Review of Research on System Thermal Inertia Modelling and Optimal Scheduling from the Perspective of Flexible Resources

The thermal inertia of the existing heating system is often considered an adverse factor, which will affect the operation of the system. However, under the perspective of resource flexibility, the thermal inertia of the system can effectively increase the flexibility of the system operation, significantly reduce the energy consumption and enhance the ability of energy supply and demand balance, and enhance the new energy integration, such as the wind power. Based on the flexible resources, it focuses on the study of the thermal inertia of the “network side” heating pipe network of the system and the optimal scheduling of the heating system. Combined with the thermal inertia of the pipe network, the operation characteristics of the power/heat output of the gas-steam combined cycle unit were analysed theoretically. On this basis, the optimal scheduling model of the system was established. Taking the energy supply system of an industrial park as an example, the model was verified to achieve a more stable power output effect of the unit.

Investigation of the co-firing of natural gas and RDF in a model combustion chamber**

The production and utilization of fuel derived from municipal solid waste (RDF/SFR) is an effective method for saving organic fuel and decreasing emissions of harmful substances and greenhouse gases at landfill and refuse dumps. Ukraine has a potential for the production of 1.5–2 million tons of RDF/SFR with a calorific value of 10–25 MJ/kg annually. In the case of involving these fuels to power sector, about 2500 GW-h of electricity and 4500 GW-h of heat can be produced annually. One of the promising variants to involve RDF/SFR to power sector is their combustion, including co-firing with natural gas, aimed at the production of heat and electricity, in particular, using the existing boilers of small and middle steam capacity in compliance with stringent ecological requirements (Directive 2010/75/EU etc.). For performing this investigation, we chose a GMP-16 gas-and-oil-fired burner, mounted into a cylindrical combustion chamber. The gas-and-oil-fired hot-water boilers of KVGM grade, designed for heating and hot water supply, are equipped with burners of this type. In computer modeling, we determined the influence of RDF additions on the co-firing with natural gas for a given geometry of the combustion chamber components (with a burner of 18.6 MW heat output). We obtained calculated dependences of temperatures, velocities, distributions of gas component concentrations, carbon remained in the solid phase, as well as the concentrations of nitrogen oxides and carbon monoxide over the combustion chamber. According to preliminary assessments, we established that additions of up to 20% RDF/SFR (by heat at input) in their co-firing with natural gas will not change substantially the technical and ecological parameters in operation of the combustion chamber.

ADJUSTMENT OF LARGE SOLAR OVEN FLAT HELIOSTAT HELIOSTATS

This paper presents an improved method for adjusting individual mirrors –facets of heliostats of a Big Solar Furnace (BSF) with a heat output of 1000 kW in Uzbekistan. Due to the fact that a BSF consists of 22,790 pieces of individual mirrors, the adjustment - setting a specific geometric position of these mirrors is very important. The process of adjusting the mirrors is very time consuming and lengthy. Often exactly the adjustments are influenced by subjective factors by the aligners. In order to improve the performance and accuracy of the alignment, the facet of heliostats has applied the Technical Vision System (TVS), as well as improved the process of assessing the state of alignment and the processing of alignment data. The TVS consisting of a video camera, an interface, a personal computer and special software allows you to visually and accurately assess the alignment conditions of the heliostat facets before and after the alignment process. Allows you to save the data in computer memory for further processing and analysis. Allows you to create a database of the alignment status of each of the 62 heliostats of LSF. Special software developed by us allows you to quickly and accurately determine the deviations of the heliostat facets from the calculated geometric points in angular minutes. Based on the data obtained, you can build histograms, graphs, etc. for visual analysis of the heliostat alignment states before and after the alignment process.

Field Test on Performance of an Air Source Heat Pump System Using Novel Gravity-Driven Radiators as Indoor Heating Terminal

The simultaneous need for energy efficiency and indoor comfort may not be met by existing air source heat pump (ASHP) technology. The novelty of this study lies in the use of a new gravity-driven radiator as the indoor heating terminal of ASHPs, aiming to provide an acceptable indoor comfort with improved energy efficiency. To confirm and quantify the performance improvement due to the proposed system retrofit, a field test was conducted to examine the system performance under real conditions. In the tests, measurements were made on the refrigerant- and air-side of the system to characterize its operational characteristics. Results showed that the proposed radiator has a rapid thermal response, which ensures a fast heat output from the system. The proposed system can create a stable and uniform indoor environment with a measured air diffusion performance index of 80%. The energy efficiency of the proposed system was also assessed based on the test data. It was found that the system’s first law efficiency is 42.5% higher than the hydraulic-based ASHP system. In terms of the second law efficiency, the compressor contributes the most to the overall system exergy loss. The exergy efficiency of the proposed system increases with the outdoor temperature and varies between 35.02 and 38.93% in the test period. The research results and the analysis methodology reported in this study will be useful for promoting the technology in search of energy efficiency improvement in residential and commercial buildings.

Materials and Energy Balance of E-Waste Smelting—An Industrial Case Study in China

The application of Nerin Recycling Technologies (NRT) in electronic waste (E-waste) smelting was introduced in this study, and the material and energy balance was calculated based on the practical data with the METSIM software (METSIM International, USA). The main results are as follows: (1) the optimized processing parameters in the NRT smelting practice were the E-waste feeding rate of 5.95 t/h, oxidation smelting duration of 3.5 h, reduction smelting duration of 0.5 h, oxygen enrichment of 21–40 vol.%, oxygen consumption of 68.06 Nm3/ton raw material, slag temperature of 1280 °C, slag composition: Fe/SiO2 mass ratio of 0.8–1.4, CaO, 15–20 wt.%, Cu in crude copper ≥ 95 wt.%, Cu in slag, 0.5 wt.%, recovery of Cu, Au, and Ag ≥ 98%; (2) 98.49% Au, 98.04% Ag, 94.11% Ni, and 79.13% Sn entered the crude copper phase in the smelting process, 76.73% Pb and 67.22% Zn volatilized to the dust phase, and all halogen elements terminated in the dust and off-gas; (3) total heat input of the process was 79,480 MJ/h, the energy released by chemical reactions accounted for 69.94% of the total, and heat from fuels burning accounted for 33.04%. The energy brought away by the off-gas was 38,440 MJ/h, which was the largest part in heat output. The heat loss with the smelting slag accounted for 28.47% of the total.

Design of thermoelectric devices for extracting foreign objects from the human body by freezing

Objectives.The purpose of the article is to consider the designs of thermoelectric devices (TEC) for extracting foreign objects (IO) from the human body by freezing with various options for removing heat from the hot junctions of the thermoelectric module (TEM).Method. Modifications of thermoelectric devices are described for extracting the IO from the human body by freezing it to a special probe. Their technical design differs in the way of heat removal from the TEM hot junctions, for which air heat removal, melting working substances and preliminary cooling of the radiator are used. The basic relationships for calculating the technical means intended for the removal of heat from the hot junctions of the TEM are presented.Result. The graphs of the dependence of the temperature change of the TEM hot junctions in time are obtained for different values of its heat output when using an air heat removal system and the time of complete penetration of various working substances used in the device.Conclusion. The data obtained show that for the operating conditions of the TEC, the temperature of the hot junctions of the TEM with an air heat sink does not go beyond the permissible limits. With a module power of 8 W, 12 W and 16 W, the temperature of the hot junctions of thermoelements stabilizes rather quickly and takes the value of 308 K, 313 K and 318 K. maintaining their stable temperature is most preferred is nickel nitrate, less - elaidic acid and paraffin. Calculations of the design of a device with a pre-cooled radiator system also show the efficiency of heat removal from the hot junctions of the TEM for the duration of the entire procedure for removing the IO from the human body.

Thermal Performance Analysis of Hydronic Ceiling Radiant Panel Heaters Under Different Parameters

A numerical analysis of a ceiling type radiant panel heater system was performed to examine the heating performance under different parameters, using the FloEFD code. Three-dimensional models of the room and radiant panel heater were created and the effects of the Reynolds number, water inlet temperature, pipe diameter and pipe runs on the heating performance of the system were examined in detail. The effects of these parameters on the total heat load, the net radiation rate, and the average surface temperature on the sheet and insulation material have been presented. The total heat load and net radiation rate obtained from the system increase with increase in the Reynolds number. Also, a rise in the water inlet temperature increases the heat output of the system. An increase of approximately 500 W was observed in the total heat output as the pipe diameter increased. It was observed, too, that the heat output increased with increase in pipe runs, although above a certain value the heat output became almost constant. The results of this study could offer information to engineers and manufacturers on the design and use of hydronic radiant systems.

Study on control strategy of output stability of wind-solar reservoir thermal system

In view of the landscape reservoir heat output coordinated control demand, based on the topology of the hybrid energy storage system of the three ports heating model, using the sunlight with the electricity output of the complementary and heat accumulation can be regulatory, intends to research a kind of based on photo-thermal storage heat and scenery electricity heating output port control method, in order to achieve the goal of fast and smooth regulating heat output fluctuations, The coordinated output control of integrated wind-landscape storage and heat collection is realized.

Methodological Bases of Optimal Load Distribution at a Thermal Power Plant with a Complex Composition of Equipment, Taking into Account Market Requirements

The features of a mathematical model for optimizing the distribution of heat and electricity at a large thermal power plant with a complex composition of equipment as part of traditional heating units and a heating CCGT are considered. The selection and justification of optimization criteria at different stages of preparation and entry of the station to the electricity and capacity market is given. The disadvantages of the previously proposed optimal distribution algorithms are analyzed in relation to thermal power plants with a complex composition of equipment and with a complex scheme for the supply of electricity and heat. A method and algorithm for solving the problem are proposed based on the equivalence of the CHP equipment and the decomposition of the problem taking into account the schemes of electricity and heat output. The description of mathematical optimization methods is given, taking into account the peculiarities of the CCGT operating modes at reduced loads. The requirements for information support when integrating the developed algorithm into the application software of the automated process control system based on the PTC are given.