This article explains the calculation and analysis method of dry and wet tube fin heat exchangers; and uses the tube row size and operating conditions actually used by a panel factory to calculate and compare the performance of oval tube rows and circular tube rows under the same windward surface area. , designed to replace the original circular tube row with an elliptical tube row. According to the calculation model analysis results of this study, under the same water flow rate in the pipe and air volume outside the pipe, replacing the round pipe with an oval pipe with the same circumference can reduce the air side pressure loss by about 31%, but the ice water side pressure loss in the pipe It will be doubled, and the heat transfer rate is increased by about 5% compared to the circular tube; if the original circular tube with an outer diameter of 12.7mm is replaced by an oval tube with a slightly larger circumference (long axis 20.15mm, short axis 8.5mm) shaped tube, the fin spacing is changed from 2.5mm to 2.92mm, the air side pressure loss can be reduced by approximately 35%, the ice water side pressure loss in the tube can be reduced by approximately 4%, and the heat transfer capacity can be increased by approximately 6%. The original operating conditions of the air conditioning system can be maintained and the heat exchanger can be directly replaced to achieve energy saving effects of reducing air side pressure loss and windmill energy consumption.
Keywords: fin heat exchanger, air conditioning system, energy saving
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In human history, the pandemic of infectious diseases has been repeated repeatedly in human history, and bacteria and viruses are the main causes of infectious diseases. Therefore, finding cheap, fast and effective bacteriostatic methods has always been an important issue in human life. Traditionally, sterilization using flame, steam, chemicals (bleach, alcohol) requires long sterilization times and the chemicals may cause discomfort to personnel. In recent years, nano-photocatalyst titanium dioxide (Photocatalyst TiO2) has become the most potential candidate material to replace traditional disinfection methods because of its good antibacterial effect and reusable characteristics with UV light. This article will introduce the properties of titanium dioxide and its photocatalytic antibacterial mechanism, hoping to enable people from all walks of life to quickly grasp the background and development of titanium dioxide used in photocatalytic antibacterial.
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Excessive exposure to acetic acid gas is extremely dangerous in confined spaces, and there are currently no commercially available chemical screens for acetic acid control. This article only provides reference for the compilation of literature collected over the years. An efficient indoor air pollutant removal porous carbon filter was developed using sodium hydroxide impregnated activated carbon (NaOH/AC) for adsorption of acetic acid. NaOH/AC screens cured at 100°C for 20 minutes gave the best results by eliminating acetic acid at an initial concentration of 400 ppm within 15 minutes at 20°C and 60% relative humidity. The NaOH/AC filter used for acetic acid adsorption has a maximum adsorption capacity of 550 mg/g. This research is expected to lead to the development of low-cost and effective porous carbon filters for indoor air purification using NaOH-modified activated carbon. Activated carbon (ACM) was synthesized from watermelon shell and modified with sodium hydroxide (NaOH/ACM) in order to improve its adsorption efficiency. The acetic acid adsorption efficiency of NaOH/ACM is 71%, which is higher than that of ACM which is 32%. Ammonium ion-exchanged α-zirconium phosphate (α-ZrP) can adsorb acetic acid with an adsorption efficiency of 95%.
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In this study, the Venturi valve combined with the air volume control was first integrated into a Venturi air volume balance valve, and the analysis and adjustment and mathematical regression curve analysis were carried out. system to test the effect of variable air volume control. The purpose of the experiment includes air volume balance and response speed. The equipment established in this research can simulate the VAV system of the building and set the flow of the local or overall system for its controller, so that it can achieve the dynamic simulation of the multi-regional dynamic variable air volume system and the air volume of each region. In this study, two kinds of air volume and various flow balances were tested, and it was found that the Venturi air volume balance valve can adjust the air volume according to the regression curve, and the accuracy can reach more than 95%. In a multi-region variable air volume (VAV) system composed of multiple Venturi air volume balance valves, according to the air volume set in this experiment, the parameter values of the controller are adjusted at the same time, so that the flow control of the system can be stable and respond quickly. The multi-zone air supply volume can reach the set air volume within seconds. The research results can be applied to the central air-conditioning VAV system to achieve the best air volume demand control, which is beneficial to the energy saving effect of the variable air volume of the fan, and the energy saving rate can reach 40~50%. The results of this study verify the feasibility of the Venturi air volume balance valve applied to the dynamic variable air volume system, which is important for air conditioning energy conservation and can effectively reduce air conditioning energy consumption.
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With the rapid development of integrated circuit process technology and the miniaturization of components, the requirements for product quality and yield are getting higher and higher. When developing nanometer-level process technology, the cleanliness of the wafer process or glass panel process environment is also relatively improved. At present, particle pollution is no longer the main factor that causes wafer defects and reduces product yield. Among them, suspended molecular pollutants (Airborne molecular pollutants, AMCs) have gradually replaced granular pollutants and become one of the main key factors affecting the yield of industrial processes.
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The Chinese government passed the Indoor Air Quality Management Law in 1999, in which the concentration of formaldehyde was set at 0.08 ppm. If the concentration of formaldehyde in the room is too high, it will affect health and even cause cancer. At present, most commercially available air purifiers use activated carbon to physically adsorb formaldehyde, but according to past studies, it has been shown that activated carbon is not effective in adsorbing formaldehyde. In order to effectively improve the removal of indoor formaldehyde pollutants, this study chose the principle of catalytic oxidation plus adsorption To conduct research, use activated alumina with platinum metal to carry out column adsorption experiments to understand its adsorption situation.
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When the medical research building conducts relevant medical research, pollutants may be produced, and some chemical pollutants (acetone, cyanomethane, ethyl acetate, hexane) may cause harm to the human body when the concentration in the air is too high, so It is very important to set up an exhaust system to effectively discharge the chemical pollutants in the indoor air from the room. However, when the indoor exhaust port is too close to the air inlet, it may cause short circulation of exhaust gas or excessive exhaust volume. It is too small to effectively discharge pollutants; in addition, if the concentration of chemical pollutants is too high, it is easy to cause the accumulation of chemical pollutants. In order to avoid the above situation, this study aimed at the relative position of the exhaust port and the air intake, the concentration distribution of the surrounding environment caused by the discharge of chemical pollutants by the exhaust air volume and the air volume of the air intake, and numerically simulated with the computational fluid dynamics software ANSYS FLUENT analyze. In addition, for the monsoon in Taiwan, this study discusses the simulation analysis of the air intake and exhaust conditions of buildings when the monsoon wind direction is easterly. According to the numerical simulation results, it is known that when the medical research building conducts relevant medical research, various chemical pollutants are produced, and the exhaust system installed in the case of this study can discharge the chemical substances in the indoor air from the room. It will enter the room through the air inlet provided by the building shell.
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This year, the Wuhan pneumonia caused by the new coronavirus in mainland China, Hong Kong, and Taiwan, is a serious epidemic caused by its rapid transmission and fatality. Only in the second-highest BSL-3, the highest BSL-4 laboratory can it be safe Processing and research to ensure the safety of researchers and the surrounding environment, and the new coronavirus not only caused extreme panic and economic depression in the society, but also paid a high price for the entire country and society. Therefore, the BSL-3 and BSL-4 high-level biological laboratories are specially introduced.
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Gloves allow for testing and easy access to isolation devices for the pharmaceutical production process to provide a high level of product and/or environment and operators. We conduct three tests on pressure decay, water tightness, and particle penetration on the testing machine. Potential pollution and risks can be minimized and maximum safety maintenance.
