Investigation On The Connection Between The Local Artificial Heat Release And The Local Temperature Changes

In recent years, a series of changes in the earth's environment (e.g. temperature rise, glaciers melt, sea level rise, etc.) make global warming a focus of many areas (e.g. scientific, political, economic, etc.). Many scholars believe that the causation of climate warming is the greenhouse effect of CO2and other greenhouse gases, while the fierce opposition still exists at the same time. The heated debate is likely to result in lost of the truth. In fact, the temperature change is a very complex process. The author believes that the keys to analyse the environmental temperature change are the differences in the temporal scale and spatial scale. In other words, the short-term (in decades scale) variation of local (citywide) temperature and long-term (in10thousands years) variation of overall (global in spatial scale) temperature may be completely different. So far, many papers have focused on global scale temperature changes of hundreds of thousand years. In this time scale, the greenhouse gas concentrations and the trend of temperature change do have a good agreement. However, we are more concerned about the impact of human activities on the temperature, and it is less than one hundred years since human being has the ability to affect the temperature change significantly. Therefore, the study of artificial effect on environmental temperature should be focused on the latest century time scale and urban spatial scale. So that the conclusions can meet social needs well and be valuable to the development of the relevant industrial policies.The energy consumption of human society leads to large amounts of heat release as same as CO2emissions. Studies have shown that CO2and other greenhouse gases affect the temperature through the absorption of solar radiation. Because of the good diffusion, the local CO2emission spreads to the global atmosphere through atmospheric circulation, and then has a long-term impact on the temperature through the cumulative absorption of solar radiation. Therefore, impact of CO2on climate change is mainly reflected in the global and long-term scales.In contrast, large quantities of artificial heat release from the energy consumption will stay in cities and the surrounding regions in a period of time and the short-term trend of the local temperature change will be impacted inevitably. How strong is that effect? What is the law of that effect? How do we assess the artificial heat release of different energy? These are the issues this dissertation focuses on.In order to clarify these issues, this dissertation is organized as follows:â‘ Analysis of the relation between artificial heat release and temperature with the theoretical model approach based on the first and second law of thermodynamics;â‘¡Validation study on the relation between artificial heat release and temperature with relevant statistical data in China;â‘¢Prediction study on future temperature of the heat release concentrated areas base on the derived temperature-heat release relation;â‘£Establishment of assessment model for heat release comparison among technologies based on the understanding of the important role of heat release in temperature rise, and the application of the assessment model.First, based on the concepts in engineering thermodynamics cycle analysis such as the concepts of the control body, control border, input and output, the environment is divided into three parts:Local, Human, and Outer. There is heat exchange among these three parts, and a structural model of artificial heat release is established to study the heat release concentrated urban environment. Theoretical derivation is given for the relation between temperature and artificial heat release. The results show that there is a linear relation between the local temperature and the local annual artificial heat release. This conclusion is clear that the heat release from energy consumption is an important driver of temperature rise.Second, the linear temperature-heat release relation derived from the theoretical research is verified with statistics data of most provinces and their capital cities of China. It is shown that the temperature-heat release relation of most provinces is consistent with the conclusion of the model derivation. There are a few exceptions, of which the explanations can also be found from the theoretical model.Third, according to the proven linear temperature-heat release relation, the future temperature prediction of the typical heat release concentrated areas, Shanghai and Beijing, is carried out. The results show that according to current trends, the increase in artificial heat release will result in serious temperature rise in these two areas to the year2030. If the heat release can be controlled reasonably and effectively, the temperature rise will be significantly reduced than original forecast. So it comes to that heat release control is an important way to curb rising temperature.Then, in order to control artificial heat release without affecting human needs, an assessment model for different energy technologies is established based on full lifecycle perspective and exergy analysis method. This model can be used to assess the energy consumption of different energy technologies, too. This model has calculated the artificial heat release and energy consumption of the energy technologies to meet per unit energy utilization demand, especially the heat release generated by the change of the ground albedo in solar energy utilization, and the energy consumption of early research&development as well as production line construction of new energy technologies. Thus, this model shows a more comprehensive and objective assessment method of the heat release and energy consumption in different energy technologies. After that, photovoltaics(PV) and coal-fired power generation are compared with the assessment model, the result shows that the artificial heat release of PV is much higher than coal-fired power generation in the full lifecycle for per kwh electricity generation, and the energy cost-recovery cycle of PV is about14years, which is much longer than the existing conclusion of3to4years.Finally, the main conclusions of this dissertation are given. Through the study we clarified that artificial heat release is an important factor that leading to climate warming. Then, this dissertation provided some views and suggestions on the means of artificial heat release control. In addition, as the outlook for further work, the author hopes that this study can contribute to the understanding of the relation between global warming and the artificial heat release.