Development of a Loss Method for Energy and Exergy Audit of Condensing Hot Water Boilers

2020 ◽  
pp. 1-23
Author(s):  
Mohsen Banifateme ◽  
Ali Behbahaninia ◽  
Saeed Sayadi
Keyword(s):  
Carbon Monoxide ◽  
Flue Gas ◽  
Residential Buildings ◽  
Direct Method ◽  
Hot Water ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Chemical Exergy ◽  
Carbon Monoxide Formation ◽  
Loss Method

Abstract Condensing boilers are used in commercial and residential buildings extensively. In this paper, a loss method is proposed to estimate the energy and exergy efficiencies of condensing hot water boilers. The presented method is based on the development of the method presented in ASME PTC 4.1. Energy loss terms consist of exhaust flue gas, carbon monoxide formation, radiation, and condensate outflow sensible heat. Exergy loss terms also include radiation losses, physical exergy of the exhaust flue gas, chemical exergy of the exhaust flue gas, increase in the chemical exergy of the flue gas due to carbon monoxide formation, condensate outflow exergy, boiler exergy destruction, and economizer exergy destruction. Energy and exergy efficiencies are calculated by estimation of these loss terms. To depict the method 's capability and compare results with the direct method, an experimental setup was designed and constructed. Results of energy and exergy audition of the boiler by applying the loss method are compared with the direct method. The results show that, although the condensing economizer improves energy efficiency, it does not improve the exergy efficiency significantly. The energy and exergy efficiencies were calculated 98.65 and 5.14 percent, respectively.

scholarly journals Energy and Exergy Analysis of Sensible Thermal Energy Storage—Hot Water Tank for a Large CHP Plant in Poland

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4842 ◽  
Author(s):  
Ryszard Zwierzchowski ◽  
Marcin Wołowicz
Keyword(s):  
Energy Storage ◽  
Ambient Temperature ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Exergy Analysis ◽  
Hot Water ◽  
Water Tank ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

The paper contains a simplified energy and exergy analysis of pumps and pipelines system integrated with Thermal Energy Storage (TES). The analysis was performed for a combined heat and power plant (CHP) supplying heat to the District Heating System (DHS). The energy and exergy efficiency for the Block Part of the Siekierki CHP Plant in Warsaw was estimated. CHP Plant Siekierki is the largest CHP plant in Poland and the second largest in Europe. The energy and exergy analysis was executed for the three different values of ambient temperature. It is according to operation of the plant in different seasons: winter season (the lowest ambient temperature Tex = −20 °C, i.e., design point conditions), the intermediate season (average ambient temperature Tex = 1 °C), and summer (average ambient temperature Tex = 15 °C). The presented results of the analysis make it possible to identify the places of the greatest exergy destruction in the pumps and pipelines system with TES, and thus give the opportunity to take necessary improvement actions. Detailed results of the energy-exergy analysis show that both the energy consumption and the rate of exergy destruction in relation to the operation of the pumps and pipelines system of the CHP plant with TES for the tank charging and discharging processes are low.

scholarly journals Comparative 3-E (Energy, Exergy & Environmental) Analysis of Oxy-Coal and Air-Coal Combustion based 500 MWe Supercritical Steam Power Plants with CO2 Capture

2020 ◽  
Vol 5 (4) ◽  
pp. 652-662
Author(s):  
Soumya Jyoti Chatterjee ◽  
Goutam Khankari ◽  
Sujit Karmakar
Keyword(s):  
Power Plant ◽  
Co2 Capture ◽  
Flue Gas ◽  
Coal Combustion ◽  
Co2 Emission ◽  
Power Plants ◽  
Exergy Destruction ◽  
Furnace Temperature ◽  
Auxiliary Power ◽  
Energy And Exergy

The comparative performance study is carried out for 500 MW Supercritical (SupC) Oxy-Coal Combustion (OCC) and Air-Coal Combustion (ACC) power plants with membrane-based CO2 capture at the fixed furnace temperature. The proposed configurations are modelled using a computer-based analysis software 'Cycle-Tempo' at different operating conditions, and the detailed thermodynamic study is done by considering Energy, Exergy, and Environmental (3-E) analysis. The result shows that the net energy and exergy efficiencies of ACC power plants with CO2 capture are about 35.07 % and 30.88 %, respectively, which are about 6.44 % and 5.77 % points, respectively higher than that of OCC power plant. Auxiliary power consumption of OCC based power plant is almost 1.97 times more than that of the ACC based plant due to huge energy utilization in the Air Separation Unit (ASU) of OCC plant which leads to performance reduction in OCC plant. However, environmental benefit of OCC based power plant is more than that of ACC based power plant with respect to CO2 emission. OCC plant emits about 0.164 kg/kWh of CO2 which is approximately 16.75 times lower than the CO2 emission in ACC based power plant. It is also analyzed that the performance of the CO2 Capture Unit (CCU) for the OCC based plant is about 3.65 times higher than the ACC based power plant due to higher concentration of CO2 (nearly 80.63%) in the flue gas emitting from OCC plant. The study also reveals that the auxiliary power consumption per kg of CO2 capture of the OCC based plant is about 0.142 kWh/kg, which is approximately 0.06 times lower than the ACC based plant. The higher performance of the OCC based power plant is found at lower value of flue gas recirculation due to the fact that reduction in exergy destruction at the mixing zone of the combustor is higher than the increase in exergy destruction of the heat exchangers at higher furnace exit temperature. But the metallurgical temperature limit of boiler tube materials restricts the use of the higher value of furnace temperature. OCC based power plant with CO2 capture can be preferred over ACC based plant with CO2 capture due to higher environmental benefits towards mitigating CO2, the key greenhouse gas on earth in spite of exhibiting lesser energy and exergy efficiencies.

Thermodynamic Analysis of Solar Cooling System for a Residential Buildings Application Capital of Iran

2019 ◽  
Author(s):  
Mohamad Javad Asgari ◽  
Amirhossein Mossafa ◽  
Mohsen Fallah
Keyword(s):  
Industrial Development ◽  
Residential Buildings ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Environmental Damage ◽  
Water Tank ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Economic Implications

The global industrial development, the increasing demand for energy, the limited availability of resources for the future generations of fossil fuels, and the prevention of environmental damage caused by their burning have led to public concern. Increasing energy consumption by buildings has led the wider global attention to its social, environmental, and economic implications. In the present study, in order to reduce the power consumption of the summer, a solar vacuum tube-collecting system, with its high efficiency, with a hot water tank and an absorption refrigeration system in a 5-story residential building in In Tehran Capital of Iran, has been investigated. In addition, the results also indicate that the main source of exergy destruction is solar collectors. In the solar collector, we have 93.22% of the exergy destruction, which accounts for 92.8% of the total exergy cascade. In addition, 18.45% of the exergy destruction occurred in the generator, which was equivalent to 1.598% of the total exergy casualties. Also, the coefficient of performance and exergy efficiency of the whole system were 0.746 and 23.5%, respectively, which showed a significant increase in total exergy efficiency compared to the conventional refrigeration system.

scholarly journals Performance evaluation of a walking beam type reheating furnace based on energy and exergy analysis

2020 ◽  
pp. 226-226
Author(s):  
Wenjie Rong ◽  
Baokuan Li ◽  
Fengsheng Qi
Keyword(s):  
Flue Gas ◽  
Exergy Analysis ◽  
Energy Utilization ◽  
Exergy Destruction ◽  
Reheating Furnace ◽  
Advanced Control ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Beam Type ◽  
Insight Into

A walking beam type reheating furnace with advanced control technology has been evaluated by combined energy and exergy analysis. In order to gain insight into the performance of the present furnace, the results of energy analysis are compared with those in published papers and the irreversibility of the furnace is analyzed via exergy destruction calculation. The results show that slabs preheated before charged into the furnace can save fuel and improve energy utilization. The structure and material of the wall and roof show good thermal insulation. However, the oxidized scale is a little more and the temperature of flue gas is high in the present reheating furnace. The energy efficiency of the furnace is 71.01%, while exergy efficiency is 51.41%, indicating a potential for energy-saving improvements of the present furnace. The exergy destruction of the furnace accounts for 28.36% of total exergy input which is mainly caused by heat transfer through a finite temperature difference (14.71%), fuel combustion (11.66%) and scale formation (1.99%).

Analysis of Energy and Exergy of an Annealing Furnace

2011 ◽  
Vol 110-116 ◽  
pp. 2156-2162 ◽  
Author(s):  
Md. Hasanuzzaman ◽  
R. Saidur ◽  
N.A. Rahim
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Energy Savings ◽  
Cost Benefit ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Annealing Furnace ◽  
Energy And Exergy ◽  
Recovery System ◽  
Exergy Losses

Furnace is the most common and important part in metal industries. The useful concept of energy and exergy utilization is analyzed to investigate the energy and exergy efficiency, exergy losses, energy savings and cost benefit of an annealing furnace. The exergy efficiency of the combustor is found to be 47.05 %. The energy and exergy efficiencies of the annealing chamber are found to be 17.74 % and 12.86 % respectively. The overall energy and exergy efficiencies of the furnace are found to be 16.86 % and 7.30 % respectively. The annealing chamber is the major contributor for exergy destruction about 57 % of the annealing furnace. By using a heat recovery system from flue gas, about 8.11% of fuel can be saved within the payback period of less than 2 months.

Detailed Energy and Exergy Analysis for a Solar Lithium Bromide Absorption Chiller and a Conventional Electric Chiller (R134a)

2011 ◽  
Author(s):  
Yang Hu ◽  
Laura A. Schaefer ◽  
Volker Hartkopf
Keyword(s):  
Solar Collector ◽  
Exergy Analysis ◽  
Cooling System ◽  
Residential Buildings ◽  
Lithium Bromide ◽  
Building Energy ◽  
Hot Water ◽  
Exergy Destruction ◽  
Absorption Chiller ◽  
Two Stage

The Building Energy Data Book (2009) [1] shows that commercial and residential buildings in the U.S. consume 39.9% of the primary energy and contribute 39% of the total CO2 emissions. In the operation of buildings, 41.8% of building energy consumption is provided for building cooling, heating, domestic hot water, and ventilation for commercial buildings, while in residential buildings, this percentage increases to 58%. In energy system analysis, the energy approach is the traditional method of assessing the way energy is used in an operation. However, an energy balance provides no information on the degradation of energy or resources during a process. The concept of exergy combines the first law and second law of thermodynamics. The exergy analysis clearly quantifies the energy quality match between the supply and demand sides, and also addresses the exergy destruction (entropy generation) in each component. In this paper, a solar thermal driven absorption cooling system was analyzed for providing cooling to a building, the Intelligent Workplace South Zone at Carnegie Mellon University. The system includes a 52 m2 parabolic trough solar collector, and a 16 kW (4 tons) two-stage lithium bromide absorption chiller. The energy model and newly developed two-stage lithium bromide absorption chiller are programmed and integrated in Engineering Equation Solver (EES). The temperature, enthalpy, entropy, mass flow rate, and mass fraction of lithium bromide in the solar absorption system were presented in steady state operation. The exergy destruction in each component is calculated. The exergy destructions for the solar collector, generator, absorber, and heat exchangers were significantly higher than those in evaporator, condenser and expansion valves, the overall energy and exegetic efficiency were also calculated.

scholarly journals Performance Analyses of a Renewable Energy Powered System for Trigeneration

2019 ◽  
Vol 11 (21) ◽  
pp. 6006 ◽  
Author(s):  
Olusola Bamisile ◽  
Qi Huang ◽  
Paul O. K. Anane ◽  
Mustafa Dagbasi
Keyword(s):  
Renewable Energy ◽  
Exergy Analysis ◽  
Hot Water ◽  
Chicken Manure ◽  
Exergy Destruction ◽  
Maize Silage ◽  
Water Chamber ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Absorption Cycle

In this research, a novel trigeneration powered by a renewable energy (RE) source is developed and analyzed. The trigeneration system is designed to produce electricity, hot water, and cooling using two steam cycles, a gas cycle, hot water chamber, and an absorption cycle. The RE source considered in the scope of this study is biogas generated from chicken manure and maize silage. The energy and exergy analysis of the trigeneration system is performed with the aim to achieve higher efficiencies. The efficiencies are presented based on power generation, cogeneration (electricity and cooling) and trigeneration. The overall trigeneration energy and exergy efficiency for the system developed is 64% and 34.51%. The exergy destruction within the system is greatest in the combustion chamber.

Advanced Exergy-Based Audition of Heat Recovery Steam Generators: A Case Study

2021 ◽  
pp. 1-32
Author(s):  
Arvin Sohrabi Babouri ◽  
Ali Behbahaninia ◽  
Saeed Sayadi ◽  
Mohsen Banifateme
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Exhaust Gas ◽  
Exergy Destruction ◽  
Steam Generators ◽  
Transfer Unit ◽  
Energy And Exergy ◽  
Loss Method

Abstract The current paper enhances the methods presented in ASME PTC 4.1 and 4.4 and proposes an exergy-based loss method for assessing heat recovery steam generators (HRSGs) performance. First, energy and exergy analyses are applied to one HRSG unit in an existing combined cycle power plant. Then, the calculated exergy destructions are further split into avoidable and unavoidable parts. The sources of inefficiency consist of three energy and exergy loss terms and two exergy destruction terms. The loss terms are associated with the release of the exhaust gas to the atmosphere, Carbon Monoxide formation, and the heat loss from the casing, while the destruction terms represent exergy destruction within the duct burner and the heat transfer unit. The advanced exergy analysis was conducted based on a realistic perspective, considering the integrated operation of both subcomponents. Results reveal that the main source of inefficiency corresponds to the losses associated with the exhaust gas from the stack. Moreover, utilizing semi-ideal heat exchangers can avoid a considerable part (18.8%) of the exergy destruction in the heat transfer unit. The HRSG exergy efficiency is obtained by 71.7% and can be increased to 75.3% in unavoidable operating conditions.

scholarly journals Life Cycle Assessment of an Innovative Hybrid Energy Storage System for Residential Buildings in Continental Climates

2021 ◽  
Vol 11 (9) ◽  
pp. 3820
Author(s):  
Noelia Llantoy ◽  
Gabriel Zsembinszki ◽  
Valeria Palomba ◽  
Andrea Frazzica ◽  
Mattia Dallapiccola ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Residential Buildings ◽  
Storage System ◽  
Energy Storage System ◽  
Hot Water ◽  
Hybrid Energy ◽  
Hybrid Energy Storage ◽  
Innovative System ◽  
The Impact

With the aim of contributing to achieving the decarbonization of the energy sector, the environmental impact of an innovative system to produce heating and domestic hot water for heating demand-dominated climates is assessed is evaluated. The evaluation is conducted using the life cycle assessment (LCA) methodology and the ReCiPe and IPCC GWP indicators for the manufacturing and operation stages, and comparing the system to a reference one. Results show that the innovative system has a lower overall impact than the reference one. Moreover, a parametric study to evaluate the impact of the refrigerant is carried out, showing that the impact of the overall systems is not affected if the amount of refrigerant or the impact of refrigerant is increased.

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