scholarly journals Analysis of test results of a household absorption refrigerating appliance on an electric and gas source of thermal energy

2021 ◽  
Vol 4 (1(60)) ◽  
pp. 49-53
Author(s):  
Daniyorbek Adambayev ◽  
Alexander Titlov
Keyword(s):  
Natural Gas ◽  
Experimental Studies ◽  
Environmentally Friendly ◽  
Operating Conditions ◽  
Hot Water ◽  
Operating Costs ◽  
Working Fluid ◽  
Electric Heater ◽  
Absorption Refrigeration ◽  
Waste Products

One of the biggest challenges for refrigeration systems is their conversion to environmentally friendly refrigerants. This attracts the attention of developers of household refrigeration equipment to absorption refrigeration devices (ARD), which include an absorption refrigeration unit (ARU). ARD working fluid consists of natural components - ammonia water solution with the addition of an inert gas (hydrogen). Therefore, the use of ARU can be considered as one of the options for transferring to environmentally friendly refrigerants. In recent years, in connection with the rapidly developing gasification of the population of Europe, an alternative has arisen - the operation of household ARD on natural gas. Natural gas can become an alternative to electrical energy in stationary operating conditions of household refrigeration appliances. Thus, the object of the study was a single-chamber household refrigerator with a low-temperature compartment "Kiev-410" (Ukraine). In this paper, the study is aimed at comparing the thermal modes of operation and the costs of operating a household ARD on electric energy and natural gas. To solve this, it was necessary to determine the temperatures at the characteristic points of the refrigeration apparatus and in the chamber, as well as the energy consumption of the absorption-type apparatus in accordance with regulatory documents, at various values of the thermal load on the thermosyphon and various ambient temperatures. The studies were carried out at elevated outdoor temperatures: 28–33 ° С. The range of thermal loads on the ARU thermosyphon electric heater was 50–130 W. The range of numerical values of natural gas consumption in the burner was (2.8–8.8) • 10-6 m3/s. In the process of conducting experimental studies of household ARD, results were obtained showing the economic prospects of working in stationary conditions on natural gas. At the same time, ARD of increased useful volume (200 dm3 and above) has the greatest prospects. The daily operating costs in them are 0.078...0.084 USD, which is 23...27 % lower than the case of using electricity. When the ARU thermosyphon is built into the heating and hot water supply system, it becomes possible to use the temperature potential of the waste products of combustion and completely eliminate operating costs.

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

Experimental Study on the Organic Rankine Cycle Power System Adopting Dual Expanders in Parallel

2014 ◽  
Author(s):  
Eunkoo Yoon ◽  
Hyun Jun Park ◽  
Hyun Dong Kim ◽  
Kyung Chun Kim ◽  
Sang Youl Yoon
Keyword(s):  
Heat Source ◽  
Power System ◽  
Water Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Working Fluid ◽  
Electric Heater ◽  
Shaft Power ◽  
Scroll Expanders

This study aims to evaluate the performance of an organic Rankine cycle (ORC) power system adopting dual expanders in parallel by experiment. A dual-expander ORC system was designed to provide competitive advantages over a general single expander ORC system in typical applications with large thermal fluctuation of heat sources such as solar heat, marine waste heat, and etc. The ORC system consists of two scroll expanders installed in parallel, a hydraulic diaphragm type pump to feed and pressurize the working fluid, R-245fa, two plate heat exchangers for the evaporator and the condenser, and two generators with shaft power torque meters. The two scroll expanders were modified from two oil-free air scroll compressors, and were tested in the ORC loop with R245fa. The maximum isentropic efficiency of each expander was measured about 53%, and the shaft power was reached to about 2kW. The hot water was used as heat source, and the water temperature was controlled up to 150 °C by the 100 kW-class electric heater. A circulating air-cooled chiller was utilized for the control of the cooling water temperature. In order to determine the static performance of the system, efficiencies and shaft powers were measured with 130 °C heat source temperature. In addition, performance tests were conducted with various working fluid mass flow rates to control pressure ratios. The characteristics and total thermal efficiency of the dual parallel expander ORC system and optimal operating modes are addressed.

scholarly journals Energy Performance Optimization in a Condensing Boiler

2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Diego Fernández-Cheliz ◽  
Eloy Velasco-Gómez ◽  
Juan Peral-Andrés ◽  
Ana Tejero-González
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Performance Optimization ◽  
Energy Performance ◽  
Primary Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Operating Parameters ◽  
Climate Conditions ◽  
Lower Heating Value

In Europe, primary energy consumption in buildings accounts for up to 25–40%, depending on the climate conditions. Space heating and Domestic Hot Water (DHW) contribute significantly to this energy consumption. Among the most common sources for heat generation in these appliances is natural gas. Condensing boilers can surpass the 100% energy performance over the lower heating value, if the operating conditions enable the water vapor in the exhaust gases to condensate. Consequently, optimizing the operating parameters of condensing boilers is necessary to decrease fuel consumption without hindering water heating needs. The present work presents an experimental approach to the operating parameters of a condensing boiler that works with natural gas. The aim is to develop a theoretical model that relates the energy performance to the water temperature set by the final user and the excess air set by the maintenance staff.

A Computational Investigation of Non-Premixed Combustion of Natural Gas Injected Into Mixture of Argon and Oxygen

2018 ◽  
Author(s):  
Martia Shahsavan ◽  
Mohammadrasool Morovatiyan ◽  
J. Hunter Mack
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Direct Injection ◽  
Dynamic Structure ◽  
Operating Conditions ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Transient Model ◽  
Large Eddy Simulation Model

Natural gas is traditionally considered as a promising fuel in comparison to gasoline due to the potential of lower emissions and significant domestic reserves. These emissions can be further diminished by using noble gases, such as argon, instead of nitrogen as the working fluid in internal combustion engines. Furthermore, the use of argon as the working fluid can increase the thermodynamic efficiency due to its higher specific heat ratio. In comparison to pre-mixed operation, the direct injection of natural gas enables the engine to reach higher compression ratios while avoiding knock. Using argon as the working fluid increases the in-cylinder temperature at top dead center and enables the compression ignition of natural gas. In this numerical study, the combustion quality and ignition behavior of methane injected into a mixture of oxygen and argon has been investigated using a three-dimensional transient model of a constant volume combustion chamber. A dynamic structure large eddy simulation model has been utilized to capture the behavior of the non-premixed turbulent gaseous jet. A reduced mechanism consists of 22-species and 104-reactions were coupled with the CFD solver. The simulation results show that the methane jet ignites at engine-relevant conditions when nitrogen is replaced by argon as the working fluid. Ignition delay times are compared across a variety of operating conditions to show how mixing affects jet development and flame characteristics.

A Computational Investigation of Nonpremixed Combustion of Natural Gas Injected Into Mixture of Argon and Oxygen

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Martia Shahsavan ◽  
Mohammadrasool Morovatiyan ◽  
J. Hunter Mack
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Numerical Study ◽  
Direct Injection ◽  
Three Dimensional ◽  
Dynamic Structure ◽  
Operating Conditions ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Transient Model

Natural gas is traditionally considered as a promising fuel in comparison with gasoline due to the potential of lower emissions and significant domestic reserves. These emissions can be further diminished by using noble gases, such as argon, instead of nitrogen as the working fluid in internal combustion engines. Furthermore, the use of argon as the working fluid can increase the thermodynamic efficiency due to its higher specific heat ratio. In comparison with premixed operation, the direct injection of natural gas enables the engine to reach higher compression ratios while avoiding knock. Using argon as the working fluid increases the in-cylinder temperature at top dead center (TDC) and enables the compression ignition (CI) of natural gas. In this numerical study, the combustion quality and ignition behavior of methane injected into a mixture of oxygen and argon have been investigated using a three-dimensional transient model of a constant volume combustion chamber (CVCC). A dynamic structure large eddy simulation (LES) model has been utilized to capture the behavior of the nonpremixed turbulent gaseous jet. A reduced mechanism consists of 22-species, and 104-reactions were coupled with the CFD solver. The simulation results show that the methane jet ignites at engine-relevant conditions when nitrogen is replaced by argon as the working fluid. Ignition delay times are compared across a variety of operating conditions to show how mixing affects jet development and flame characteristics.

scholarly journals Theoretical studies of natural gas vaporization of an air-methane mixture in a diesel engine cylinder

2021 ◽  
Vol 7 (Special) ◽  
pp. 1-1
Author(s):  
Ivan Storozhev ◽  
Sergey Romanov ◽  
Timofey Alushkin ◽  
Anatoly Palyanov
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Combustion Engine ◽  
Experimental Studies ◽  
Working Fluid ◽  
Thermal Calculation ◽  
Theoretical Studies ◽  
Engine Cylinder ◽  
Methane Mixture ◽  
Gas Nozzle

This article presents theoretical studies of the vaporization of natural gas of an air-methane mixture in a diesel engine cylinder. These studies were conducted in order to find a rational volume of methane supplied to the cylinder of a diesel engine. Having carried out a thermal calculation of the working processes of the gas engine, we obtained the size of the gas droplet supplied to the engine cylinder, which should have a size of no more than 0.405 mm. Having evaluated the experimental studies conducted in this area, the dependence of the nozzle diameter of the nozzle and the diameter of the gas droplet was revealed, it was determined that with a pressure drop on the gas nozzle equal to 0.2 MPa, the diameter of the gas droplet practically coincides with the diameter of the nozzle. Based on this, the diameter of the nozzle of the gas nozzle sprayer is not more than 0.35...0.4 mm. The conclusion of this article is that it is possible to determine the optimal volume of gas supplied and assess the real picture of the processes taking place in the cylinder of a diesel engine only. Keywords: INTERNAL COMBUSTION ENGINE, WORKING FLUID, FUEL, VAPORIZATION, GAS, COMBUSTION

scholarly journals Adsorption gas Heat Pump fuelled with hydrogen enriched natural gas blends: the analytical simulation model development and validation

2020 ◽  
Vol 197 ◽  
pp. 08002
Author(s):  
Matteo Sforzini ◽  
Gianluigi Lo Basso ◽  
Romano Paiolo ◽  
Livio De Santoli ◽  
Fabrizio Cumo
Keyword(s):  
Natural Gas ◽  
Simulation Model ◽  
Heat Pump ◽  
Energy Performance ◽  
Operating Conditions ◽  
Hot Water ◽  
Relative Standard Error ◽  
Outlet Temperature ◽  
Experimental Campaign ◽  
Relative Standard

This study deals with the implementation of an analytical model to simulate the energy performance associated to a commercial Gas adsorption Heat Pump, when H2NG (Hydrogen Enriched Natural Gas) blends are used as fuel. In detail, a water source heat pump manufactured by Robur (GAHP-WS) has been used as a reference device for building the simulation model within the MATLAB-Simulink environment. Thereafter, the simulation results have been validated by the experimental campaign, testing on field and in actual operating conditions the heat pump. Specifically, the model has been developed by implementing the WaterAmmonia mass and energy balances for each component. It is able to evaluate fuel consumption, efficiency in terms of GUE, required thermal power from the cold heat sink as well as the water outlet temperature at the evaporator, once the heating load is used as the main input. The experimental campaign for the model calibration and validation has been carried out over the winter season. Additionally, the heat pump performance has been detected when it operates to supply hot water at 60 °C and 55 °C, and it is fuelled with growing hydrogen fractions, starting from 0% vol., 5% vol. up to 10% vol. In the end, the standard errors as well as the relative ones affecting the main output parameters have computed for the validation process. From the outcomes it emerges that the average relative standard error related to all load conditions is lower than 2.5% for natural gas operation. On the contrary, it ranges between 2.5% and 4% when H2NG at 5% and 10% by volume have been burnt.

scholarly journals Experimental Studies of the Heat Exchange Between the Water Film and the Casting Roller in the Thermal Preconditioning Chamber

2021 ◽  
pp. 42-46
Author(s):  
Alexander Pereselkov ◽  
Olga Kruglyakova
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Flow Rate ◽  
Large Diameter ◽  
Experimental Studies ◽  
Water Film ◽  
Scientific Paper ◽  
Operating Conditions ◽  
Hot Water ◽  
Thermal Preparation

When the casting roller is cooled or heated in the preconditioning chamber the water is supplied to its surface by flat-jet nozzles. The visual inspection of the model of the casting roller showed that a considerable part of it can be covered with the water film spreading from sprinkling zones. It was established that the heat conductivity in the roller body is considered to be a crucial thermal preparation factor in the conjugate heat-exchange problem for the roller of a large diameter at Bio criterion values exceeding 20. Hence, it is sufficient to provide an essential level of the heat transfer that corresponds to the heat transfer coefficient of 2000 W/(m2∙K) to provide appropriate operating conditions for the thermal preparation of the roller. The conditions are also met in sprinkling zones. Due to this fact this scientific paper studies the heat exchange conditions under the water film that spreads between the adjacent sprinkling zones. A range of changes in the flow rate of the spreading water film was determined experimentally. The conditions of heat exchange between the surface of alpha-calorimeter and the water film were analyzed depending on its flow rate and the heat meter surface temperature. A generalized correlation equation was derived. It was established that the heat exchange intensity in sprinkling zones and under the spreading water film meets technological roller treatment conditions in the preconditioning chambers. The obtained research data can be used for the rational arrangement of the collectors and flat-jet nozzles in casting roller preconditioning chambers to reduce the cold and hot water consumption and cut down operating costs.

scholarly journals ОСОБЛИВОСТІ ТЕРМОІМПУЛЬСНОГО ОЧИЩЕННЯ ПОВЕРХОНЬ І КРОМОК ДЕТАЛЕЙ ВІД ЗАБРУДНЕНЬ ПІСЛЯ МЕХАНІЧНОЇ ОБРОБКИ

2018 ◽  
pp. 36-46
Author(s):  
Алексей Васильевич Лосев ◽  
Игорь Валерьевич Бычков ◽  
Вячеслав Викторович Коллеров ◽  
Анна Сергеевна Селезнева
Keyword(s):  
Experimental Studies ◽  
Cost Effective ◽  
Operating Conditions ◽  
Working Fluid ◽  
Body Parts ◽  
Hydraulic Systems ◽  
Cost Component ◽  
Internal Surfaces ◽  
And Control

The requirements for the quality of aviation technology are decisive in the creation of technological systems that ensure the industrial purity of products. But the cost component of the finishing and stripping technologies is also important, the value of which depends on the chosen method of removing liquids, for example, from hydraulic units of aircraft. Reliable and cost-effective manufacture of parts with specific geometric and technological properties is the main goal of industrial production. In a market economy, the production of competitive products is a necessity, and it is always the choice of a rational, stable price-quality ratio. The quality of engineering products is a multifactorial problem, depending on the complex of systemic organizational and technological measures. In the production of aircraft technology, quality assurance is associated with dependability and a guaranteed resource that is vital due to specific operating conditions. One of the most important measures to ensure the reliability and guaranteed life of aviation products is to ensure industrial cleanliness. Cleaning from microparticles, macro- and micro-hauler surfaces and edges of parts after mechanical types of processing is included in the complex of these measures. The most problematic is the cleaning of body parts with a complex configuration of external and internal surfaces. The need to remove liquids and other technological pollution is explained by functional, ergonomic and aesthetic reasons. If ergonomic and aesthetic factors do not affect the technical characteristics of products, then the functional ones are directly related to the operability of machines and mechanisms. Functional causes are the prevention of failures of hydraulic distribution and control devices, as well as the prevention of increased wear of critical parts occurring when friction pairs of solid metal particles enter the gaps, difficulties in assembling and positioning, reducing fatigue strength and so on. Burrs cause turbulence in the flow of gas or liquid, disrupting the flow uniformity. It is obvious that the mutually influencing processes occurring in the hydraulic systems of machines, in violation of working conditions, lead to an increase in negative phenomena. The peculiarity of the use of purification technologies is the need to remove liquids from 100% of the parts included in the autonomous system of mechanisms. If at least one detail is left untreated, then the working fluid, when in contact with contaminated surfaces, washes away these contaminants and spreads them throughout the system, while the most sensitive elements are damaged. The reasons for the need to clean the surface and edges of parts from technological contamination are given. A brief review of the results of modeling and research on the removal of burrs in the environment of detonating gas mixtures has been performed. The features of the thermopulse process are considered and the results of numerical and experimental studies are presented. A comparative analysis of the energy intensity of removing burrs of various metals is shown.

scholarly journals Prospects and problems of using liquefied natural gas as fuel on river ships in the northern steaming line of Russia

2021 ◽  
pp. 99-107
Author(s):  
Lev V. Ivanov ◽  
Alexey V. Soloviev ◽  
Ernest V. Rumiantcev
Keyword(s):  
Natural Gas ◽  
Diesel Fuel ◽  
Energy Efficient ◽  
Main Type ◽  
Environmentally Friendly ◽  
Liquefied Natural Gas ◽  
Fuel Tank ◽  
Operating Costs

The article discusses the prospects for the modernization of projects of ships operating in the water areas of the main Siberian rivers, for the use of liquefied natural gas (LNG) as the main type of fuel, as well as problems associated with the adaptation of existing ship designs. LNG is a cheap, energy efficient, and more environmentally friendly analogue of traditional diesel fuel (DF). Unification of adaptation projects for common types of main engines of ships from northern shipping companies will significantly reduce operating costs. Modernization problems are associated with the storage of fuel stock on ships. The lower density of LNG in comparison with diesel fuel, as well as the need to use a cryogenic fuel tank, reduces the autonomy of the ship's operation on LNG. The analysis carried out in the article showed that with modernization, the autonomy of navigation in terms of fuel reserves can decrease by 2 times

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