scholarly journals Development of a 1 kW Micro-Polygeneration System Fueled by Natural Gas for Single-Family Users

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8372
Author(s):  
Alfredo Gimelli ◽  
Massimiliano Muccillo
Keyword(s):  
Natural Gas ◽  
Gasoline Engine ◽  
Dynamic Pressure ◽  
Energy Generation ◽  
Primary Energy ◽  
Small Scale ◽  
Single Family ◽  
Engine Operation ◽  
Performance And Emissions ◽  
Chp System

The use of primary energy saving techniques and renewable energy systems has become mandatory to tackle the effects of global temperature rise. As a result, a transition is taking place from centralized energy generation to distributed energy generation. Starting from the experience concerning a 15 kW micro-CHP plant previously designed at DII, this paper addresses the development of a 1 kW micro-CHP system fueled by natural gas for single-family users. Specifically, the paper presents a wide experimental investigation aimed at optimizing performance and emissions of a small scale two-stroke spark ignition gasoline engine properly modified to be fueled with natural gas to make the engine more suitable for cogeneration purposes. The described activity was carried out at the DII of the University of Naples Federico II. Rigorous laboratory tests were conducted with the engine in order to characterize both gasoline and CNG operation in terms of brake mechanical power, overall efficiency and exhaust gas emissions in different operating regimes. Furthermore, several physical quantities associated with the engine operation were measured through several sensors in order to optimize performance and emissions achieved when the engine is fueled with CNG. In particular, dynamic pressure variations inside the cylinder were measured and analyzed to evaluate the effect of the adopted fuel on the optimum ignition-timing angle and cyclic dispersion.

Assessing Double Injection and Intake Air Temperature Effects on Gasoline HCCI Engine Performance and Emissions Using Fully-Automated Experiments and Micro-Genetic Algorithms

2002 ◽  
Author(s):  
Mustafa Canakci ◽  
Eric Hruby ◽  
Rolf D. Reitz
Keyword(s):  
Air Temperature ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Spray Angle ◽  
Injection Timing ◽  
Engine Operation ◽  
Double Injection ◽  
Performance And Emissions ◽  
Engine Performance And Emissions

Homogeneous charge compression ignition (HCCI) is receiving attention as a new low emission engine concept. Little is known about the optimal operating conditions for this engine operation mode. Combustion at homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and PM as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to a HCCI direct-injection gasoline engine. The engine features an electronically controlled low-pressure common rail injector with a 60°-spray angle that is capable of multiple injections. The use of double injection was explored for emission control, and the engine was optimized using fully-automated experiments and a micro-genetic algorithm (μGA) optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing, and split injection parameters (percent mass of the fuel in each injection, dwell between the pulses). The engine performance and emissions were determined at 700 rev/min with a constant fuel flow rate at 10 MPa fuel injection pressure. The results show that significant emissions reductions are possible with the use of optimal injection strategies.

scholarly journals Influence of Atlantic Microclimates in Northern Spain on the Environmental Performance of Lightweight Concrete Single-Family Houses

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4337
Author(s):  
Daniel González-Prieto ◽  
Yolanda Fernández-Nava ◽  
Elena Marañón ◽  
Maria Manuela Prieto
Keyword(s):  
Global Warming ◽  
Natural Gas ◽  
Global Warming Potential ◽  
Energy Demand ◽  
Lightweight Concrete ◽  
Primary Energy ◽  
Hot Water ◽  
Embodied Energy ◽  
Single Family ◽  
Northern Spain

The use of lightweight concrete for the construction of single-family houses has become increasingly popular in Spain. In this paper, single-family houses with different shape factors and window-to-wall ratios are analysed from both a thermal and environmental perspective using Passive House Planning Package (PHPP) software to calculate the energy demand. The study has been carried out for different Atlantic microclimates (coastal, inland, and mountain) in northern Spain. What most affects the thermal energy used for air conditioning is the variation of the microclimates, so the study focuses mainly on this aspect. Operational energy for heating has decreased greatly via the use of high degree of insulation and hence the next task is to decrease the total energy consumed taking into account the embodied energy. Impacts on Primary Energy and Global Warming Potential are calculated using a cradle-to-grave approach. The energy use for heating and domestic hot water is analysed for different thicknesses of insulation under three energy supply scenarios: electricity only (for 2018 and with the Spanish decarbonisation plan for 2030); heat pump plus electricity; and natural gas boiler. Even for houses with a good level of insulation, the ratio of operational-to-total impacts varies significantly: from 46% to 87% for primary energy and from 31% to 75% for global warming potential, depending on the shape factor of the house, the microclimate and the heat supply scenario. By applying future environmental policies, electricity can become a more environmentally friendly option than natural gas.

scholarly journals Renewable Energy Generation Scenarios Using 3D Urban Modeling Tools—Methodology for Heat Pump and Co-Generation Systems with Case Study Application †

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 403 ◽  
Author(s):  
Verena Weiler ◽  
Jonas Stave ◽  
Ursula Eicker
Keyword(s):  
Heat Pump ◽  
Distribution System ◽  
District Heating ◽  
Energy Generation ◽  
Primary Energy ◽  
Modeling Tools ◽  
District Heating System ◽  
Heat Demand ◽  
Chp System

In the paper, a method was developed to automatically dimensionalize and calculate central energy generation and supply scenarios with a district heating system for cities based on 3D building models in the CityGML format and their simulated heat demand. In addition, the roof geometry of every individual building is used to model photovoltaic energy generation potential. Two types of supply systems, namely a central heat pump (HP) system and a large co-generation (combined heat and power-CHP) system (both with a central storage and district distribution system), are modeled to supply the heat demand of the area under investigation. Both energy generation models are applied to a case study town of 1610 buildings. For the HP scenario, it can be shown that the case study town’s heat demand can be covered by a monovalent, low-temperature system with storage, but that the PV only contributes 15% to the HP electricity requirement. For the CHP scenario, only 61% of the heat demand can be covered by the CHP, as it was designed for a minimum of 4000 operating hours. Both the PV and the CHP excess electricity are fully injected into the grid. As a result, the primary energy comparison of both systems strongly depends on the chosen primary energy factors (PEF): with given German regulations the CHP system performs better than the HP system, as the grid-injected electricity has a PEF of 2.8. In the future, with increasingly lower PEFs for electricity, the situation reverses, and HPs perform better, especially if the CHP continues to use natural gas. Even when renewable gas from a power to gas (P2G) process is used for the CHP, the primary energy balance of the HP system is better, because of high conversion losses in the P2G process.

Development of a Recuperated Flameless Combustor for an Inverted Brayton Cycle Microturbine Used in Residential Micro-CHP

2017 ◽  
Author(s):  
Michel Delanaye ◽  
Andrés Giraldo ◽  
Rabia Nacereddine ◽  
Mehdi Rouabah ◽  
Valentina Fortunato ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Large Scale ◽  
High Efficiency ◽  
Low Cost ◽  
Primary Energy ◽  
Brayton Cycle ◽  
Cfd Modelling ◽  
Great Opportunity ◽  
Chp System

The paper presents recent work in the development of a clean and efficient natural gas combustor for a micro-CHP system based on a gas turbine for the residential sector. The large scale deployment of natural gas micro-CHP systems represents a great opportunity to contribute to a reduction of CO2 emissions by a substantial increase of the efficiency of primary energy source conversion. A micro-CHP system, well designed for a residential application, which means a power of 1kWe output and high efficiency (larger than 20%), may reduce annual household emissions up to factors close to 2.5. The micro-CHP system developed in this work uses a small gas turbine and an inverted Brayton cycle which advantageously allows the use of substantially larger turbomachinery components than a conventional pressurized Brayton cycle. The paper presents a new counterflow recuperator. Its design has been thoroughly studied by advanced 3D CFD to obtain compactness and high efficiency at low cost. A new flameless combustor has been developed in order to reduce to single digits the emissions of pollutants (NOx and CO) and obtain a highly efficient and stable combustion for various gases. The design methodology based on 3D CFD modelling is presented as well as experimental results demonstrating the performance of the recuperated flameless combustor for various operationg conditions.

Analysis of experimental results with an active pre-chamber ultra-lean burn SI engine

2020 ◽  
pp. 146808742097454
Author(s):  
Christoph Müller ◽  
Stefan Pischinger ◽  
Sascha Tews ◽  
Andreas Müller ◽  
Knut Habermann
Keyword(s):  
Natural Gas ◽  
Fuel Consumption ◽  
Gasoline Engine ◽  
Combustion Process ◽  
Experimental Investigations ◽  
Major Step ◽  
Lean Burn ◽  
Hybrid Powertrain ◽  
Engine Operation ◽  
Gasoline Engines

To ensure that private cars can continue to be used in the future, they must become significantly more efficient and at the same time emit considerably less pollutants. In addition to pure electric drives, further optimized gasoline engines in hybrid powertrain configurations still offer major potentials in this respect. A major step toward increasing efficiency can be achieved by extremely lean burn combustion. If, in addition to low fuel consumption, this operation should also simultaneously reduce NOx raw emissions, lean-burn operation with relative air/fuel ratios of λ≥ 2 must be enabled in wide ranges of the engine operation map. Within the scope of this publication, results of experimental investigations with a lean burn pre-chamber ignition system applied to a small gasoline engine with 75 mm bore and 90.5 mm stroke are presented. In this context, the effects of the pre-chamber design on emissions and fuel consumption are examined. By comparing different pre-chamber enrichments with natural gas and conventional RON98 gasoline, it can be shown that with the direct liquid injection of gasoline into the pre-chamber similar good thermodynamic results as with natural gas can be achieved with the advantage of easier integration of a single fuel system. Due to its significantly improved lean burn capability with relative air/fuel rations of up to λ = 3, combined with low specific indicated NOx raw emissions of less than 0.1 g/kWh, the presented lean-burn combustion system offers excellent conditions for further efficiency improvements of electrified powertrains. WLTP cycle simulations based on measured engine maps for the developed combustion process resulted in a fuel consumption reduction of up to 10%. At the same time, NOx raw emissions below the Euro 6d limit of 60 mg/km can be achieved.

High efficiency gas-turbine power generator GTU-2U

2020 ◽  
Vol 2 (4) ◽  
pp. 185-195
Author(s):  
M. Yu. Egorushkov ◽  
V. Yu. Ivanov ◽  
A. A. Murugov ◽  
A. V. Sheverdin
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Power Supply ◽  
Energy Generation ◽  
Gas Production ◽  
Liquefied Natural Gas ◽  
Small Scale ◽  
Mode Of Operation ◽  
Small Capacity

Introduction: the analysis of the main areas of energy transition (energie wende) from fossil fuels and nuclear power generation to renewable sources of energy has identified the following four key problems: electric power shortage; ageing of power generation facilities; insufficient infrastructure; growing demand for gas fuel. In Russia, distributed small-scale power generation facilities serve those consumers who have no access to centralized power supply or network channels of regular power generation. A combination of versatile approaches to electric power generation should be applied in the course of designing a specific energy generation facility in this context.Methods: the research project represents an analysis of the works written by the leading Russian and foreign researchers specializing on power engineering, namely, energy supply to consumers. The expert assessment method has identified the niches which are best fitted by gas turbine facilities. Computerized and simulation modeling techniques were used to perform the analytical and statistical processing of the project findings.Results and discussion: the trend for the structural improvement of small-scale liquefied natural gas facilities has been identified in the course of the research. The author has substantiated development of systems for power supply to smallcapacity liquefied natural gas production facilities. The proposed gas turbine GTU-2U is designated for generation of electric energy, if in operation as a standalone facility as part of a centralized heating and power plant in the standalone mode of operation, or in case of concurrent operation along with an energy generation system within the framework of distributed small capacity networks. The co-authors have substantiated the unit’s practical application and identified the GTU-2U distribution market both in Russia and abroad: small capacity distributed power generation industry and power supply to small-capacity liquefied natural gas production facilities. The latter is a relatively new market which is in the process of proactive development both in mature and developing economies. This power supply pattern will enable to monetize gas deposits, located far from pipelines and to supply gas to hard-to-access regions.Conclusion: the key trends in the development of the contemporary power generation industry are considered in the article. Gas turbine unit GTU-2U has been designed. This unit is capable of generating power both as a standalone facility, as a component of a centralized heating and power plant in the standalone mode of operation, or in case of concurrent operation along with an energy generation system. Its strengths substantiate its practical application both in the Russian and international power generation markets.

Strategies for Reduced NOx Emissions in Pilot-Ignited Natural Gas Engines

2002 ◽  
Author(s):  
Sundar R. Krishnan ◽  
Kalyan K. Srinivasan ◽  
Weidong Gong ◽  
Scott Fiveland ◽  
Satbir Singh ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Nox Reduction ◽  
Engine Performance ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pilot Injection ◽  
Engine Operation ◽  
Performance And Emissions ◽  
Inlet Conditions

The performance and emissions of a single-cylinder, natural gas fueled engine using a pilot ignition strategy have been investigated. Small diesel pilots (2–3 percent on an energy basis), when used to ignite homogeneous natural gas-air mixtures, are shown to possess the potential for reduced NOx emissions while maintaining good engine performance. The effect of pilot injection timing, intake charge pressure, and charge temperature on engine performance and emissions with natural gas fueling was studied. With appropriate control of the above variables, engine-out brake specific NOx emissions could be reduced to the range of 0.07–0.10 g/kWh from the baseline diesel (with mechanical fuel injection) value of 10.5 g/kWh. For this NOx reduction, the decrease in fuel conversion efficiency from the baseline diesel value was approximately 1–2 percent. Total unburned hydrocarbon (HC) emissions and carbon monoxide (CO) emissions were higher with natural gas operation. Heat release schedules obtained from measured cylinder pressure data are also presented. The importance of pilot injection timing and inlet conditions on the stability of engine operation and knock are also discussed.

Strategies for Reduced NOx Emissions in Pilot-Ignited Natural Gas Engines

2003 ◽  
Vol 126 (3) ◽  
pp. 665-671 ◽  
Author(s):  
S. R. Krishnan ◽  
K. K. Srinivasan ◽  
S. Singh ◽  
S. R. Bell ◽  
K. C. Midkiff ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Nox Reduction ◽  
Engine Performance ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pilot Injection ◽  
Engine Operation ◽  
Performance And Emissions ◽  
Inlet Conditions

The performance and emissions of a single-cylinder natural gas fueled engine using a pilot ignition strategy have been investigated. Small diesel pilots (2–3% on an energy basis), when used to ignite homogeneous natural gas-air mixtures, are shown to possess the potential for reduced NOx emissions while maintaining good engine performance. The effects of pilot injection timing, intake charge pressure, and charge temperature on engine performance and emissions with natural gas fueling were studied. With appropriate control of the above variables, it was shown that full-load engine-out brake specific NOx emissions could be reduced to the range of 0.07–0.10 g/kWh from the baseline diesel (with mechanical fuel injection) value of 10.5 g/kWh. For this NOx reduction, the decrease in fuel conversion efficiency from the baseline diesel value was approximately one to two percentage points. Total unburned hydrocarbon (HC) emissions and carbon monoxide (CO) emissions were higher with natural gas operation. The nature of combustion under these conditions was analyzed using heat release schedules predicted from measured cylinder pressure data. The importance of pilot injection timing and inlet conditions on the stability of engine operation and knock are also discussed.

A Novel Small Scale Liquefied Natural Gas Production Process at Filling Stations: Thermodynamic Analysis and Parametric Investigation

2016 ◽  
Author(s):  
M. A. Ancona ◽  
M. Bianchi ◽  
L. Branchini ◽  
A. De Pascale ◽  
F. Melino ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Production Process ◽  
Thermodynamic Analysis ◽  
Primary Energy ◽  
Gas Production ◽  
Liquefied Natural Gas ◽  
Energy Market ◽  
Small Scale ◽  
Generation Process

In the last years, the increased demand of the energy market has led to the increasing penetration of renewable energies in order to achieve the primary energy supply. However, simultaneously natural gas still plays a key role in the energy market, mainly as gaseous fuel for stationary energy generation, but also as liquefied fuel, as an alternative to the diesel fuel, in vehicular applications. Liquefied Natural Gas (LNG) is currently produced in large plants directly located at the extraction sites. In this study, the idea of realizing plug & play solutions to produce LNG directly at vehicle’s filling stations has been investigated. A novel process of LNG production for filling stations has been analyzed, consisting in a single stage Joule-Thompson isenthalpic expansion process, with intercooled compression. Furthermore, the presented layout has been developed with the purpose of optimizing the energy consumption of the plant, obtaining moderately pressurized LNG. With the aim of investigating the feasibility of this novel LNG generation process, a thermodynamic analysis has been carried out and presented in this study. Moreover, the minimization of energy consumption has been investigated with a parametric analysis, in order to optimize the LNG production and to maximize the efficiency of the process. Furthermore, novel performance indicators have been defined, in order to account the efficiency of the LNG production process. Results of the optimization analysis show that, with the proposed layout, an energy consumption equal to about 1.9 MJ/kg of produced LNG can be achieved.

The Steady and Dynamic Performance of an Innovative Natural Gas CHP System

2008 ◽  
Author(s):  
Lin Fu ◽  
Xiling Zhao ◽  
Shigang Zhang ◽  
Yi Jiang ◽  
Hui Li ◽  
...  
Keyword(s):  
Natural Gas ◽  
Flue Gas ◽  
Combustion Engine ◽  
Dynamic Performance ◽  
Thermal Inertia ◽  
Utilization Efficiency ◽  
Small Scale ◽  
Exhaust Gas ◽  
Set Up ◽  
Chp System

In the last decade, technological innovation and changes in the economic and regulatory environment have resulted in increased attention to distributed energy systems (DES). Combined heating and power (CHP) systems based on the gas-powered internal combustion engine (ICE) are increasingly used as small-scale distribution co-generators. This paper describes an innovative ICE-CHP system with an exhaust-gas-driven absorption heat pump (AHP) that has been set up at the energy-saving building in Beijing, China. The system is composed of an ICE, an exhaust-gas-driven AHP, and a flue gas condensation heat exchanger (CHE), which could recover both the sensible and latent heat of the flue gas. The steady performance and dynamic response of the innovative CHP system with different operation modes were tested. The results show that the system’s overall efficiency could reach above 90% based on lower heating value (LHV) of natural gas; that is, the innovative CHP system could increase the heat utilization efficiency 10% compared to conventional CHP systems, and the thermally activated components of the system have much more thermal inertia than the electricity generation component. The detailed test results provide important insight into CHP performance characteristics and could be valuable references for the control of CHP systems. The novel CHP system could take on a very important role in the CHP market.

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