Water Cooling Method to Improve the Performance of Field-Mounted, Insulated, and Concentrating Photovoltaic Modules

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Matthew K. Smith ◽  
Hanny Selbak ◽  
Carl C. Wamser ◽  
Nicholas U. Day ◽  
Mathew Krieske ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Crystalline Silicon ◽  
Cooling System ◽  
Effective Means ◽  
Operating Conditions ◽  
Energy Output ◽  
Mechanical Degradation ◽  
Water Cooling ◽  
Local Climate ◽  
Pv Modules

The installation rate of crystalline silicon photovoltaic (PV) modules worldwide is at an all-time high and is projected to continue to grow as the cost of PV technology is reduced. It is important to note that PV power generation is heavily influenced by the local climate. In particular, for crystalline silicon-based PV devices, as the operating temperature of the panel increases, the efficiency decreases. Higher operating temperatures also lead to accelerated material and mechanical degradation, potentially compromising system effectiveness over the lifetime of the panels. In addition, atmospheric pollution can cause particle deposition on the surface of PV modules (soiling), reducing the amount of solar irradiance that reaches the PV material and reducing panel efficiency. Various cooling and cleaning methods have been proposed in the literature to mitigate these problems. In this study, a uniform film of water was continuously recirculated by pumping over the surface of a solar panel using an emitter head attached to the top of the panel. The water cooling technique was able to maintain panel temperature below 40 °C while adjacent untreated panels were operating near 55 °C. Besides the efficiency improvements due to cooling, the film of water also kept the panels clean, avoiding any reduced power output caused by panel soiling. Additional studies were carried out with artificially chilled cooling fluid, insulating materials, and side mirrors to examine the cooling system performance under different installation scenarios. Water cooling is concluded to be an effective means of increasing the efficiency of monocrystalline silicon photovoltaic panels. Under normal operating conditions, the increased energy output from the panels is more than sufficient to compensate for the energy required to pump the water.

Performance Characteristics of Capacity Control of Industrial Water Cooler Using Pulse Modulation Valves

2010 ◽  
Vol 297-301 ◽  
pp. 790-795
Author(s):  
W.J. Choi ◽  
H.W. Kim ◽  
Seung Moon Baek ◽  
H.J. Kang ◽  
Ho Saeng Lee ◽  
...  
Keyword(s):  
Machine Tools ◽  
Cooling System ◽  
Load Capacity ◽  
Suction Side ◽  
High Accuracy ◽  
Operating Conditions ◽  
Water Cooling ◽  
Pulse Modulation ◽  
Vapor Injection ◽  
Water Cooling System

Recently, the technical trend for machine tools is focused on enhancing of speed and accuracy. For high speed and high accuracy, the thermal deformation must minimize in machine tools. To minimize the thermal influence, accurate machine tools need to be adopted to a cooling system with high precision. In this study, we suggest a high accuracy water cooling system using PMV(Pulse Modulation Valve) control. In this system, we use a compressor which is able to be driven under the condition of unloading to improve the efficiency of the PMV control. And a vapor refrigerant from the suction side of the compressor is injected back into the compressor suction side using a solenoid valve. The PMV control can be used by this method. Also, by comparing with the existing ON-OFF control method on identical operating conditions, we evaluated the efficiency and reliability of the new method. This method showed a shorter reaction time than that of the existing method. Also, the efficiency and performance improved by lower compressor work using the vapor injection without compressor stop. This study shows that the COP of this system decreased when load capacity of compressor was decreasing. In addition, the precision of this system using PMV was higher than for the ON/OFF type. This result will be used for a basis data of comparative experiment with inverter control and to manufacture of high accuracy water cooling system.

scholarly journals Investigation of the thermal effect of a tubular permanent magnet actuator with a water cooling channel for active lateral suspension of a high-speed train

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401881966
Author(s):  
Dong-wook Kim ◽  
Jung-Hyun Woo ◽  
Kyoung-Su Park
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Ride Comfort ◽  
Cooling System ◽  
Operating Conditions ◽  
Design Parameters ◽  
Water Cooling ◽  
Transfer Coefficients ◽  
Permanent Magnet Actuator ◽  
Water Cooling System

Worldwide, high-speed rail is becoming an increasingly popular and efficient means of transport. However, increasing the speed of a train leads to major reductions in stability and ride comfort. Here, we develop a tubular permanent magnet actuator to overcome these problems. To increase actuator thrust, the electromagnetic circuit requires a high current and, thus, becomes hot. We use a water cooling system with 12 straight copper channels to reduce the temperature. We calculate heat transfer coefficients using empirical convection correlations between laminar flow in the channels and experimental results. The predicted, tube surface temperatures correlated well with the experimental data. We evaluated the effects of flow rate and initial water temperature on various design parameters. The cooling system allowed application of a current greater than 100 A, developing a thrust force of over 8000 N. Thus, the system was robust under harsh operating conditions. We measured the thrust and cogging forces and the performance of the water cooling system in terms of the maximum acceptable temperature. The thrust was high and the cogging torque was low, greatly reducing lateral vibration; the temperature remained below the acceptable maximum.

Evaluation of an Integrated Photovoltaic-Thermal Option for HVAC Cooling System in UAE

2015 ◽  
Author(s):  
Mohamed Gadalla ◽  
Amani Al Hammadi ◽  
Dina Gadalla
Keyword(s):  
Alternative Energy ◽  
Cooling System ◽  
Cooling Capacity ◽  
Commercial Buildings ◽  
Integrated System ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Energy Output ◽  
Energy And Exergy ◽  
New Interpretation

This paper investigates the integration of a photovoltaic-Thermal Collector (PV/T) and a Triple Effect Absorption System (TEAS) for cooling residential as well as commercial buildings. Energy and exergy analyses are conducted to examine the performance of the recommended system and to investigate the variation of different operating conditions and PV/T characteristics on the overall performance of the PV/T collector. Power and heat generated by the PV/T system are used to mainly drive mainly the TEAS by supplying power and heat to the HTG. This paper studies the effect of the of average solar radiation for different months during the year on the Coefficient of Performance (COP) and/or the overall efficiency of the (PV/T) collector integrated with TEAS to produce 10 kW of cooling capacity. This paper also investigates how the rate of energy output of the PV/T collector. It is found that energetic and exergetic efficiencies of the PV/T collector as well as the overall energetic and exergetic efficiencies of the integrated system decrease with increasing the solar irradiance. The analyses show that the maximum energetic and exergetic COPs obtained for PV/T integrated with TEAS are 2.32 and 2.06; respectively. Finally, this paper provides a new interpretation in which alternative energy is utilized in operating HVAC cooling systems and presents a new insight into one of the most sustainable integrated systems that can be applied in residential and commercial buildings in the UAE.

Performance Evaluation of Combined Photovoltaic Thermal Water Cooling System for Hot Climate Regions

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
M. Salem Ahmed ◽  
A. S. A. Mohamed ◽  
Hussein M. Maghrabie
Keyword(s):  
Surface Temperature ◽  
Cooling System ◽  
Back Surface ◽  
Back Side ◽  
Water Cooling ◽  
Electrical Efficiency ◽  
Pv Module ◽  
Hot Climate ◽  
Pv Modules ◽  
Water Cooling System

Solar electric power generation utilizing photovoltaic (PV) modules is associated with low electrical efficiency that substantially decreases as its surface temperature exceeds an appropriate limit, particularly in hot climate regions. Consequently, it is required to keep PV modules relatively under a condition of low temperature using a cooling system as possible. The present experimental study evaluates the performance of the combined photovoltaic thermal (PV/T) module employing a water cooling system attached to the back surface during June for the city of Sohag in Egypt. The experimental results show that utilizing a water cooling system decreases the average surface temperature of the PV module from 44.8 °C to 30.3 °C on the back side and from 46.6 °C to 36.9 °C on the front side. The maximum value of the thermal heat gain of the PV/T module that is maintained at noon equals 230 W, and the corresponding value of the electrical power output is 34.4 W. Furthermore, the electrical efficiency of the PV/T module is 8% higher than that of the PV module without a water cooling system. Finally, the maximum and average values of the overall efficiency of PV/T module are 76.4% and 68.9%, respectively.

scholarly journals Experimental and Theoretical Validation of One Diode and Three Parameters–Based PV Models

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2140
Author(s):  
Rui Castro ◽  
Miguel Silva
Keyword(s):  
Crystalline Silicon ◽  
Theoretical Data ◽  
High Irradiance ◽  
Operating Conditions ◽  
Computational Time ◽  
Electrical Behavior ◽  
Pv Modules ◽  
Iterative Equations ◽  
3P Model ◽  
Theoretical Results

The present paper defines and assesses a new simplified method to represent the photovoltaic (PV) modules’ electrical behavior, based on the commonly used one diode and three parameters (1D + 3P) model, addressing two main objectives. The first one is to quantify and assess, at different operating conditions, the PV modules electrical behavior estimations’ accuracy provided by the well-known 1D + 3P, through a comparison based on experimental and theoretical results. The second one concerns the performance assessment of the 1D + 3P model’s suggested approximation, aiming at simplifying the mathematics instead of solving complex iterative equations, which hinges on higher computational time to obtain accurate results. Hence, experimental and theoretical data were considered, aiming at performing a thorough comparison with more than 17,000 PV modules being assessed, which was achieved by using both the California Energy Commission (CEC) database and PVsyst software. The findings show that the already known 1D + 3P model delivers satisfactory power output estimations for crystalline silicon modules and high irradiance conditions. However, its performance worsens when considering Low Irradiance and thin-film technology. In comparison with the original model, accurate results were obtained with the new simplified suggested 1D + 3P for all irradiance conditions and technologies assessed, thus proving its validity and capability of circumventing the aforementioned challenges.

scholarly journals Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

2019 ◽  
Vol 15 ◽  
pp. 963-970 ◽  
Author(s):  
Sora Park ◽  
Jeung Gon Kim
Keyword(s):  
Ball Milling ◽  
Mechanochemical Synthesis ◽  
Polymeric Materials ◽  
Solvent Free ◽  
Energy Output ◽  
Polymerization Temperature ◽  
Mechanical Degradation ◽  
Trimethylene Carbonate ◽  
Rate Acceleration ◽  
Conventional Solution

Mechanochemical polymerization is a rapidly growing area and a number of polymeric materials can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation.

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

scholarly journals Efficient Cell Segmentation from Electroluminescent Images of Single-Crystalline Silicon Photovoltaic Modules and Cell-Based Defect Identification Using Deep Learning with Pseudo-Colorization

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4292
Author(s):  
Horng-Horng Lin ◽  
Harshad Kumar Dandage ◽  
Keh-Moh Lin ◽  
You-Teh Lin ◽  
Yeou-Jiunn Chen
Keyword(s):  
Deep Learning ◽  
Defect Detection ◽  
Crystalline Silicon ◽  
Cell Segmentation ◽  
Solar Pv ◽  
Single Crystalline Silicon ◽  
Defect Inspection ◽  
Defect Identification ◽  
Pv Modules ◽  
A Cell

Solar cells may possess defects during the manufacturing process in photovoltaic (PV) industries. To precisely evaluate the effectiveness of solar PV modules, manufacturing defects are required to be identified. Conventional defect inspection in industries mainly depends on manual defect inspection by highly skilled inspectors, which may still give inconsistent, subjective identification results. In order to automatize the visual defect inspection process, an automatic cell segmentation technique and a convolutional neural network (CNN)-based defect detection system with pseudo-colorization of defects is designed in this paper. High-resolution Electroluminescence (EL) images of single-crystalline silicon (sc-Si) solar PV modules are used in our study for the detection of defects and their quality inspection. Firstly, an automatic cell segmentation methodology is developed to extract cells from an EL image. Secondly, defect detection can be actualized by CNN-based defect detector and can be visualized with pseudo-colors. We used contour tracing to accurately localize the panel region and a probabilistic Hough transform to identify gridlines and busbars on the extracted panel region for cell segmentation. A cell-based defect identification system was developed using state-of-the-art deep learning in CNNs. The detected defects are imposed with pseudo-colors for enhancing defect visualization using K-means clustering. Our automatic cell segmentation methodology can segment cells from an EL image in about 2.71 s. The average segmentation errors along the x-direction and y-direction are only 1.6 pixels and 1.4 pixels, respectively. The defect detection approach on segmented cells achieves 99.8% accuracy. Along with defect detection, the defect regions on a cell are furnished with pseudo-colors to enhance the visualization.

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