Evacuated Tube Solar Collector System Research Articles

Evaluation of a micro-particle-enhanced phase-change material integrated heat pipe evacuated tube solar collector system using lanthanum oxide/water nanofluid

ABSTRACT In this study, the thermal performance of a microparticle-enhanced form-stable phase change material (PCM) integrated heat pipe evacuated tube solar collector (ETSC) system is evaluated through outdoor experimentation. The study examines the thermal performance of PCM-enhanced ETSC using acetamide with varying percentages of expanded graphite (EG) at 10, 15, and 20 wt% and aluminum microparticles at 1, 2, and 5 wt%, focusing on the use of EG at different concentrations and microparticles. The microparticle-enhanced form-stable PCM is integrated into the tube only. The system was tested under open environmental conditions, comparing outcomes with a normal ETSC system, considering water outlet temperature, charging-discharging behaviors, collector efficiency, and energy analysis. The study revealed that the micro-particle enhanced PCM integrated heat pipe ETSC system significantly improved thermal performance, energy storage and release capabilities, and efficiency in generating heat at lower solar irradiance, compared to conventional ETC systems. The maximum collector efficiency of 47.4% is achieved when utilizing acetamide with 10% EG and 2% Al, which is 10.9% more than conventional ETSC. The study explores the use of lanthanum oxide/water nanofluid in solar collectors, revealing that increasing nanoparticle concentrations enhances water outlet temperature, heat gain, and solar thermal collector efficiency up to 64.14%.

Thermodynamic analysis of an evacuated tube solar collector system for industrial building application: A case study

In this study, a modified solar-Organic Rankine Cycle (ORC) assisted hydrogen production system for two different scenarios was experimentally investigated. In the study, evacuated tube solar collector (ETSC), ORC system, proton exchanger membrane electrolyzer (PEMe) unit is discussed with a holistic perspective. The presented work includes energy and exergy analysis of solar-ORC assisted hydrogen production. According to scenario 1 (S-1), only the case of hydrogen production from the installed system is considered. According to Scenario 2 (S-2), the both electrical energy and hydrogen production from the installed system is examined. As a result of the study, the energy efficiency in S-1 and S-2 operating modes was calculated as 9.553% and 16.02%, respectively. Additionally, the highest exergy efficiency for both scenarios was calculated as 6.129% in the S-2 scenario. Furthermore, hydrogen production amount of the S-1 and S-2 scenarios was calculated as 743.1 kg/annual and 371.5 kg/annual, respectively.

Thermal performance investigation of energy storage based U-pipe evacuated tube solar collector: An experimental study

In this study thermal performance comparison of a custom made U-Pipe evacuated tube solar collector (ETC) vs commercially available heat pipe ETC (HPETC) was investigated experimentally. The performance comparison was performed over several days with and without thermal storage media. Results from testing without thermal storage media showed U-Pipe ETC achieved higher peak water temperatures than that of HPETC, maximum of 31 °C, resulting in 13% efficiency enhancement of U-Pipe ETC compared with HPETC. Results from testing with storage materials showed peak temperatures for fin and water tank of the U-Pipe ETC as 47 °C and 38.7 °C, respectively, whereas heat pipe showed values of 60 °C and 36.7 °C for max fin and water temperatures, respectively. Further performance enhancement to the U-Pipe ETC system was investigated through integration of phase change material (PCM)72 with added 1wt% multi-walled carbon nanotubes (MWCNT) nanoparticles. Peak temperatures recorded for this experiment were 63.9 °C and 43.3 °C for the U-Pipe fin and water tank, respectively. The results from this study show that the U-Pipe setup was able to achieve higher water temperatures than that of the HPETC setup. Incorporation of nano-PCM allowed for slower heat release in the water, extending useful duration of latent heat storage capability.

Assessing the performance of the evacuated tube solar collector using smart curtain through (PSO based PID) controller and Nano fluids

This research revealed control on nanofluid temperature in the evacuated tube solar collector system, where nanofluid used in ETSC as working fluid to increase heating system thermal efficiency. Smart curtain was used to shadow the evacuated tube solar collector in heating or cooling conditions to control the temperature of the nanofluid. Moreover, (PSO based PID) controller which is an artificial intelligence method was ‎applied to control on the shadow the evacuated tube solar collector. Where the curtain's main idea is to control the polarization of the sun's radiation, the work of the curtain refers to the parameters: the first parameter is the nano fluid temperature and the second is the ambient temperature, and one output parameter is defined by (distance parameter).

Control on Temperature of Hybrid Nanofluid in Evacuated Tube Solar Collector Using Smart Curtain

This research was revealed control on temperature hybrid nanofluid in evacuated tube solar collector system, where the hybrid nanofluid utilized as working fluid in ETC for enhancement the thermal performance for heating device. The smart curtain was used for purpose shadow the evacuated tube solar collector for controlling on temperature of the hybrid nanofluid in heating or cooling conditions. In addition, Adaptive neuro fuzzy inference system (ANFIS) a way of artificial intelligence was applied to control on the shadow the evacuated solar tube collector. Where the main principle of the curtain is to control the polarization of the sun radiation, the curtain work depends on three parameters were applied in ANFIS technique, two parameters are input variable like as (temperature of hybrid nanofluids (inlet, outlet) and ambient temperature, and one output parameter represents by (distance parameter).

Thermal performance of phase change material integrated heat pipe evacuated tube solar collector system: An experimental assessment

This manuscript presents an experimental investigation of heat pipe evacuated tube solar collector with and without phase change material for water heating application under the same weather conditions. In this study, a comparative analysis of two systems has been done in the same weather condition. Where evacuated tubes of the first system (evacuated tube collector-A) were left without phase change material and second system (evacuated tube collector-B) was integrated with SA-67 as phase change material. In order to ensure the thermal and chemical stability of the selected phase change material, thermal cycling treatment was carried out. The results showed that SA-67 has excellent chemical and thermal stability even after 1500 thermal cycling treatment.In order to analyze the thermal performance of the designed systems, the experiment was conducted with five different water flow rates (8, 12, 16, 20 and 24 L per hour). The daily thermal efficiency of evacuated tube solar collector with and without phase change material was varied in the range of 42–55% and 79–87% respectively. Although, the daily energy efficiency of evacuated tube collector integrated with phase change material was 37.56%, 35.31%, 36.69%, 32.34%, and 32.73% higher than evacuated tube collector without phase change material for water flow rates of 8, 12, 16, 20 and 24 L per hour respectively. The daily thermal efficiency for both systems was maximum at the flow rate of 20 L per hour. The heat transfer parameters for the designed systems have also been evaluated and compared.

Experimental performance evaluation of a novel designed phase change material integrated manifold heat pipe evacuated tube solar collector system

In this study, the thermal performance of a novel solar collector integrated with stearic acid as phase change material has been investigated. In this design, the solar radiation was collected by heat pipe equipped evacuated tubes and then stored in manifold integrated with phase change material. The stored thermal energy of phase change material then transferred to water flowing through bundle of finned copper pipes placed inside the manifold. In present study, the design, the operating principle and the experimental investigation of the developed system have been presented. The developed system was investigated with different mass flow rates and also discussed the influence of varying mass flow rate on the thermal performance of system. The experimental investigation of designed and developed system has been carried out for two modes i.e. mid-day charging mode and full-day charging mode. It has been observed that for considered mass flow rates, thermal efficiency of the system was varied in the range of approximately 52–62% for full-day charging mode while for mid-day charging mode, it was varied between 55 and 72%. The maximum value of thermal efficiency was approximately 72.52% at mass flow rate of 24 LPH for mid-day charging mode. The efficiency of phase change material for both modes was varied in the range of approximately 61–64%. The annual cost and annual fuel cost of the developed system are much lower than conventional system. Also, the initial capital cost for the developed system can be recovered after 6 years of operation. However, there is no recovery of initial investment for electricity based water heating system.The proposed system overcomes two problems associated with conventional heat pipe evacuated tube solar collector: elimination of heat pipe overheating problem and low thermal conductivity of phase change materials. By this novel design of manifold, the influence of thermal stratification on the thermal performance of solar collectors can be completely eradicated.

Improving the performance of heat pipe-evacuated tube solar collector experimentally by using Al2O3 and CuO/acetone nanofluids

Research has been undertaken on heat pipe evacuated tube solar collector (HP-ETSC) for hot water applications, which is common in most Middle East regions. The enhancement in thermal performance by using various types of acetone based nanofluids has been explored. This work includes two experimental parts of the gravity-assisted heat pipe (GAHP) installed in evacuated tube solar collector system. The first part is designed to reach the optimal performance conditions for HP-ETSC which is charged with acetone as a working fluid inside the GAHP. Various values of filling ratios (40, 50, 60, 70 and 80%) and tilt angles (30°, 45° and 60°) are considered. The results show that there is an optimal performance at filling ratio equal to 70% and inclination angle equal to 45° when compared with other values during the course of study. This indicates that the importance of fully integrating design process right from the outset of the system design if GAHP is to be installed into an ETSC system to give the maximum possible solar energy benefits of efficient hot water solar collector designs. The main objective of the second experimental investigation is analyzing the impact of the two types of nanofluid (Al2O3 and CuO/acetone-based) on the thermal performance of the HP-ETSC. These two nanofluids are used as working fluid inside the GAHP and two concentration values (0.25% and 0.5% vol.) at the optimal conditions from the first experimental part. On the basis of the present study, it is recommended that HP-ETSC systems should be charged with nanofluids for thermal performance enhancement (20–54%) and efficiency (15–38%).

Carbon nanotube nanofluid in enhancing the efficiency of evacuated tube solar collector

Abstract The use of solar thermal collectors is one of the promising options for heating and/or cooling due to the green nature (pollution free) and abundance of the solar energy in many parts of the world. Improvement of thermal performance of solar collectors is important for better energy conversion. In this regard, many studies reported in literature tried to modify geometry of the collectors. On the other hand, nanofluids as heat transfer fluids could be a promising option for the efficiency enhancement of solar collectors. In this study, heating performance of an evacuated tube solar collector system initially operated with water is considered for improvement using nanofluid. The collector (about 20 kW heating capacity) is a part of an absorption cooling system. The aim of the present study is to analyze the effect of Single Walled Carbon Nanotube–water nanofluid on the collector performance. Thermal efficiency improvement is assessed based on comparative analyses between collector working with ordinary water and that with nanofluid. The results indicate that up to 56.7% and 66% of efficiencies are observed when the collector is operated with water and 0.2 vol% nanofluid, respectively. Therefore, nanofluids are promising to enhance the efficiencies of solar collectors.

A numerical model for optimal receiver array and mass flow rate in residential solar water heating systems

ABSTRACTIn this paper, the performance of a pressurised evacuated tube solar collector system using internal heat pipes is presented. The system was optimised for the seasonal supply of hot service water for residential use in Pretoria, South Africa. The prediction of seasonal hourly performance trends along with the maximum thermal performance at the optimal receiver array and manifold mass flow rate was of major concern in this investigation. A mathematical model representing the thermal performance of the system was developed and numerically implemented in Engineering Equation Solver. The dynamic performance of collectors with 15, 20 and 25 tubes was determined throughout all the seasons. Moreover, the performance of the residential solar water heating system with a 20-tube collector was investigated in detail for mass flow rates of 0.03, 0.05 and 0.07 kg/s.

Estimation and optimization of thermal performance of evacuated tube solar collector system

In this study, artificial neural networks (ANNs) and adaptive neuro-fuzzy (ANFIS) in order to predict the thermal performance of evacuated tube solar collector system have been used. The experimental data for the training and testing of the networks were used. The results of ANN are compared with ANFIS in which the same data sets are used. The R2-value for the thermal performance values of collector is 0.811914 which can be considered as satisfactory. The results obtained when unknown data were presented to the networks are satisfactory and indicate that the proposed method can successfully be used for the prediction of the thermal performance of evacuated tube solar collectors. In addition, new formulations obtained from ANN are presented for the calculation of the thermal performance. The advantages of this approaches compared to the conventional methods are speed, simplicity, and the capacity of the network to learn from examples. In addition, genetic algorithm (GA) was used to maximize the thermal performance of the system. The optimum working conditions of the system were determined by the GA.