scholarly journals Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Thomas Semenou ◽  
Daniel R. Rousse ◽  
Brice Le Lostec ◽  
Hervé F. Nouanegue ◽  
Pierre-Luc Paradis
Keyword(s):  
Mathematical Modeling ◽  
Solar Collector ◽  
Thermal Model ◽  
Heat Recovery ◽  
Significant Rise ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Combined Model ◽  
Air Mass ◽  
Collector Efficiency

Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC) with dual intake in order to remove stagnation problems in the plenum and ensure a better thermal efficiency and more heat recovery. A thermal model and a pressure loss model were developed. Then, the combined model was validated with experimental data from the Solar Rating and Certification Corporation (SRCC). The results show that the collector efficiency can be up to 70% and even 80% regardless of operating conditions. The temperature gain is able to reach 20°K when the solar irradiation is high.

The Effect of Using a Heat Recovery Absorber on the Performance and Operating Cost of the Solar Ammonia Absorption Cycles

1997 ◽  
Vol 119 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Saghiruddin ◽  
M. Altamush Siddiqui
Keyword(s):  
Economic Analysis ◽  
Flat Plate ◽  
Solar Collector ◽  
Heat Recovery ◽  
Theoretical Study ◽  
Operating Cost ◽  
Operating Conditions ◽  
Tubular Type ◽  
Ammonia Absorption ◽  
The Cost

Economic analysis of ordinary and evacuated tubular type flat-plate collectors have been carried out for operating absorption cycles with and without heat recovery absorber. Water-ammonia, NaSCN-NH3 and LiNO3-NH3 have been selected as the working fluids in the cycles. Use of a heat recovery absorber, in addition to the primary absorber in the conventional absorption cycles, lead to improvement in the system performances by about 20–30 percent in the H2O-NH3 and 33–36 percent in the NaSCN-NH3 and LiNO3-NH3 mixtures. Subsequently, there is a considerable amount of reduction in the cost of the solar collector required to operate them. For the set of operating conditions, in this theoretical study, the cost reduces to about 25 percent in the H2O-NH3 and 30 percent in the NaSCN and LiNO3-NH3 cycles.

Analysis and Assessment of Tower Solar Collector Driven Trigeneration System

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Abdul Khaliq ◽  
Mathkar A. Alharthi ◽  
Saeed Alqaed ◽  
Esmail M. A. Mokheimer ◽  
Rajesh Kumar
Keyword(s):  
Energy Efficiency ◽  
Solar Collector ◽  
Lithium Bromide ◽  
Rankine Cycle ◽  
Significant Rise ◽  
Exergy Efficiency ◽  
Integrated System ◽  
Operating Conditions ◽  
Heating And Cooling ◽  
And Performance

Abstract This paper describes the development and performance assessment of a tower solar collector driven integrated system operating in trigeneration mode to generate electricity, heating, and cooling, in a carbon-free manner. The proposed system applies a heliostat-based central receiver unit as a base of solar energy input to drive the steam Rankine cycle which is combined with the process heater and the lithium bromide-water operated absorption chiller. An analysis is performed to monitor the behavior of energy and exergy efficiency at various operating conditions of the proposed trigeneration system. The computed results are authenticated with the reported literature. A comparison is made between the present findings and reported results in the form of exergy efficiency, total exergy destroyed, and energy efficiency. Consideration of process heat and cold along with electricity provides a promising increase in energy efficiency from 15.8% to 64.1% while the exergy efficiency is enhanced from 16.9% to 24.4%. Variation in direct normal irradiations from 600 W/m2 to 1000 W/m2 results in the significant rise of energetic and exergetic outcomes of the proposed trigeneration system. Out of 100% solar exergy supplied to the proposed trigeneration, 24% is generated as the exergetic output, 1.6% is lost to ambient, and the remaining 74.4% is the exergy destroyed in the system components.

Study of Characteristic of Evacuated Flat Plate Type Solar Collector With Flow Boiling

2007 ◽  
Author(s):  
Masahiro Taniguchi ◽  
Shigeki Hirasawa ◽  
Shunsaku Nakauchi ◽  
Tadayoshi Tanaka
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Collector Plate ◽  
Collector System ◽  
Heat Collector ◽  
Collector Efficiency

An evacuated solar collector system with flow boiling in tube has high collector efficiency of solar energy. In this paper, we present experimental and simulation results for characterizing an evacuated flat plate solar collector. By comparing the experiment results with six boiling heat transfer correlation equations, we found that Sani’s correlation is closest to our experimental results. Subsequently, this paper reports on how various factors impact collector efficiency. Collector efficiency decreases with decreasing flow rate of the working fluid, with decreasing solar irradiation, with reduction of thickness and thermal conductivity of the heat collector plate. Collector efficiency increases with decreasing saturation temperature of the working fluid, with decreasing vacuum pressure in the collector, with small bending angle of the heat collector tube. Collector efficiency does not change with change of inside diameter of the heat collection tube, and with change of inlet subcooling temperature of the working fluid.

Heat Exchanger Theory Applied to the Design of Water- and Air-Heating Flat-Plate Solar Collectors

1988 ◽  
Vol 110 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Gregory J. Kowalski ◽  
Arthur R. Foster
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flat Plate ◽  
Solar Collector ◽  
Operating Conditions ◽  
Solar Collectors ◽  
Heat Transfer Characteristics ◽  
Air Heating ◽  
Collector Efficiency ◽  
The Difference

A general method for the design of flat-plate solar collectors based on solar collector theory has been developed. It can be applied to both liquid- and air-heating solar collectors. The solar collector efficiency is determined by the product of the effectiveness (ε) and the insolation use factor (IUF). The effectiveness describes the heat transfer characteristics of the collector and is shown to be a function of a solar number of transfer units (SNTU) and a parameter ψ. For an air-heating collector, the ψ parameter equals the collector efficiency factor, while for a liquid-heating collector it must account for the difference between the plate and tube heat transfer areas. The effectiveness and SNTU parameters are similar to the effectiveness and NTU parameters used in heat exchanger design methods. The IUF is a measure of the operating conditions of the collector. It represents the difference between the transmittance-absorptance product and the ratio of the minimum heat loss to the insolation on the exterior cover. The relationship between the effectiveness and the SNTU parameter is general for all nonconcentrating collectors. One advantage of this method over the traditional Hottel-Whillier method is that it separates the heat transfer characteristics of the solar collector from its optical properties and the operating conditions.

Parametric Study of Photovoltaic Thermal Solar Collector Using An Improved Parallel Flow

2020 ◽  
Vol 2 (1) ◽  
pp. 19-24
Author(s):  
Sakhr Mohammed Sultan ◽  
Chih Ping Tso ◽  
Ervina Efzan Mohd Noor ◽  
Fadhel Mustafa Ibrahim ◽  
Saqaff Ahmed Alkaff
Keyword(s):  
Thermal Conductivity ◽  
Energy Balance ◽  
Parametric Study ◽  
Solar Collector ◽  
Parallel Flow ◽  
Operating Conditions ◽  
Balance Equations ◽  
Conductivity Type ◽  
Pv Module ◽  
Sunny Weather

Photovoltaic Thermal Solar Collector (PVT) is a hybrid technology used to produce electricity and heat simultaneously. Current enhancements in PVT are to increase the electrical and thermal efficiencies. Many PVT factors such as type of absorber, thermal conductivity, type of PV module and operating conditions are important parameters that can control the PVT performance. In this paper, an analytical model, using energy balance equations, is studied for PVT with an improved parallel flow absorber. The performance is calculated for a typical sunny weather in Malaysia. It was found that the maximum electrical and thermal efficiencies are 12.9 % and 62.6 %, respectively. The maximum outlet water temperature is 59 oC.

scholarly journals Component-Oriented Modeling of a Micro-Scale Organic Rankine Cycle System for Waste Heat Recovery Applications

2021 ◽  
Vol 11 (5) ◽  
pp. 1984
Author(s):  
Ramin Moradi ◽  
Emanuele Habib ◽  
Enrico Bocci ◽  
Luca Cioccolanti
Keyword(s):  
Electric Power ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pump Efficiency ◽  
Micro Scale

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.

Effect of shape/size and distribution of microgeometries of textures on tribo-performance of crankpin bearing

2021 ◽  
pp. 135065012110105
Author(s):  
Nguyen Van Liem ◽  
Wu Zhenpeng ◽  
Jiao Renqiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Contact Force ◽  
Distribution Density ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Combined Model ◽  
Obvious Effect ◽  
Area Density

The effect of the shape/size and distribution of microgeometries of textures on improving the tribo-performance of crankpin bearing is proposed. Based on a combined model of the slider-crank mechanism dynamic and hydrodynamic lubrication, the distribution density, area density, and shape of spherical textures, square-cylindrical textures, wedge-shaped textures, and a hybrid between spherical texture and square-cylindrical texture on the crankpin bearing's tribo-performance are investigated under different operating conditions of the engine. The tribological characteristic of the crankpin bearing is then evaluated via the indexes of the oil film pressure p, asperity contact force, friction force, and friction coefficient of the crankpin bearing. The research results show that the distribution density with n = 12 and m = 6, and area density with α = 30% of various microtextures have an obvious effect on ameliorating the crankpin bearings tribo-performance. Concurrently, at the mixed lubrication region, the shape of the square-cylindrical texture on improving the tribo-performance is better than the other shapes of the spherical texture, wedge-shaped texture, and spherical and square-cylindrical texture. Particularly, all the average values of the asperity contact force, friction force, and friction coefficient with a square-cylindrical texture are significantly reduced by 14.6%, 19.5%, and 34.5%, respectively, in comparison without microtextures. Therefore, the microtextures of the spherical texture applied on the bearing surface can contribute to enhance the durability and decrease the friction power loss of the engine.

Analysis of Vapor Evaporation Loss in Filling Gasoline into Tank

2011 ◽  
Vol 347-353 ◽  
pp. 372-375 ◽  
Author(s):  
Wei Qiu Huang ◽  
Feng Li ◽  
Shu Hua Zhao ◽  
Jing Zhong
Keyword(s):  
Mass Transfer ◽  
Experimental System ◽  
Pilot Scale ◽  
Convective Transport ◽  
Operating Conditions ◽  
Vapor Concentration ◽  
Air Mass ◽  
Evaporation Loss ◽  
Gas Space ◽  
Gasoline Evaporation

A pilot-scale experimental system of filling gasoline into a tank was built to investigate gasoline vapor-air mass transfer in the tank gas space and the vapor evaporation loss from the tank in different operating conditions. The results showed that the higher the location of filling pipe exit inside the tank, the quicker the speed of the filling gasoline, and the higher the initial vapor concentration in the tank gas space, then the more severe the vapor-air convective transport and the larger the gasoline evaporation loss rates.

Waste Heat Recovery in a Cruise Vessel in the Baltic Sea by Using an Organic Rankine Cycle: A Case Study

2015 ◽  
Author(s):  
Fredrik Ahlgren ◽  
Maria E. Mondejar ◽  
Magnus Genrup ◽  
Marcus Thern
Keyword(s):  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Maritime Transportation ◽  
Working Fluid ◽  
Net Power Output

Maritime transportation is a significant contributor to SOx, NOx and particle matter emissions, even though it has a quite low CO2 impact. New regulations are being enforced in special areas that limit the amount of emissions from the ships. This fact, together with the high fuel prices, is driving the marine industry towards the improvement of the energy efficiency of current ship engines and the reduction of their energy demand. Although more sophisticated and complex engine designs can improve significantly the efficiency of the energy systems in ships, waste heat recovery arises as the most influent technique for the reduction of the energy consumption. In this sense, it is estimated that around 50% of the total energy from the fuel consumed in a ship is wasted and rejected in fluid and exhaust gas streams. The primary heat sources for waste heat recovery are the engine exhaust and the engine coolant. In this work, we present a study on the integration of an organic Rankine cycle (ORC) in an existing ship, for the recovery of the main and auxiliary engines exhaust heat. Experimental data from the operating conditions of the engines on the M/S Birka Stockholm cruise ship were logged during a port-to-port cruise from Stockholm to Mariehamn over a period of time close to one month. The ship has four main engines Wärtsilä 5850 kW for propulsion, and four auxiliary engines 2760 kW used for electrical consumers. A number of six load conditions were identified depending on the vessel speed. The speed range from 12–14 knots was considered as the design condition, as it was present during more than 34% of the time. In this study, the average values of the engines exhaust temperatures and mass flow rates, for each load case, were used as inputs for a model of an ORC. The main parameters of the ORC, including working fluid and turbine configuration, were optimized based on the criteria of maximum net power output and compactness of the installation components. Results from the study showed that an ORC with internal regeneration using benzene would yield the greatest average net power output over the operating time. For this situation, the power production of the ORC would represent about 22% of the total electricity consumption on board. These data confirmed the ORC as a feasible and promising technology for the reduction of fuel consumption and CO2 emissions of existing ships.

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