scholarly journals Experimental Study on the Performance of a Phase Change Slurry-Based Heat Pipe Solar Photovoltaic/Thermal Cogeneration System

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Hongbing Chen ◽  
Yutong Gong ◽  
Ping Wei ◽  
Pingjun Nie ◽  
Yaxuan Xiong ◽  
...  
Keyword(s):  
Phase Change ◽  
Heat Pipe ◽  
Thermal Energy ◽  
Unit Area ◽  
Energy Performance ◽  
Hot Water ◽  
Electrical Performance ◽  
Working Fluid ◽  
Solar Pv ◽  
T System

By employing phase change slurry (PCS) as working fluid for the heat pipe solar PV/T system, the study is designed to investigate the electrical and thermal energy performance of the system. Meanwhile, through examining the performance difference between water-based and PCS-based heat pipe solar PV/T systems, 30% alkyl hydrocarbon PCS is proved to be a suitable working fluid for optimized energy performance based on the combined consideration of the thermophysical and rheological properties. Both static and dynamic stability tests show that 30% alkyl hydrocarbon PCS has a good stability for low-temperature thermal energy storage. A testing rig is constructed consisting of two identical heat pipe solar PV/T cogeneration systems A and B, in which water and 30% alkyl hydrocarbon PCS are, respectively, employed as working fluids; the energy performance of those two PV/T systems are investigated and compared with each other under the same testing condition. The results indicate that the application of PCS to the heat pipe PV/T system leads to a significant improvement in thermal performance and a modest growth in electrical performance. The daily heat gains and overall average efficiency of system B are 4.2 MJ/m2 (per unit area of PV/T panel) and 59.3%, respectively, 27.3% and 9.3% higher than those of system A. Per unit area of the heat pipe PV/T panel could produce 55.2 L domestic hot water of about 45°C on a sunny day.

scholarly journals Theoretical and Experimental Evaluation of the Working Fluid Temperature Levels in a CPV/T System

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3077
Author(s):  
Carlo Renno
Keyword(s):  
Thermal Energy ◽  
Integrated System ◽  
Hot Water ◽  
Experimental Comparison ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Cooling Fluid ◽  
Operation Conditions ◽  
Temperature Levels ◽  
T System

A linear focus Concentrator Photovoltaic and Thermal (CPV/T) system can match the thermal demands of a user. The evaluation of the cooling fluid temperature levels of a CPV/T system is fundamental to understand if this system is capable of satisfying the typical thermal requirements of a residential user (heating, cooling and domestic hot water). First, an experimental line-focus CPV/T system, realized in the Laboratory of Applied Thermodynamics of the University of Salerno (Italy), has allowed to determine the cooling fluid temperature at the CPV/T system outlet. Successively, the cooling fluid temperatures, experimentally obtained, have been compared with the same temperatures calculated by means of a theoretical model under the same operation conditions. A deviation in terms of the percentage relative error between theoretical and experimental results included between about 0.5% and 5%, has been found. The goodness of the theoretical–experimental comparison in terms of the temperature of the operation fluid at the CPV/T system outlet has represented a fundamental point to evaluate theoretically, by means of the TRNSYS software, the other levels of temperature of an integrated system, constituted by CPV/T system, thermal tank and user, for different temporal scenarios (hourly, weekly, monthly and yearly). The input data of the TRNSYS model are: Direct Normal Irradiance (DNI), Triple-Junction (TJ) cell temperature and environmental conditions. A tank model is also adopted to satisfy the thermal energy demand peaks, and the temperature stratification in the tank linked to the CPV/T system, as function of the height, is obtained in winter and summer. It is important to define these thermal levels to verify if a CPV/T system is capable to satisfy the residential user energy demands or a thermal energy integration is necessary in some periods of the year. A good stratification has been noted in the summer season, with temperature values that are variable between about 40 and 90 °C. From April to October, the tank average temperature is generally resulted about 10 °C higher than the temperature required by the fluid sent to the residential user, and a very low integration is then necessary. It has been verified that the CPV/T system covers a large part of the thermal energy needs of the residential user during the year; the coverage is limited only in the winter months.

scholarly journals Controllable and flexible energy production in a water-based photovoltaic/thermal system

2019 ◽  
Vol 8 (4) ◽  
pp. 473
Author(s):  
AA. Aminou Moussavou ◽  
AK. Raji ◽  
M. Adonis
Keyword(s):  
Thermal Energy ◽  
Heat Dissipation ◽  
Thermal Power ◽  
Hot Water ◽  
Working Fluid ◽  
Solar Photovoltaic ◽  
Photovoltaic Thermal System ◽  
Pv Cell ◽  
Useful Heat ◽  
T System

A combined solar photovoltaic and thermal (PV/T) system is not just a product that makes our life easier, nor is it a luxury. In the future economics will make the use of the PV/T system essential. The purpose of this to improve the energy balance in a PV/T system, by control-ling the thermal energy (useful heat) production for the domestic hot water as well as the electrical production. Simulation and analysis of a simplified model of the PV/T system for cooling the PV cell and heating the working fluid inside of the absorber pipe attached at the back of the PV cell were implemented in MATLAB /Simulink software. The optimal electrical and thermal power were obtained by selecting a par-ticular value of Rse that partially converts the output of the PV cell into useful thermal energy. It was discovered that increasing the chosen value of Rse results in higher heat dissipation in the PV/T cell, an increase in thermal efficiency, and also a decrease in electrical efficiency.  

scholarly journals Influence of void ratio on phase change of thermal energy storage for heat pipe receiver

2016 ◽  
Vol 25 (2) ◽  
pp. 275-287 ◽  
Author(s):  
X. Gui ◽  
T. Li ◽  
D. Yuan ◽  
Sh. Liang ◽  
D. Tang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Heat Pipe ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Void Ratio

scholarly journals Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (2S2) ◽  
pp. 143-147 ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Hot Water ◽  
Working Fluid ◽  
Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

scholarly journals Enhancement of the Thermal Energy Storage Using Heat-Pipe-Assisted Phase Change Material

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6176 ◽  
Author(s):  
Hamidreza Behi ◽  
Mohammadreza Behi ◽  
Ali Ghanbarpour ◽  
Danial Karimi ◽  
Aryan Azad ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Heat Pipe ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Liquid Fraction ◽  
Energy Storage Applications ◽  
Change Material

Usage of phase change materials’ (PCMs) latent heat has been investigated as a promising method for thermal energy storage applications. However, one of the most common disadvantages of using latent heat thermal energy storage (LHTES) is the low thermal conductivity of PCMs. This issue affects the rate of energy storage (charging/discharging) in PCMs. Many researchers have proposed different methods to cope with this problem in thermal energy storage. In this paper, a tubular heat pipe as a super heat conductor to increase the charging/discharging rate was investigated. The temperature of PCM, liquid fraction observations, and charging and discharging rates are reported. Heat pipe effectiveness was defined and used to quantify the relative performance of heat pipe-assisted PCM storage systems. Both experimental and numerical investigations were performed to determine the efficiency of the system in thermal storage enhancement. The proposed system in the charging/discharging process significantly improved the energy transfer between a water bath and the PCM in the working temperature range of 50 °C to 70 °C.

A comprehensive review on the impact of nanofluid in solar photovoltaic/thermal system

2021 ◽  
pp. 095440622110556
Author(s):  
E Manikandan ◽  
K Mayandi ◽  
M Sivasubramanian ◽  
N Rajini ◽  
S Rajesh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Physical Properties ◽  
Energy Resource ◽  
Green Energy ◽  
Electrical Performance ◽  
Solar Photovoltaic ◽  
Solar Pv ◽  
The Impact ◽  
Thermo Physical Properties ◽  
T System

Solar energy is a major renewable energy resource used in power production, heating processes, and other applications such as domestic and industrial utilization. It is an abundant form of green energy. Different techniques have been made for energy conversion and one among them is solar photovoltaic/thermal (PV/T) system. Unfortunately, the greatest cause of concern is the rise in temperature of solar PV cells, which will have a negative effect on electrical performance. Thereby, eliminating excess heat on PV cells with heat transfer fluids to lower the temperature of the cells can improve electrical efficiency. A nanofluid is a promising heat transfer fluid to effectively enhance the system efficacy compared with conventional fluids. As the nanoparticle size is very small, the surface area of the nanoparticle is large so it enhances the heat transfer rate. Thereby, recently it has taken on a new dimension for research studies to enhance its thermal behavior for engineering application. This review paper discusses about the importance of nanofluid in solar PV/T system and advantages of employing nanofluid in PV/T system which has high thermo-physical properties. Nanoparticle and nanofluid preparation methods were presented. The thermo-physical properties like thermal conductivity, viscosity, density, and specific heat capacity were also discussed.

A review on the application of photovoltaic thermal systems for building façades

2019 ◽  
Vol 41 (1) ◽  
pp. 86-107 ◽  
Author(s):  
Ahmad Riaz ◽  
Ruobing Liang ◽  
Chao Zhou ◽  
Jili Zhang
Keyword(s):  
Thermal Energy ◽  
Large Scale ◽  
Electrical Energy ◽  
Building Envelope ◽  
Hot Water ◽  
Working Fluid ◽  
Thermal Systems ◽  
Air Supply ◽  
Building Facades ◽  
Photovoltaic Thermal System

The hybrid photovoltaic-thermal system has shown great progress. Electrical energy is produced from PV panels while thermal energy is produced via a working fluid carried through the panels. In this paper, the vertical PV/T is introduced using working fluids such as air and liquid, which serve to control the excess temperature of the PV panels as well as to collect heat to be made available as thermal energy. Installations of PV/T systems on building façades, as well as integration with other technologies such as heat pipe and heat pump are also discussed. Current studies of such building integration technologies are also explored, including the scale of application. This study aims to provide constructive information which can be used in future development of building facades for large-scale applications, to contribute to future sustainable development. Practical application: This study helps researchers and engineers who are considering photovoltaic thermal systems for building façades to have better understanding of its effect on electrical and thermal energy – for space heating, fresh air supply and hot water supply – using an active building envelope.

Analysis of Flow Through Packed Bed of Spheres Containing Phase Change Materials for Thermal Energy Storage Applications

2019 ◽  
Author(s):  
Vinit V. Prabhu ◽  
Ethan Languri ◽  
Kashif Nawaz
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Response Time ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Response Rate ◽  
Packed Bed ◽  
Hot Water

Abstract The research on thermal energy storage (TES) systems have received a lot of attention in recent decades for sustainable use of thermal energy in various industrial and residential applications. The existing challenge in designing the TES is the response time of charging and discharging cycles that keeps these systems away from wide utilization in industries. Literature data show that beside the low thermal conductivity of most phase change materials (PCMs) as active media in TES systems, the poor flow distribution may be another factor affecting the response rate. This study aims to considerably reduce the response time by packing the PCMs in a bed of spheres made of high thermal conductivity material. The response rate during the charging cycle is studied numerically by passing hot water at 70 °C over the packed bed of spheres. The numerical analysis is performed using ANSYS Fluent 19. The PCM used in this study is a paraffin and has a melting point of 48 °C. The response rate of the system is studied and it is compared to other similar systems mentioned in literature. The amount of energy storage is also studied by changing the flow rate of water.

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