5290423
Energy-Saving Benefits of Adiabatic Humidification in the Air Conditioning Systems of Semiconductor Cleanrooms
This paper aimed to evaluate the applicability of adiabatic humidification in the heating, ventilation, and air conditioning (HVAC) systems of semiconductor cleanrooms. Accurate temperature and humidity control are essential in semiconductor cleanrooms and high energy consumption steam humidification is commonly used. Therefore, we propose an adiabatic humidification system employing a pressurized water atomizer to reduce the energy consumption. The annual energy consumption of three different HVAC systems were analyzed to evaluate the applicability of adiabatic humidification. The studied cases were as follows: (1) CASE 1: a make-up air unit (MAU) with a steam humidifier, a dry cooling coil (DCC), and a fan filter unit (FFU); (2) CASE 2: a MAU with the pressurized water atomizer, a DCC, and a FFU; and (3) CASE 3: a MAU, a DCC, and a FFU, and the pressurized water atomizer installed in the return duct. The energy saving potential of adiabatic humidification over steam humidification has been proved, with savings of 8% and 23% in CASE 2 and CASE 3 compared to CASE 1, respectively. Furthermore, the pressurized water atomizer installed in the return duct exhibits greater energy saving effect than when installed in the MAU.
111434798
Design, Installation and Commissioning Of Clean Room and Hvac Facility for Stem Cell Technologies and Regenerative Medicine
Today, many manufacturing process requires that spaces to be designed to control particulate and microbial contamination while maintaining clean room facility with reasonable installation and operating costs. Clean room facilities are typically used in manufacturing, packaging and research facilities associated with these industries: Semiconductor, Pharmaceutical, Hospitals, Aerospace and Miscellaneous applications. This project deals with "Design, Installation and Commissioning of Clean room and HVAC facility for Stem cell technologies and Regenerative Medicine". In this thesis, the system design thermal loads , filtration level and cleanness, pressures produced in the constructed building by varying normal brick wall ,brick wall with attached panels are calculated..Clean rooms are designed as per ISO14644-4 guidelines to maintain proper air flow in order to used proper cleanness. The HVAC facility shall be achieved by using the equipments like Air cooled condensing unit, Air handling units and etc..As a First step towards the project, the system design load calculations will be done. Air Quantity calculation, Supply/Return air Diffusers, Return Air Risers and Terminal filters selection, Temperature, RH, Lighting and Fan requirements are as per attached design data sheets. The classes of cleanliness, filtration and other requirements are to be as per the room list, layout drawings .The minimum fresh air quantities shall be as per the basis of design above while the exhaust air quantities shall be as based on the quantities of the leakages and pressures to be maintained in the rooms and Also the leakage rates considered through the doors to be through the doors to be through a normal single leaf door or double leaf door for the suggested pressure differentials to be suitably considered.
40144685
Cleanroom Energy Optimization Methods
The design and operation of semiconductor cleanrooms play an important role in the advancement of many of today’s technology needs as the use of microelectronic products become engrained in our society. Cleanroom construction has averaged double-digit growth through the 1990’s and into early 2000. Advances in factory technology have placed demands on all aspects of cleanroom design, construction, materials, and so on. Much of this growth has been centered in hot climate of the sunbelt. Energy efficiency has not been a high priority for the semiconductor industry in the past, since costs related to this issue have historically represented a relatively small percentage of overall operating costs. From a Semiconductor
110233086
Power consumption benchmark for a semiconductor cleanroom facility system
Abstract Benchmarking is an important step in implementing energy conservation in a semiconductor fabrication plant (hereafter referred to as “fab”). A semiconductor cleanroom facility system is complicated, usually comprised of several sub-systems, such as a chilled water system, a make-up system, an exhaust air system, a compressed air system, a process cooling water (PCW) system, a nitrogen system, a vacuum system, and an ultra-pure water (UPW) system. It is a daunting task to allocate energy consumption and determine an optimum benchmark. This study aims to establish the energy benchmark of a typical 8-in. DRAM semiconductor fab through field measurement data. Results of the measured energy consumption index were: chilled water system (including chiller, chilled water pump and cooling tower): 0.257 kW/kW (=0.9 kW/RT) in summer and 0.245 kW/kW (=0.86 kW/RT) in winter air recirculation air system: 0.00018 kWh/m 3 make-up air system: 0.0042 kWh/m 3 general exhaust air system: 0.0007 kWh/m 3 solvent exhaust air system: 0.0021 kWh/m 3 acid exhaust air system: 0.0009 kWh/m 3 alkaline exhaust air system: 0.0025 kWh/m 3 nitrogen system: 0.2209 kWh/m 3 compressed dry air system: 0.2250 kWh/m 3 process cooling water system: 1.3535 kWh/m 3 and ultra-pure water system: 9.5502 kWh/m 3 . These data can be used to assess the efficiency of different energy-saving schemes and as a good reference for factory authorities. The PCW system's status before and after implementing energy conservation is discussed.
110837273
Power consumption of semiconductor fabs in Taiwan
This paper reports and analyzes power consumption for nine representative semiconductor fabs in Taiwan. The power consumption data were obtained by surveys and site visits. Analysis results indicate that the average power consumption for the fabs is 2.18 kW/m2 and the average cooling load is 0.434 RT/m2. The average power consumption per unit product (wafer) area is 1.432 kWh/cm2, which is consistent with the data (3.1 kWh/cm2 in 1983 to 1.41 kWh/cm2 in 1995) reported by the US Department of Commerce and Dataquest. The facility system consumes the most of the power consumption (about 56.6%) of the semiconductor fabs. Process tools are the next largest power consuming item, accounting for 40.4% of the power consumed in the fabs. A facility system includes the chiller plant, makeup air, recirculation air, exhaust air, gases, compressed dry air, process cooling water, vacuum and ultra-pure water systems. The power consumption of the different facility components is analyzed and compared.
110628398
Makeup air systems energy-saving opportunities
Makeup air semiconductor clean spaces can vary from 1 cfm/ft{sup 2} (5.08 L/s {center dot} m{sup 2}) to 10 cfm/ft{sup 2} (50.81 L/s {center dot} m{sup 2}) and typically averages 5 cfm/ft{sup 2} (25.4 L/s {center dot} m {sup 2}). Accordingly, the energy requirements to cool, dehumidify, preheat, and/or humidify are significant and can represent 30% to 65% of the total thermal energy required to maintain a cleanroom environment. Because of high energy requirements, cost-effective means to reduce energy costs can influence unit production costs. The greatest opportunity for significant energy savings can be achieved by reducing or displacing mechanical cooling or fuel-generated heating requirements. The primary focus of this paper is to present and discuss various concepts of heat recovery, dual-temperature cooling, direct and indirect evaporative cooling, and heat rejection directed toward makeup air systems that can achieve these objectives. In addition, equipment-sizing considerations not necessarily applicable to systems that are less energy intensive or that operate continuously are explored.
111362589
A comparative study on energy consumption for HVAC systems of high-tech FABs
The unique system dynamics of five different HVAC designs including the RCU (recirculation air unit) system, the MAU (make-up air unit) + RCU system, the MAU + RCU + FCU (fan coil unit) system, the MAU + axial fan system, and the MAU + FFU (fan-filter unit) system for a typical 200 mm DRAM wafer fabrication plant are discussed and compared. The energy performances of the RCU system, the MAU + RCU system, the MAU + RCU + FCU system, and the MAU + axial fan system are 3.8, 1.19, 1.12 and 1.08, respectively, folds that of the most efficient MAU + FFU system. The MAU + axial fan system exhibits slight less efficient in energy performance, compared with the MAU + FFU system. The most influential factor on energy performance between these two systems is the design of the noise abatement system, especially the pressure drop of the silencer, which dominates almost half of the internal static pressure of axial fan. When the static pressure of silencer of the MAU + axial fan system is reduced to 50 Pa, energy consumption of these two systems is comparable. Bypassing a certain portion of FAB return air to mix with make-up air can maximally reduce 50% of energy consumption of the RCU system.
110652972
Saving energy in the make-up air unit (MAU) for semiconductor clean rooms in subtropical areas
The energy requirements to cool, dehumidify, preheat and/or humidify outdoor air are significant in the make-up air unit (MAU) of clean room air-conditioning systems, and can represent 30% to 65% of the total thermal energy required to maintain a clean room environment. Because of these high-energy requirements, cost-effective means to reduce energy costs can influence unit production costs. Reducing or displacing mechanical cooling or electrical heating requirements can achieve the greatest opportunity for significant energy savings. This paper, therefore, aims to improve the energy performance of the MAU system by properly arranging compositions of components of a typical MAU applied in a semiconductor clean room. Explicitly, we investigated the influence of various factors including the fan location (draft-through type vs. push-through type), chilled water system (single-chilled water temperature system vs. two chilled water temperature system) and reheating scheme (electrical heating vs. hot water provided by heat recovery chiller). The result shows that the draw-through type accompanied by two chilled water temperature system with heat recovery function exhibits the lowest electrical power consumption.
108489572
Energy saving in semiconductor fabs by out-air handling unit performance improvement
We shows methods of energy saving. The energy consumed in semiconductor fabs is classified into two categories, the manufacturing system and the air conditioning. The energy for the air conditioning is further classified into fresh air intake, recirculation (clean room) air conditioning and cooling system of the manufacturing system. The moisture in the fresh air is condensed on a heat exchange-fin of the air-handling unit (AHU). This condensation decreases thermal exchange and increases intake-air resistance and removal of it improves the performance. So we removed it, and 24% improvement of coefficient of heat exchange is achieved. Using this result, a 5% energy saving of the refrigerator is obtained. If the result is applied to all of the heating, ventilation, and air conditioning (HVAC) system, 3% energy saving is obtained.
111816312
Ultrasonic humidification: System integration, energy, and indoor air quality engineering issues
Ultrasonic humidification has become increasingly popular for both indoor air quality and energy related reasons. The central thrust of this paper is to explore these two areas in depth. Application of ultrasonic humidification, however, raises a number of design and operational issues that are not important with steam humidification. The three main issues, also emphasized in this paper, are heating coil requirements, supply air temperature control sensor placement, and the impact of the size and number of stages of humidification on supply air temperature control hunting. Finally, the analytical tools, currently missing from both private and large public domain energy analysis software, are developed in this paper and applied to a specific academic library building located in central Pennsylvania.
94964137
Comparing low-pressure and high-pressure fogging systems in naturally ventilated greenhouses
The cooling performance of a low-pressure (405 kPa working pressure) and a high-pressure fogging system (6.89 MPa) was evaluated. Experiments were conducted in two empty, naturally ventilated greenhouses under summer conditions for a period of about two months. One greenhouse was used as the treatment greenhouse (fogged house) and another was used as the control house (un-fogged house). Cooling efficiency was defined by the ratio of the temperature difference between the un-fogged and fogged greenhouses to the difference between the temperature in un-fogged house and the wet-bulb temperature in the fogged greenhouse. Evaporation efficiency was defined as the ratio of fog evaporation rate to spray rate. Cooling efficiency and evaporation efficiency were compared for the low-pressure and high-pressure systems after accounting for differences in weather conditions under which the two systems were operated. It is suggested that on average evaporation efficiency for the high-pressure system was at least 64% greater than the low-pressure system; cooling efficiency for the high-pressure system was at least 28% greater than for the low-pressure system.
98674328
Cooling Efficiency of Fogging Systems for Greenhouses
The cooling efficiency η c of wet pad and fan systems, which is currently used for fogging systems, is defined assuming that the dry bulb temperature in the greenhouse T db , i is lower than the outside dry bulb temperature T db , o and is measured directly at the outlet of the wet pad. However, in the case of η c of a fogging system, T db , i is typically measured at different locations in the greenhouse to obtain an average value. The inside air is sensibly heated mainly by solar energy transmitted into the greenhouse under sunny summer conditions. Then T db , i is often higher than T db , o , giving negative values of η c . Even though, T db , i is lower than T db , o , the current definition of η c gives unrealistic values due to the latent heat added to the inside air. In this study, η c of a fogging system was newly defined, taking into consideration the sensible and latent heat added to the greenhouse air. The definition is based on the energy and mass (water vapour) balance of the un-cooled air in the greenhouse during the operation of fogging. The value of η c was determined for an experimental greenhouse with a floor area of 26 m 2 and contained 150 potted tomato plants. The greenhouse was cooled intermittently at a fogging rate of 10 g s −1 for three different fogging times of 30, 60 and 90 s with interval times of 90, 180 and 270 s, respectively. The results showed that a fogging cycle of 60 s on, 180 s off provided a relatively higher value of η c than other cycles. Under this condition, two approximate expressions of η c could be used to estimate the η c value with an error less than ±5%.
111247203
Capturing energy-saving opportunities in make-up air systems for cleanrooms of high-technology fabrication plant in subtropical climate
Abstract Operation of make-up air units (MAUs) for cleanrooms of high-technology fabrication plant in subtropical climates is very energy intensive, in that it is expected to deliver conditioned air at elevated airflow rates, compared to conventional commercial applications. Optimizing the design of MAU via reducing or displacing mechanical cooling or electrical heating processes can improve energy efficiency in cleanrooms since cleanroom air-conditioning systems typically use 30–65% of the total energy consumption in a high-tech fabrication plant [1] . This paper investigates the difference in energy efficiency performance of MAU systems with different pre-cooling and preheating/humidification schemes. Additionally, a comparative study was carried out for humidification schemes including wet media, directly atomized water, steam, and two-phase flow. The results show that energy recovery by DCC water return method exhibits the best energy efficiency among a total of eight schemes evaluated in this study. In addition, wet media scheme is the best humidification scheme in winter time, compared with the other three types of humidification schemes.
107953576
Designing Clean Room HVAC Systems
The purpose of the clean room air-conditioning system is to supply airflow in sufficient volume and cleanliness to support the cleanliness rating of the room. Air is introduced into the clean room in a manner to prevent stagnant areas where particles could accumulate. The air must also be conditioned to meet the clean-room temperature and humidity requirements. In addition, enough conditioned makeup air must be introduced to maintain the specified positive pressurization.
19342289
Inlet Fogging of Gas Turbine Engines: Part B — Fog Droplet Sizing Analysis, Nozzle Types, Measurement and Testing
The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years, coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part B of the paper treats the practical aspects of fog nozzle droplet sizing, measurement and testing presenting the information from a gas turbine fogging perspective. This paper describes the different measurement techniques available, covers design aspects of nozzles, provides experimental data on different nozzles and provides recommendations for a standardized nozzle testing method for gas turbine inlet air fogging.Copyright © 2002 by ASME
55785563
Experimental investigations on impaction pin nozzles for inlet fogging system
Increasing power demands have necessitated the development of energy efficient systems in the industrial sector. At present, about 10% of the overall electric power used by large industrial plants is consumed by high-capacity compressors supplying compressed air. Likewise, in a gas turbine power plant, nearly half the generated power is used for driving the compressor. The work of compression is proportional to inlet air temperature, and cooling the inlet air can save considerable amount of power in large turbo machines during hot summer months. Inlet fogging is a popular means of inlet air cooling, and fog nozzles are the most critical components in an inlet fogging installation. Majority of these installations employ impaction pin nozzles. In the present work, experiments are conducted over a wide range of operating parameters in variable length wind tunnels of different cross sections in order to investigate the performance of impaction pin nozzle in inlet fogging. Flow visualization and measurements are carried out to analyze the fog behavior and identify suitable nozzle locations in typical air ducts. The results show that impaction pin nozzles are suitable for inlet fogging applications.
117383454
Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles
Properties of Gases. Uniform Particle Motion. Particle Size Statistics. Straight-Line Acceleration and Curvilinear Particle Motion. Adhesion of Particles. Brownian Motion and Diffusion. Thermal and Radiometric Forces. Filtration. Sampling and Measurement of Concentration. Respiratory Deposition. Coagulation. Condensation and Evaporation. Atmospheric Aerosols. Electrical Properties. Optical Properties. Bulk Motion of Aerosols. Dust Explosions. Bioaerosols. Microscopic Measurement of Particle Size. Production of Test Aerosols. Appendices. Index.
17600185
Analysis of a Building Energy Efficiency Certification System in Korea
The Korean government has established a national plan for the promotion of zero energy buildings to respond to climate change and energy crises. To achieve this plan, several energy efficiency policies for new and existing buildings have been developed. The Building Energy Efficiency Certification System (BEECS) aims to promote the spread of high energy-efficient buildings by evaluating and certifying building energy performance. This study discussed Korean building energy efficiency policies and analyzed especially the influence of the BEECS on the actual energy consumption of a residential building and calculated energy performance of non-residential buildings. The BEECS was evaluated to have influence on gas and district heating consumption in residential buildings. For non-residential buildings, a decreasing trend was shown in calculated primary energy consumption in the years since the BEECS has been enacted. Appropriate improvements of the certification system were also discussed by analyzing relationship between building characteristics and their energy consumptions.