Externally Fired Micro Gas Turbine and ORC Bottoming Cycle: Optimal Biomass/Natural Gas CHP Configuration for Residential Energy Demand

2015 ◽  
Author(s):  
Sergio Mario Camporeale ◽  
Patrizia Domenica Ciliberti ◽  
Bernardo Fortunato ◽  
Marco Torresi ◽  
Antonio Marco Pantaleo
Keyword(s):  
Energy Efficiency ◽  
Natural Gas ◽  
Gas Turbine ◽  
Energy Demand ◽  
Rankine Cycle ◽  
Small Scale ◽  
Residential Energy ◽  
Micro Gas Turbine ◽  
Residential Energy Demand ◽  
Heat Demand

Small scale Combined Heat and Power (CHP) plants present lower electric efficiency in comparison to large scale ones, and this is particularly true when biomass fuels are used. In most cases, the use of both heat and electricity to serve on site energy demand is a key issue to achieve acceptable global energy efficiency and investment profitability. However, the heat demand follows a typical daily and seasonal pattern and is influenced by climatic conditions, in particular in the case of residential and tertiary end users. During low heat demand periods, a lot of heat produced by the CHP plant is discharged. In order to increase the electric conversion efficiency of small scale micro turbine for heat and power cogeneration, a bottoming ORC system can be coupled to the cycle, however this option reduces the temperature and quantity of cogenerated heat available to the load. In this perspective, the paper presents the results of a thermo-economic analysis of small scale CHP plants composed by a micro gas turbine (MGT) and a bottoming Organic Rankine Cycle (ORC), serving a typical residential energy demand. For the topping cycle three different configurations are examined: 1) a simple recuperative micro gas turbine fuelled by natural gas (NG), 2) a dual fuel EFGT cycle, fuelled by biomass and natural gas (50% energy input) (DF) and 3) an externally fired gas turbine (EFGT) with direct combustion of biomass (B). The bottoming cycle is a simple saturated Rankine cycle with regeneration and no superheating. The ORC cycle and the fluid selection are optimized on the basis of the available exhaust gas temperature at the turbine exit. The research assesses the influence of the thermal energy demand typology (residential demand with cold, mild and hot climate conditions) and CHP plant operational strategies (baseload vs heat driven vs electricity driven operation mode) on the global energy efficiency and profitability of the following three configurations: A) MGT with cogeneration; B) MGT+ ORC without cogeneration; C) MGT+ORC with cogeneration. In all cases, a back-up boiler is assumed to match the heat demand of the load (fed by natural gas or biomass). The research explores the profitability of bottoming ORC in view of the following tradeoffs: (i) lower energy conversion efficiency and higher investment cost of high biomass input rate with respect to natural gas; (ii) higher efficiency but higher costs and reduced heat available for cogeneration in the bottoming ORC; (ii) higher primary energy savings and revenues from feed-in tariff available for biomass electricity fed into the grid.

Externally Fired Micro-Gas Turbine and Organic Rankine Cycle Bottoming Cycle: Optimal Biomass/Natural Gas Combined Heat and Power Generation Configuration for Residential Energy Demand

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Sergio Mario Camporeale ◽  
Patrizia Domenica Ciliberti ◽  
Bernardo Fortunato ◽  
Marco Torresi ◽  
Antonio Marco Pantaleo
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Energy Demand ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Small Scale ◽  
Residential Energy ◽  
Micro Gas Turbine ◽  
Residential Energy Demand ◽  
Heat Demand

Small-scale combined heat and power (CHP) plants present lower electric efficiency in comparison to large scale ones, and this is particularly true when biomass fuels are used. In most cases, the use of both heat and electricity to serve on-site energy demand is a key issue to achieve acceptable global energy efficiency and investment profitability. However, the heat demand follows a typical daily and seasonal pattern and is influenced by climatic conditions, in particular in the case of residential and tertiary end users. During low heat demand periods, a lot of heat produced by the CHP plant is discharged. In order to increase the electric conversion efficiency of small-scale micro-gas turbine for heat and power cogeneration, a bottoming organic Rankine cycle (ORC) system can be coupled to the cycle, however, this option reduces the temperature and the amount of cogenerated heat available to the thermal load. In this perspective, the paper presents the results of a thermo-economic analysis of small-scale CHP plants composed of a micro-gas turbine (MGT) and a bottoming ORC, serving a typical residential energy demand. For the topping cycle, three different configurations are examined: (1) a simple recuperative micro-gas turbine fueled by natural gas (NG); (2) a dual fuel externally fired gas turbine (EFGT) cycle, fueled by biomass and natural gas (50% share of energy input) (DF); and (3) an externally fired gas turbine (EFGT) with direct combustion of biomass (B). The bottoming ORC is a simple saturated cycle with regeneration and no superheating. The ORC cycle and the fluid selection are optimized on the basis of the available exhaust gas temperature at the turbine exit. The research assesses the influence of the thermal energy demand typology (residential demand with cold, mild, and hot climate conditions) and CHP plant operational strategies (baseload versus heat-driven versus electricity-driven operation mode) on the global energy efficiency and profitability of the following three configurations: (A) MGT with cogeneration; (B) MGT+ ORC without cogeneration; and (C) MGT+ORC with cogeneration. In all cases, a back-up boiler is assumed to match the heat demand of the load (fed by natural gas or biomass). The research explores the profitability of bottoming ORC in view of the following trade-offs: (i) lower energy conversion efficiency and higher investment cost of biomass input with respect to natural gas; (ii) higher efficiency but higher costs and reduced heat available for cogeneration with the bottoming ORC; and (iii) higher primary energy savings and revenues from feed-in tariff available for biomass electricity fed into the grid.

scholarly journals Environmental Impacts of a Solar Dish Coupled With a Micro-Gas Turbine for Power Generation

2021 ◽  
Vol 9 ◽  
Author(s):  
A. Agostini ◽  
C. Carbone ◽  
M. Lanchi ◽  
A. Miliozzi ◽  
M. Misceo ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Environmental Impacts ◽  
Energy Demand ◽  
Solar Power ◽  
Ghg Emissions ◽  
Primary Energy ◽  
Small Scale ◽  
Energy Mix ◽  
Micro Gas Turbine ◽  
Primary Energy Demand

Concentrated solar power (CSP) systems are regarded as a renewable energy source technology that can contribute to decoupling the energy mix from fossil fuel combustion and related environmental impacts. However, current small-scale CSP technologies (e.g., Dish-Stirling) have not entered the market yet due to high costs, complexity, and poor reliability. The EU-funded OMSoP (Optimised Microturbine Solar Power) project aimed at solving the small-scale CSP shortcomings by coupling a solar dish with the consolidated and relatively cheap technology of the micro gas turbine (MGT). In this study, an environmental life cycle assessment analysis of the production and operation of a CSP-MGT system is performed following an eco-design approach, thus identifying the environmental hotspots and how the system can be improved in terms of environmental impacts. The results of the analysis, per unit of electricity produced, were compared to other renewable technologies with the same level of dispatchability to better evaluate strengths and weaknesses of the system under exam. With regard to climate change, the greenhouse gas (GHG) emissions of the CSP-MGT system resulted in the same range as those generated by photovoltaic systems. However, the system can substantially be optimized and the GHG emissions per kWh can be reduced up to 73% with respect to the built prototype. The GHG emissions are much lower than the current Italian energy mix (by up to 94%). To reduce the environmental burden of CSP-MGT plants, the system design here considered should be revised by improving the component’s performance and significantly reducing the reflective surface and therefore the structural materials for the dish foundation and frame. The replacement of steel in the dish frame with aluminum increases all the environmental impact parameters and primary energy demand (17%–27% depending on the environmental category considered) but slightly reduces abiotic element depletion (by 9%).

A Study on the Performance of Steam Injection in a Typical Micro Gas Turbine

2013 ◽  
Author(s):  
Ward De Paepe ◽  
Frank Delattin ◽  
Svend Bram ◽  
Francesco Contino ◽  
Jacques De Ruyck
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Accurate Determination ◽  
Steam Injection ◽  
Power Production ◽  
Small Scale ◽  
Stable Operation ◽  
Micro Gas Turbine ◽  
Heat Demand

Microturbines are very promising for small-scale Combined Heat and Power (CHP) production. Due to the simultaneous production of heat and power, the Turbec T100 microturbine CHP System has the potential of realizing considerable energy savings, compared to classic separate production. The power production however is strictly bound to the heat production. A reduction in heat demand will mostly lead to a shutdown of the unit, since electric efficiency is too low and not competitive with electricity from the net. The reduced amount of running hours has a severe negative impact on the lifetime profitability of the unit. A solution is proposed by injecting auto-generated steam in the T100 micro Gas Turbine (mGT), in order to increase electric efficiency during periods with low heat demand. By doing so, a forced shut down of the unit can be avoided. The goal of this study was to investigate and quantify the beneficial effect of steam injection on the performance of a typical recuperated mGT. This paper reports on an extended series of steam injection experiments performed on a Turbec T100 microturbine. Previous experiments revealed the necessity for a more accurate determination of the mass flow rate and more precise compressor characteristics. Therefore the test rig was equipped with an additional oxygen analyzer in the exhaust and a pressure gauge to allow for the accurate determination of the pressure ratio. Experiments with steam injection in the compressor outlet of the T100 were performed to demonstrate and validate the benefits of introducing steam in the cycle and to verify its ability to handle the injected steam. It is expected that the mGT will produce a constant power at reduced shaft speed and increased electric efficiency. Steam injection experiments validated the increase in electric efficiency during stable operation of the mGT. At nominal 100 kWe power production, the replacement of 3.5% of the air mass flow with steam (adiabatic steam injection limit) resulted in an absolute electric efficiency increase of 1.7%. The experiments successfully demonstrated the potential for steam/water injection in the T100 mGT.

scholarly journals Saving energy in residential buildings: the role of energy pricing

2021 ◽  
Vol 167 (1-2) ◽  
Author(s):  
Jens Ewald ◽  
Thomas Sterner ◽  
Eoin Ó Broin ◽  
Érika Mata
Keyword(s):  
Energy Demand ◽  
Income Elasticity ◽  
Residential Buildings ◽  
Policy Framework ◽  
Energy Prices ◽  
Residential Energy ◽  
Residential Energy Demand ◽  
Long Run ◽  
Zero Carbon

AbstractA zero-carbon society requires dramatic change everywhere including in buildings, a large and politically sensitive sector. Technical possibilities exist but implementation is slow. Policies include many hard-to-evaluate regulations and may suffer from rebound mechanisms. We use dynamic econometric analysis of European macro data for the period 1990–2018 to systematically examine the importance of changes in energy prices and income on residential energy demand. We find a long-run price elasticity of −0.5. The total long-run income elasticity is around 0.9, but if we control for the increase in income that goes towards larger homes and other factors, the income elasticity is 0.2. These findings have practical implications for climate policy and the EU buildings and energy policy framework.

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