scholarly journals EXERGY-BASED CONTROL STRATEGY IN A DWELLING VENTILATION SYSTEM WITH HEAT RECOVERY

2020 ◽  
Vol 10 (2) ◽  
pp. 44-47
Author(s):  
Volodymyr Voloshchuk ◽  
Mariya Polishchuk
Keyword(s):  
Heat Recovery ◽  
Operation Mode ◽  
Ventilation System ◽  
Primary Energy ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Spent Fuel ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Operational Modes

The paper presents energy and exergy analysis of a typical dwelling ventilation system with heat recovery for Ukrainian climatic conditions using a quasi-steady state approach over 24-hour time-steps. Evaluation of such systems on the base of the first law of thermodynamics demonstrates that heat recovery is beneficial for the whole variety of operational modes. Such methodology identifies as a thermodynamic inefficiency only energy losses to the surroundings with the exhaust air. The exergy-based analysis can detect additional inefficiencies due to irreversibilities within the components of the system. As a result the exergetic investigations show that for the ventilation systems there are operating conditions for which heat recovery increases exergy of fuel expended to provide the ventilation air compared to cases without bringing any recovery of heat and additional power consumption to drive the air flow by the fans. For the specified system, in case of switching ventilation unit to the operation mode of lower values of spent fuel exergy it is possible to provide annual saving of the primary energy sources from 5 to 15%.

NUMERICAL SIMULATION AND PARAMETRIC STUDIES FOR EVALUATION OF BALANCED VENTILATION AND EARTH AIR EXCHANGERS SYSTEM COUPLED TO A DOMESTIC BUILDING

2013 ◽  
Vol 21 (01) ◽  
pp. 1350002 ◽  
Author(s):  
YOUNES KARTACHI ◽  
ABDELLAH MECHAQRANE
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
High Efficiency ◽  
Residential Buildings ◽  
Ventilation System ◽  
Primary Energy ◽  
Climatic Conditions ◽  
Design Parameters ◽  
Climate Data ◽  
The Impact

In this study, we analyze the impact of ventilation heat recovery with the heating and cooling potential of earth air heat exchanger in real climatic conditions in domestic buildings in the Middle Atlas region. In our case study, we calculate the primary energy used by a domestic building built as per the conventional house design parameters required by the Moroccan regulation. We use climate data for the city of Fes in Northern Moroccan. Three system configurations were considered. The first was the mechanical extract ventilation system both with and without heat recovery. The second was the mechanical extract ventilation system with earth to air heat exchanger system (EAHEX), and the third system was the mechanical balanced ventilation system coupled with EAHEX system. Primary energy use strongly influences natural resources efficiency and the environmental impacts of energy supply activities. In this study we explore the primary energy implications of the mechanical balanced ventilation system coupled with the EAHEX system in residential buildings. The results of this study shows that the use of a balanced ventilation system, with a high efficiency instead of a mechanical extract ventilation system, decreases the final and primary energy consumption. Moreover, it decreases or increases the CO2 emission depending on the primary energy sources.

scholarly journals Exergy-based Control of a Dwelling Ventilation System with Heat Recovery

2019 ◽  
pp. 114-116
Author(s):  
Volodymyr Voloshchuk ◽  
Mariya Polishchuk
Keyword(s):  
Power Consumption ◽  
Heat Recovery ◽  
Operation Mode ◽  
Ventilation System ◽  
Primary Energy ◽  
Energy Sources ◽  
Annual Saving ◽  
Operating Modes ◽  
Ventilation Systems

On the base of exergy-based approach it is shownthat for the ventilation systems there are operating modes forwhich heat recovery increases exergy of fuel expended to providethe ventilation air compared to cases without bringing anyrecovery of heat and additional power consumption to drive theair flow by the fans. For the specified system, in case of switchingventilation unit to the operation mode of lower values of spentfuel exergy it is possible to provide annual saving from 5 to 15 %of the primary energy sources.

scholarly journals Energy and Exergy Analysis of Different Exhaust Waste Heat Recovery Systems for Natural Gas Engine Based on ORC

2019 ◽  
Author(s):  
Guillermo Valencia ◽  
Armando Fontalvo ◽  
Yulineth Cardenas ◽  
Jorge Duarte ◽  
Cesar Isaza
Keyword(s):  
Natural Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Natural Gas Engine ◽  
Exhaust Waste Heat ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Net Power Output

One way to increase overall natural gas engine efficiency is to transform exhaust waste heat into useful energy by means of a bottoming cycle. Organic Rankine cycle (ORC) is a promising technology to convert medium and low grade waste heat into mechanical power and electricity. This paper presents an energy and exergy analysis of three ORC-Waste heat recovery configurations by using an intermediate thermal oil circuit: Simple ORC (SORC), ORC with Recuperator (RORC) and ORC with Double Pressure (DORC), and Cyclohexane, Toluene and Acetone have been proposed as working fluids. An energy and exergy thermodynamic model is proposed to evaluate each configuration performance, while available exhaust thermal energy variation under different engine loads was determined through an experimentally validated mathematical model. Additionally, the effect of evaportating pressure on net power output , absolute thermal efficiency increase, absolute specific fuel consumption decrease, overall energy conversion efficiency, and component exergy destruction is also investigated. Results evidence an improvement in operational performance for heat recovery through RORC with Toluene at an evaporation pressure of 3.4 MPa, achieving 146.25 kW of net power output, 11.58% of overall conversion efficiency, 28.4% of ORC thermal efficiency, and an specific fuel consumption reduction of 7.67% at a 1482 rpm engine speed, a 120.2 L/min natural gas Flow, 1.784 lambda, and 1758.77 kW mechanical engine power.

scholarly journals Energy and exergy analysis of a flat plate collector using collector test equations

2020 ◽  
Vol 180 ◽  
pp. 02016
Author(s):  
Adina-Teodora Gheorghian ◽  
Tudor Prisecaru ◽  
Mihaela Cristina Ciobanu
Keyword(s):  
Flat Plate ◽  
Weather Conditions ◽  
Optimization Criterion ◽  
Climatic Conditions ◽  
Geometric Optimization ◽  
Solar Irradiation ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Exergetic Analysis ◽  
Flat Plate Collector

This paper presents the energetic and exergetic analysis of a widely used flat plate collector based on the collector testing equations. The evaluation of the performances of the collector is done under the climatic conditions corresponding to a typical meteorological year in Constanta, Romania. Using a dimensionless-geometric optimization criterion, the climatic conditions for which the energy efficiency and exergetic efficiency have the maximum values are determined. The optimal weather conditions for the collector's operation are: the solar irradiation of 916 W/m2 and the air temperature of 15.4 °C; under these conditions, the energy and exergy efficiencies of the collector are 57% and 4.8%, respectively.

Performance of a compression ignition engine operated with sunflower ethyl ester under different engine loads

2014 ◽  
Vol 25 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Emin Açıkkalp ◽  
Hasan Yamık ◽  
Yakup İçingür
Keyword(s):  
Ethyl Ester ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Effective Work ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Maximum Work ◽  
Partial Loads

This study investigated the performance of a compression ignition engine operating with sunflower ethyl ester. A thermodynamic analysis, including energy and exergy analysis at different engine loads (20%, 40%, 60%, 80%, 100%), was conducted. The study calculated the first and second law efficiency, effective work, heat exergy losses and exergy destruction values at 10 different engine speeds for 5 loads. Maximum work, maximum thermal efficiency, maximum exergy efficiency and maximum volumetric efficiency are determined to be 6.45 kW, 0.26, 0.24 and 0.71 respectively. Finally, optimum operating conditions are discussed and it was determined that the engine should be operated at a lower engine speed for partial loads.

scholarly journals INVESTIGATION OF THE ENERGY RECOVERY POTENTIALS IN VENTILATION SYSTEMS IN DIFFERENT CLIMATES

2018 ◽  
Vol 16 (2) ◽  
pp. 203 ◽  
Author(s):  
Miklos Kassai ◽  
Laszlo Poleczky ◽  
Laith Al-Hyari ◽  
Laszlo Kajtar ◽  
Jozsef Nyers
Keyword(s):  
Energy Recovery ◽  
Heat Recovery ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Weather Data ◽  
High Definition ◽  
Engineering Practices ◽  
Available Information ◽  
Different Climates ◽  
Ventilation Systems

The aim of this research study was to investigate the energy recovery potentials in ventilation systems under different climatic conditions. The well-known heating degree day from the literature was updated using the weather data of cities with different climates from the past 40 years. As the novelty of this research with the developed procedure drawn up in this study, the energetic possibilities of heat recovery under various climate and operating conditions may be examined in more detail and more realistically than with the methods and available information of current engineering practices. To achieve this long-term and high definition the weather data of several cities are processed in order to evaluate the possibilities of heat recovery on a daily and annual basis.

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