chp system
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2022 ◽  
Vol 251 ◽  
pp. 114985
Author(s):  
Farid Jalili Jamshidian ◽  
Shiva Gorjian ◽  
Mehdi Shafieefar

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8372
Author(s):  
Alfredo Gimelli ◽  
Massimiliano Muccillo

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.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8216
Author(s):  
Pablo Benalcazar ◽  
Przemysław Kaszyński ◽  
Jacek Kamiński

In the power and heat sectors, the uncertainty of energy and carbon prices plays a decisive role in the rationale for decommissioning/repurposing coal-fired CHP (combined heat and power) systems and on investment decisions of energy storage units. Therefore, there is a growing need for advanced methods that incorporate the stochastic disturbances of energy and carbon emission prices into the optimization process of an energy system. In this context, this paper proposes an integrated method for investigating the effects of uncertain energy and carbon prices on the operational patterns and financial results of CHP systems with thermal energy storage units. The approach combines mathematical programming and Monte Carlo simulation. The computational process generates feasible solutions for profit maximization considering the technical constraints of the CHP system and the variation of energy and carbon emission prices. Four scenarios are established to compare the operational patterns and economic performance of a CHP system in 2020 and 2030. Results show that in 2020, there is an 80% probability that the system’s annual profit will be less than or equal to €30.98 M. However, at the same probability level, the annual profit in 2030 could fall below €11.88 M. Furthermore, the scenarios indicate that the incorporation of a thermal energy storage unit leads to higher expected profits (€0.74 M in 2020 and €0.71 M in 2030). This research shows that coal-fired CHP plant operators will face costly risks and potentially greater challenges in the upcoming years with the increasing regulatory and financial pressure on CO2 emissions and the EU’s plan of phasing out fossil fuels from electricity and heat generation.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8096
Author(s):  
Marialaura Di Somma ◽  
Martina Caliano ◽  
Viviana Cigolotti ◽  
Giorgio Graditi

Through the integration of multiple energy carriers with related technologies, multi-energy systems (MES) can exploit the synergies coming from their interplay for several benefits towards decarbonization. In such a context, inclusion of Power-to-X technologies in periods of excess renewable electricity supply, removes the need for curtailment of renewable electricity generation. In order to achieve the environmental benefits of MES without neglecting their economic feasibility, the optimal design problem is as crucial as challenging and requires the adoption of a multi-objective approach. This paper extends the results of a previous work, by investigating hydrogen-based non-conventional storage for PV power in the eco-energetic optimization of an MES. The system under study consists of a reversible fuel cell (r-SOC), photovoltaic (PV), electric heat pump, absorption chiller and thermal storage, and allows satisfying the multi-energy needs of a residential end-user. A multi-objective linear problem is established to find the optimal MES configuration including the sizes of the involved technologies with the goal of reducing the total annual cost and the fossil primary energy input. Simulation results are compared with those obtained in previous work with a conventional nanogrid where a combined heat and power (CHP) system with gas-fired internal combustion engine and a battery were present instead of an r-SOC. The optimized configuration of the non-conventional nanogrid allows achieving a maximum primary energy reduction amounting to 66.3%, compared to the conventional nanogrid. In the face of the environmental benefits, the non-conventional nanogrid leads to an increase in total annual costs, which, compared to the conventional nanogrid, is in the range of 41–65%.


2021 ◽  
Vol 2120 (1) ◽  
pp. 012001
Author(s):  
Chee Yau Hew ◽  
Li Wan Yoon ◽  
Yoke Kin Wan

Abstract The huge amount of biomass waste and palm oil mill effluent (POME) generated during oil extraction has prompted the need for a more sustainable framework in waste management. Since oil palm biomass waste is rich in lignocellulosic content, it can be potential to be converted into green energy such as bioelectricity via different pathway of processes such as the thermal conversion pathway and biochemical conversion pathway. This study proposes a mathematical approach to synthesise a sustainable supply chain of biomass to electricity by implementing the combined heat and power (CHP) system in palm oil mill. The optimum pathway of supply chain based on the technical, economical, and environmental aspects is generated. The purpose of this approach is to assists the industry players or owners to make decision in choosing the location of the pre-treatment technology, transportation method, location of power plant and configuration of CHP. A generic superstructure is first developed to achieve the objective. Then, a series of generic mathematical equations will then be formulated based on the pathways demonstrated in the generic superstructure. The mathematical equations involve general mass and energy balance, cost computation and carbon emission. The fuzzy optimisation concept will be adopted in this research to trade-off the conflicting objectives (maximize profit and minimize carbon footprint) in order to generate the optimum pathway. A palm oil-based bioelectricity supply chain case study in Selangor, Malaysia is solved to illustrate the presented approach. According to the optimised result in this case study, a total of 3,753.36 MW of bioelectricity can be generated per year. The result proved that the optimum pathway is feasible by comparing with the existing oil palm biomass-based power plant in Sarawak, where only 375 MW of electricity is generated by oil palm biomass. On the other hand, RM 7.25 million per year of net profit is estimated with a payback period of 2.81 years. Moreover, the CHP system is able to achieve 570 million kg CO2 per year.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6625
Author(s):  
Jie Liu ◽  
Sung Chul Kim ◽  
Ki Yeol Shin

Unlike a general commercial building, heating for a building with an indoor swimming pool is highly energy-intensive due to the high energy demand for swimming water heating. In Korea, the conventional heating method for this kind of building is to use boilers and heat storage tanks that have high fuel costs and greenhouse gas emissions. In this study, a combined heat and power (CHP) system for such a building using the electricity and waste heat from a Phosphoric Acid Fuel Cell (PAFC) system was designed and analyzed in terms of its primary energy saving, CO2 reduction, fuel cell and CHP efficiency, and economic feasibility. The mathematical model of the thermal load evaluation was used with the 3D multi-zone building model in TRNSYS 18 software (Thermal Energy System Specialists, LLC, Madison, MI, USA) to determine the space heating demand and swimming pool heat losses. The energy efficiency of the fuel cell unit was evaluated as a function of the part-load ratio from the operating data. The fundamental components, such as the auxiliary boiler, thermal storage tank, and heat exchanger are also integrated for the simulation of the system’s operation. The result shows that the system has a high potential to improve the utilization efficiency of fuel cell energy production. Referring to the local condition of the energy market in Korea, an economic analysis was also carried out by using a specific FC-CHP capacity at 440 kW. The economic benefit is significant in comparison with a conventional heating system, especially for the full-time operating (FTO) mode. The net profit made by comparison with the conventional energy supply system is about 178,352 to 273,879 USD per year, and the payback period is expected to be 6.9 to 10.7 years under different market conditions.


2021 ◽  
Author(s):  
Grzegorz Przybyła ◽  
Łukasz Ziółkowski ◽  
Mateusz Buczak ◽  
Zbigniew Żmudka

This paper presents the experimental results of a Combined Heat and Power (CHP) prototype based on a SI V-twin internal combustion engine driving a synchronous generator. The paper presents the criteria that were used to select the combustion engine and the electrical generator for the prototype. The internal combustion engine has been adapted to be fuelled by natural gas or LPG, with the possibility of controlling the load in two ways, i.e. by changing the throttle position (quantitatively) and/or the value of the excess air ratio by changing the fuel dose at a constant throttle position (qualitatively). The applied method of control allows to improve the efficiency of the engine especially in the range of partial loads. The experimental tests were carried out at a constant speed of 1500 rpm. During the tests, the fuel consumption of the internal combustion engine, the composition of the exhaust gas at the outlet of the exhaust system, the electrical parameters of the synchronous generator and the temperature at selected locations of the CHP system instance were measured. According to the obtained results, there was a slight increase in the efficiency of electricity generation with the application of the developed method of control of the combustion engine. The maximum power generation efficiency for Natural Gas (NG) was higher compared to LPG by more than 2 percentage points.


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