Air Mass Flow Rate Research Articles

Seasonal thermo-enviro-economic performance analyses of concentrated PV/T integrated with humidification-dehumidification water desalination system

Concentrated solar photovoltaic thermal offers a great opportunity for water desalination by applying some thermally driven techniques. Humidification–dehumidification water desalination is appropriate for moderate installations and runs on low temperatures matching the attainable output of low concentrated photovoltaic thermal systems. So, in this paper, thermo-enviro-economic performance analyses of an integrated system consisting of compound parabolic collectors partially covered with photovoltaic cells powering humidification dehumidification water desalination system is theoretically introduced. The system performance is conducted at a seasonal scale using MATLAB throughout the whole year under the weather of New Borg El-Arab city-Alexandria-Egypt. The results indicate that raising the flow rate of the working fluid of the system increases the desalination output, reduces the PV cell temperature, and enhances PV efficiency. At a fluid flow rate of 0.02 kg/s suitable for PV safety temperature, the cell maximum and minimum temperature are 79 and 42.5 °C, maximum and output power is 6 and 3.8 kW, and maximum and minimum efficiency is 17.2 and 14.2 % respectively. The output water temperature is 73 and 36.9 °C in summer and winter, respectively. The desalination system produces maximally 4.7, 6.2, and 3.8 L/h at water to air mass flow rate ratios of 1.5, 2, and 3, respectively. The maximum achieved average monthly desalination system gain output ratio is 3.15 with an overall system efficiency of 41 %. The average annual system thermal energy and exergy yield is approximately 176 and 0.2 kWh, respectively. The annual freshwater cost is $0.0351/Liter. The system mitigates an annual average of 7.2 tons of CO2 emissions.

Enhancing reliability and efficiency of solar chimney by phase change material Integration: An Experimental study

The Solar Chimney Power Plant (SCPP) presents an eco-friendly and straightforward technique for converting solar radiation into electricity. However, the performance limitations and reliability challenges of SCPPs are inherently linked to the variability and intermittency of solar radiation. To tackle this issue, using phase change materials (PCMs) can enhance the thermal energy storage and release capabilities of SCPPs. This study aims to explore the impact of PCM on the exergy efficiency and performance of a solar chimney. Two pilot solar chimneys with identical dimensions were constructed, each featuring a 4 m height chimney and a 5 m diameter collector. One solar chimney was equipped with hydrated salt PCM as an energy storage layer, while the other operated without PCM. Both systems' power production and ventilation potential were evaluated using theoretical turbines, and subsequent exergy analysis discerned the operational behavior and efficiency of the systems. Results indicate that PCM increased the average air mass flow rate through the solar system during the day. The average daily air mass flow rate was 0.045 kg/s with PCM and 0.033 kg/s without PCM. Notably, mean pressure drops resulting from the airflow through the turbine were 2.44 and 1.83 Pa in the presence and absence of PCM, respectively, over a complete day. Additionally, PCM improved exergy efficiency by about 19 % due to enhanced thermal energy storage.

Experimental study for the effect of changing flow on absorption in wetted wall column

Gas absorption is the unit operation in which one or more soluble components of gas mixture are dissolved in a liquid. The absorption may be a purely physical phenomenon or may involve chemical reaction with one or more constituents in the liquid solution. In order to obtain the highest rate of absorption, gas and liquid streams flow in opposite directions in counter-current flow. The unit in this work has been designed to help grasp the basic principles of the chemical and physical aspects involved in absorption. This study unit is made of borosilicate transparent glass in order to show the water spread in the column and get the visual distribution of fluids behavior which helps to fully understand the phenomenon. In this work, the wetted wall column is used to determine gas/liquid mass transfer coefficients, which is essential to design absorption towers. This study investigates the absorption of oxygen from air into deoxygenated water (prepared by nitrogen sparing) in liquid film controlled absorption experiment. The liquid film mass transfer coefficients calculated at various mass flow rates of water and air. This work also studies the effect of water flow(expressed by Sherwood number) and air flow (expressed by Reynolds number)on oxygen concentration in the oxygenation and de-oxygenation process so affect on absorption process. From results, found that relation between Reynolds and Sherwood in wetted wall column been proportional this mean when we increase flow rate of water from 4 to 12 L/hr or air from 60 to 180 L/hr in wetted wall; concentration of oxygen in water out increase which mean absorption is better. Also, the final equation shows linear relation between Reynolds and Sherwood in wetted wall column. All these result help in understanding absorption process and factors influence in efficiency of towers used in real plant and helpful in design absorption tower.

The augmentation of the heat recovery by using evaporative cooling in HVAC applications: Experimental study

An experimental study was conducted to investigate the impact of evaporative cooling on heat recovery within HVAC systems. This study involved the development of a specialized test rig comprising two air passages connected by a wickless heat pipe heat exchanger (wickless HPHE). Additionally, an evaporative cooling pad was integrated into the cold air return duct. The evaporative cooling process effectively lowered the temperature of the cold air, which was subsequently directed through the wickless HPHE condenser. This occurred at a variable mass flow rate ratio, in contrast to the constant mass flow rate of warm air passing through the wickless HPHE evaporator section. The study encompassed a range of mass flowrate ratios, specifically 1, 1.5, and 2. The thermosiphon heat pipe was charged with acetone at a 60 % filling ratio. The results clearly demonstrated that evaporative cooling played a pivotal role in enhancing the heat exchanger's performance. Notably, the temperature differential observed in the wickless HPHE evaporator surpassed that in the HPHE condenser, primarily due to the influence of evaporative cooling. The highest temperature difference recorded in the HPHE evaporator was 17.8 °C, indicative of the most substantial heat recovery achieved. Importantly, the effect of evaporative cooling significantly improved the performance of the wickless HPHE by more than 48 %.

Modelling and performance investigation of a solar chimney power plant with glass-covered solar collector

ABSTRACT Solar chimney power plants (SCPP) exploit solar radiation to create an up-draft airflow to run a turbine. This article proposes an innovative design of an SCPP that consists of transparent glass covered solar collector. Outdoor experiments have been carried out in the arid climates of Tikrit city, Iraq, with galvanized metal tower installed instead of conventional PVC solar towers. Performance of the SCPP has been studied with and without transparent cover for collector periphery heights of 2 and 4 cm. Measurements of ambient temperature, chimney inlet temperature, interior and outlet air temperatures, humidity, air mass flow rate, and solar irradiance values were recorded from 9:00 am to 4:00 pm throughout the month of May 2021. Results show that the solar chimney collector with a periphery height of 2 cm performed better than that with the 4-cm periphery height. In addition, using transparent cover in SCPP increases the air outlet temperature by 16.4°C and air flowrate augments by around 34%. Thermal efficiency of the solar chimney with non-covered tower is found to be 10.3% whereas for a glass covered tower it increases to 14.6%, which is a remarkable 41% enhancement. Likewise, mechanical and electrical power output augment by 39.6% and 40.3% using transparent cover in SCPP. Such innovation in SCPP design is proven apposite for hot arid climates.

Thermal Performance of Hybrid PV/T-TEC Air Collector with Perforated-Finned Absorber Plate

PV/T-TEC collector is a device that can produce thermal energy and electrical energy at the same time. The electrical performance may be increased by absorbing residual heat from the PV surface. Due to the temperature difference available between the hot and cold sides of this collector, additional electrical energy can be also generated by using the TEC to increase the total efficiency. The purpose of this study is to evaluate the thermal effect of using both fins and TECs acting as a heatsink. Thus, the perforated zone with a dimension of 100 x 50 x 2 mm was manufactured by lancing and bending processes. Furthermore, 44 pieces of TECs were placed inside the perforated-finned zone and were attached underneath the PV surface to allow a convection heat transfer process. The model collector was then tested by using a solar simulator under 1100 W/m2 with different fluid mass flow rates ranging from 0 to 0.339 kg/s. To meet the test requirements, environmental fluid flow was also implemented and simulated by a fan with an air velocity of 1 m/s. The results showed that increasing the air mass flow rate as a working fluid by five times can reach the operating temperature of the model collector by about 64 °C (24% decrease) and 74 °C (26% decrease) for both with and without environmental fluid flow, respectively. Meanwhile, under the same test conditions, the maximum value for the temperature difference of TEC sides is found to be 5.6 °C for both with and without ambient fluid flow.

Thermal analysis of an integrated solar combined cycle power plant and its application in southern Iraq

Recently, simple cycle play a significant role in electric power production in Iraq. However, those units suffer from low thermal efficiency and low power output. In the present work, theoretical study is carried out aiming to improve the performance of (AL-Amara station 125MW). The present work includes three parts: the first part focus on the effect of ambient temperature on the performance of simple cycle including mass flow rate, power output, thermal efficiency and other parameters. In the second parts, a modification to simple cycle is implanted to be a combined cycle. The third part is studied the benefit of using solar unit for producing more steam to be supplied to the heat recovery steam generator wishing to produce more power and low emissing. Regarding, to simple gas turbine unit, the obtained results show that the mass flow rate is decreased nearly (10.8%) when the ambient temperature increased from (15-50) ºC. However, this reduction in mass flow rate of air is led to significant reduction in power output and thermal efficiency nearly (22.6%,13.2%) respectively. In the second parts, applying combine mode show a significant increase in power output and thermal efficiency nearly (32.5% and 32.3%) respectively. while the specific fuel consumption is decrease nearly (32.19%). Finally, the third parts when solar units are used, the gathered results show an acceptable increase for the amount of steam produced via solar units (21.02kg/s). The overall performance of the integrated cycle shows that the power output and the thermal efficiency increased nearly (11.28%and10%).

Minimum Quantity Lubrication (MQL) Supply through Internal Cooling Channels in Drilling Processes

Minimum quantity lubrication (MQL) technologies possess great potential for improving the sustainability of manufacturing processes, which can reduce the absolute quantity of metalworking fluid (MWF) and also enable near-dry chips that are easier to recycle. During drilling in particular, the MWF is transported to the contact zone through internal cooling channels of the drilling tool. The MWF supply and its associated flow behaviour in the transfer from the outlet of the cooling channels to the contact zone have not been sufficiently investigated yet. Great potential is seen in the proper delivery of the MQL into the contact zone. This work aims to visualize and quantify the cooling lubricant supply into the cutting zone using the MQL technique. The visualization of the MQL application is made possible by high-speed shadowgraphic imaging. Detailed image processing is used to evaluate the resulting images. The developed evaluation routine allows for the assessment of the impact of the main process parameters such as the varying pressure of the aerosol generator and the cooling channel diameter. It is found that the oil leaves the cooling channels at the tip of the drill bit in the form of ligaments. An increase in pressure and cooling channel diameter leads to an increase in the frequency of oil ligament separation. Three main flow regimes are identified with different separation frequencies. Low inlet pressures result in intermittently dispersed droplets. The most upper pressure levels lead to an almost continuous dispersion of the oil. At the same time, the air and oil mass flow rates also increase.

Analisis Perbandingan Kinerja Alat Pengering Rumah Kaca Tipe Rotari Sistem Tertutup Dengan Sistem Semi Tertutup Terintegrasi Dengan Tungku Biomasa Menggunakan Penukar Kalor Dua Tingkat Untuk Mengeringkan Ikan Nila

The aim of this research is to compare the performance of an open system rotary type greenhouse effect dryer (APERK-TR-STP) system 1 with a closed system (APERK-TR-SST) system 2 for drying tilapia fish. In the APERK-TR- system, 1 fish is dried from an initial weight of 90.56 kg (initial water content 69.08% wet basis (bb) to a final weight of 30.33 kg (final moisture content 20% bw) at an average temperature 56.38 oC with a mass air flow rate of 0.459 kg/s takes 12 hours. Meanwhile in the APERK-TR-SST system 2 tilapia fish are dried from an initial weight of 91.49 kg (initial water content 69.40% bw) up to final weight of 19.27 kg (final moisture content 20% bw) at an average temperature of 53.98 oC with an air mass flow rate of 0.459 kg/s required 12 hours

Film Cooling Modeling in a Turbine Working under the Unsteady Exhaust Flow of Pulsed Detonation Combustion

Pressure gain combustors (PGCs) have demonstrated significant advantages over conventional combustors in gas turbine engines by increasing the thermal efficiency and reducing the pollution emission level. PGCs use shock waves to transfer energy which contributes to the increase in outlet total pressure. One of the major obstacles in the actual implementation of PGCs in the gas turbine cycle is the exploitation of the highly unsteady flow of the combustor outlet with the downstream turbine. Because of the higher outlet temperature from the PGCs, the turbine blade cooling becomes essential. Due to the highly fluctuating unsteady flow of PGCs, 3D CFD simulation of turbines becomes very expensive. In this work, an alternative approach of using a 1D unsteady Euler model for the turbine is proposed. One of the novel aspects of this paper is to implement the turbine blade cooling in the unsteady 1D Euler model. The main parameters required for the turbine blade cooling are the cooling air mass flow rate, temperature, and pressure. Due to the introduction of coolant flow, the blades are no longer adiabatic and the mass flow rate across the turbine is not constant. Comparing the 1D Euler results against zero-dimensional calculation and 3D CFD approach showed a very good match for both steady and unsteady simulations confirming the applicability of the 1D method.

Experimental and numerical analysis of the forced draft wet cooling tower

Cooling towers are essentially large boxes designed to maximize the evaporation of water. The inlet water temperature and water to air mass flow rate ratio (L/G) significantly affect the performance of the cooling tower. The number of a transfer unit (NTU), Merkel number (Me), Lewis number (Le), and efficiency of the cooling tower define the performance of the forced cooling tower. In this research paper, different inlet water temperatures ranging from 28 °C to 42 °C and (L/G) ranging from 0.5, 1, and 1.5 were used to investigate the performance of the forced cooling tower. Mathematical modeling equations were used to calculate NTU, Me, Le, and efficiency at different inlet water temperatures and (L/G). Engineering equation solver (EES) software was used to solve these mathematical modeling equations. Further, an experimental investigation was carried to find forced cooling tower performance at different inlet water temperatures and (L/G), and results were compared with the theoretical results. The results revealed that increasing the inlet water temperature, NTU, Me, Le, and efficiency increased and were directly related to each other. Further, NTU and efficiency were increased by increasing (L/G). At the same time, the Me and Le reduced with (L/G). Finally, an acceptable and better agreement has been obtained between experimental and theoretical results. Based on obtained results, it has been concluded that higher values of inlet water temperature and (L/G) provided the higher performance of the forced cooling tower.

Design space investigations of scramjet engines using reduced-order modeling

Conceptual design studies performed with reduced-order approaches allow feasibility and sizing considerations of air-breathing engines to be configured at an affordable computational cost. The present study is devoted to exploring the design space of a dual-mode ramjet engine operating in scramjet mode by means of reduced-order analysis to assess the effects of propulsive system design configurations on component level and overall performance characteristics. The approach proposed in this work combines axisymmetric flow configuration used for the design of supersonic/hypersonic intakes and solutions of one-dimensional flow governing equations coupled with finite-rate chemistry and thermophysical properties tables in the numerical domains of the combustor and nozzle components. The scramjet design space is generated by varying parameters which are flight Mach number and altitude, intake truncation angle, intake exit Mach number and equivalence ratio. Performance outputs of total pressure recovery factor, compression ratio, captured air mass flow rate, intake startability index, thrust, specific impulse, fuel consumption and overall efficiency are computed for each design scenario. The generated database is visualized via performance maps and analyzed in terms of propulsive characteristics. A feature importance study is also conducted to quantify the effects of design parameters on the propulsive performance.

Research on the Optimization of a Diesel Engine Intercooler Structure Based on Numerical Simulation

As a device for cooling charged air before it enters the cylinder, the intercooler is an indispensable part of the regular operation of a booster diesel engine. To solve the problem of the insufficient cooling performance of an intercooler for a high-power supercharged diesel engine, in this study, the flow field in the intercooler is simulated using the computational fluid dynamics (CFD) model of porous media, and the performance data measured using the steady flow test bench are used to provide boundary conditions for the calculation. The effects of the charged air mass flow rate and the tube bundle’s transverse spacing on the heat dissipation performance of the intercooler are analyzed and compared. The calculation results show that, under the condition of satisfying the regular operation of the diesel engine, the heat transfer coefficient of the intercooler heat dissipation belt increases with the increase in air mass flow and the spacing of cooling pipes, and the heat transfer coefficient can be increased by up to 57%. Still, excessive spacing of the cooling water pipes increases pressure loss in the charged air. Finally, the transverse spacing of the tube bundle is set to 17 mm, ensuring the pressure drop in the charged air, and the heat dissipation performance of the intercooler is increased by 6.04%. This paper provides a feasible solution for further optimizing the heat dissipation performance of intercoolers. Finally, grey correlation theory is used to study the correlation between air mass flow, cooling water pipe spacing, and intercooler heat dissipation performance. The correlation values are 0.8464 and 0.8497, respectively, indicating a significant relationship between air mass flow, cooling water pipe spacing, and intercooler heat dissipation performance.

Application of artificial intelligence to investigate the performance and flow pattern near staggered piece in V-ribs with aligned gaps roughness in solar air heater using relevant input parameters

The present work findings of an experimental investigation on a rectangular duct used in a solar air heater (SAH) to increase heat transfer and frictional characteristics and improve flow near the roughness. The rough SAH surface is created by staggered V-ribs and aligned gaps. For Reynolds numbers 3000–14,000, relative gap breadth (g/e) is changed from 2 to 5, while other parameters are maintained constant: relative roughness pitch (P/e) = 10, relative staggered rib position (P'/P) = 0.4, relative staggered rib size (w/g) = 1, and relative roughness height (e/Dh) = 0.0434. The Nusselt number (Nu) and friction factor (f) are found as 2.16 and 2.73 times higher than a flat plate under the identical operating and flow conditions. The overall augmented behavior of rough SAH considering frictional characteristics is calculated in terms of Thermal enhancement factor (TEF) as 1.56. The impact of gap width on flow pattern is examined by using ANSYS Academic Research CFD 15.0. ANN outperformed GMDH. The air mass flow rate was revealed to be the most sensitive influencing element in a sensitivity analysis.

Effect of Differential Mass Flow Rate on the Thermal Performance of Double Duct Packed Bed Solar Air Heaters

The present paper investigates the effect of differential air mass flow rate on the thermal performance of parallel pass packed bed solar air heater. The range air flow rates over which the parallel pass system yields higher thermal performance as compared to counter pass system have been identified and presented. The effect of fraction of total mass flow rate in the respective ducts of the parallel pass packed bed solar air heater has shown to be dominant parameter in determining the effective thermal efficiency of the heater.

Smoke exhaust characteristics under stack effect of natural ventilation by shaft in high-altitude tunnel

The number of high-altitude tunnels is increasing year by year and natural ventilation of shafts is widely used as a critical component of the ventilation system. For the design of ventilation systems, it is particularly crucial to consider the smoke exhaust performance of shafts in low-pressure environment. Therefore, this study simulates tunnel fires with natural ventilation by shaft in high-altitude areas, aiming to analyze the impact of atmospheric pressure on smoke exhaust performance and smoke exhaust capacity by natural ventilated shafts at 50 to 100 kPa atmospheric pressure. It appears from the results that the increasing of ambient pressure can enhance the ability of air entrainment and natural smoke exhaust, and thus plug-holing is more likely. In which condition, fresh air can be expelled straight from the shaft, reducing smoke exhaust efficiency. As ambient pressure increases, the critical shaft height for plug-holing decreases. By analyzing the smoke exhausting process by shaft and smoke flow, smoke exhaust capacity can be evaluated by obtaining the mass flow rate of exhausted smoke and fresh air from the shaft under various atmospheric pressures and fire source power and. It could be said that increasing ambient pressure and shaft height can improve the smoke expulsion performance before plug-holing. However, once plug-holing happens, the increase of shaft height can no longer expel more smoke but much more air is exhausted by shaft. It is hoped that this work will serve as a guideline for ventilation systems design in high-altitude tunnels.

Experimental evaluation of combined humidifier-dehumidifier desalination with thermoelectric module for simultaneous use of heating and cooling

The objective of this study was to assess the performance of a Humidifier-Dehumidifier (HDH) desalination system paired with thermoelectric cooling, in order to achieve effective water desalination. The system employed the thermoelectric module's heating and cooling capabilities to warm the water entering the HDH system and remove moisture from the humid air. An investigation was conducted to examine the impact of varying sea water mass flow rate (SWMFR) and air mass flow rate (AMFR) on the performance characteristics of the system. These metrics include gain output ratio (GOR), coefficient of performance (COP), fresh water generation, and dehumidifier efficiency. The data collected clearly demonstrated that the performance of the system was significantly influenced by the WMFR and AMFR. The ideal values for the amount of fresh water produced, COP, GOR, and dehumidifier efficiency were determined to be 140 gs per hour, 0.93, 0.7 and, 52.5 %, respectively. The experimental assessment showcased the capability of the integrated HDH desalination with thermoelectric cooling system as a highly efficient and economically viable approach for desalination, particularly in regions with limited water resources.

Experimental study of photothermal conversion of heat absorbers filled with metal foams of different pore densities

High output temperature and photothermal conversion effectiveness were achieved with the absorber platform structure. A novel solar receiver was manufactured to integrate pre-heating and thermal conversion, aiming to enhance heat utilization and output temperature. This work is based on the engineering design and experimental testing of a solar cavity-receiver containing a porous copper foam that can volumetrically absorb high-flux radiation and heat up, through convection with air flow. The air outlet temperature, outer wall temperature, thermal performance, and efficiency were experimentally determined by pore density, air mass flow rate and solar irradiance. Additionally, the temperature growth of unit incident power (?),the unit volume efficiency growth rate (?) and output temperature were employed to evaluate the thermal conversion characteristics of the endothermic body(copper foam).The results indicated that the air outlet temperatures can reach 500?C with lower input power. Furthermore, it was found that under a pore density of 30 pores per inch and a flow rate of 60 L?min-1, the photothermal conversion efficiency of the absorber with copper foam reached as high as 87.61%, which is 35.04% significantly higher than that of an absorber without copper foam. The manageable solar receiver design proved to deliver a high-temperature air flow (approximately 500?C) with a reasonably high thermal efficiency(over 85%).

Investigation of hydrogen-enriched kerosene-fueled rotating detonation engine with multi-column film cooling

To address the thermal protection challenges associated with the rotating detonation engine (RDE) in engineering applications, this study employs a three-dimensional numerical simulation based on the Eulerian–Lagrangian model to investigate the flow field of the kerosene-fueled rotating detonation with hydrogen addition. We explore the interaction between the rotating detonation flow field and the cooling air induced by multiple columns of uniformly distributed film cooling holes and also analyze the cooling effectiveness of film cooling. In the flow field where the rotating detonation wave passes through the film hole periodically at a high frequency, an increase in the number of film hole columns can decrease the fluctuation amplitude of the cooling air mass flow rate, and the recovery time of the blockage of film cooling holes shortens within a complete rotating detonation cycle. At a low injection pressure of 0.4 MPa, the cooling jet can barely be injected into the combustor. As the injection pressure increases to 0.6 and 0.8 MPa, the mass flow rate of cooling air increases significantly with enhanced cooling efficiency; however, a further rise to 1.0 MPa may result in the detachment of cooling air from the surface, without providing additional improvements in the protection area and cooling efficiency. Along the axial direction of the RDE, film cooling holes demonstrate an enhancement in cooling efficiency, which is found to maximize near the outlet.

Performance assessment of a system to provide steady high temperature air via solar thermal suspension flow technology with storage and combustion back-up

The imperative for economically viable sources of high-temperature heat without contributing to net carbon emissions has become a pressing global concern, particularly in the context of industrial chemical processes. Solar thermal heat generation emerges as a pivotal solution in addressing this formidable challenge. By concentrating sunlight to achieve high temperatures, solar thermal technology can provide the intense heat required for various industrial applications, including chemical processes, without relying on fossil fuels. This not only helps reduce greenhouse gas emissions but also enhances energy efficiency and sustainability in energy-intensive industries. However, the full integration of solar thermal systems into energy-intensive industrial processes necessitates continued advancements of new technologies to achieve temperatures in the order of 1000 °C. In this paper, the performance of a high temperature concentrating solar thermal plant based on a 50MWth suspension flow solar particle receiver sub-system integrated with sensible thermal storage and combustion backup is analyzed, to supply steady output of reheated air to a downstream thermochemical process. The analysis is performed with transient mathematical models of the receiver and packed bed thermal storage sub-systems considering solar resource variability, written in a Simulink environment, to estimate useful annual thermal gain, thermal efficiency, solar share and levelized cost of solar heat, for a range of parameters including particle mass loading, air mass flow rate, thermal storage capacity and solar multiple. The time-dependent temperature fields of the receiver and thermal losses, together with their influence on the performance of the combined system are reported for each condition with a transient input solar resource spanning over a whole year. New insights are provided of the relative tradeoffs between these parameters on the overall system performance, solar share and levelized cost of solar energy. Also reported is the sensitivity of the levelized cost to different system combinations sized to provide a solar share of up to 75 % of the yearly process thermal demand, along with the influence of the specific costs of the system components varied in the range of ± 60 %.