Optimal Ecological Performance Investigation of a Quantum Harmonic Oscillator Brayton Refrigerator

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaowei Liu ◽  
Lingen Chen ◽  
Shuhuan Wei ◽  
Fankai Meng
Keyword(s):  
Harmonic Oscillator ◽  
Loss Rate ◽  
Ecological Function ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Ecological Performance ◽  
Heat Leakage ◽  
Classical Approximation ◽  
Quantum Friction

Abstract A model for the quantum Brayton refrigerator that takes the harmonic oscillator system as the working substance is established. Expressions of cooling load, coefficient of performance (COP), and ecological function are derived. With numerical illustrations, the optimal ecological performance is investigated. At the same time, effects of heat leakage and quantum friction are also studied. For the case with the classical approximation, the optimal ecological performance, and effects of heat leakage and quantum friction are also investigated. For both general cases and the case with classical approximation, the results indicate that the ecological function has a maximum. The irreversible losses decrease the ecological performance, while having different effects on the optimal ecological performance. For the case with classical approximation, numerical calculation with friction coefficient μ = 0.02 and heat leakage coefficient Ce = 0.01 shows that the cooling load (RE) at the maximum ecological function is 6.23% smaller than the maximum cooling load (Rmax). The COP is also increased by 12.1%, and the exergy loss rate is decreased by 27.6%. Compared with the maximum COP state, the COP (ɛE) at the maximum ecological function is 0.55% smaller than the maximum COP (ɛmax) and that makes 7.63% increase in exergy loss rate, but also makes 6.17% increase in cooling load and 6.20% increase in exergy output rate.

Modelling and Simulation of a Solar Single Effect Absorption Cooling System in Aspen Hysys®

2016 ◽  
Author(s):  
Erni S. Ramos ◽  
Guillermo E. Valencia ◽  
Adriana M. Jiménez ◽  
Marisol Osorio ◽  
Marley C. Vanegas
Keyword(s):  
Loss Rate ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Second Law ◽  
Total Solar Radiation ◽  
Steady State Condition ◽  
Aspen Hysys ◽  
Absorption Cooling ◽  
Single Effect

As an alternative to conventional vapor compression cooling systems, a thermodynamic analysis with the integration of Aspen Hysys® and MatLab® to a solar driven single effect LiBr - Water absorption cooling is conducted in this paper under meteorological conditions for Barranquilla in Colombia supplied with a solar captive system integrated by 15 flat plat solar collectors Barilla F22AR. First law and second law of thermodynamic are applied to system in order to calculate the thermodynamic states and exergy of each stream of the system, in addition to the Coefficient of performance and second law exergy efficiency of the chiller, and exergy loss rate for every component and the whole system. The influence of monthly variation of total solar irradiance on COP, exergy efficiency and exergy loss rate is evaluated in this study under steady state condition for each month of the year. The results of this study show a proportional relationship between heat loads calculated in each component and the heat flow supplied by the solar captive system to the generator, moreover the total solar radiation is directly related to the COP and inversely proportional exergy efficiency.

Exergy-Based Ecological Optimization of an Irreversible Quantum Carnot Heat Pump with Spin-1/2 Systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaowei Liu ◽  
Lingen Chen ◽  
Yanlin Ge ◽  
Huijun Feng ◽  
Feng Wu ◽  
...  
Keyword(s):  
Heat Pump ◽  
Performance Comparison ◽  
Ecological Function ◽  
Performance Characteristics ◽  
Numerical Examples ◽  
Ecological Performance ◽  
Special Cases ◽  
Heating Load ◽  
Ecological Optimization

AbstractBased on an irreversible quantum Carnot heat pump model in which spin-1/2 systems are used as working substance, an exergy-based ecological function and some other important parameters of the model heat pump are derived. Numerical examples are provided to investigate its ecological performance characteristics. The influences of various irreversibility factors on the ecological performance are discussed. Performance comparison and discussion among maximum points of ecological function, heating load, and so on, are conducted. At last, three special cases are discussed.

Thermodynamic Performance of an Actual Thermo-Acoustic Refrigeration Micro-Cycle

2012 ◽  
Vol 614-615 ◽  
pp. 64-68
Author(s):  
Tuo Wang ◽  
Feng Wu ◽  
Jin Hua Fei ◽  
Ming Fang Liu
Keyword(s):  
Coefficient Of Performance ◽  
Pressure Amplitude ◽  
Cooling Load ◽  
Acoustic Effect ◽  
Thermodynamic Performance ◽  
Monotonically Increasing Function ◽  
Analytic Expressions ◽  
New Type ◽  
The Relationship ◽  
Increasing Function

Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.

Increase of energy efficiency ratio of a direct evaporative cooler by dynamic behavior with energy and exergy analysis

2021 ◽  
pp. 095440622110420
Author(s):  
Behzad Omidi Kashani
Keyword(s):  
Energy Efficiency ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Dynamic State ◽  
Circulation Rate ◽  
Cooling Load ◽  
Efficiency Ratio ◽  
Static State ◽  
Circulation Pump ◽  
Water Rate

The present research is about increasing the energy efficiency ratio (EER) in current direct evaporative coolers (DEC) in Iran. Increasing the cooling load and reducing the electrical energy consumption simultaneously (increasing the energy efficiency ratio (EER)) in DEC are the main goals of manufacturers and consumers of this device. When the circulation water pump runs continuously (static state), the circulation water rate is about 1.89 to 2.90 times of the amounts recommended in the reasonable standards. In order to adjust the circulation water rate to the recommended amount by standards, the present study has utilized repetitive cyclic scheduling programs to reduce the circulation rate to the optimal amount, (by turning the circulation pump on and off by dynamic pattern operation). In other words, the circulation pump stays on only for a certain period of a working cycle, and then the pump stays off for the rest of it. The cooling load and EER were measured based on ASHRAE 133 (2015). The results indicated that the cooling load in the dynamic state increased by 5.03 and 6.18 percent compared to the static state at low and high fan speeds, respectively. Moreover, in comparison with the static state, the amount of electrical energy consumed (kW-hr) in the dynamic state decreased by 8.8 and 4.2 percent at low and high fan speeds, respectively. Finally, the coefficient of performance (COP or EER) of the DEC in the dynamic state is increased by 15.16 and 10.78 in comparison with the static state at low and high fan speeds, respectively.

scholarly journals ENERGY IMPLEMENTATION OF SOLAR PANELS FOR REFRIGERATOR NEEDS LOAD FISHING RESULTS 80 WATT MAXIMUM CAPACITY 20 KG

2019 ◽  
Vol 4 (1) ◽  
pp. 19-31
Author(s):  
A. YUNUS NASUTION ◽  
ADITYA PRATAMA
Keyword(s):  
Power Consumption ◽  
Solar Panel ◽  
Coefficient Of Performance ◽  
Total Power ◽  
Cooling Load ◽  
Solar Panels ◽  
Average Output ◽  
Average Value ◽  
Battery Capacity ◽  
Compressor Power

The initial problems of fishermen still use their semi-modern catches and still use ice cubes as a cooling medium, due to the lack of innovation in the development of the cooling media caught by fishermen. The implementation of solar panel energy is the beginning for the development of refrigerator power consumption caught by fishermen. The goal is to calculate the cooling load on the refrigerator, calculate the Coefficient of performance (COP) at the refrigerator and the loading factors at the refrigerator, where the average ambient temperature is 34 ℃ and the temperature to be achieved is 0℃, the fisherman results used in the study this is a shrimp with a capacity of 20 kg and the cooling time is 4 hours. Where the total cooling load value is 244.29 Watt, multiplied by 10% safety factor, so the overall cooling load is 268.72 Watts, refrigerant mass flow rate is 0.0012 Kg / s, the evaporator capacity is 261 Watt, compressor power is 15.6 Watt, The coefficient of performance (COP) value was 16.73 while for the refrigerant capacity was 0.074 Tons of refrigerant, the loading factors in the study were used to run a refrigerator with 80 Watt power for 4 hours, so that the total refrigerator load was 320 Wh (Watt hour) , to produce 320 Wh power is used 2 solar panel modules with a capacity of 50 Wp (Watt Peak), and uses a solar change controller (SCC) with a capacity of 10 A. The output power of the solar panel is influenced by the intensity of the sun's light emitted, from the test obtained an average value the average output of solar panels is 90.6 watts, while the total power generated in 11 test points is 536 watts, the type used is polycrystalline, solar panels battery and inverter capacity must be greater than the refrigerator power consumption, in this study used a 12V 35 Ah battery capacity and 500 Watt Inverter

Integrated Systems for Cogeneration and Absorption Chilling: Comparison for Varying Chiller COPs

1999 ◽  
Author(s):  
R. Tang ◽  
M. A. Rosen
Keyword(s):  
Steam Turbine ◽  
Integrated System ◽  
Coefficient Of Performance ◽  
Integrated Systems ◽  
Base Case ◽  
Cooling Load ◽  
Absorption Chillers ◽  
Multi Stage ◽  
Wide Range ◽  
Thermodynamic Effects

Abstract The thermodynamic effects are demonstrated of integrating steam turbine-based cogeneration systems with absorption chillers. A wide range of realistic extraction steam pressures and coefficient of performance (COP) values of absorption chillers are considered. A simple model of a steam turbine-based cogeneration plant is used for the evaluation of the integrated system. The integrated systems are evaluated based on the ratio of fuel consumption between a base case (one-stage absorption chiller with a COP value of 0.6) and several alternative cases (multi-stage absorption chillers with COP values ranging from 0.6 to 1.5). Two categories of scenarios are considered: (i) cases where the cooling load is fixed; and (ii) cases where the cooling load is fixed and the electrical output for the integrated system is set equal to that for the base case.

Assessment of Photovoltaic Capabilities in Urban Environments: A Case Study of Islamabad, Pakistan

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Muhammad Zubair ◽  
Sajid Ghuffar ◽  
Muhammad Shoaib ◽  
Ahmed Bilal Awan ◽  
Abdul Rauf Bhatti
Keyword(s):  
Deep Learning ◽  
Solar Energy ◽  
Urban Areas ◽  
Capital City ◽  
Coefficient Of Performance ◽  
Energy Yield ◽  
Cooling Load ◽  
Zero Energy ◽  
Net Zero Energy ◽  
Net Zero

Abstract Photovoltaic (PV) estimation in an urban environment requires detection of rooftop area, design of PV system based on optimization on PV placement distance and the study of additional benefit of lower cooling load of building by shading provided by PV panels. The study is aimed at policymakers to introduce renewable energy policy toward net-zero energy buildings in urban areas. In this research, the capital city of Pakistan, Islamabad, is analyzed for rooftop PV capabilities using deep learning algorithms. The area of the rooftop is calculated by extracting buildings in high-resolution satellite imagery using a deep learning algorithm. The site location is analyzed for available solar energy resources. The distance between the rooftop-PV array is optimized based on self-shading losses, coefficient of performance, energy yield, net-zero energy analysis, and reduction of cooling load of the building provided by PV arrays as shading devices. The 40-km2 area of Islamabad considered in this research can generate 1038 GWh of solar energy annually from its 4.3-km2 rooftop area by installed capacity of 447 MW PV panels rows placed at 0.75 m apart. The electricity generated by Islamabad can curtail residential load from the national grid and form a near net-zero energy zone while the electrical energy from the grid can be provided to the industries to enhance the economy and reduce unemployment in Pakistan.

EXERGY ANALYSIS OF THE PERFORMANCE OF A VARIABLE REFRIGERANT FLOW (VRF) AIR CONDITIONING SYSTEM

2011 ◽  
Vol 19 (01) ◽  
pp. 57-68 ◽  
Author(s):  
MIGUEL PADILLA
Keyword(s):  
System Performance ◽  
Air Conditioning ◽  
Exergy Analysis ◽  
Control Volume ◽  
Hvac Systems ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Air Conditioning System ◽  
Operational Conditions ◽  
Highly Sensitive

Commercial multiple evaporators variable refrigerant flow (VRF) HVAC systems present many advantages such as being energy saving and the capability of adjusting refrigerant mass flow rate according to the change of high rises occurrence. This paper deals with an experimental control volume exergy analysis in a VRF air conditioning system. The experimental results show that the brunt of the total exergy destroyed in the whole system occurs in the outdoor unit, where the exergy destroyed in the condenser is more important. The values of coefficient of performance (COP) obtained for the tests increase as the system reaches operational conditions imposed in every indoor unit zone. The VRF system analyzed is highly sensitive to the action of the constant speed compressor. The use of an inverter compressor improves the system performance by adjusting the power consumption according to the cooling load in the evaporators.

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