Analysis of Influence of 1000MW Unit Boiler Side Wind, Side Wind and Solar Radiation on Direct Air Cooling System

In the operation of direct air-cooled units, there are many factors that affect the safety and economy of the unit. The “hot air recirculation” and “backfill” phenomena caused by lateral wind, the influence of high ambient wind on the heat transfer performance of the air cooling unit near the windshield wall, and the “hot air recirculation” phenomenon caused by the back wind of the furnace, these may affect the direct air cooling unit. Safe and economical operation. Through carrying out on-site test research, collecting the actual operating conditions of the unit operation, the organic combination of laboratory simulation data and actual data is provided to provide a strong basis for the development of corresponding technologies.

Performance Simulation Analysis of Modular Heat Dissipation Unit

In this paper, GT suite software is used to model the cooling system of military special vehicles with multiple power sources. The power drive system is composed of main engine, auxiliary engine and four hub motors. By constructing modular cooling unit, the volume of radiator and the layout of cooling unit are changed. While the total volume of radiator is unchanged, the cooling capacity of cooling system is improved. Firstly, the problem is simplified and modeled by high-temperature and low-temperature double circuit. The main engine with power of 600kW and auxiliary engine with power of 200kW are combined into a high-temperature circuit. The water temperature of the circuit is higher, about 90 ºC; Four hub motors with power of 440kw and their electrical components are combined into a low temperature circuit. The water temperature of this circuit is about 60 ºC. By modifying the volume, layout and number of radiators, the temperature of the dual circuit is analyzed, and it is found that when the total radiator volume remains the same, the cooling effect of the multi-radiator layout is better.

Effective Condensing Dehumidification in a Rotary-Spray Honey Dehydrator

This paper presents a mathematical model of the heat and mass transfer processes for a rotary-spray honey dehydrator with a heat pump and a closed air circuit. An analytical calculation model, based on the energy balance equations of the dehydrator and heat pump, was used to model the transient dehydration process of honey in a dehydrator. The presented article includes a different approach to modelling both the dryer and the heat pump assisting the drying process. The novel quality of this study lies in the use of original equations to determine the heat and mass transfer coefficients between honey and air and using an actual model of a cooling unit to model the honey dehydration process. The experimentally verified calculation algorithm enables an analysis of the effects of air flow rate, mixer rotation speed, and cooling unit power on the efficiency of the drying process. The dehydrator calculation model was used to minimize the drying time by selecting the optimal evaporative temperature values of the cooling unit. For fixed mixer speed and air flow rates, optimal values of evaporation temperatures allow for 8–13% reduction in honey drying time and an increase in the specific moisture extraction rate (SMER) by 4–32%.

EFFICIENT CONTROL OF FUNCTIONING OF ELECTRICAL GAS PREPARATION COMPLEX TO TRANSPORTATION BY MAIN PIPELINE

The article discusses the problem of increasing the effi ciency of the linear section of the main gas pipeline system by developing eff ective control algorithms for the operating modes of the gas cooling unit. To develop control algorithms for a gas cooling unit, adapted mathematical models of thermal processes in air-cooled gas devices and in a gas pipeline are used. It is shown that when considering the dynamic modes, the gas pipeline system can be represented as consisting of two dynamic links. The link “gas cooling unit”, which includes up to 24 electric drives with heat exchangers, is characterized by relatively short time constants. In the main gas pipeline, heat exchange processes proceed much more slowly. This circumstance allows the main att ention to be focused on the development of an eff ective control system for the cooling plant. The control is carried out by discrete or continuous change in the fl ow rate of the cooling air through the heat exchanger by adjusting the number of switched on air coolers and changing the fan speed. The search for control algorithms for air coolers is carried out by formulating and solving the problem of minimizing the root-mean-square deviation of the gas temperature at the outlet from the heat exchanger from the required value. To implement the obtained control algorithms, a functional diagram of the automatic control system for the operating modes of the gas cooling unit has been developed.

Design and Modelling of a Cooling Unit by Adsorption Geothermal Heat Pump in a Tropical Climate Zones

This work is a contribution of a modelling of air conditioner by adsorption for a habitat in a tropical climate. The system mainly consists of a captor adsorber powered by a geothermal pump, a condenser and an evaporator. We use the zeolite/methanol couple and the different thresholds temperatures to define the thermodynamic system cycle. Moreover, we use a methodology based on nodal approach to establish heat and mass transfer equations. Dubinin-Astakhov thermodynamic model is employed to express the mass adsorbed, the coefficient of performance (COP) and the cold production. We make use of the climatic data in Comoros for 2009-2019 period to obtain the ambient temperature. The model validation is done by comparing the shape of the cycle we obtain with the state of the art. First, the results show a relationship between temperature, pressure and adsorbed mass. The increase in temperature is accompanied by an increase of pressure and an increase of adsorbed mass, and in the same way a decrease in the temperature causes a decrease of the pressure as well as a decrease of adsorbed mass. The mixture zeolite/methanol reaches 356K at the regeneration temperature with an input water temperature of 363K. We observed the influence of main important parameters on the mixture temperature such as fluid input temperature, fluid velocity or zeolite thermal conductivity. Finally, we show the thresholds temperatures influence on the COP and the cold production at evaporator.

Deployment of State-of-the-Art Horizontal Pumping System HPS Technology in Two Water Wells to Avoid ESP Workovers

The objective of this paper is to present the findings obtained from a detailed engineering evaluation resulting from trial testing two state-of-the-art surface horizontal pumping systems (HPS's) in two water supply wells. The two horizontal pumping systems were deployed as an alternative to downhole electrical submersible pumps (ESPs) to provide the benefits of eliminating ESP workover costs, modularity regarding wellsite deployments, and enhanced maintenance operations. For this trial test evaluation method, two HPS's were deployed to boost water production to the water injection plant (WIP). To ensure a thorough evaluation, the trial test well candidates were designed to accommodate both a subsurface ESP as well as a surface HPS to provide an accurate comparison, and representation, between the different artificial lift methods. The trial test and comparison method described in this paper focused primarily on the following items; maintenance and well intervention requirements, evaluation of operational availability, including potential for cavitation and effects of interference, maximum production rates, as well as root cause engineering evaluations for mechanical seals and cooling unit auxiliary motors. Various best practices and mitigation measures were identified and are presented in this paper. With regard to the results, it was observed that each artificial lift method comprised a set of advantages and disadvantages. The decision on which type of technology to use can be dependent on several factors. Overall, the HPS's demonstrated the ability to supply water production to the WIP. The HPS did experience operational challenges in providing higher production requirements. Additional challenges were also observed in the sealing mechanism as well as the auxiliary cooling unit. Precautionary pump tripping automated protocols were taken to prevent pump cavitation due to sub-optimal intake pressure resulting from possible interference. The HPS, unlike the ESPs, did not require any workover as it is located at the wellsite and therefore resulted in substantial cost savings and was easy to maintain due to its surface application. In summary, this paper adds a new and very beneficial evaluation of HPS's, and highlights best practices and lessons learned to the existing body of literature. The new information discussed in this paper is highly beneficial to engineering selections of artificial lift methods and to the successful implementation of HPS's in the industry.

Metallic Oxides for Innovative Refrigerant Thermo-Physical Properties: Mathematical Models

Nano-refrigerant is announced to become an excellent refrigerant, which often improves heat transfer efficiency in the cooling systems. Different materials can be applied to be suspended in traditional coolants in the same way as nanoparticles. In this comprehensive research, mathematical modeling was used to investigate the effect of suspended nanoparticles (Al2O3, CuO, SiO2 and ZnO) on 1,1,1,2-Tetrafluoroethane, R-134a. The thermal conductivity, dynamic viscosity, density and specific heat capacity of the nano-refrigerant in an evaporator pipe were investigated. Compared to conventional refrigerants, the maximum increase in thermal conductivity was achieved by Al2O3/R-134a (96.23%) at a volume concentration of 0.04. At the same time, all nano-refrigerant types presented the same viscosity enhancement of(45.89%) at the same conditions. These types of complex thermophysical properties have enhanced the heat transfer tendencies in the pipe. Finally, the nano-refrigerant could be a likely working fluid generally used in the cooling unit to improve high-temperature transfer characteristics and save energy use.

Design analysis and Work load characteristics of a Micro data Center

Data centers are large-scale data storage and processing systems. It is made up of a number of servers that must be capable of handling large amount of data. As a result, data centers generate a significant quantity of heat, which must be cooled and kept at an optimal temperature to avoid overheating. To address this problem, thermal analysis of the data center is carried out using numerical methods. The CFD model consists of a micro data center, where conjugate heat transfer effects are studied. A micro data center consists of servers aligned with air gaps alternatively and cooling air is passed between the air gaps to remove heat. In the present work, the design of data center rack is made in such a way that the cold air is in close proximity to servers. The temperature and airflow in the data center are estimated using the model. The air gap is optimally designed for the cooling unit. Temperature distribution of various load configurations is studied. The objective of the study is to find a favorable loading configuration of the micro data center for various loads and effectiveness of distribution of load among the servers.

3D Unsteady Simulation of a Scale-Up Methanation Reactor with Interconnected Cooling Unit

The production of synthetic natural gas (SNG) via methanation has been demonstrated by experiments in bench scale bubbling fluidized bed reactors. In the current work, we focus on the scale-up of the methanation reactor, and a circulating fluidized bed (CFB) is designed with variable diameter according to the characteristic of methanation. The critical issue is the removal of reaction heat during the strongly exothermic process of the methanation. As a result, an interconnected bubbling fluidized bed (BFB) is utilized and connected with the reactor in order to cool the particles and to maintain system temperature. A 3D model is built, and the influences of operating temperature on H2, CO conversion and CH4 yield are evaluated by numerical simulations. The instantaneous and time-averaged flow behaviors are obtained and analyzed. It turns out that the products with high concentrations of CH4 are received at the CFB reactor outlet. The temperature of the system is kept under control by using a cooling unit, and the steady state of thermal behavior is achieved under the cooling effect of BFB reactor. The circulating rate of particles and the cooling power of the BFB reactor significantly affect the performance of reactor. This investigation provides insight into the design and operation of a scale-up methanation reactor, and the feasibility of the CFB reactor for the methanation process is confirmed.

Improving the performance of the air-cooling unit in the cooling system of a radar

The article discusses the issues of reducing the size of the cooling unit of the antenna of a radar station by improving the gas-dynamic processes occurring in the air-cooling unit. The results of the experimental studies of the gas flow in a plate-fin heat exchanger, being blown by one axial fan are presented. The feasibility of changing the number of axial fans for organizing a more uniform flow around the heat-exchange surfaces has been determined by calculation and theoretical methods. The calculation results are confirmed by experimental studies of the air flow in the segment of the heat exchanger, which is provided by a smaller fan.