Supply Outlet Research Articles

Statistical Modeling of Head Loss through Duct Fittings in Conditioned Air Distribution Systems

Fractions of the total head loss which constitute the loss through duct fittings, obtained in an earlier study, for varying numbers of supply outlets and lengths of index duct run were used in a regression analysis to obtain second order equations which gave a general increase of the fraction from 0.598 to 0.713 for an increase in number of outlets from 3 to 19 and for a corresponding increase of 11.2 m to 43.2 m in index duct length. The correlation coefficient between the fraction of loss through duct fittings and each of the variables of number of supply outlets and length of index duct run was 0.823, which was found to be acceptable for a 95% confidence level. The ratios are useful for quick estimate of total pressure losses in conditioned air distribution systems which are needed in determining the fan pressure requirements.

Based on Class D Amplifier Magnetic Resonance Wireless Transmission Technology

Radio capable of transmitting power transmission is carried out via electromagnetic waves, thus eliminating the need of a new power supply cord and outlet. This article highlights and summarizes the three main ways the existing wireless transmission technologies, including electromagnetic induction wireless transmission technology, far-field radiation wireless transmission technology, magnetically coupled resonant wireless transmission technology, the basic principles. And proposed resonance energy transfer mode radio based on Class D amplifier, and then describes in detail the basic principles of magnetic resonance energy transfer system radio various parts of the circuit.

Performance evaluation of an air conditioning system with different heights of supply outlet applied to a sleeping environment

Abstract Because of the increased expectations on thermal comfort and indoor air quality in sleeping environments at a low energy consumption, it is necessary to develop new air conditioning systems applied to sleeping environments. In recent years, a large number of studies on task/ambient air conditioning (TAC) have been carried out due to its excellent ventilation and energy saving performance. However, compared to full volume air conditioning (FAC), there exists an inadequacy on thermal control for TAC because cooled air is directly delivered to the space around a human body. Hence, the TAC and FAC systems have their own pros and cons in aspects of thermal, ventilation and energy saving performances, and the position of a supply outlet in an air conditioning (A/C) system significantly influences its operating performances. Therefore, a study on the performance evaluations of an A/C system installed in an experimental bedroom with its supply outlet positioned at five different heights has been carried out, and the study results are presented in this paper. The study results suggested that overall speaking, the A/C system performed the best at a supply air temperature of 23 °C, an air flow rate of 50 L/s and a fresh air flow rate of 13 L/s at H1100 setting, among all study cases. On the other hand, the A/C system performed the best at H800 setting among the five height settings.

Advanced air distribution for minimizing airborne cross-infection in aircraft cabins

The performance of personalized ventilation combined with local exhaust at each seat was studied for the purpose of minimizing airborne cross-infection in spaces whose occupants are sedentary, such as transportation environments. Experiments were carried out in a simulated aircraft cabin section (3 rows, 21 seats). One breathing thermal manikin simulated an “infected” passenger as a source of pollution, and a second breathing manikin simulated an “exposed” passenger. The personalized ventilation supplied clean air at 6 or 10 L/s (12.7 of 21.2 cfm) from in front of each manikin's face. Air was withdrawn at a rate of 6 or 10 L/s (12.7 or (21.2 cfm) by the local exhaust system, which consisted of two exhaust terminals, one on each side of the head of the “infected” manikin. The cabin was ventilated with 180 L/s (381 cfm) of fresh air. Freon was mixed with the air exhaled by the “infected” manikin to simulate airborne pathogens. The airflow from the personalized supply outlet pushed the contaminated exhaled air backward, where it was exhausted before it had mixed with cabin air. This resulted in a substantial decrease of the tracer gas concentration in the air inhaled by the “exposed” manikin and in the air exhausted from the cabin.

Development of home power management system

This study aimed at the design and development of a prototype Power Management System for home which will enhance energy user behavior for achieving energy consumption efficiency. It allows the user to transfer management of supply to appliances at home to a real time monitoring, switching and control device with four regulated and one unregulated supply outlets. The PIC16F887 Microcontroller was programmed to provide 24 hour real-time timing power consumption management according to user-supplied timing parameters made available to the programmed Code with the help of the PCF8583 real time clock. The home power management system developed under test produced outputs which exhibited good correlation with the input supply. Whereas the input to the device was 186V, the output for ports 1, 2, 3, 4 and 5 were respectively 187V, 185V, 184V, 185V and 183V which is a satisfactory input-output correlation. The unit also exhibited good implementation of the timing algorithm for all programmed outputs. It switched and OFF at the set times for the regulated ports showing that power was managed as desired in accordance with the inputted timing parameters. The user only has to set the timing parameters once and thereafter the device maintains these settings until such a time as the user decide to change them. Also the user does not have to surrender the decision on when power is switched ON to the device to make by making predictions based on whatever criteria. This ensures that the user retains certain level of control over the device in terms choice of when appliances should be powered. This flexibility in an automation system is one strong point of this device. Keywords: Real-time, Power Consumption Management, Timing algorithm Nigerian Journal of Technological Research , 8(2), 2013

Thermal Comfort Analysis of a Ship Air-Conditioning System Using Solidworks Flow Simulation

The focus of this work is to simulate and optimize thermal comfort in a ship air-conditioning system by evaluating the performance of different types of air supply outlets. Thermal comfort analyses were performed in Solidworks Flow Simulation software by changing the number, type and position of air supply outlets and the comfort was optimized by evaluating the values of temperature, velocity, PMV (Predicted mean vote) & PPD (Predicted Percentage Dissatisfied). It was concluded from the results obtained from different analyses that air supply outlet is a vital part in any type of HVAC (Heating ventilation & air conditioning) system design, as its number, type and position has significant effect on the air distribution and thermal comfort in a subject space. It was also deduced that improper selection of air supply outlet can result in room air stagnation, unacceptable temperature gradients, and undesirable velocities in the occupied zone that may lead to occupant discomfort. Through this work the importance and effectiveness of CFD (computational fluid dynamics) design tools, in the design & optimization of HVAC systems has been evaluated and it was concluded that CFD design software like Solidworks flow simulation provide an excellent provision to validate different aspects of HVAC design before actual construction.

Experimental and numerical investigations on stratified air distribution systems with special configuration: Thermal comfort and energy saving

In this paper, using a newly defined cooling coil load calculation method for stratified air distribution (STRAD) systems, the effects of separate location of the return and exhaust grilles on thermal comfort and energy saving are experimentally investigated. The results clearly demonstrated the extra energy saving potentials for STRAD systems with separate locations of return and exhaust grilles. After using the experimental results to validate our CFD method, numerical investigation is carried out for an office setting. Decreasing the height of return grille will increase exhaust air temperature and significantly reduce the cooling coil load. However, the risk of poor thermal comfort caused by too large temperature difference between the head and foot levels also increased, when the return inlet is located close to the floor level. Locating the exhaust grilles at ceiling level and close to external wall while locating the return grilles at the upper boundary of the occupied zone are recommended in practice. It is demonstrated that the purpose to simultaneously achieve satisfied thermal comfort and prominent energy saving can be attained with a STRAD system via deliberate locations of supply outlets and return and exhaust grilles in relation to the heat source locations.

Analysis of anti-condensation mechanism on superhydrophobic anodic aluminum oxide surface

Wetting theory about superhydrophobic surfaces reveals that hydrophobicity of surfaces has great relationship with surface roughness and surface free energy. Adopt electrochemical plus fluorine silane modified method to prepare superhydrophobic surface on anodic aluminum oxide surface, which not only enhances surface roughness, but also reduces surface free energy, even the static contact angle can reach 159.2° and anti-condensation is authenticated. Based on the experimental findings, analyze the reason of anti-condensation on superhydrophobic surfaces: one is that the density of droplets formed on superhydrophobic surfaces is low and the number of droplets is little; the other is bigger static contact angle and smaller rolling angle on superhydrophobic surfaces make droplets easy to detach on smaller tilt angle. This research can solve some condensation problems of equipment using in HVAC systems, such as heat exchangers in air conditioning system, cold radiation boards, air supply outlets, and so on.

Analysis of the Solar Wall Heat Transfer and Energy Saving of Residential Ventilation

It is the considerable measure that adopting the ventilation solar wall to make up the indoor air in winter because this method embodies the effective use of renewable energy. This paper analyzes the needed volume of make-up air in the different conditions of indoor air exhaust in winter and builds a solar wall to heat the make-up air. Under the conditions of different solar wall size of air channel thickness and so on, Conclusions can be simulated by using CFD software. When the optimum cavity width B is 50mm, the height of air supply outlet D is 30mm and the volume of make-up air is 200 m3/h,the maximum temperature rise of the air rises to 24°C.But when the volume of make-up air is 600 m3/h, there has the best energy-saving effect.

A three-dimensional microfluidic approach to scaling up microencapsulation of cells

Current applications of the microencapsulation technique include the use of encapsulated islet cells to treat Type 1 diabetes, and encapsulated hepatocytes for providing temporary but adequate metabolic support to allow spontaneous liver regeneration, or as a bridge to liver transplantation for patients with chronic liver disease. Also, microcapsules can be used for controlled delivery of therapeutic drugs. The two most widely used devices for microencapsulation are the air-syringe pump droplet generator and the electrostatic bead generator, each of which is fitted with a single needle through which droplets of cells suspended in alginate solution are produced and cross-linked into microbeads. A major drawback in the design of these instruments is that they are incapable of producing sufficient numbers of microcapsules in a short-time period to permit mass production of encapsulated and viable cells for transplantation in large animals and humans. We present in this paper a microfluidic approach to scaling up cell and protein encapsulations. The microfluidic chip consists of a 3D air supply and multi-nozzle outlet for microcapsule generation. It has one alginate inlet and one compressed air intlet. The outlet has 8 nozzles, each having 380 micrometers inner diameter, which produce hydrogel microspheres ranging from 500 to 700 μm in diameter. These nozzles are concentrically surrounded by air nozzles with 2 mm inner diameter. There are two tubes connected at the top to allow the air to escape as the alginate solution fills up the chamber. A variable flow pump 115 V is used to pump alginate solution and Tygon® tubing is used to connect in-house air supply to the air channel and peristaltic/syringe pump to the alginate chamber. A pressure regulator is used to control the flow rate of air. We have encapsulated islets and proteins with this high throughput device, which is expected to improve product quality control in microencapsulation of cells, and hence the outcome of their transplantation.

Analysis of indoor air quality in surgical operating rooms using experimental and numerical investigations

The present work fosters experimental measurements and mathematical modelling techniques to primarily determine the thermal and the relative humidity characteristics in the air-conditioned surgical operating room. The present work also demonstrates the effect of the various designs of surgical operating rooms and operational parameters on the flow pattern and temperatures characteristics. This study is a part of a more comprehensive investigation of the more important factors affecting the air environments in surgical operating room. Measured and predicted temperatures and relative humidity profiles are shown to be in good agreement. The present paper introduces several recommendations regarding the optimum design requirements of operating rooms to provide hygiene and comfort environment. Low humidity affects comfort and health. The present work offers examples of measured relative humidity profiles in an operating room in (New Kasr El-Aini Teaching Hospital – 1200 beds – Cairo University – Egypt). These experimental results were carried out to verify the proposed numerical procedure and particularly in the vicinity of the supply outlets and operating table.

Model Experimental Study on Stratified Air Distribution with 2D-PIV for High Ceiling Industrial Plant

At present, the research ways of stratified air-conditioning technology mainly have two types, experimental study and numerical simulation. In this paper, a transparent Plexiglas model was designed, of which the size was supposed to be 1/50 of the real scale. PIV technology was innovatively applied into the experiment to measure the air distribution of an industrial plant. Different air supply velocities and different kinds of air supply outlets were taken into account to discuss the influence of them. Results revealed that as the jet velocity increased gradually, the airflow’s stratification effect became more evident. When the aspect ratio changed from 1:2 to 1:8, the diffusion degree in vertical direction increased obviously. In comparison with the rectangular air supply outlet, the circular one had lower decay, longer jet distance and better contractibility. The experimental findings are useful for optimizing the design of air distribution in high ceiling industrial plant.

Wellhead anti-frost technology using deep mine geothermal energy

The auxiliary shaft is an important location for coal mine heating in the winter, where the main purpose of heating is to prevent icing of the shaft. Wellhead heating requires characteristics of openness, no-noise and big heat loads. The original coal-fired boiler heating mode causes significant waste of energy and environmental pollution due to the low efficiency of the heat exchange. Therefore, to solve these problems, we will use deep mine geothermal energy to heat the wellhead by making full use of its negative pressure field and design a low-temperature water and fan-free heating system. Through numerical calculations we will simulate temperature fields, pressure fields and velocity fields under different air supply temperatures, as well as different air supply outlet locations and varying number of radiators in the wellhead room of a new auxiliary shaft to find the proper layout and number of radiators that meet wellhead anti-frost requirements from our simulation results, in order to provide guidelines for a practical engineering design. Tests on the Zhangshuanglou auxiliary shaft wellhead shows good, look promising and appear to resolve successfully the problem of high energy consumption and high pollution of wellhead heating by a coal-fired boiler.

Nature-Inspired Energy- and Material-Efficient Design of a Polymer Electrolyte Membrane Fuel Cell

A design procedure is presented that improves the energy efficiency and saves catalyst material of a polymer electrolyte membrane fuel cell (PEMFC). The method is demonstrated for a single cell in a stack and uses the theorem of equipartition of entropy production to maximize energy efficiency. The gas supply and water outlet systems, designed to produce entropy uniformly, have a fractal structure inspired by the human lung. The tree-like gas distributor engraved in the bipolar plates may eliminate the need for porous transport layers. Mathematical solutions are given for the optimal height, macroporosity, and nanoporous column width of the electro-catalytic layer beneath the gas supply system. It is shown that the optimal macroporosity of the catalytic layer is equal to 1/2 for the model chosen and that the optimal height of the catalytic layer depends upon the coefficient for first-order reaction kinetics at the cathode, the diffusion constant for oxygen in the gas phase, and the oxygen concentration of...

Expiry of medicines in supply outlets in Uganda

The expiry of medicines in the supply chain is a serious threat to the already constrained access to medicines in developing countries. We investigated the extent of, and the main contributing factors to, expiry of medicines in medicine supply outlets in Kampala and Entebbe, Uganda. A cross-sectional survey of six public and 32 private medicine outlets was done using semi-structured questionnaires. The study area has 19 public medicine outlets (three non-profit wholesalers, 16 hospital stores/pharmacies), 123 private wholesale pharmacies and 173 retail pharmacies, equivalent to about 70% of the country's pharmaceutical businesses. Our findings indicate that medicines prone to expiry include those used for vertical programmes, donated medicines and those with a slow turnover. Awareness about the threat of expiry of medicines to the delivery of health services has increased. We have adapted training modules to emphasize management of medicine expiry for pharmacy students, pharmacists and other persons handling medicines. Our work has also generated more research interest on medicine expiry in Uganda. Even essential medicines expire in the supply chain in Uganda. Sound coordination is needed between public medicine wholesalers and their clients to harmonize procurement and consumption as well as with vertical programmes to prevent duplicate procurement. Additionally, national medicine regulatory authorities should enforce existing international guidelines to prevent dumping of donated medicine. Medicine selection and quantification should be matched with consumer tastes and prescribing habits. Lean supply and stock rotation should be considered.

COMPARISON BETWEEN CONVENTIONAL HVAC SYSTEM AND DISPLACEMENT VENTILATION SYSTEM WITH CEILING SUPPLY OUTLET

In previous paper, two types of displacement ventilation were investigated by computational fluid dynamics (hereafter CFD) simulations and experiments. This paper presents thermal environment and ventilation performance of a full scale mock-up kitchen model with two types of ventilation systems. i.e. the displacement ventilation with ceiling supply outlet and the conventional HVAC system with VHS and punkah louver. In the experiments, these ventilation systems were compared in order to evaluate air temperature and contaminant concentration distributions in the kitchen. In the CFD simulations, the positions of supply opening of displacement ventilation were studied. Three types of commercial kitchens were simulated by CFD simulation, i.e. kitchens for European restaurant, Japanese one and Chinese one were modeled. In addition, indexes of ventilation efficiency e.g. Direct Capture Efficiency (hereafter DCE) and Effective Ventilated Volume (hereafter EVV) were calculated on the basis of the CFD results.

Experimental analysis on the air distribution of powerhouse of Hohhot hydropower station with 2D-PIV

Hohhot hydropower station is being built from the year of 2007. There are many complicated heating facilities and equipment in the powerhouse, such as electricity generators and transformer. The air distribution of the powerhouse is affected by the complex heat sources. In this paper the model size is 1/50 of the real scale and 2D-PIV is used to study the air distribution in the model of large underground space. The supply outlet is located on the roof and the heat source is located on the floor. The different supply air conditions and heat release rate are discussed. Three air supply are discussed: v/ v 0 = 0.75, v/ v 0 = 1, v/ v 0 = 1.25 ( v 0 is designed air supply speed, v 0 = 0.94 m/s). And we also carry out three heat release rates: Q/ Q 0 = 0.75, Q/ Q 0 = 1, Q/ Q 0 = 1.25 ( Q 0 is designed heat release rate, Q 0 = 7.12 W). The results show that the supply air velocity has a remarkable effect on air distribution characteristics of the large space and occupant zone velocity. However, it is also observed that the heat release rate has little effect on air distribution of large space and occupant zone velocity. The air supply velocity and the air inlet location should be paid more attention in designing air distribution. The experimental findings are useful for optimizing the design of air distribution in a large space with complex heat sources.

CFD ANALYSIS FOR DETACHED HOUSE

This paper describes the distribution of local air exchange efficiency (εp) in the living room when the layout of supply outlets and exhaust inlets and the position of air-conditioners is changed.The results are as follows;(1) The value of mean εp of breathing zone becomes about 1.0 because fresh air spread completely in the room when airconditioners are operated.(2)In the case when air-conditioners are not operated, the mean εp becomes smaller than 1.0, and the poor area of ventilation efficiency becomes large.(3) Ventilation efficiency is influenced by the layout of the supply outlets and exhaust inlets.

EXPERIMENTS AND CFD SIMULATIONS ON DISPLACEMENT VENTILATION SYSTEM WITH CEILING SUPPLY OUTLET

In working spaces such as commercial kitchens in which heat, contaminants and odor are generated from cooking, it is important to remove polluted air and heat efficiently and to supply make-up air for the occupied zone. The energy consumption with ventilation system in the commercial kitchen is very large. It is very important to reduce the energy consumption of a commercial kitchen.Displacement ventilation system can give a good solution to such situation. However the area of floor and wall in Japanese commercial kitchens is small, so it is difficult to apply a conventional displacement ventilation system to a commercial kitchen in Japan.In this paper, two types of displacement ventilation were investigated by computational fluid dynamics (hereafter CFD) simulations and experiments. In case A, conventional displacement ventilation with supply opening installed at the wall was studied. In case B, the supply outlet was installed at the ceiling and indoor temperature and tracer gas concentration were compared to the result case A. In addition, indexes of ventilation efficiency e.g. Direct Capture Efficiency (DCE) and Effective Ventilated Volume (EVV) were calculated on the basis of the CFD results.

Investigation of transient thermal environments

Human beings are commonly exposed to transient thermal environments in their daily life. But most of the studies on indoor thermal environment have been conducted under steady-state conditions. The aim of this paper is to summarize the investigation on human responses to transient thermal environment carried out by the indoor environment group at Tsinghua University, and to predict the possibility of using their research findings in practice. Human responses to transients have some special characteristics, which could be beneficial to environmental control. Air movement is especially effective at realizing a transient thermal environment, offsetting higher air temperature or operative temperature in warm climates. Based on the analysis of measured data, the characteristics of air movement outdoors are different from artificial air supply such as fans or air supply outlets, in the probability distribution of their velocities, turbulence intensity, and power spectrum. Based on subjective experiments, it is evident that artificial air movement, which is mainly simulated with outdoor airflow characteristics, has the highest occupant preference in warm conditions. Experimentally simulated air movement improves not only whole-body cooling, but also local cooling as from personal air supplies. Finally, it is important that introducing simulated natural air movement into the space in warm or hot conditions could significantly decrease the building's energy consumption.