Clean Air Conditioning System Research Articles

Design of Centralized Energy Station for Clean Air Conditioning System in a Factory

Design of Centralized Energy Station for Clean Air Conditioning System in a Factory

Designing, Modelling and Experimental Investigation of Direct Evaporative Cooling System Coupled With Commercial Desiccant Dehumidifier

Abstract With the increasing demand of clean and energy-efficient air conditioning systems, evaporative air cooling technique is gaining significant attention owing to less energy consumption and environmentally safe technology in comparison with conventional refrigerant-based air conditioners. In this study, commercial desiccant dehumidifier is coupled with experimentally developed direct evaporative cooling (DEC) system to first dehumidify the air and then pass it through DEC to achieve human thermal comfort level defined by ASHRAE standards. Under the climatic conditions of Islamabad, Pakistan, multiple experiments were carried out at different temperatures, flowrate, and relative humidity of air during November, when air temperature and relative humidity were in the range of 25–30 °C and 40–60%, respectively. To analyze the system performance under summer ambient conditions, indoor temperature was increased by 8–10 °C and relative humidity by 15–25% in laboratory. Experimental analysis showed that the system can provide human comfort level for a range of temperature 29–39.7 °C and relative humidity of 65–80% at flowrate of 180 m3/h. To achieve thermal comfort at higher humidity level, DEC is coupled with commercial desiccant dehumidifier. However, due to desiccant regeneration by an electric heater in the dehumidifier, the overall power consumption of the whole system increases up to 1.95 kW. Two well-known indices coefficient of performance (CoP) and energy efficiency ratio (EER) are used to analyze the system performance. Experimental analysis revealed that CoP decreases with the increasing specific humidity of air, decreasing ambient temperature, and flowrate.

Performance analysis and improvement of air filtration and ventilation process in semiconductor clean air-conditioning system

The air-conditioning system in modern industrial cleanrooms can be very energy intensive due to large air change rates per hour and high airflow resistance. This study focuses on the actual performance and potential improvements of the filtration and ventilation process in cleanrooms. On-site measurements were conducted in three semiconductor cleanrooms to investigate the actual performance of clean air-conditioning systems. The results reveal that the unmatched particle concentrations of outdoor air and return air increase the filtration load. The indoor workshops are often guaranteed excessively, leading to large amount of redundant airflow rates. Both make the actual ventilation system energy intensive. Therefore, a new air filtration and ventilation system in industrial cleanrooms is introduced in this research. The proposed system filters outdoor air and return air separately before mixture and avoids their mixing loss. It indicates that 25.8% to 45.0% of the total energy can be reduced due to lower airflow resistance. Proper return airflow rate of the cleanrooms are proposed to avoid airflow redundancy, and as a result, 32.9% to 50.7% of potential energy can be saved compared with the original system.

Research on temperature and humidity decoupling control of clean air conditioning system

In the clean air conditioning system, in order to ensure that the temperature and humidity in the room are within the allowable accuracy range, it is necessary to control the dew point temperature. However, due to the inconsistency of the temperature and humidity control systems, the delay and inertia time constant of each channel are very different, so the dew point temperature is difficult to control. In order to achieve accurate control, multiple valves are opened at the same time in the system, which leads to energy loss, and usually a single circuit works normally. But when multiple chains work at the same time, the system is not easy to be stable. Therefore, in order to ensure the long-term safe operation of multi-parameter control system, making full use of mature technology and single variable control experience is an effective method to manage multi-parameter system.

New indicators for air quality and distribution characteristics of pollutants in China

China has been suffering from an increasingly worse issue of air pollution over these years, which has not only caused a severe impact on the indoor environment, but also presented a tough challenge to clean production and a serious threat to human health. At present, China continues to adopt Air Quality Index (AQI) for the assessment of outdoor air pollution, which takes into consideration only the most serious pollutant and thus neglects the effects of other pollutants during the same period. In consideration of the wide-ranging impact of various pollutants, a new Total Air Quality Index (TAQI) is proposed to describe the widespread effects of six criteria pollutants on air quality. Based on the current indicators applied in China, TAQI could reveal the contribution made by each kind of pollutant to the overall air quality as indicated by Contribution Rate (CR). In this study, the daily average values for the concentration of six pollutants across 103 individual cities nationwide as collected from 2015 to 2017 are taken as the data source. According to the new indicators, the CRs of six pollutants in China are first explored. Then, the pollution situation facing these 103 cities within three years is categorized into five different groups by cluster analysis, and the characteristics of each group are summarized. Finally, the five most representative cities are identified by correlation analysis to explore the seasonal variation characteristics of pollutants. As revealed by this study, particulate matter and NO2 are the primary pollutants, which exhibit a range of obvious spatial and temporal variation characteristics. The findings of this study are expected to draw public attention to the gaseous contaminants (especially NO2), guide the control measures of indoor and outdoor pollutants, and assist with the design of clean air conditioning system.

Estimation of the efficiency of the treatment of split-systems in residential areas in order to reduce the level of the prevalence of diseases of the respiratory system

The purpose of work: comparison of prevalence among residents, which use or fail to use to clean split systems. Collected information about morbidity rate in 235 cases people during 3 years. The usage of split-systems without their regular cleaning leads to the gain in the level of the prevalence of respiratory diseases by 172.7% if compared with persons, who have no air conditioning systems at home. Also, the average number of disability days increases by 218.1%) and average time of the duration of the disease increases by 71.9%. The annual treatment of split-systems and regular cleaning of filters allowed to reduce the number of diseases. In comparison with the group of people, who fail to clean air conditioning systems, the drop of morbidity rate by 56.6%, average number of disability days by 63.3% and average time of diseases by 30.9% was observed. Regular treatment of air conditioning systems cannot completely repay the morbidity rates to the level of the control group. In comparison with the people, who use no air conditioning systems, the owners of split-systems with regular treatment have lung diseases by 18.4% more often. The average number of disability days and the average time of diseases increased by 16.9% and 18.8%. These changes can be explained by the impact of unfavorable (cooling) microclimate. The impact of split-systems on the health of the population requires a comprehensive study and the subsequent development of normative documents regulating their safe use.

Study on energy-saving design and operation of hospital purification air conditioning system

In order to ensure the cleanliness of operating room, clean air conditioners are installed in the clean operation departments in hospitals in China. Purification air conditioning system is an air conditioning system with a special function that ensures the cleanliness of the operating room and the required temperature and humidity in the operating room to avoid infection. This paper took the energy-saving design of the clean air-conditioning system of the clean operation department of the First Affiliated Hospital of Wenzhou Medical College, Zhejiang, China, as an example to illustrate the energy-saving methods such as layout optimization, air-conditioning division, secondary return air setting and operation mode adjustment. The energy consumption of primary return air technology and secondary return air technology was calculated. The results showed that energy-saving design could save nearly one-third of energy, improve the level of air-conditioning operation and management, reduce costs, and improve resource utilization, which is of great significance to social development.

The Status of Research on Clean Air Conditioning System in Hospital Operation Room

With the gradual improvement of medical level, the influence of the operating room environment on surgical results is becoming more and more obvious. This paper reviews the current situation and significance of clean air conditioning systems in different operating rooms of hospitals, and explores the application of environmental control technology in the operating room, such as the form of airflow in the operating room, the selection of air-conditioning system and equipment, indoor heat and humid air treatment process, control of pollutant concentration, and so on, which reveals the important impact of the operating room airflow environment on surgery and forecasts the application of clean air-conditioning system in the hospital operating room.

반도체 웨이퍼 제조공정 클린룸 구조, 공기조화 및 오염제어시스템

Objectives: The purpose of this study was to examine clean room(C/R) structure, air conditioning and contamination control systems and to provide basic information for identifying a correlation between the semiconductor work environment and workers' disease. Methods: This study was conducted at 200 mm and 300 mm semiconductor wafer fabrication facilities. The C/R structure and air conditioning method were investigated using basic engineering data from documentation for C/R construction. Furthermore, contamination parameters such as airborne particles, temperature, humidity, acids, ammonia, organic compounds, and vibration in the C/R were based on the International Technology Roadmap for Semiconductors(ITRS). The properties of contamination control systems and the current status of monitoring of various contaminants in the C/R were investigated. Results: 200 mm and 300 mm wafer fabrication facilities were divided into fab(C/R) and sub fab(Plenum), and fab, clean sub fab and facility sub fab, respectively. Fresh air(FA) is supplied in the plenum or clean sub fab by the outdoor air handling unit system which purifies outdoor air. FA supply or contaminated indoor air ventilation rates in the 200 mm and 300 mm wafer fabrication facilities are approximately 10-25%. Furthermore, semiconductor clean rooms strictly controlled airborne particles(≤ 1,000 #/ft³), temperature(23±0.5℃), humidity(45±5%), air velocity(0.4 m/s), air change(60-80 cycles/hr), vibration(≤ 1 cm/s²), and differential pressure(atmospheric pressure + 1.0-2.5 mmH2O) through air handling and contamination control systems. In addition, acids, alkali and ozone are managed at less than internal criteria by chemical filters. Conclusions: Semiconductor clean rooms can be a pleasant environment for workers as well as semiconductor devices. However, based on the precautionary principle, it may be necessary to continuously improve semiconductor processes and the work environment.

LCA of the Clean Air Conditioning System in Pharmaceutical Industry

In this paper, the air conditioning system in pharmaceutical industry throughout the life cycle energy efficiency had been evaluated according to the SETAC and ISO had put forward the idea of "life cycle assessment. The purpose was to adopt reasonable measures of energy saving technology to minimum the energy consumption to the clean air conditioning system and minimal impact on the environment load. At the same time, the economy was reasonable. Clean air conditioning wind system in a pharmaceutical factory was been as an example. The energy saving renovation of clean air conditioning system and the effect of energy saving renovation were analyzed. CO2 emissions were analyzed in its life cycle stage which provided a reference for other engineering.

Analysis of the Influence Factors of Energy Consumption in Pharmaceutical Industry

Abstract. Influence factors of energy consumption of air conditioning system in pharmaceutical industry had a perplexing relationship. The impact of energy consumption would have certain difference under different boundary conditions. The single factor analysis of energy consumption on the clean air conditioning system can not accurately reflect the significant level. Therefore, in the paper, orthogonal test and variance analysis method were adopt to determine the relationship between primary and secondary influence factors from ten major influencing factors on the clean air conditioning system in pharmaceutical industry which can guide the research on energy consumption.

Energy Saving Analysis of Clean Air Conditioning System in Pharmaceutical Company

The pharmaceutical industry building adopts the centralized air conditioning system with the characteristics of complicated structure, numerous equipments, relatively concentrated, high level of energy consumption, flexibility larger. In this paper, a clean air conditioning system of freeze-dried powder production workshop at a pharmaceutical company in northern China was been as an example. Energy consumption before and after the use of energy saving technology was been compared. The energy consumption and energy efficiency was been argument. It was a very good reference to other pharmaceutical companies.

Research on Energy Saving Diagnosis of Clean Air Conditioning System in Pharmaceutical Industry

The purpose of building energy efficiency diagnosis was to find out the problems existing in the process of using energy and analysis the potential of energy saving to guide the owner who should improve the building energy efficiency as far as possible to reduce building energy consumption. This paper involves only the research on energy saving diagnosis of clean air conditioning system in pharmaceutical industry.

FDA inspections reveal ugly truth

With hundreds of fungal meningitis infections and dozens of deaths caused by contaminated methylprednisolone manufactured at the New England Compounding Center (NECC), patients and health professionals alike are wondering how this could have happened. Recently released reports documenting FDA's inspections of NECC and allied company Ameridose have shed some light on the question.

A case study on energy saving of the facility systems for 12-inch semiconductor wafer fabs in Taiwan

In recent years, the semiconductor wafer fabs have begun to produce 12-inch wafers instead of 8-inch wafers as the new generation process technology has evolved. The production area increases, and the energy consumption of production buildings is also increased. In a semiconductor fab, besides the processing equipments, the plant facility system consumes most of energy. The facility system contains chilled water systems, outside air supply systems, circulating air systems, exhaust-gas treatment systems, vacuum systems, process cooling water systems, ultra-pure water systems and compressed-air systems. Considering the gradual depletion of energy sources and the soaring energy cost, energy saving has become an important project to high energy consumption semiconductor fabs. Therefore, this paper presents a case study on the energy saving of a clean air conditioning system and facility of 12-inch semiconductor fabs. The energy saving schemes contain four cases: (1) Case 1: The gas consumption of the organic substance processing system of direct firing type is compared with that of regenerative heat recovery type; (2) Case 2: The energy consumption of the cooling tower adopting high and low speed operations is compared with that adopting a frequency converter; (3) Case 3: The low vacuum system of the clean room adopts the phone call system to switch on/off the pump, and (4) Case 4: The make up air unit of the clean room adopts the run around system to recover heat. As for the energy saving efficiency, Case 1 can save NT$9,881,616 of gas cost annually; Case 2 can save NT$2,398,913 annually; Case 3 can save NT$317,004 annually, and Case 4 can save NT$1,738,758 annually. Through the aforementioned four manipulations, 25.24% of the total energy consumption of the corresponding facilities can be saved. Key words: Semiconductor fab, energy consumption, energy saving.