Papers by Keyword: Cooling System

Abstract: This study presents a hybrid solar thermal self-regulating power generation system, designed for installation on rooftops and other small spaces. In addition to functioning as a solar water heater, the system also incorporates a power generation mechanism, promoting the adoption of green energy within general households beyond industrial or government contexts. Unlike conventional solar systems that are often constrained by cost and space requirements, this device can be easily added to existing structures, enhancing user acceptance and facilitating broader participation in energy conservation and carbon reduction efforts. Experimental results shows that at the temperature difference between the thermoelectric modules reaches 17.5°C, the system can generate up to 23W of electrical power. Even during nighttime, the system can still generate electricity by utilizing the thermal energy stored in the water tank during the day, achieving an output power of up to 10W.

Abstract: This study investigates the heat management in Duplex Stainless Steel (DSS) wall specimens produced by the Wire Arc Additive Manufacturing (WAAM), by optimizing the thermal cycles during their construction. A reduction in the inter-pass time was found to induce heat accumulation, which causes wall flaring, affects the ferrite/austenite balance, and leads to a reduction in the hardness of the mechanical part produced by DSS. In contrast, the introduction of an external cooling system enhances the geometry and helps control the temperature and microstructure of the produced parts, thereby achieving the required hardness. Therefore, the use of the external cooling system enables the production of parts with desirable mechanical properties in a shorter time.

Abstract: In this paper, the Cumulative Usage Factor (CUF) of a High Pressure Core Cooling System (HPCS) reactor nozzle of a Boiling Water Reactor was calculated. This fatigue damage has been caused by the sudden injection of cold water into the reactor vessel through such nozzle. For this purpose, a three-dimensional analysis was carried out. Accordingly, a transient heat transfer analysis was developed. The temperature distribution was determined. With this information, the stress analysis was carried out. The safe end was restricted to move along its axial direction and the forging end was free to expand axially and radially. The resultant stress field established the magnitude of the alternative stresses. In the last step, a fatigue analysis was developed. The most critical point is the junction of the nozzle with the thermal sleeve. The fatigue performance was evaluated during a period of sixty years. It was assumed that 1.5 cycles per year will take place. The fatigue curves of ASME code section III were used. The results showed that the Cumulative Usage Factor (CUF) vary with the temperature injection, being 0.4090 when the water injected was 4.44°C and 0.3797 when the water temperature was 37.77°C. Both of them were estimated for a period of 60 years of operation. Therefore, damage is reduced as the temperature of the injected water increases. Besides, it is advisable to at least follow the recommendations of the NUREG ́s 1800 and 1801 [1, 2]. In this way, the aging of the nozzle is adequately managed.

Abstract: Microcontroller Arduino Mega and ATmega is a computer chip that needed and developed to control system or process. Microcontroller Arduino Mega and ATmega can be used to temperature control systems [1][2][3], the room lighting control, security control, the hazard warning [4], scheduling, monitoring water flow and dams actuator door and etc. Most studies on the microcontroller is focused on the functional capability of a microcontroller to read or measure the object. In addition to aspects of good function, microcontroller must have a high sensitivity in order to avoid delay or in-accuracies in the sensor reading measured object such as temperature. Microcontrollers has some advantages and disadvantages of the process accuracy depends on the processor and the ability microcontroller. In this paper focuses on the measurement errors that occur on microcontroller Arduino Mega and ATmega 8535 with a temperature sensor LM 35 and hygrometer digitizes dt05 for the application process cooling and heating sea water controls. The volume of sea water is measured is 3 to 35 litters with a temperature set point 28°C of lower temperatures above 25°C and 31°C. The results show that the maximum error obtained by using microcontroller Arduino Mega is 1,32°C or 13,2 mV and ATmega 8535 is 0,2°C or 2 mV. Also the microcontroller Arduino Mega is more suitable for control temperature measurement in the process of heating and cooling sea water.

Abstract: This present study reports results of performance evaluation of a solar-driven dual parallel-connected ejector (DPE) cooling system using the concept of solar fraction (SF). The experiments were conducted in July and August, 2015 from 09:00 to 16:00 hours at School of Renewable Energy Technology (SERT), Naresuan University, Thailand, with a solar collector area of 2.4 m², auxiliary heater of 3 kW, operating at boiler pressure of 2 bar and using water as working fluid. Temperature was measured for inlet and outlet of solar collector. The results showed that the solar collector supplied about 24% of energy required to operate the system. The solar collector performance was 11% and the monthly average SF was 23.9% for July and 23.5% for August.

Abstract: Welding with micro-jet cooling is an innovate technology. It is possible to get structure of weld metal deposit (WMD) with a very high amount of acicular ferrite (on the level of 70 %) that is not valuable for other processes. It corresponds with good impact toughness of weld. In the paper parameters of micro-jet cooling and mechanical structure of weld will be present and compared with welding without micro-jet cooling. Results of investigation are very optimistic. That technology should be treated for welding of other materials.

Abstract: The coolant (water) pump assumes an important role of cooling system in IC engines. With upgrading of the engine power by turbocharging and turbo inter cooling, the water pump capacity needs to be increased corresponding to the power. This capacity enhancement has to be achieved without calling for a major change in the existing water pump, envelop and related fitment details. This requires a clear understanding of centrifugal pump for its performance parameter. One such engine is upgraded by turbocharging from 195PS to 240PS @2200 rpm. Improving water pump flow by changing the impeller dimensions, impeller casing, increase the suction, delivery pipe diameter had been done. Validation of the water pump in its actual engine installation was taken up as a part of the research work. Flow rate comparison of the new pump with the existing pump was made and the results were analyzed. The new water pump gives better flow rates for the engine speeds up to1800 rpm, beyond which the flow rate is slightly lesser than the existing pump.

Abstract: In the last years there has been an increased demand to lower the impact of industrial activities on environment quality. Cutting fluids, among other products, are an important pollutant but they have often been associated with the need for a higher productivity of machining processes. Cutting fluids are a mean of reducing temperature in the cutting area, friction and tool wear but they also represent 7% to 17% of the production costs. Other problems raised by cutting fluids are: microorganism infestation, which can cause pulmonary and dermatological diseases and poor lubrication or corrosion caused by some of the chemicals. Dry cutting is regarded as the cleanest cooling method, but it has a reduced heat dissipation efficiency and practically there is no lubrication. Other relatively new green solutions concern the use of minimum quantity lubrication (MQL) and cryogenic machining.

Abstract: This study examines the design of heat exchanger made of copper tube for cooling electric vehicle car battery system and the effects of base fluid and nanofluid (as coolants) channeling inside the heat exchanger to increase heat transfer between the compartment of the electric vehicle car and the heat exchanger and comparison between them. The nanofluid (CuO/pure water) was prepared by dispersing a nanoparticle (CuO) in base fluid (pure water). nanofluid (CuO/pure water) with a nominal diameter of 50 nm at volume concentrations (0.27 Vol. %) at batteries’ compartment temperature was used for these investigations. The analysis showed that secondary cooling system by means of nanofluid (CuO/pure water) has advantages in improving the thermal conductivity and heat transfer coefficient, better from base fluid (pure water) also in Nusselt number. This results work on reducing the electric power loss in the form of thermal energy from batteries. This led to increase in the efficiency of the electric vehicle car battery, hence also improved the performance of the EV car and battery lifetime.

Abstract: The article considers the problems of the mathematical modeling of thermal physics of the tool for nanostructuring burnishing. Physical and equivalent heat diagram of the system are developed. On the basis of the equivalent heat transfer diagram, the equivalent circuit and the system of equations of the mathematical model are created. The dependence of the tool indenter tip temperature on cooling system thermal parameters is obtained. The comparison of efficiency of heat removal from the tool indenter when using the developed two-circuit cooling system and the system supplying lubricant cooling liquid through the lathe centre spindle, as well as when applying nanostructuring burnishing without cooling is carried out.