Performance analysis of a combined cooling, heating, and power system driven by a waste biomass fired Stirling engine

Author(s):  
J Harrod ◽  
P J Mago

Due to the soaring costs and demand of energy in recent years, combined cooling, heating, and power (CCHP) systems have arisen as an alternative to conventional power generation based on their potential to provide reductions in cost, primary energy consumption, and emissions. However, the application of these systems is commonly limited to internal combustion engine prime movers that use natural gas as the primary fuel source. Investigation of more efficient prime movers and renewable fuel applications is an integral part of improving CCHP technology. Therefore, the objective of this study is to analyse the performance of a CCHP system driven by a biomass fired Stirling engine. The study is carried out by considering an hour-by-hour CCHP simulation for a small office building located in Atlanta, Georgia. The hourly thermal and electrical demands for the building were obtained using the EnergyPlus software. Results for burning waste wood chip biomass are compared to results obtained burning natural gas to illustrate the effects of fuel choice and prime mover power output on the overall CCHP system performance. Based on the specified utility rates and including excess production buyback, the results suggest that fuel prices of less than $23/MWh must be maintained for savings in cost compared to the conventional case. In addition, the performance of the CCHP system using the Stirling engine is compared with the conventional system performance. This comparison is based on operational cost and primary energy consumption. When electricity can be sold back to the grid, results indicate that a wood chip fired system yields a potential cost savings of up to 50 per cent and a 20 per cent increase in primary energy consumption as compared with the conventional system. On the other hand, a natural gas fired system is shown to be ineffective for cost and primary energy consumption savings with increases of up to 85 per cent and 24 per cent compared to the conventional case, respectively. The variations in the operational cost and primary energy consumption are also shown to be sensitive to the electricity excess production and buyback rate.

2021 ◽  
Vol 144 ◽  
pp. 14-21
Author(s):  
Vladimir P. Polevanov ◽  

The growth in primary energy consumption in 2019 by 1.3% was provided by renewable energy sources and natural gas, which together provided 75% of the increase. China in the period 2010–2020 held a leading position in the growth of demand for energy resources, but according to forecasts, India will join it in the current decade.


Author(s):  
James C. Harrod ◽  
Pedro J. Mago

Over the past decade, rising energy demand and cost have created a surge of interest in alternative methods of power generation. As a result, the implementation of combined cooling, heating, and power (CCHP) systems has become a potential candidate for substitution in conventional power generation. The evaluation of a CCHP system must be based on its potential for savings in cost and primary energy reduction. In general, a CCHP system includes several components to satisfy the electric and thermal demands of the facility. These components include the prime mover, heat recovery system, auxiliary boiler, absorption chiller, heating coil unit, and hot water system unit. In practice, the most common prime mover used in CCHP technology is the internal combustion engine, which is limited by low thermal efficiency and poor emissions. Hence, this paper proposes the use of a Stirling engine prime mover that makes use of waste wood chips for fuel. In addition to the standard CCHP components, the Stirling engine houses heat exchangers to aid heat addition and rejection processes. These heat exchangers must be considered along with the other components when analyzing energy requirements. The goal of this study is to determine how the operational characteristics of a constant output biomass-fired Stirling CCHP system are affected by the performance of the individual CCHP system components. The results of this sensitivity analysis are useful in determining the most important parameters to be considered when implementing and designing the system. Results suggest that fuel cost, engine efficiency, engine size, chiller efficiency, and the Stirling engine’s hot side heat exchanger play the most important roles in the CCHP system operational cost. For example, the results show that increasing the engine size leads to increases in primary energy. In addition, an optimum engine size is suggested for cost savings, with smaller and larger engines both leading to increases in operational cost.


2011 ◽  
Vol 335-336 ◽  
pp. 1525-1529
Author(s):  
You Shan Gao ◽  
Ai Hong Wang

Abstract. This paper analyzed the primary energy consumption and emission of VOC, CO, NOx, SO2, PM, CO2, CH4, N2O during natural gas (NG) exploitation, it showing that more than 65% of VOC, NOX, SOx, CH4, CO2and greenhouse gas were discharged by electric energy and heat energy consumption during NG exploitation in all technique energy emission. Because of its important in NG exploitation, the consumption of electric energy and heat energy and its emissions produced should be reduced in order to reduce the emissions of NG exploitation.


2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt

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.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2538
Author(s):  
Praveen K. Cheekatamarla

Electrical and thermal loads of residential buildings present a unique opportunity for onsite power generation, and concomitant thermal energy generation, storage, and utilization, to decrease primary energy consumption and carbon dioxide intensity. This approach also improves resiliency and ability to address peak load burden effectively. Demand response programs and grid-interactive buildings are also essential to meet the energy needs of the 21st century while addressing climate impact. Given the significance of the scale of building energy consumption, this study investigates how cogeneration systems influence the primary energy consumption and carbon footprint in residential buildings. The impact of onsite power generation capacity, its electrical and thermal efficiency, and its cost, on total primary energy consumption, equivalent carbon dioxide emissions, operating expenditure, and, most importantly, thermal and electrical energy balance, is presented. The conditions at which a cogeneration approach loses its advantage as an energy efficient residential resource are identified as a function of electrical grid’s carbon footprint and primary energy efficiency. Compared to a heat pump heating system with a coefficient of performance (COP) of three, a 0.5 kW cogeneration system with 40% electrical efficiency is shown to lose its environmental benefit if the electrical grid’s carbon dioxide intensity falls below 0.4 kg CO2 per kWh electricity.


2018 ◽  
Vol 882 ◽  
pp. 215-220
Author(s):  
Matthias Koppmann ◽  
Raphael Lechner ◽  
Tom Goßner ◽  
Markus Brautsch

Process cooling and air conditioning are becoming increasingly important in the industry. Refrigeration is still mostly accomplished with compression chillers, although alternative technologies are available on the market that can be more efficient for specific applications. Within the scope of the project “EffiCool” a technology toolbox is currently being developed, which is intended to assist industrials users in selecting energy efficient and eco-friendly cooling solutions. In order to assess different refrigeration options a consistent methodology was developed. The refrigeration technologies are assessed regarding their efficiency, CO2-emissions and primary energy consumption. For CCHP systems an exergetic allocation method was implemented. Two scenarios with A) a compression chiller and B) an absorption chiller coupled to a natural gas CHP system were calculated exemplarily, showing a greater overall efficiency for the CCHP system, although the individual COP of the chiller is considerably lower.


2005 ◽  
Vol 9 (3) ◽  
pp. 7-14 ◽  
Author(s):  
Hiromi Yamamoto ◽  
Kenji Yamaji

The uses of fossil fuels cause not only the resources exhaustion but also the environmental problems such as global warming. The purposes of this study are to evaluate paths to ward sustainable energy systems and roles of each renewable. In order to realize the purposes, the authors developed the global land use and energy model that figured the global energy supply systems in the future considering the cost minimization. Using the model the authors conducted a simulation in C30R scenario, which is a kind of strict CO2 emission limit scenarios and reduced CO2 emissions by 30% compared with Kyoto protocol forever scenario, and obtained the following results. In C30R scenario bio energy will supply 33% of all the primary energy consumption. How ever, wind and photo voltaic will supply 1.8% and 1.4% of all the primary energy consumption, respectively, because of the limits of power grid stability. The results imply that the strict limits of CO2 emissions are not sufficient to achieve the complete renewable energy systems. In order to use wind and photo voltaic as major energy resources we need not only to reduce the plant costs but also to develop unconventional renewable technologies. .


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