Energy Balance of Stirling Engine Cogeneration and Installation Potentiality in Cold Region Houses

A Stirling engine (SEG) using woody biomass is a power generation system that can reduce greenhouse gas discharge. However, improvement of generation efficiency and development of a product are required strongly. In this paper, the energy flow is investigated in experimenting in Test SEG. These results are installed into the energy demand pattern of a cold region houses with much heat demand, and the amount of fuel consumption, power generation efficiency, and a greenhouse gas amount of emission are investigated. Operations of the proposed system are SEG base-load operation and SEG power-load-following operation. Moreover, when there is less exhaust heat of the SEG than a heat demand amount, electric heat pump is operated. From analysis results, the energy cost, the greenhouse gas emission characteristic, the auxiliary heat source, and the operation plan of a heat storage tank due to the conventional method and the proposed system are described. It is thought that greenhouse gas and the energy cost of the SEG cogeneration made to follow power load are advantageous compared with the SEG base-load operation. However, it turned out that improvement in the speed of the load response characteristic of the SEG is required as a future subject. Copyright © 2008 John Wiley & Sons, Ltd.

Power generation in remote locations requires the advancement of efficient and long-lasting power generation technologies. One possible solution is a microreactor, which uses heat pipes to transport fission heat from a nuclear source to Stirling engines producing energy. In this context, TERRA (Advanced Fast Reactor Technology) project conducted by the Institute for Advanced Studies (IEAv) developed a Stirling engine and copper-water heat pipes for an initial study of both coupled devices. However, before using a nuclear source, it is necessary to understand the thermal behavior of the devices using an electrical heating source. Thus, the objective of this work is to test experimentally if a copper heat pipe can carry the necessary heat to activate the Free Piston Stirling engine. For this, it was necessary to develop a copper adapter to connect the pipe to the engine. The pipe was connected to the engine and temperatures were collected using T-thermocouples. The results of the experiments showed that the heat pipe was able to transport 28 W to the Stirling engine, which ran continuously. The maximum heat pipe temperatures were 253°C and the Stirling engine ran at 212°C in the hot source. Therefore, it was demonstrated that the IEAv´s copper-water heat pipe is capable of conducting the necessary heat to activate the IEAv´s Stirling engine and produce electricity. The results will form the basis for the future application of a nuclear source.

Thermo-environmental analysis of a new molten carbonate fuel cell-based tri-generation plant using stirling engine, generator absorber exchanger and vapour absorption refrigeration: A comparative study

This chapter consists of two sections, ‘Energy Cost of an Independent Microgrid with Control of Power Output Sharing of a Distributed Engine Generator’ and ‘Improvement of Power Generation Efficiency of an Independent Microgrid Composed of Distributed Engine Generators’. In the 1st section, small kerosene diesel-engine power generators are introduced into an independent microgrid, and power and heat are supplied to 20 houses. If the proposed system is introduced into a community with little heat demand, effectiveness will decrease greatly. The 2nd section investigates the power generation efficiency and power cost of an independent microgrid that distributes the power from a small diesel engine power generator. When the number of distributions of the engine generator is installed, the cost of the fuel decreases.

Stirling engine is being received more and more attention with the development of renewable energy utility. The paper described the design and simulation of a 3-KW Stirling engine based on a testing V-type machine while in the process of manufactured at the Huazhong University of Science and Technology. The engine was driven by solar energy. Based on the testing machine, the heater model of variable heat source, regenerator model and complete appliance model were built, and the thermal performance was simulated and shown under a typical sunlight in the area of Wuhan. The results suggested that the output power curve of Stirling engine appeared as the shape of a saddle in consideration that the radiant energy density of solar energy was non-constant, and electrical heating was employed to serve as the auxiliary heat source. There was about 1.83 KW output work of the manufactured engine during the simulation, and the effective efficiency was about 25.4%. DOI: http://dx.doi.org/10.11591/telkomnika.v10i6.1405 Full Text: PDF

The purpose of this chapter is to investigate the effects of some mainstream policy schemes in the power sector on the reduction of CO2 emissions. The first part of this chapter is the analysis on the effects of promoting generation (fuel) efficiency of fossil-fuel power generation, specifically assuming more efficient coal-fired power plants that recently indicates increased presence in the Japanese power sector. Improvement in generation efficiency of fossil-fuel power plants is expected to reduce emissions of carbon dioxide mainly from a technological aspect. However, overall effects on carbon reduction in the whole industry would be ambiguous since it also depends on market structure. The increased efficiency in generation leads to an improvement in cost conditions of fossil-fuel power producers relative to their rivals. It enables them to expand their generation and market share. Analyzing the Cournot oligopoly model, it is shown that an improvement in fossil-fuel power generations produces two effects: the ‘saving effect’ and the ‘rebound effect’. The total CO2 emission in the whole industry decrease if the former effect exceeds the other, and vice versa. In addition, it is indicated that a rise in the generation efficiency would increase a difficulty of implementing carbon tax. In the second part of this chapter, I study the combination of feed-in tariff and carbon tax; that would be worthy to investigate since they could possibly complement each other. FIT policy could be financed by the revenue of carbon tax, and a reduction in electricity supply by the carbon tax would be lessen by supporting renewable power generations under FIT. It is demonstrated that FIT had the combined effects: it fosters a competitive environment in addition to indirectly reduces CO2 emissions. The result indicates that the combination of these policies would produce potential welfare gains.

Analysis of the generation efficiency of disaggregated renewable energy and its spatial heterogeneity influencing factors: A case study of China

Thermal modeling of a trigeneration system based on beta-type Stirling engine for reductions of fuel consumption and pollutant emission

Decarbonizing the residential building sector by replacing gas boilers with electric heat pumps will dramatically increase electricity demand. Existing models of future heat pump demand either use daily heating demand profiles that do not capture heat pump use or do not represent sub-national heating demand variation. This work presents a novel method to generate high spatiotemporal resolution residential heat pump demand profiles based on heat pump field trial data. These spatially varied demand profiles are integrated into a generation, storage, and transmission expansion planning model to assess the impact of spatiotemporal variations in heat pump demand. This method is demonstrated and validated using the British power system in the United Kingdom (UK), and the results are compared with those obtained using spatially uniform demand profiles. The results show that while spatially uniform heating demand can be used to estimate peak and total annual heating demand and grid-wide systems cost, high spatiotemporal resolution heating demand data is crucial for spatial power system planning. Using spatially uniform heating demand profiles leads to 15.1 GW of misplaced generation and storage capacity for a 90% carbon emission reduction from 2019. For a 99% reduction in carbon emissions, the misallocated capacity increases to 16.9-23.9 GW. Meeting spatially varied heating load with the system planned for uniform national heating demand leads to 5% higher operational costs for a 90% carbon emission reduction. These results suggest that high spatiotemporal resolution heating demand data is especially important for planning bulk power systems with high shares of renewable generation.

China's retrofitting measures in coal-fired power plants bring significant mercury-related health benefits

This study aims to model a hybrid power system that can continuously generate power by switching between two possible thermal sources: solar radiation and combustion energy from synthesis gases. The system comprised a hybrid energy receiver, solar dish, Stirling generator, fluidized‐bed gasifier, boiler, and water tank. The solar dish was a dual‐reflection solar collector that used two mirrors, namely the main and subordinate concentrators, to concentrate a broad expanse of solar radiation onto a hybrid energy receiver. The fluidized‐bed gasifier was employed for the production of synthesis gases. The synthesis gases were combusted to provide an auxiliary heat source for the Stirling generator when solar radiation was insufficient. Solar radiation or combustion energy was alternatively introduced into the hybrid energy receiver and converted to power by a 1‐kW‐scale beta‐type Stirling engine. In this manner, the Stirling generator could serve as a base‐load power plant regardless of solar conditions. In this study, a complete quantitative model was developed for a demonstration plant by incorporating thermodynamic and dynamic models of the beta‐type Stirling engine, a ray‐tracing model for the dual‐reflection solar dish, an energy model of the hybrid energy receiver, and experimental data for the fluidized‐bed gasifier. The performance response of the system during switching between solar radiation and combustion energy was predicted. The modeling results indicated that switching can result in a continuous power output ranging from 600 to 1200 W. With synthesis gas combustion as the auxiliary heat source, the hybrid Stirling power system can be operated continuously, and the overall power output is increased by 109.82% compared to a conventional concentrated solar power system that only uses solar radiation.

Energy, exergy, environmental, and economic modeling of combined cooling, heating and power system with Stirling engine and absorption chiller

formula omitted] discharge characteristic of PEM-FC/hydrogen-gas-engine hybrid cogeneration

One of the critical problems currently being faced by agriculture industry in developing nations is the alarming rate of groundwater depletion. Irrigation accounts for over 70% of the total groundwater withdrawn everyday. Compounding this issue is the use of polluting diesel generators to pump groundwater for irrigation. This has made irrigation not only the biggest consumer of groundwater but also one of the major contributors to green house gases. The aim of this thesis is to present a solution to the energy-water nexus. To make agriculture less dependent on fossil fuels, the use of a solar-powered Stirling engine as the power generator for on-farm energy needs is discussed. The Stirling cycle is revisited and practical and ideal Stirling cycles are compared. Based on agricultural needs and financial constraints faced by farmers in developing countries, the use of a Fresnel lens as a solar-concentrator and a Beta-type Stirling engine unit is suggested for sustainable power generation on the farms. To reduce the groundwater consumption and to make irrigation more sustainable, the conceptual idea of using a Stirling engine in drip irrigation is presented. To tackle the shortage of over 37 million tonnes of cold-storage in India, the idea of cost-effective solar-powered on-farm cold storage unit is discussed.

Optimized multi-criteria performance of a poly-generation layout including a Stirling engine and a supercritical Brayton cycle using biogas and methane as two potential fuels of a topping gas turbine cycle