperature

Thermal energy storage systems help to couple thermal energy generation and process demand in cogeneration facilities. One single deposit with two design temperatures and one main temperature step in sensible thermal energy storage define the thermocline systems. Performance of one high size real thermocline thermal energy storage system is analysed. Starting from temperature and mass flow rate data registered by the plant control system, one advanced thermodynamic analysis is performed. The quality of heat storage is analysed in terms of evaluation of the stratification in the thermocline zone. The temperature data registered at 21 positions is extended by displacement analysis generating detailed profiles. Fraction of recoverable heat, thermocline width, stratification indices based on energy and exergy analysis, and mean temperature gradients in the thermocline region are calculated. These parameters are monitored under real operation conditions of the plant. The calculated parameters are studied to check their distribution and correlation. First and Second Law indices show parallel behaviour and two values are found that delimit situations of high and low values of mean temperature gradients. It was observed that buoyancy generates uniform forced movement with the right water temperature entering the diffusers, but good control strategies are essential to avoid mixing. The system demonstrated great stability in this use.

Thermal Energy Requirements of Air-Conditioning Systems

1971 ◽  
Vol 93 (2) ◽  
pp. 172-176
Author(s):  
M. E. Lackey
Keyword(s):  
Thermal Energy ◽  
Air Conditioning ◽  
Waste Heat ◽  
Energy Requirements ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Absorption Refrigeration System ◽  
Air Conditioning Systems

The thermal energy requirements for air conditioning by compressive and absorption methods were determined for light-water, thermal-breeder, and fast-breeder reactors. The energy required to produce a ton-hour of refrigeration varied from 5100 Btu to 13,100 Btu by absorption and from 5600 to 8800 Btu by compression. The amount of waste heat dissipated to the environment at the reactor site as a consequence of producing a ton-hour of air conditioning ranged from an increase of 21,000 Btu for the electric-motor-driven refrigeration system to a decrease of 6000 Btu for the absorption refrigeration system.

Numerical investigation of induced thermal impacts from high-temperature thermal energy storage in porous aquifers

2021 ◽  
Author(s):  
Bo Wang ◽  
Jens-Olaf Delfs ◽  
Christof Beyer ◽  
Sebastian Bauer
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Capacity ◽  
Storage Temperature ◽  
Thermal Recovery ◽  
Pumping Rate ◽  
Background Temperature ◽  
C 30

<p>High-temperature aquifer thermal energy storage (HT-ATES) in the geological subsurface will affect the temperature distribution in and close to the storage site, with potential impacts on groundwater flow and biogeochemistry. Quantification of the subsurface space affected by a HT-ATES operation is thus required as one basis for urban subsurface space planning, which would allow to address potential competitive and conflicting uses of the urban subsurface. Therefore, this study shows a quantitative evaluation of induced thermal impacts and subsurface space required for a synthetic ATES operated at varying temperature levels.</p><p>A hypothetic seasonal HT-ATES operation is simulated using the coupled groundwater flow and heat transport code OpenGeoSys. A well doublet system consisting of fully screened “warm” and “cold” wells 500 m apart is used for the storage operation. A sandy aquifer typical for the North German Basin at a depth of 110 m and with a thickness of 20 m in between two confining impermeable layers is used as storage formation. Seasonal cyclic storage is simulated for 20 years, assuming charging and discharging for six months each. During charging, water with the aquifer background temperature of 13°C is extracted at the "cold" well, heated to 70°C and reinjected at the “warm” well using a pumping rate of 30 m³/h. During discharging, the stored hot water is retrieved at the "warm" well using the same pumping rate and reinjected at the “cold” well after heat extraction at aquifer background temperature.</p><p>The simulation results show that during a single storage cycle using a storage temperature of 70°C 7.51 GWh of thermal energy is injected, of which 4.79 GWh can be retrieved. This corresponds to a thermal recovery factor of 63.8% and thus an effective storage capacity of 0.43 kWh/m<sup>3</sup>/K can be deduced in relation to the heat capacity of the storage medium. For storage temperatures of 18°C, 30°C and 50°C, the effective storage capacity is 0.56 kWh/m<sup>3</sup>/K, 0.55 kWh/m<sup>3</sup>/K and 0.49 kWh/m<sup>3</sup>/K, respectively. By delineating the subsurface volume with a temperature increase larger than 1°C, the subsurface space used for and affected by the storage operation at the storage temperature of 70 °C is determined to be 10.56 million m³. In relation to the retrieved thermal energy, a subsurface volume of 2.2 m<sup>3 </sup>is thus required to retrieve one kWh of heat energy at 70 °C injection temperature. At lower temperatures of 18°C, 30°C and 50°C, the subsurface space required is 1.77 m<sup>3</sup>/kWh, 1.54 m<sup>3</sup>/kWh and 1.76 m<sup>3</sup>/kWh, respectively. The lower effective storage capacity and the relatively larger required space, which correspond to a lower thermal recovery factor, are caused by induced thermal convection and higher heat losses by conduction at higher temperatures.</p>

Analysis of Thermal Energy Storage to a Combined Heat and Power Plant

2021 ◽  
Vol 9 (9) ◽  
pp. 1313-1320
Author(s):  
Shahim Nisar
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Demand ◽  
Power Plants ◽  
Heat Storage ◽  
Packed Bed ◽  
Water Tank ◽  
Latent Heat Storage ◽  
Storage Methods

Abstract: Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. TES systems are used particularly in buildings and in industrial processes. This paper is focused on TES technologies that provide a way of valorizing solar heat and reducing the energy demand of buildings. The principles of several energy storage methods and calculation of storage capacities are described. Sensible heat storage technologies, including water tank, underground and packed-bed storage methods, are briefly reviewed. Additionally, latent-heat storage systems associated with phase-change materials for use in solar heating/cooling of buildings, solar water heating, heat-pump systems, and concentrating solar power plants as well as thermo-chemical storage are discussed. Finally, cool thermal energy storage is also briefly reviewed and outstanding information on the performance and costs of TES systems are included.

scholarly journals Seasonal Energy Flexibility Through Integration of Liquid Sorption Storage in Buildings

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2944
Author(s):  
Luca Baldini ◽  
Benjamin Fumey
Keyword(s):  
Energy Storage ◽  
Heat Pump ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy System ◽  
Coefficient Of Performance ◽  
Electric Load ◽  
Single Family ◽  
Electricity Grid

The article estimates energy flexibility provided to the electricity grid by integration of long-term thermal energy storage in buildings. To this end, a liquid sorption storage combined with a compression heat pump is studied for a single-family home. This combination acts as a double-stage heat pump comprised of a thermal and an electrical stage. It lowers the temperature lift to be overcome by the electrical heat pump and thus increases its coefficient of performance. A simplified model is used to quantify seasonal energy flexibility by means of electric load shifting evaluated with a monthly resolution. Results are presented for unlimited and limited storage capacity leading to a total seasonal electric load shift of 631.8 kWh/a and 181.7 kWh/a, respectively. This shift, referred to as virtual battery effect, provided through long-term thermal energy storage is large compared to typical electric battery capacities installed in buildings. This highlights the significance of building-integrated long-term thermal energy storage for provision of energy flexibility to the electricity grid and hence for the integration of renewables in our energy system.

scholarly journals Development of a Latent Heat Thermal Energy Storage Material-Based Refrigeration System

2021 ◽  
Vol 39 (2) ◽  
pp. 469-476
Author(s):  
Taiwo O. Oni ◽  
Jacob B. Awopetu ◽  
Samson A. Adeleye ◽  
Daniel C. Uguru-Okorie ◽  
Anthony A. Adeyanju ◽  
...  
Keyword(s):  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Performance Characteristics ◽  
Coefficient Of Performance ◽  
Evaporator Temperature ◽  
Salt Hydrate ◽  
Compressor Work ◽  
Thermal Energy Storage Material

The present research focuses on application of thermal energy storage on a convectional refrigerator to enhance its performance. Salt hydrate was used as latent heat thermal energy storage (LHTES) material to convert the convectional refrigerator to a LHTES material-based refrigerator. The cabinet of the convectional refrigerator was loaded with 10 kg of water at a temperature of 28℃ and experiments were conducted on it to know the time taken for the evaporator temperature (TE) to reach -5℃, and determine the performance characteristics of the convectional refrigerator. The experiments were repeated on the LHTES material-based refrigerator to compare its performance characteristics with those of the convectional refrigerator. The results reveal that the evaporator of the LHTES material-based refrigerator attains the temperature of -5℃ forty minutes before the same temperature (-5℃) was attained in the evaporator of the convectional refrigerator. For the interval of evaporator temperature (−5∘C≤TE≤−1∘C) considered for evaluation of the performance characteristics of the refrigerators in this work, when TE drops from 1℃ to -5℃, the coefficient of performance (COP) for the LHTES material-based refrigerator and convectional refrigerator decreases from 7.36 to 4.62 and 6.44 to 4.15, respectively; the refrigerating effect decreases from 118.41 kJ/kg to 111.80 kJ/kg and 113.37 kJ/kg to 106.69 kJ/kg, respectively; the compressor work increases from 15.10 kJ/kg to 23.18 kJ/kg and 17.60 kJ/kg to 25.68 kJ/kg, respectively. The higher value of the COP and refrigerating effect, and the lower value of the compressor work of the LHTES material-based refrigerator compared with those of the convectional refrigerator imply that there is an improvement in the performance of the refrigerator with the LHTES material. The current work broadens research on the use of a LHTES materials to enhance the performance of a refrigerator.

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