Abstract

The purpose of this research is to investigate the essential parameter in energy integration of distillation columns sequence via Thermal Pinch Analysis, which is the minimum temperature difference, Δ𝑇𝑚𝑖𝑛. The distillation process of five alkane components has been selected as a case study for this research. From there, the shortcut simulations of all possible sequences have been simulated by using a process simulation software. Then, the energy consumption will be ranked accordingly whereby the lowest will be further simulated via a rigorous simulation before the application of the Thermal Pinch Analysis with a range of Δ𝑇𝑚𝑖𝑛 from 5 to 40 °C. Next, the energy requirement before and after the Thermal Pinch Analysis has been compared to determine the energy saving and to generate the economic analysis. According to the parametric analysis result, the optimum Δ𝑇𝑚𝑖𝑛 is in between the range of 20 to 25°C and the best sequence is Sequence 3 (direct-direct-indirect) which recorded 7.72% of total energy saving, USD 1274.45 MM per year of cost utility and USD 1.91 MM of capital expenditure. This can be termed as a conclusive remark to state the importance of ΔTmin role in balancing the energy saving of the process with the costs incurred for the process.

Abstract

The Internet of Things (IoT) has created the opportunity for the development of new features such as virtual reality (VR), augmented reality (AR), mixed reality (MR) and extended reality (XR) and is now beginning to become more and more mature techniques. However, the implementation of these concepts has not been as fast in the industry as one might imagine. Tests that were conducted at some mining businesses, shows on many possible areas of use that can save energy and reduce COâ‚‚ emissions and as well travel costs. In addition, it was verified that AR supported so that the remedy time was significantly reduced, thus minimizing production stoppages by more than 50% of the time, which in the end affects the Swedish GDP (BNP) positively. One concrete example with the alternative with AR was to solve a problem in a mine in Australia, where a three-year-old problem in a mine hoist was solved over an recorded AR call which later on was showed to 12 experts, from different parts of the world, over a skype meeting, saving principally some 15 MWh per person, or a total of 150 MWh, due to avoiding the long flights. In addition, a lot of time and by this money was saved as well! Predictions about how much energy can be saved are made if 50% of all the world’s business travel is replaced by AR concepts, which was investigated in this essay. The amount corresponds to all of Sweden’s total direct carbon dioxide emissions in one year which accounts for 70 Mton COâ‚‚ per year.

Abstract

This paper presented an off-design framework of gas turbine (GT) and its corresponding waste heat recovery system (WHRS) composed of a heat recovery steam generator (HRSG) and an organic Rankine cycle (ORC). Two different GT control strategies named turbine inlet temperature control (TITC) and inlet air throttling control (IATC) methods were chosen, as well as a novel combined IAT-TITC method was proposed. The CHP system was optimized based on the maximum thermal efficiency first at GT full-load conditions. Then, the off-design evaluation was conducted to predict the part-load conditions and system performance. Results showed that the novel proposed IAT-TITC method effectively increased the thermal efficiency during the entire part-load conditions, and could avoid the low temperature exhaust gas phenomenon. The maximum efficiency difference between traditional TITC and new IAT-TITC was about 13.78% at half-load conditions.

Abstract

A balance correction test method(BCTM) based on a double-sided heat flow meter is proposed in this study, which is used to optimize the thermal performance testing method of the building envelope. The accuracy and applicability of this method are verified by using the measured data of typical buildings in China’s hot summer and cold winter regions. The results show that: for walls in the steady state and unidirectional unsteady state heat transfer process, the balance correction test method can accurately obtain the thermal performance parameters of the wall, and the error is only 6.48%, 5.56% and 5.8%, and this method can effectively shorten the measurement time and calculation period.

Abstract

The safety and efficiency of boilers are tightly related to the performance of boiler tube. 20G steel is widely used in the manufacturing of boiler tube. The corrosion behaviors of 20G exposed in precipitated sodium sulfate under high temperature/ pressure were investigated experimentally. Samples are placed in a setup for corrosion and subsequently analyzed by scanning electron microscope, energy dispersive spectroscopy (SEM / EDS) analysis and X-ray diffraction (XRD). The results indicate that the mass fraction of Fe elements on the surface decreases with time from 86.50% (t = 24 h) to 75.75% (t = 72 h). In the range of experiment temperature, higher temperature has positive effect on the formation of crystal structures.

Abstract

Green and efficient development is an inevitable requirement for sustainable development of shale gas industry in China. This paper selects 24 indicators from five dimensions of resource endowment, economy, technology, environment and policy to construct the evaluation indicator system of green and efficient development of shale gas resources in China, and applies the fuzzy-AHP method to comprehensively evaluate the green and efficient development of shale gas resources in China. The results show that the influencing extent on shale gas green and efficient development is resource endowment, technology, policy, economy and environment in turn, and resource endowment and development technology are the key to green and efficient development of shale gas in China. However, to realize the green and efficient development of China’s shale gas, the coordinated development of all aspects is necessary. Therefore, some suggestions are put forward based on the development status of China’s shale gas industry.

Abstract

There are typically two methods for building energy modeling, which are physical based models and data-driven models. However, the simulation results of physical base energy models often deviate greatly from real cases. While the traditional data-driven energy models are more reliable but only applicable to buildings with historical data record. In this paper, we propose a framework of hybrid building energy models developed based on heterogeneous database which contains integration of building formation, field-tested energy data and simulated energy data. This hybrid energy forecasting model is able to predict building energy in the absence of energy record of the target building. The framework consists of three parts: key variables identification, data integration, heterogeneous database and hybrid energy forecasting model development. A chiller energy forecasting model is developed as a case study to demonstrate the feasibility of this framework. The mean cross testing CV-RMSE and R2 of chiller energy forecasting energy model are 0.17 and 0.86 respectively which are fairly acceptable when historical energy data of target building is not available.

Abstract

In order to prevent global warming, the formation of a zero-emission society is critical. As a solution, a “PV

Abstract

After the molten slag was granulated by centrifugal granulation, it would fly in the granulation bin for a period of time. The slag particles exchanged heat with the cold air and water wall by convection and radiation was a typical multi-component unsteady phase-change thermal process. The study of heat characteristics of the air-cooled phase transition of slag particles has important guiding significance for the enhancement of the cooling rate and design of the granulation chamber. In the paper, the solidification-melting model coupled with the radiation heat transfer model method was used to investigate the effects of the temperature of air and water wall, the velocity of air, and diameter of slag particles on the cooling characteristics. The variable thermal conductivity, variable viscosity, variable density at different temperature range and the physical properties of the phase transition temperature zone were fully considered in the model. The results indicated that the solidification time of the particles decreased with the decrease of the temperature and of cooling air, the increase of the velocity of air, the reduction of the temperature of the water wall and the reduction of the diameter of slag particles. Moreover, the diameter of slag particles has the most significant influence, and the temperature of the water wall had the least impact. By adjusting the above influencing factors, the cooling rate of the slag particles can be accelerated to prevent them from sticking to the water wall.

Abstract

In this paper, the tube-fin evaporator used in diesel engine-Organic Rankine Cycle experiment is built, simulated and analyzed. By changing the inlet conditions on the shell side of the evaporator, the relationship between the internal heat transfer performance, flow performance and inlet conditions of the evaporator is analyzed. The heat transfer performance of the evaporator is analyzed by using Field Synergy Theory and the maximum pressure rise of the cross section of the front tube bundle(pm), the influence degree of ORC system on diesel engine is determined, and the matching relationship between the evaporator and diesel engine is evaluated. The results show that, due to the unique exhaust characteristics of diesel engine, the evaporator needs to coordinate with diesel engine, so as to achieve better heat transfer and flow performance, reduce losses and make full use of energy with little influence on the power performance and economy of diesel engine.