The Research And Applied Analysis Of Small Natural-gas Stirling Cool-Heat-Electricity Cogeneration

One of the main uses of the energy is to provide user with electricity, heat (bath-water) and cool. The traditional way of separately supply makes the efficiency not high. However, the small-scaled cogeneration of cool, heat and electricity can save the energy extremely by synthesis providing these energies to user. The advantage of small cogeneration is fossil fuel can be used in grades and be used up. The benefit of small cogeneration comes from invest saving of electricity line construction and declining the loss of electricity transport as they can be constructed near the user. Therefore, the small-scaled cogeneration gets a lot of countries support strongly. Moreover, along with the expansion of the clean fuel such as natural gas and coal etc, the small-scaled systems, which use the clean fuel, has been extensively researched and has become the emphasis to be generalized.The small-scaled cogeneration system needs the device that converts the fuel into electric power. The Stirling engine is just this device, which it caused the researcher biggest interest as it appeared. It have advantages such as high efficient, low pollution, low noise etc. So, the Stirling engine is very suit to be used for the big city with high population density.The cool-heat-electricity cogenerations have different outputs. We can't compare the cool, heat and electricity directly because of them in different "status". So we change these energy forms into uniform as "utilization efficiency of the original fuel". Based the "utilization efficiency of the original fuel", the different cogeneration projects of Stirling engine have been analyzed and optimized. However, the energy economy is only a static analysis. We can't draw a whole conclusion from this analysis. Therefore the analysis of dynamic investment and sensitivity has been carried on. At last, the project of Stirling cogeneration has been decided.Obviously, the Stirling engine is the key device in the cogeneration. Although the technology of Stirling is mature in our nation. But we should design aspecialized gas combustor for the Stirling engine which uses the natural gas as its fuel. The combustor must be designed compact and the temperature distribution must be uniform. Also the combustion system must arrive at high burning efficiency, stability and low exhaust. The design work is very hard. And the simulation method has been applied in design. First the burning parts have been optimized by 3d simulation and at last a set of burning system has been designed. The details of the burning and exhaust have been simulated based on the designed combustor dimension. In the experiment, the engine, which equipped with the gas combustor, comes to a high efficiency. The exhaust of the engine is low in partial load but it quickly raises high in full load. So, according to the theory of NOx restrain, the low NOx burner construction is preparatory designed and simulated.After the cogeneration analysis finished and the device exploits completely, we set up one test system for Stirling engine and Li-Br absorbed air-conditioner. The result of running experiment indicates that the efficiency of cogeneration is better than single generation's. The cogeneration outputs of cool, heat and electricity are stabile and reliable.When user adopts the Stirling cogeneration, the running mode should be studied because the user load is variable with seasons and times and the electricity price is also fluctuant in a day. In this paper, the method has been put forward to simulate the cogeneration by statistic the user load hour by hour. The running modes have been studied by the simulation of two modes which one is "the heat determine the electricity" and the other one is "the electricity determine the heat". The actual running mode was determined by the simulation results.In actual cogeneration running, the cogeneration must be controlled to come to good performance because there have so many output parameters. One total control strategy was put forward in the last.