Absorber Tube Research Articles

Experimental evaluation on characteristics of a falling-film flow on the horizontal tube subject to ultrasonic field

The falling-film flow characteristics significantly influence the heat and mass transfer process in the horizontal tube absorber. This study experimentally investigates the effect of ultrasonic field on the flow mode transition and thickness distribution of the liquid film on the horizontal tube. The water-calcium chloride (CaCl2/water) was selected as the working fluid. The effects of the factors, such as the tube diameter, tube spacing, solution concentration, ultrasonic power, sound source distance and ultrasonic incidence angle, on the hydrodynamics of the liquid flow were analyzed. The results show that the mode transition Reynolds number increases with the increasing ultrasonic power, but reduces comparing to that without ultrasound. Moreover, in the column mode, the fluctuation range of the film thickness decreases with the increase of the ultrasound power; and the ultrasonic field help increase the average film thickness outside the tube and enhance the uniformity of liquid film.

CFD analysis of rib roughened solar evacuated tube collector for air heating

Using Computational Fluid Dynamics analysis, thermo-hydraulic performance of a rib roughened solar evacuated tube collector has been evaluated for different relative roughness pitch and mass flow rate values. Half portion of absorber tube is roughened and heated uniformly with a heat input of 1000 W/m2. The investigated roughness geometry parameters include relative roughness pitch (P/e) of the order 6–12 whereas relative roughness height is having a fixed value of 0.071. Reynolds number was varied from 2500 to 8000. In contrast to a smooth solar evacuated tube collector, Nusselt number and frictional resistance of a roughened solar evacuated tube collector increased by 1.88 and 2.89 times respectively. Thermo-hydraulic performance parameter of roughened solar evacuated tube collector was found to be 1.36 corresponding to Reynolds number and P/e values of 8000 and 10 respectively which indicates considerable benefit of applying rib roughness in a solar evacuated tube collector.

The method of determination for sulfur dioxide in the air of workplace by ion chromatography without derivatization

Objective: To establish a method for the determination of sulfur dioxide (SO2) in the air of workplace, which including the process of collection by absorption in triethanolamine aqueous solution and the process of analysis and detection by iron chromatography directly without derivatization. Methods: SO2 in the air of workplace was collected at a flow rate of 0.5 L/min for 15 min through 10 ml of 3% triethanolamine aqueous solution filled in a porous glass plate absorption tube. The absorption solution passed through IonPacAS14A analytical column (4 mm×250 mm) and IonPacAG14 protective column (4 mm×50 mm) at a column temperature of 30 ℃, using Na2CO3 (3.0 mmol/L) -NaHCO3 (1.0 mmol/L) as mobile phase with the flow rate of 1.2 ml/min, and was detected by conductivity detector. Results: It showed that SO2 in triethanolamine solution could be stored for at least 7 d at room temperature (25 ℃) and 37 ℃. There was a linear relationship within the determination range of 0-8.00 μg/ml, the linear correlation coefficient was 0.9999. The sampling absorption efficiency was 98.1%-100.0%, the detection limit of the method was 0.018 μg/ml, the minimum detection concentration was 0.024 mg/m3 (based on V0=7.5 L) . The recovery rate was 99.22%-101.69%, the intra batch precision was 0.41%-1.34%, and the inter batch precision was 0.73%-1.77%. Conclusion: The method has the advantages of simple operation, high sensitivity and good accuracy. It can prevent SO2 from being oxidized and realize the direct detection of SO2 in the air of workplace without derivation.

Effect of off-center finned absorber tube and nanoparticle shape on the performance of two-fluid parabolic solar collector containing nanofluid: An application of artificial neural network

The present paper aims to evaluate the effect of using an off-center finned absorber tube on the efficiency of a two-fluid parabolic trough solar collector (PTC) filled with a nanofluid (NF) with different nanoparticle (NP) shapes and diameters. Simulations are conducted for different Reynolds numbers and solid volume fractions (SVFs) using both the single-phase method (SPM) and two-phase method (TPM) with Fluent software. It was found that the energy efficiency of the two-fluid PTC is higher than the single-fluid PTC. In addition, the outcomes revealed that the energy efficiency of the PTC elevates with using an off-center finned absorber tube, increasing the Reynolds number and decreasing the SVF. Moreover, it was reported that the use of TPM instead of the SPM entails a rise in the energy efficiency of the PTC. Among the studied cases, the highest energy efficiency was equal to 58.9%, which belonged to the two-fluid PTC with off-center finned absorber tube filled with the NF with SVF of 1% containing spherical NPS with diameter of 40 nm at Reynolds number of 5000. Finally, the artificial neural network was employed to assess the sensitivity of energy efficiency to the Reynolds number.

Optimization of thermal efficiency on solar parabolic collectors using phase change materials - experimental and numerical study.

Solar energy is a one-of-a-kind renewable energy source that has many uses, and in the thermal applications, it is receiving more attention and is becoming more feasible. The present work presents numerical and experimental studies to investigate the performance of a parabolic trough solar concentrator (PTC) integrated with a thermal energy storage system. A new receiver design is built that stores thermal energy using phase change material (PCM). A concentric absorber tube with two different kinds of PCM - MgCl2·6H2O and erythritol (filling the annular-space of absorber tube) - were used to construct a PTC, and its thermal performance and thermal efficiency were investigated under two different HTF flow rates of 0.005 kg/s and 0.033 kg/s. Solar energy is transformed into heat, which is then used to store in the PCM before being discharged to cold water, which is the final heat transfer fluid in the receiver's inner pipe. The simultaneous studies of the PTC with and without PCM are investigated. A commercial Mat Lab's operating model through an imperialist competitive algorithm of the entire PTC system is presented, and the numerical results were compared to the experimental results, which were carried out with and without PCM in PTC. With the PCM in PTC (0.005 kg/s and 0.033kg/s), the HTF exhibited gain in peak temperatures of 11°C (erythritol) and 9°C (MgCl2·6H2O) at 0.05 kg/s, whereas the peak temperatures further increase to 14°C (erythritol) and 12°C (MgCl2·6H2O) respectively at 0.033 kg/s, as compared to HTF without PCM. Average thermal efficiency of PTC with HTF flow rate of 0.033 kg/s was highest with usage of erythritol (40.6%), among all the cases. The experimental and predicted thermal efficiency performance indices for different flow rates and PCM are found to be with a deviation of around ± 1.9%, demonstrating the accuracy of the developed numerical model.

An Experimental and Analytical Study of Influential Parameters of Parabolic Trough Solar Collector

Energy plays a vital role in all human life activities. Due to the problems caused by fossil fuels in recent decades such as global warming, greenhouse gas emissions, ozone depletion, etc., the use of renewable and clean energy has been considered. An experimental facility for the acquisition of reliable data from Parabolic Trough Solar Collectors (PTCs) was established to develop a robust analytical model. A wide range of Heat Transfer Fluid (HTF) flow rates (0.0372-0.1072 kg/s) and solar radiation (400-900 W/m2) were used to determine PTC parameters such as the outlet temperature of HTF loss and temperature distribution. Vacuum conditions in the receiver were considered effective in terms of thermal efficiency. Also, three types of HTF including two oil fluids (Syltherm 800 and S2) and water were examined. The temperature distribution showed that when Syltherm 800 or S2 passed through the absorber tube, the outlet temperature was higher than water: 2.84 % for Syltherm 800 and 3.72 % for S2. Since the absorber tube temperature was much higher than water, the heat loss in this condition was considered for oil HTF. Of note, the results demonstrated that use of the vacuum tube could diminish heat loss for the oil HTF. The effect of solar intensity increases from 600 W/m2 to 900 W/m2 on the maximum temperature of the receiver tube indicated that when Syltherm 800 was used as an HTF, this temperature increased by 35.1 % (from 167 °C to 219 °C), while this percentage was 32.7 % and 6.8 % for S2 and water, respectively.

A hybrid approach of surface and direct absorption of solar radiation on parabolic solar collector.

This paper presents a novel approach of utilizing a spectrally selective coating inside the absorber tube of a solar parabolic collector for enhanced photothermal conversion. The photothermal performance of a hybrid system that incorporates an internal coating and nanofluid is analyzed in the present work. The internal coating developed is a composite of PMMA/CuO/Epoxy and as applied using the simple dip-coating technique. The maximum weighted solar absorptance of the internal coating was found to be 57.51%. The significance and interactions of the coating process variables, like concentrations of PMMA and CuO and the number of dips, were analyzed using the central composite design (CCD) of response surface methodology (RSM). An optimized coating (Concentration of PMMA and CuO: 4997.7 and 170.8 mg/30 ml, Number of Dips: 4) was arrived at based on the desirability function. Prior to the introduction of internal coating on the parabolic solar collector, a lab-scale photothermal conversion study was carried out using the optimized internal coating. The results revealed the superior performance of the internal coating when compared with that of pure surface absorption and direct absorption. Finally, the optimized internal coating was incorporated in a parabolic collector, with CuO nanofluid as a working fluid. Maximum efficiency of 62.80% was obtained for the hybrid system the internal coating and CuO nanofluid, compared to 31.6% for a direct absorption solar collector.

Hydrothermal characteristics of a double flow parabolic trough solar collector equipped with sinusoidal-wavy grooved absorber tube and twisted tape insert

PurposePresent investigation conducts a study on the hydrothermal features of a double flow Parabolic Trough Solar Collector (PTSC) equipped with sinusoidal-wavy grooved absorber tube and twisted tape insert filled with nanofluid. This paper aims to present an effectual PTSC which is comprised by nanofluid numerically by means of finite volume method.Design/methodology/approachThe beneficial results such as pressure drop inside the absorber tube, mean predicted friction factor, predicted average Nusselt number and hydrothermal Performance Evaluation Criteria (PEC) are evaluated and reported to present the influences of numerous factors on studied interest outcomes. Effects of different Reynolds numbers and environmental conditions are also determined in this investigation.FindingsIt is found that using the absorber roof (canopy) can enhance the heat transfer ratio of PTSCs significantly during all studied Reynolds numbers. Also, it is realized that the combination of inner grooved surface, outer corrugated surface and inserting turbulator can improve the thermal-hydraulic characteristics of PTSCs sharply.Originality/valueNovel PTSC (N.PTSC) filling with two Heat Transfer Fluids (HTFs), inner and outer surface corrugated absorber tube, absorber roof and inserting twisted tape (N.PTSC.f) has the highest PEC values among all novel configurations along all investigated Reynolds numbers which is followed by configurations N.PTSC with two HTFs and inserting twisted tape (N.PTSC.e), N.PTSC with two HTFs and outer surface corrugated absorber tube (N.PTSC.b) and N.PTSC with two HTFs and inner surface corrugated absorber tube (N.PTSC.c), respectively. N.PTSC.f Nusselt number values can overcome the high values of friction factor, and therefore is introduced as the most efficient model in the current study.

Numerical investigation and neural network modeling of the performance of a dual-fluid parabolic trough solar collector containing non-Newtonian water-CMC/Al2O3 nanofluid

The performance of a novel parabolic trough collector (PTC) equipped with a non-circular absorber tube and a solid insulation is investigated numerically using the Eulerian-Eulerian two-phase method. The water-CMC/Al2O3 nanofluid is considered as the working fluid. The impacts of the Reynolds number, nanoparticle volume concentration, nanoparticle diameter and insulation angle on the performance metrics are examined. The results showed that the changes of collector efficiency with Reynolds number has an ascending-descending pattern. In addition, it was found that the highest collector efficiency is 61.7%, which belongs to the case of dual-fluid collector with a novel tube and insulation angle of 90° containing nanofluid with φ=1.5% and nanoparticle diameter of 100 nm. Finally, the artificial neural network was employed to provide a predictive model for the collector efficiency. It was found that the neural network consisting of eight neurons has a high potential in forecasting the efficiency of the novel collector. The maximum deviation was less than 0.2% and this high accuracy caused the R-square for the neural network to be 0.9998.

Modeling of natural convection of a concentrated solar power receiver absorber tube in interaction with neighbouring absorbers

Concentrated Solar Power (CSP) technology stands out among other renewable energy sources not only because of its ability to address current energy security and environmental challenges but because its energy can be stored for future use. To ensure optimum performance in this system, the heat losses need to be evaluated for better design.
 This work studies the natural convection in the receiver absorber tube of a CSP plant taking into consideration the influence of neighboring absorbers. A 2-Dimensional model was adopted in this study. Initially, a single absorber tube was considered, it was subjected to heat flux at the top wall, the bottom wall was insulated and a temperature differential was set up at the lateral walls. The dimensionless forms of Navier-Stokes and energy equations were solved using the finite element formulation of COMSOL Multiphysics software. The result obtained for a single absorber tube showed good agreement with existing research works. This validated model was then extended to multiple absorber tubes (two to six absorber tubes). On the basis of the study, there is an observed increase in the intensity and dominance of convective heat transfer with an increase in the number of absorber tubes. This is occasioned by an increase in the average surface temperature as well as average Nusselt number. For the Rayleigh number of 104, 105 and 106, the average Nusselt number increases with the number of absorber tubes by 13.87 %, 6.26 %, and 1.55 %, respectively. This increment suggests effect of thermal interactions among the neighboring absorber tubes

Experimental performance analysis of a parabolic trough solar air collector with helical-screw tape insert: A comparative study

Heat transfer improvement efforts in parabolic trough air collectors (PTAC) are long-sought and much anticipated by many researchers, however, alternative heat transfer improvement methods such as helical screw tape insert inside the receiver tube has yet to be experimentally investigated. Therefore, in this study, a dual-function PTAC for low-medium temperature applications was experimentally tested in an indoor environment to assess its thermal characteristics. To increase the heat transfer performance, a helical screw tape was inserted along the pathway of air flow inside the receiver tube. To observe the effect, the PTAC system was tested with a helical screw tape insert and smooth absorber tube and the results were compared. Moreover, energy, exergy and thermal–hydraulic analysis of the PTAC was performed. Results show that the helical screw tape inserted PTAC always yields a much better performance in terms of overall collector efficiency and exergy efficiency. Overall results prove that the temperature rise improvement across the PTAC was remarkable, improving the efficiency by 56%–71% so that the role of the helical screw tape insert is to ensure an improved heat exchange. The findings validate the potential and elucidate specific conclusions for the practice of such heat exchange improvement methods in parabolic trough air collectors.

Analysis and simulation of thermal performance of a PTC with secondary reflector

In this paper, a numerical simulation of fluid flow and conjugate heat transfer in a solar thermal parabolic trough collector (PTC) system is presented. The simulation is being carried out on a prototype designed in the Mechanical Laboratory in order to analyze the performance of this system. The main objective is to compare the system performance with and without a secondary reflector (SR). PVSYST software is used to provide numerical temporal values of the solar heat flux in Laghouat city (ALGERIA). Solar flux density values for four days in different seasons have been taken. SolTrace code is used to determine the heat flux distribution on the absorber tube. The conjugate heat transfer and fluid flow equations in the tube absorber are solved by using ANSYS-CFX CFD software. A comparison between two cases (traditional PTC and PTC with parabolic secondary reflector) with the same working fluid (Therminol VP-1) is carried out. The obtained results show that the system performance are practically the same for the four seasons. Moreover, the performance of the system with a second collector is better than that without a second reflector with a ratio of about 1.65.

Performance comparison of the solar-driven supercritical organic Rankine cycle coupled with the vapour-compression refrigeration cycle

Abstract In this study, a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors (PTCs) coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production. Thermal efficiency, exergy efficiency, exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters. A computer program was developed in engineering equation-solver software for analysis. Influences of the PTC design parameters (solar irradiation, solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube), turbine inlet pressure, condenser and evaporator temperature on system performance were discussed. Furthermore, the performance of the cogeneration system was also compared with and without PTCs. It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance. The highest values of exergy efficiency, thermal efficiency and exergy destruction of the cogeneration system were 92.9%, 51.13% and 1437 kW, respectively, at 0.95 kW/m2 of solar irradiation based on working fluid R227ea, but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a. It was also obtained from the results that PTCs accounted for 76.32% of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.

Experimental Investigation on Performance Parameters Affecting the Efficiency of Water Type PV/Thermal Collectors with Modified Absorber Configurations

In this study, efficiency of water-type photovoltaic/thermal (PV/T) modules that convert solar energy into both electrical and thermal energy were investigated. By using identical photovoltaic (PV) cells, one PV module and five PV/T modules differed in thermal structure with different diameters, amount and layout of absorber tubes, and type of absorber sheets were fabricated with lamination technique. Firstly, the electrical efficiency of all samples under Standard Test Conditions was tested by a sun simulator. Efficiency values were between 12.56% and 12.68% under STC. Furthermore, outdoor tests were carried out to investigate the effect of temperature on PV modules in ambient conditions using PV/T samples. In order to determine the efficiency of the units, parameters such as solar irradiation, voltage and current values, inlet and outlet water temperature and flow rate of PV/T modules and ambient temperature were measured. It was observed that the electrical performance of PV/T modules was higher than that of the PV module due to the cooling effect of water circulation over the cells. PV/T module with the highest thermal efficiency was also determined. Total efficiency value of PV/T modules in outdoor conditions were attained between 60.68% and 67.14%.

Numerical simulation of the temperature distribution of elliptical cavity tube receivers in the parabolic trough solar collector

The elliptic cavity tube absorber is used in the parabolic trough solar collectors to increase the optical efficiency and decrease the thermal loss. But the non-uniform heat flux distribution on the tube receiver will cause non-uniform temperature distribution, thus leading to asymmetric thermal stress and deformation of the tube receiver. In this paper, the geometric as well as thermal parameters of the elliptical cavity tube receiver are analysed through numerical simulation. The temperature distribution of the tube receiver in the single-phase liquid zone, viz. the water zone and the vapour zone, is analysed. It is found from this study that there are two extreme temperature areas in the elliptical cavity tube receiver. When the major semi-axis of the elliptical cavity is 63mm, the maximum temperature of the water zone is the largest, which occurs at (-35mm, 0mm) of the tube receiver. When the major semi-axis of the elliptical cavity is 67mm, the maximum temperature appears at (-9mm, 0mm) in the vapour zone, and the minimum temperature rise appears at (-13.88mm, 0mm).

Thermo-hydraulic analyses of the absorber tube with molten salt-based nanofluid and porous medium inserts

In this work, a new combination technique of molten salt-based nanofluid and porous medium inserts is presented for the thermo-hydraulic performance improvement of the absorber tube. The effects of porous medium configurations, porosities, nanoparticle concentrations, materials, and Reynolds numbers are discussed in terms of the flow and heat transfer characteristics as well as the performance evaluation criterion (PEC). According to the results, the enhanced tube inserted with wall attached type porous medium can achieve much better heat transfer performance. Molten salt-based nanofluid shows considerable heat transfer performance inside the tube with a porous medium, compared with pure molten salt flow inside a smooth tube. Among the four kinds of materials, the best one for the porous medium is copper. The combination for the best thermo-hydraulic performance is proposed with the 0.125% (mass fraction) molten salt-based nanofluid and the absorber tube with copper metal foam (porosity of 0.9005), after systematically comparing the simulation results. This combination accomplishes the best heat transfer enhancement with 12.44 times of Nusselt number higher than pure molten salt inside the smooth tube at the Reynolds number of 1×104. The peak PEC value of 5.98 is reached at the Reynolds number of 6×104. Finally, the improvement of the thermo-hydraulic performance of this combination technique was proved through physical discussions based on the temperature and velocity profiles.

Optimizing research on large-aperture parabolic trough condenser using two kinds of absorber tubes with reflector at 500 °C

Increasing the aperture of the parabolic trough concentrator (PTC) can effectively reduce costs and help promote. This paper proposed a circle and semicircle absorber tubes (AT) with a flat reflector (FR) in it for the large-aperture PTC system and the size of the AT was determined for the PTC with 8 m aperture width and 80° half rim-angle. The result shown the PTC system using a semi-circular AT with a diameter of 100 mm has the highest average thermal efficiency of 71.6% with DNI 400–1000 W/m2 at about 500 °Cand has best uniformity of 38.8%. However, its deformation is highest and 1.7 and 1.6 times other two ATs. Therefore, how to reduce the deflection has become a research direction in the future. Currently, the circular AT with a diameter of 80 mm is the most practical with an average thermal efficiency of 69.1% and a minimum deflection.

Fault Analysis of Solar Thermal Systems in Bhutan

The Royal Government of Bhutan has accorded the highest priority towards diversifying the energy-mix through the promotion of renewable energy technologies. There is a national target to generate 3 MW equivalent of energy from the installation of solar thermal systems alone. However, little investment and priority are given for development of solar thermal applications. Some of the present existing solar water heating (SWH) systems are exhibiting faults which leads to low consumer confidence in SWH technology due to the non-functioning of previous installations which is very detrimental in this introductory stage. This study aims to identify problems of existing SWH systems through field surveys and develop a draft guideline to avoid faults in the future. To analyse the problems with existing SWH systems in Bhutan, the first phase of the study consists of collecting secondary information and opinion from the relevant government sector, local installing companies and end-users. The information on the manufacturer’s products, policy barriers, markets and consumer challenges is also collected. Base on this information, findings on the limitation of existing policy instrument and gap in demand and supply side is described. The second phase of the study comprises field visits to existing SWH system sites. The field surveys of twelve representative existing SWH systems are analyzed. Out of twelve sites, eight SWH systems had critical faults which causes major failure of the system and the other four sites had minor faults. To analyse the faults of existing SWH systems, faults are classified into design faults, plumbing circuit faults, solar collector faults, absorber faults, installation faults and user behavior faults. The major faults which lead to the failure of the existing SWH system are plumbing failure, condensation inside the collector and absorber tube leakage. The causes and solutions of the faults are discussed.

Thermal Performance Enhancement Using Absorber Tube with Inner Helical Axial Fins in a Parabolic Trough Solar Collector

In the present work, a parabolic trough solar (PTC) collector with inner helical axial fins as swirl generator or turbulator is considered and analyzed numerically. The three-dimensional numerical simulations have been done by finite volume method (FVM) using a commercial CFD code, ANSYS FLUENT 18.2. The spatial discretization of mass, momentum, energy equations, and turbulence kinetic energy has been obtained by a second-order upwind scheme. To compute gradients, Green-Gauss cell-based method has been employed. This work consists of two sections where, first, four various geometries are appraised, and in the following, the selected schematic of the collector from the previous part is selected, and four various pitches of inner helical fins including 250, 500, 750 and 1000 mm are studied. All the numerical results are obtained by utilizing the FVM. Results show that the thermal performance improvement by 23.1% could be achieved by using one of the proposed innovative parabolic trough solar collectors compare to the simple one. Additionally, the minimum and maximum thermal performance improvement (compare to the case without fins) belong to the case with P = 250 mm by 14.1% and, to the case with P = 1000 mm by 21.53%, respectively.

Thermal stress and fatigue damage of central receiver tubes during their preheating

• Transient temperature and thermal stress in tubes of CSP receivers are modelled. • The Vant-Hull algorithm is used to define the incident heat flux during tube preheat. • Large temperature gradients and a stress peak occur in the first 120 s of preheat. • The standard Vant-Hull algorithm may be unable to preheat tubes in windy conditions. • Fatigue damage due to preheat is less than 5%, avoiding creep-fatigue interaction. Preheating of the absorber tubes of a central receiver is a crucial operation in the start-up of current solar power tower plants (SPT) working with molten salt as a heat transfer fluid. In the preheating, a subset of the heliostat field is aimed at the receiver to produce an incident heat flux capable of heating the tube walls before they are filled with the molten salt. Incident radiation should be kept above a minimum as an insufficient level of preheating may lead to the freezing of the incoming flow of molten salt, interrupting the receiver operation. However, too much incident heat flux in the preheating causes severe thermal gradients in the walls of the tubes, leading to extremely high thermal-stresses and the eventual fatigue damage of the receiver. The present work numerically characterizes the temporal evolution of the temperature and thermal-stresses in the absorber tubes made of Haynes 230 alloy. This is done for two examples of SPT plants, i.e. Gemasolar and Dunhuang, with the aim of detecting when and where the largest temperature gradients and mechanical stresses appear during the tube preheating and evaluate their impact on the fatigue damage of the receiver tubes. The results show that during the first seconds of preheating, the front side to the tube is rapidly heated but the temperature at rear side of the tube is barely modified, causing a great non-uniformity of temperatures. This effect is enhanced when the tube diameter is increased because the heat requires more time to reach the rear side of the tubes. The peak values of the temperature gradient and the von Mises stress are reached during the first minutes of the preheating. Besides, under windy conditions, the preheating procedure proposed by Vant-Hull may be insufficient to preheat the receiver. Furthermore, in all the cases analyzed, the estimated fatigue damage of the tube is much less than the 5 % upper limit to avoid significant creep-fatigue interaction. This indicates the Vant-Hull algorithm does not compromise the structural integrity of the studied receiver tubes.