Performance Analyses of Photovoltaic Thermal Integrated Concentrator Collector Combined With Single Effect Absorption Cooling Cycle: Constant Flow Rate Mode

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Md. Meraj ◽  
M.E. Khan ◽  
Md. Azhar
Keyword(s):  
Climatic Conditions ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Inlet Temperature ◽  
New Delhi ◽  
Absorption System ◽  
Simulation Code ◽  
Single Effect ◽  
Performance Analyses

Abstract In the present communication, performance analyses of interconnected N number of fully covered semitransparent photovoltaic thermal integrated concentrator collectors combined with single effect vapor absorption refrigeration system have been carried out. The proposed system was analyzed under the constant mass flowrate of collectors’ fluid. Mathematical expressions have also been derived for generator temperature of the absorption unit as a function of both design and operating parameters. Further, simulations have been performed for a typical day of May month of New Delhi climatic conditions. Performance parameters have been evaluated such as collector exit temperature, generator inlet temperature, electrical power output, electrical efficiency, overall thermal energy gain, instantaneous thermal efficiency, overall exergy gain and coefficient of performance of the absorption system. The simulation code has been written in matlab. From the present analyses, the following salient conclusions have been drawn: Operating generator temperature of the absorption system is suitable for five number of photovoltaic thermal-integrated parabolic concentrator collector connected in series. The proposed system will continue operating for 5 h during May month in New Delhi climate conditions. The maximum solar coefficient of performance, refrigeration coefficient of performance, and exergy coefficient of performance are reported as 0.1551, 0.8344, and 0.2697, respectively, for the proposed novel system under given design and operating conditions. Additionally, the effects of other design parameters of this novel system have also been investigated.

INFLUENCE OF THE SOLUTION HEAT EXCHANGER EFFICIENCY ON THE PERFORMANCE OF A SINGLE EFFECT H2O-LiBr ADIABATIC ABSORPTION SYSTEM

2011 ◽  
Vol 19 (02) ◽  
pp. 107-112 ◽  
Author(s):  
GEYDY GUTIÉRREZ URUETA ◽  
PEDRO RODRÍGUEZ AUMENTE ◽  
MARIA RODRÍGUEZ HIDALGO ◽  
ANTONIO LECUONA NEUMANN
Keyword(s):  
Heat Exchanger ◽  
Strong Solution ◽  
Heat Transfer Process ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Test Facility ◽  
Absorption System ◽  
Experimental Conditions ◽  
Single Effect ◽  
Absorption Cycle

This work analyzes the effect that particular operating conditions of a single effect H2O - LiBr adiabatic absorption system have on a plate-type solution heat exchanger efficiency. The corresponding influence of such efficiency on the performance of facility under study is evaluated. As a result of the design of experimental test facility, the functioning of the strong solution circuit leads to take into account some particular operating conditions which affect the correct performance of the solution heat exchanger. For some experimental conditions, the strong solution side is not completely filled by the solution fluid. As a consequence of this, the heat transfer process is affected, reducing the solution heat exchanger efficiency and changing greatly the resulting coefficient of performance (COP) of the absorption facility. In order to illustrate this phenomenon, this paper offers graphical results including: solution working temperatures, solution heat exchanger efficiency and COP in a time sequence of an experiment, as well as for fixed steady-state operating conditions. These results show the importance of a correct functioning of the solution heat exchanger on the performance of an absorption system. The results are useful for researchers interested in new absorption cycle designs.

Exergy Analysis of Single-Effect Vapor Absorption System Using Design Parameters

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Khursheed Afroz Ansari ◽  
Md. Azhar ◽  
M. Altamush Siddiqui
Keyword(s):  
Energy Exchange ◽  
Operating Conditions ◽  
System Component ◽  
Design Parameters ◽  
Absorption System ◽  
Vapor Absorption ◽  
Shell And Tube ◽  
Single Effect ◽  
Internal Irreversibility ◽  
Control Volumes

Abstract In the present communication, internal irreversibility at each component of a single-effect vapor absorption refrigeration system has been evaluated and presented. The irreversibility is induced owing to the pressure drop in the shell and tube and energy exchange between the working fluids. Each component of the system is considered to be a shell and tube-type energy exchanger with slight modifications depending upon the applications. Each energy exchanger is divided into three control volumes, namely, tube wall, shell, and tube for which both energy and exergy balances are applied to evaluate the exergy destruction rate (EDR). Moreover, the overall EDR in the energy exchanger is then estimated in the form of pumping work and energy exchange duty. This objective function is further simplified in the form of design parameters such as tube diameter, friction coefficient, number of tubes, number of baffles, and overall heat transfer coefficient for the energy exchanger. In addition to this, optimum generator temperature and minimum EDR of each component of the absorption system have been tabulated and presented. Results show that for a single tube, UA value in the system component ranges from 2.99 W/K to 48.9 W/K depending on the operating conditions and design parameters of the system. Also, the number of tube in the system components ranges from 1108 tubes to 24803 tubes and the number of baffles in the respective components ranges from 2 to 7.

CFD Modeling of a Catalytic Flat Plate Fuel Reformer for Hydrogen Generation

2010 ◽  
Author(s):  
Kranthi K. Gadde ◽  
Panini K. Kolavennu ◽  
Susanta K. Das ◽  
K. J. Berry
Keyword(s):  
Flat Plate ◽  
Catalytic Combustion ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Design Parameters ◽  
Practical Implementation ◽  
Channel Height ◽  
Inlet Temperature ◽  
Two Dimensional

In this study, steam reforming of methane coupled with methane catalytic combustion in a catalytic plate reactor is studied using a two-dimensional mathematical model for co-current flow arrangement. A two-dimensional approach makes the model more realistic by increasing its capability to capture the effect of parameters such as catalyst thickness, reaction rates, inlet temperature and velocity, and channel height, and eliminates the uncertainties introduced by heat and mass transfer coefficients used in one-dimensional models. In our work, we simulate the entire flat plate reformer (both reforming side and combustion side) and carry out parametric studies related to channel height, inlet velocities, and catalyst layer thickness that can provide guidance for the practical implementation of such design. The operating conditions chosen make possible a comparison of the catalytic plate reactor and catalytic combustion analysis with the conventional steam reformer. The CFD results obtained in this study will be very helpful to understand the optimization of design parameters to build a first generation prototype.

scholarly journals Thermodynamic analysis of a single effect lithium bromide water absorption system using waste heat in sugar industry

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 507-517
Author(s):  
Balaji Kumar ◽  
Iniyan Selvarasan ◽  
Gurubalan Annadurai ◽  
Senthilkumar Ramalingam
Keyword(s):  
Steam Turbine ◽  
Energy Savings ◽  
Waste Heat ◽  
Sugar Industry ◽  
Operating Parameter ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Absorption System ◽  
Beneficial Use ◽  
Vapor Absorption

Energy analysis plays a vital role in the industry due to the use of electrical energy, global warming, and economy crises. This paper describes the waste heat available in the exhaust of the steam turbine and beneficial use of the waste heat. The sugar industry steam turbine exhaust carries enthalpy of steam at 2500 kJ/kg, this thermal energy can be put into beneficial use as the heat source to the vapor absorption refrigeration system to compensate energy required for DC thyrist motor, and this can also be used for cold storage. Energy savings in terms of cost and fuels are calculated. Investigation on the heat and mass transfer in evaporator has been carried out in vapor absorption system by varying the operating parameter. Less circulation ratio is required to increase the coefficient of performance. The inlet temperature of the coolant should be less for achieving higher coefficient of performance.

Performance Evaluation of a Catalytic Flat Plate Fuel Reformer for Hydrogen-Rich Reformate

2013 ◽  
Author(s):  
Susanta K. Das ◽  
K. Joel Berry
Keyword(s):  
Flat Plate ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Design Parameters ◽  
Practical Implementation ◽  
Channel Height ◽  
Inlet Temperature ◽  
Optimized Design ◽  
Two Dimensional ◽  
Transfer Coefficients

A two-dimensional computational fluid dynamics (CFD) model is used for reforming methane with the help of catalytic combustion and reformation in a catalytic flat plate reformer. The two-dimensional approach makes the computational model more realistic by eliminating the uncertainties introduced by heat and mass transfer coefficients used in one-dimensional models. It also increased its capability to capture the effect of design parameters such as catalyst thickness, reaction rates, inlet temperature and velocity, and channel height has on producing high purity reformate gas. In order to carry out parametric studies related to various design parameters, in our present work, we simulate the entire flat plate reformer domain by considering full electro-kinetics that provide guidance for the practical implementation of such design. We chose different designs and operating conditions in such a way which makes possible to build a catalytic flat plate fuel reformer prototype. Based on the CFD results obtained in this study, we built a first generation catalytic flat plate fuel reformer prototype using the optimized design parameters. The performance of the fuel reformer prototype is tested with a 5-cell high temperature PEM fuel cell stack.

scholarly journals METHODOLOGY FOR DETERMINING THE MAIN INDICATORS OF THE TEMPERATURE AND DYNAMIC CHARACTERISTICS OF THE COOLING SYSTEM OF AN ENERGY VEHICLE DURING OPERATION

2021 ◽  
pp. 75-79
Author(s):  
Ekaterina Parlyuk ◽  
Nikolay Bol'shakov
Keyword(s):  
Internal Combustion Engines ◽  
Cooling System ◽  
Climatic Conditions ◽  
Thermal Balance ◽  
Operating Conditions ◽  
Design Parameters ◽  
Industrial Complex ◽  
Design Features ◽  
Engine Operation ◽  
Temperature Dynamic

The efficiency of internal combustion engines of energy facilities operating in the conditions of enterprises of the agro-industrial complex depends on the stability of the thermal regime of the engine. Its provision is entrusted to the cooling system, in this article which is a radiator with a polyurethane core. The temperature regime of the engine operation affecting a number of factors is given and described - these are design parameters (design features of the radiator and the features of the working process of the radiator, taking into account the operating conditions of the tractor) and operational, which take into account the operating mode of the tractor and natural and climatic conditions. According to the research results during the operation of the tractor in steady conditions, the temperature of the coolant in the system is stable, respectively, the temperature field of the air flow at the inlet and outlet of the radiator with a polyurethane core also stabilizes. To take them into account, the coefficient of thermal properties of the radiator is introduced, which depends on the external and internal temperature-dynamic effects of the environment, and a diagram is constructed that shows the dependence of the temperature of the coolant flowing in the radiator on the generated load of the tractor during operation in the field. At the same time, the temperature-dynamic characteristic of the tractor does not depend on the design features of the engine, but on the power developed by the engine. Therefore, the heat removed from the engine into the coolant is calculated by us through the engine power. Based on this, the characteristic of the thermal balance of the engine and the heat transfer of the radiator during the operation of the tractor at full load are considered, taking into account the change in gears within the speed limits, a graph of the thermal balance of the engine and radiator versus speed is built. Based on the calculations, it was concluded that the use of the characteristics of the traction-dynamic balance of the tractor can serve as the basis for the general analysis and calculated and experimental operating modes of the automotive polymer radiator and the cooling system as a whole, taking into account the loads, climatic conditions and operating parameters of the cooling system

Enhancement of the performance of bubble absorber using hybrid nanofluid as a cooled absorption system

2019 ◽  
Vol 29 (10) ◽  
pp. 3857-3871 ◽  
Author(s):  
Rawya Ben Jaballah ◽  
Mohamed Bechir Ben Hamida ◽  
Jehad Saleh ◽  
Mohammed A. Almeshaal
Keyword(s):  
Numerical Model ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Operating Conditions ◽  
Design Parameters ◽  
Hybrid Nanofluid ◽  
Absorption System ◽  
Content Type ◽  
Cooling Medium ◽  
High Heat Transfer

Purpose The purpose of this paper is to investigate the enhancement of the performance of bubble absorber using hybrid nanofluid as a cooled NH3/H2O absorption system to reduce their size and to find the best fitting model. A numerical model for ammonia-water bubble absorber was developed to show the influence of operating conditions and design parameters on the absorber performance. Design/methodology/approach A finite difference numerical method is used to solve the numerical model. The model is subjected to the inlet conditions of liquid, vapor and coolant flow regimes. The absorber modeling was divided into small elements along the absorber length. Findings The model proposed is validated with previously published works. Then agreement between the both is considered as good. Research limitations/implications Numerical results/The use of hybrid nanofluids. Originality/value The results showed that the hybrid nanofluid is the best cooling medium. Very high heat transfer rates are obtained because of the high thermal conductivity and specific heat of hybrid nanofluid, and consequently, the absorber size decreases. It was also found that the absorber thermal load and the mass absorption flux increase with increasing of solid volume fraction. Also, the existence of an optimal absorber length was revealed, required for complete absorption when using hybrid nanofluid as a cooling medium. It is recommended that using hybrid nanofluid to remove the heat from the absorber is the best candidate for NH3/H2O absorption performance enhancement.

Exergonomic Optimization of an Air-Conditioning System

1997 ◽  
Vol 119 (1) ◽  
pp. 62-69 ◽  
Author(s):  
G. Cammarata ◽  
A. Fichera ◽  
L. Mammino ◽  
L. Marletta
Keyword(s):  
Air Conditioning ◽  
Thermodynamic Cycle ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Mechanical Equipment ◽  
Air Conditioning System ◽  
Real Cost ◽  
Optimum Configuration ◽  
Decision Variables

In this paper, exergonomic theory is applied to an air-conditioning system for optimization purposes. The investigation is addressed to an all-air system with air recirculation, The thermodynamic cycle includes a mixing plenum, a cooling and heating coil, chiller, and heater. The thermodynamic model is stated according to recent formulations of exergy for moist air streams, while the economic model is based on cost balance equations and real cost data for mechanical equipment. The objective function to minimize includes the following decision variables: fresh to total air rate, coefficient of performance for the chiller, inlet temperature of water for the cooling and the heating coils, temperature difference of the same streams. For the exergonomic optimization, the authors followed the approach proposed by Tsatsaronis (1984). The optimum configuration is obtained through an iterative procedure aimed at the design improvement. The results show that there is considerable room for improvement with respect to a system based on typical design parameters.

Dynamic Performance Investigation of Single-Effect NH3 + LiNO3 and NH3 + NaSCN Solar Cooling Cycles: A Case Study for Western Indian Climate

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Nishant Modi ◽  
Bhargav Pandya ◽  
Vinay Kumar ◽  
Jatin Patel
Keyword(s):  
Dynamic Performance ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Sodium Thiocyanate ◽  
Lithium Nitrate ◽  
Ambient Conditions ◽  
Evaporator Temperature ◽  
Water Storage Tank ◽  
Single Effect

Abstract This article compares the dynamic behavior of solar-assisted novel salt-based ammonia/sodium thiocyanate (NH3 + NaSCN) and ammonia/lithium nitrate (NH3 + LiNO3) single-effect absorption refrigeration cycles. An evacuated tube collector (ETC) is attached with fully mixed hot water storage tank to power the absorption system. Variations in ambient conditions are determined for Gujarat Region of India and their effects on absorption cycles are quantified throughout the days for the months of April to September. System performance is investigated and compared on terms of coefficient of performance (COP), refrigeration capacity, efficiency and solar COP (SCOP). At same operating conditions, it is found that the NH3 + LiNO3 cycle can achieve much lower evaporator temperature (−13.1 °C) then NH3 + NaSCN cycle (−7.5 °C) and maximum possible COP for NH3 + NaSCN cycle is 0.73 and 0.68 for NH3 + LiNO3 cycle. The working limit of NH3 + LiNO3 cycle is wide ranging and narrow for NH3 + NaSCN cycle due to high crystallization possibility. SCOP varies from 0.18 to 0.43 for NH3 + NaSCN cycle and 0.17 to 0.39 for NH3 + LiNO3 cycle over the period of 6 months. Based on these findings, the suitable working cycle is justified.

Numerical Modeling and Thermal Analysis of an Adsorption Refrigeration System

2015 ◽  
Vol 23 (04) ◽  
pp. 1550033 ◽  
Author(s):  
Anirban Sur ◽  
Randip K. Das
Keyword(s):  
Thermophysical Properties ◽  
Cooling System ◽  
Isosteric Heat ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
Simulation Code ◽  
Mass Transfer Processes ◽  
Different Temperatures

The aim of this paper is to develop a complete, precise and simple numerical model based on the thermophysical properties of an adsorptive cooling system (using activated carbon–methanol pair), analyze and discuss the heat and mass transfer processes and identify the parameters which influence the system performance. In the design of adsorption refrigeration system, the characteristics of both adsorbate–adsorbent pairs and system operating conditions are very important. So in this model, different thermophysical properties of working pair such as, specific heat, density, isosteric heat of adsorption and desorption, and different temperatures of the system are considered. A simulation code, written in FORTRAN, is carried out. The performance of the system is assessed in terms of refrigeration effect and coefficient of performance (COP).

Sign in / Sign up

Export Citation Format

Share Document