Technical and Tariff Scenarios Effect on Microturbine Trigenerative Applications

2003 ◽  
Author(s):  
Stefano Campanari ◽  
Ennio Macchi
Keyword(s):  
Energy Savings ◽  
Optimization Procedure ◽  
Operating Mode ◽  
Primary Energy ◽  
Environmental Benefits ◽  
Time Step ◽  
Simulation Code ◽  
Heating And Cooling ◽  
Target Energy ◽  
Micro Turbine

The paper considers the use of gas fired Micro Turbine Generators (MTG) for tri-generation (combined production of electricity, heating and cooling) applications in tertiary buildings. The importance of the adopted MTG technology is investigated, showing that the high electrical efficiency levels achievable by future advanced ceramic MTGs would improve dramatically the economic competitiveness of the application, as well as the primary energy savings and environmental benefits. Calculations are performed by the simulation code TRIGEN, capable of optimizing the plant operating mode in each time step and integrating the results over the entire year. The requirement of a “target” energy saving index on the optimization procedure is also addressed.

Technical and Tariff Scenarios Effect on Microturbine Trigenerative Applications

2004 ◽  
Vol 126 (3) ◽  
pp. 581-589 ◽  
Author(s):  
Stefano Campanari ◽  
Ennio Macchi
Keyword(s):  
Energy Savings ◽  
Optimization Procedure ◽  
Operating Mode ◽  
Primary Energy ◽  
Environmental Benefits ◽  
Time Step ◽  
Simulation Code ◽  
Heating And Cooling ◽  
Target Energy ◽  
Micro Turbine

The paper considers the use of gas fired micro turbine generators (MTG) for trigeneration (combined production of electricity, heating, and cooling) applications in tertiary buildings. The importance of the adopted MTG technology is investigated, showing that the high electrical efficiency levels achievable by future advanced ceramic MTGs would improve dramatically the economic competitiveness of the application, as well as the primary energy savings and environmental benefits. Calculations are performed by the simulation code TRIGEN, capable of optimizing the plant operating mode in each time step and integrating the results over the entire year. The requirement of a “target” energy saving index on the optimization procedure is also addressed.

Microturbines and Trigeneration: Optimization Strategies and Multiple Engine Configuration Effects

2002 ◽  
Author(s):  
Stefano Campanari ◽  
Luca Boncompagni ◽  
Ennio Macchi
Keyword(s):  
Heat Pump ◽  
Energy Savings ◽  
Operating Mode ◽  
Time Interval ◽  
Economic Aspects ◽  
Turbine Generator ◽  
Peak Demand ◽  
Simulation Code ◽  
Load Variations ◽  
Micro Turbine

This paper investigates energy savings and economic aspects related to the use of microturbine generators in commercial buildings either for cogeneration (electricity+heat) or for trigeneration (electricity, heat and cold). In all calculations, reference is made to a 25 kWel–class commercial micro-turbine generator (MTG), tested by the authors. Various plant schemes are considered, based on one or several MTG sets. The possibility of generating heat and/or cold also by an electrically driven inverse-cycle air-to-water heat pump/chiller system is also considered. Calculations are based on the simulation code TRIGEN developed by the authors. The code provides detailed energy, economic and emission yearly balances. The plant operating mode is optimized in each time interval. The results indicate that, due to large load variations, (i) the optimum turbine nominal output is in the range of about 70% of the electric peak demand, (ii) energy savings are marginal, (iii) advantages related to splitting the overall capacity on more than one unit are marginal and (iv) the addition of an absorption machine improves the plant economics.

scholarly journals Mathematical modeling and optimization of tri-generation systems with reciprocating engines

2010 ◽  
Vol 14 (2) ◽  
pp. 541-553 ◽  
Author(s):  
Mirko Stojiljkovic ◽  
Mladen Stojiljkovic ◽  
Bratislav Blagojevic
Keyword(s):  
Mathematical Model ◽  
Energy Savings ◽  
Optimization Procedure ◽  
Electrical Energy ◽  
Primary Energy ◽  
Optimal Operation ◽  
Electrical Heating ◽  
Heating And Cooling ◽  
Operational Optimization ◽  
Reciprocating Engines

Tri-generation systems are used to simultaneously produce electrical, heating, and cooling energy. These systems are usually more efficient than conventional systems for separate production and have smaller distribution losses since they are often located closer to the consumer. For achievement of the best technical and/or financial results, tri-generation plants have to be properly, i. e. optimally designed and operated. Operational optimization is used for short term production planning, control of tri-generation systems operation and as a part of design level optimization. In this paper an approach to operational optimization of tri-generation plants with reciprocating engines is presented with the following mathematical model. It is also explained how this algorithm might be embedded in some larger optimization procedure. In this approach, the importance of the part load performance of different units of the tri-generation systems is emphasized, especially of co-generation unit, i. e. engine generator set and thus it relies on manufacturers' data and is characterized with relatively high level of details examined. Mathematical model is based on the equipment performance based constraints and demand satisfaction based constraints with the possibility to add more equations if appropriate. Objective function for optimization is benefit-cost function. Optimal operation regimes for typical days for each month are obtained and analyzed. Impact of electrical energy price on pay-back period and primary energy saving is analyzed. Primary energy savings are determined and compared to maximal value that could be obtained.

Microturbines and Trigeneration: Optimization Strategies and Multiple Engine Configuration Effects

2004 ◽  
Vol 126 (1) ◽  
pp. 92-101 ◽  
Author(s):  
S. Campanari ◽  
L. Boncompagni ◽  
E. Macchi
Keyword(s):  
Heat Pump ◽  
Energy Savings ◽  
Operating Mode ◽  
Commercial Buildings ◽  
Time Interval ◽  
Economic Aspects ◽  
Peak Demand ◽  
Simulation Code ◽  
Load Variations ◽  
Large Load

This paper investigates energy savings and economic aspects related to the use of microturbine generators in commercial buildings either for cogeneration electricity+heat or for trigeneration (electricity, heat and cold). In all calculations, reference is made to a 25kWel-class commercial microturbine generator (MTG), tested by the authors. Various plant schemes are considered, based on one or several MTG sets. The possibility of generating heat and/or cold also by an electrically driven inverse-cycle air-to-water heat pump/chiller system is also considered. Calculations are based on the simulation code TRIGEN developed by the authors. The code provides detailed energy, economic and emission yearly balances. The plant operating mode is optimized in each time interval. The results indicate that, due to large load variations, (i) the optimum turbine nominal output is in the range of about 70% of the electric peak demand, (ii) energy savings are marginal, (iii) advantages related to splitting the overall capacity on more than one unit are marginal, and (iv) the addition of an absorption machine improves the plant economics.

scholarly journals The effect of a density gradient in groundwater on ATES system efficiency and subsurface space use

2018 ◽  
Vol 45 ◽  
pp. 85-103
Author(s):  
Martin Bloemendal ◽  
Theo N. Olsthoorn
Keyword(s):  
Thermal Energy ◽  
Energy Savings ◽  
Salinity Gradient ◽  
Primary Energy ◽  
Density Gradients ◽  
Buoyancy Flow ◽  
Heating And Cooling ◽  
Vertical Hydraulic Conductivity ◽  
The Impact ◽  
Research Show

Abstract. A heat pump combined with Aquifer Thermal Energy Storage (ATES) has high potential in efficiently and sustainably providing thermal energy for space heating and cooling. This makes the subsurface, including its groundwater, of crucial importance for primary energy savings. ATES systems are often placed in aquifers in which salinity increases with depth. This is the case in coastal areas where also the demand for ATES application is high due to high degrees of urbanization in those areas. The seasonally alternating extraction and re-injection between ATES wells disturbs the preexisting ambient salinity gradient causing horizontal density gradients, which trigger buoyancy flow, which in turn affects the recovery efficiency of the stored thermal energy. This section uses analytical and numerical methods to understand and explain the impact of buoyancy flow on the efficiency of ATES in such situations, and to quantify the magnitude of this impact relative to other thermal energy losses. The results of this research show that losses due to buoyancy flow may become considerable at (a relatively large) ambient density gradients of over 0.5 kg m−3 m−1 in combination with a vertical hydraulic conductivity of more than 5 m day−1. Monowell systems suffer more from buoyancy losses than do doublet systems under similar conditions.

scholarly journals Energy, environmental and economic analysis of electric vapour compression and gas driven absorption heat pumps for single-family houses

2021 ◽  
Vol 312 ◽  
pp. 06001
Author(s):  
Giorgio Villa ◽  
Rossano Scoccia ◽  
Tommaso Toppi ◽  
Marcello Aprile
Keyword(s):  
Energy Savings ◽  
Primary Energy ◽  
Heat Pumps ◽  
Hot Water ◽  
Single Family ◽  
Time Step ◽  
Dynamic Simulations ◽  
Emission System ◽  
Operative Costs ◽  
Vapour Compression

The aim of this paper is to compare energy consumptions, CO2 emissions, and operative costs of condensing boilers, electric vapour compression heat pumps and gas driven absorption heat pumps to provide space heating and domestic hot water. The analysis is performed for 140 m2 single-family houses in five different Italian cities whose envelope features depend on the location. For each location, two different envelope conditions are considered. The first one is a non-insulated building, while the second one is the same building, but an external thermal insulation is added on vertical walls and roof. To avoid internal renovation, radiators are maintained as emission system. Combined dynamic simulations are performed to appreciate building and system interactions. A 6 second time step is set to evaluate properly interactions and the DHW profile demand. In addition, the GHP dynamic model is a grey box model experimentally validated. The results show that electric vapour compression heat pumps reach the highest non-renewable primary energy savings (>32%) compared to condensing boilers, but their operative costs are higher due to the higher specific cost of electricity in Italy. Gas driven absorption heat pumps achieve a lower consumption reduction than electric heat pumps (>22%), but they have also the minimum operative cost among the three technologies.

Saving Primary Energy Consumption Through Exergy Analysis of Combine Distillation and Power Plant

2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt
Keyword(s):  
Energy Consumption ◽  
Power Plant ◽  
Heat Pump ◽  
Heat Recovery ◽  
Energy Savings ◽  
Primary Energy ◽  
Heat Pumps ◽  
Saturated Steam ◽  
Distillation Unit ◽  
Primary Energy Consumption

Industrial heat pumps are heat-recovery systems that allow the temperature ofwaste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses ofintegrating backpressure turbine ofa power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency ofthe primary fuel is calculated for different operating range ofthe heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperaturedifference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.

scholarly journals Dynamic Modelling of LNG Powered Combined Energy Systems in Port Areas

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3640
Author(s):  
Davide Borelli ◽  
Francesco Devia ◽  
Corrado Schenone ◽  
Federico Silenzi ◽  
Luca A. Tagliafico
Keyword(s):  
Energy Savings ◽  
Ghg Emissions ◽  
Dynamic Modelling ◽  
Energy Systems ◽  
Energy System ◽  
Primary Energy ◽  
Time Behavior ◽  
Vapor Compression Refrigeration Cycle ◽  
Integrated Energy System ◽  
Energy Share

Liquefied Natural Gas (LNG) is a crucial resource to reduce the environmental impact of fossil-fueled vehicles, especially with regards to maritime transport, where LNG is increasingly used for ship bunkering. The present paper gives insights on how the installation of LNG tanks inside harbors can be capitalized to increase the energy efficiency of port cities and reduce GHG emissions. To this purpose, a novel integrated energy system is introduced. The Boil Off Gas (BOG) from LNG tanks is exploited in a combined plant, where heat and power are produced by a regenerated gas turbine cycle; at the same time, cold exergy from LNG regasification contributes to an increase in the efficiency of a vapor compression refrigeration cycle. In the paper, the integrated energy system is simulated by means of dynamic modeling under daily variable working conditions. Results confirm that the model is stable and able to determine the time behavior of the integrated plant. Energy saving is evaluated, and daily trends of key thermophysical parameters are reported and discussed. The analysis of thermal recovering from the flue gases shows that it is possible to recover a large energy share from the turbine exhausts. Hence, the system can generate electricity for port cold ironing and, through a secondary brine loop, cold exergy for a refrigeration plant. Overall, the proposed solution allows primary energy savings up to 22% when compared with equivalent standard technologies with the same final user needs. The exploitation of an LNG regasification process through smart integration of energy systems and implementation of efficient energy grids can contribute to greener energy management in harbors.

scholarly journals Towards Sustainable Energy Retrofitting, a Simulation for Potential Energy Use Reduction in Residential Buildings in Palestine

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Simulation Models ◽  
Water Heating ◽  
Heating And Cooling ◽  
Space Cooling ◽  
Cooling Loads

Since buildings are one of the major contributors to global warming, efforts should be intensified to make them more energy-efficient, particularly existing buildings. This research intends to analyze the energy savings from a suggested retrofitting program using energy simulation for typical existing residential buildings. For the assessment of the energy retrofitting program using computer simulation, the most commonly utilized residential building types were selected. The energy consumption of those selected residential buildings was assessed, and a baseline for evaluating energy retrofitting was established. Three levels of retrofitting programs were implemented. These levels were ordered by cost, with the first level being the least costly and the third level is the most expensive. The simulation models were created for two different types of buildings in three different climatic zones in Palestine. The findings suggest that water heating, space heating, space cooling, and electric lighting are the highest energy consumers in ordinary houses. Level one measures resulted in a 19–24 percent decrease in energy consumption due to reduced heating and cooling loads. The use of a combination of levels one and two resulted in a decrease of energy consumption for heating, cooling, and lighting by 50–57%. The use of the three levels resulted in a decrease of 71–80% in total energy usage for heating, cooling, lighting, water heating, and air conditioning.

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