Industrial Air Conditioning Research Articles

Моделирование САУ подогревом и охлаждением воздуха для установки промышленного кондиционирования воздуха

Моделирование САУ подогревом и охлаждением воздуха для установки промышленного кондиционирования воздуха

Experimental Investigation of Water Cooler System by Using Eco-Friendly Refrigerant (R-134a)

With the recent government regulations, of banning the ozone depleting substances and Kyoto protocol later on curtaining to the use of substances which contribute to global warming, conventional refrigerants are to be replaced by the environment friendly refrigerants. Present day mankind depends heavily on refrigeration for his daily needs. This can be noticed by wide range of applications such as for home refrigeration, comfort cooling, preservation and transport, commercial and industrial air conditioning, hospitals, offices etc. These refrigeration system works on simple vapour compression refrigeration cycle. The water cooler system also works on simple vapour compression refrigeration cycle and uses R134a as a refrigerant. It is environment friendly. The performance of refrigerant R134a has been found and the results were used to evaluate the behavior of the system under varying load conditions and to measure the COP of the system. The water cooler system has been designed and fabricated specially for small capacity.

SYNTHESIS OF OPTIMAL LINEAR-QUADRATIC DIGITAL CONTROLLER FOR INDUSTRIAL CONDITIONING WITH STEAM HUMIDIFIER

For industrial complexes artificial microclimate (ICAM) proposed a methodology to develop a comprehensive mathematical model of industrial air conditioning in the space of a condition that involves the analysis of the structure of an automatic control system (ACS) and the development of appropriate control algorithms. On the basis of the developed methodology received a comprehensive model for technological schemes of industrial air conditioners as a single multidimensional control object. For the proposed methods use dynamic models of climatic equipment in the space of States . For the General model ICAM presents matrices that define a comprehensive model of industrial air conditioner with a steam humidifier. The algorithm of synthesis of multidimensional linear-quadratic digital controller (LQDC) for ICAM developed. The problem of synthesis of optimal LQDC considered and synthesized matrix feedback LQDC, which the state parameters of the control object determines the trajectory of the vector of optimal exposure that minimizes the quadratic criterion. From the classical procedure of synthesis LQDC the proposed algorithm is characterized by the presence of the logical selection of accessories for optimal control. This approach allows us to rethink the synthesis of ACS, as air conditioning is based on the separation of the mutual impact of the regulatory options. This allows you to transfer the control system is conditioned to a qualitatively new level and ensures the efficient use of energy for artificial microclimate systems. The obtained formulas are recommended experts on design automation of control systems and optimization of existing ones.

Applications to Engineering Physics for Reducing Air Pollution

Taking advantage of modern technology of the macro ionization of air in the air conditioning systems in order to promote the industrial air conditioning systems can be an appropriate way to resolve industrial centers and hospital's pollution, and also resolve monitoring of air in the urban tunnels. Breathing space around us is a mixture of particles and neutral and charged molecules, so by looking back at industrial achievements of tools and instruments of the air conditioners, electrical discharge method is practical and appropriate. In addition to refining of air pollutants, there is also the possibility of removing germs. Macro Air Ionization Technology (MAIT) in the industrial, hospital and urban tunnels is one of the offering methods of increasing healthy air as usual methods in environment. MAIT is a hi-tech equipment for improving air. One of these technologies is Negative Air Ionization Technology (NAIT). In the NAIT equipment air molecules after ionization change Negative Ion Concentrations in the room, tunnels and sheds. The negative ion molecules especially oxygen, will provide a healthy environment for plants growth process. Using NAIT, anions have the ability to conquest the microbes and microorganism. According to the performed research, utilizing the air ventilation modern technologies, have an efficient effect on the quantity and quality of important place as hospitals. For this reason, negative ion injections by MAIT into the air could be a part of research policies in developing and least developing countries for effective exploitation and correction of the Health and Safety Executive (HSE) conditions, as it was the part of basic research policies in last 40 years in developed countries. In this paper, we try to introduce hi-tech MAIT equipment based on corona discharge method.

THE DYNAMIC MODEL OF HEAT-MASS EXCHANGE PROCESSES IN THE chamber of the sprayer moistening

Mathematical modeling of dynamic processes heat-mass exchange for a chamber of the sprayer moistening which is used in systems of an artificial microclimate for cooling and for the adiabatic moistening of air is observed. On the basis of the equations of material and thermal balance three equivalent models: in the form of systems of differential equations; state space; in the form of transfer functions, which allow to spend modeling of transients in a chamber of the sprayer moistening on the basic channels of influence are gained. Sampling of dynamic model is defined by methods of a control system synthesis of the industrial air conditioner and tastes of researcher. For raise of accuracy of mathematical calculations in paper experimental definition of factors heat-mass exchange which allows adapting dynamic model for concrete operating conditions of a chamber of the sprayer moistening is offered.The offered mathematical dependences are conveniently realized in the environment of Matlab. The instance of modeling of transients for sprayer humectants of air conditioner KCKP-80, which is manufactured by company VEZA is resulted. The gained transients have aperiodic character without delay. The analysis of transients after the possible channels of adjusting confirmed their high inertance, that is why during automation of industrial conditioners it follows to give up regulative influences in the chamber of the moistening after the change of temperature and expense of water on moistening.The dynamic model of sprayer humectants can be used by specialists on automation for the analysis and adjustment of parameters of control systems of industrial air conditioners.

Performance analysis of a new desiccant pre-treatment electrodialysis regeneration system for liquid desiccant

Liquid desiccant air-conditioning system (LDAS) is a novel air-conditioner with good energy saving potential. As a renewable energy, solar thermal energy (TH) can be used to regenerate desiccant for LDAS. One problem of the solar regeneration system is that solar energy will depend on weather conditions, which means that the solar regeneration system cannot meet the dehumidification requirements all the time. In this paper, a new desiccant pre-treatment electrodialysis (ED) regeneration system is proposed in order to improve the reliability and the performance of solar desiccant regeneration system for LDAS. The new system makes comprehensively use of solar energy and can work reliably under the variable conditions. Moreover, the new system can be used in the deep dehumidification field, which is required in industrial air-conditioning. Analysis of the new system, the solar TH regeneration system and the PV-ED regeneration system is made and the results reveal that the new system will be more energy efficient than others under the ideal operational condition. Among all factors, the most influential one is the concentration of desiccant at the entrance of concentrate cells in the ED regenerator, and the new system should be running under the ideal operational condition as possible.

Active Mechanical Vibration Control of Rotary Compressors for Air-conditioning Systems

Recent power electronics and variable-frequency motor drive technologies have been applied to air conditioners to improve efficiency and power density. However, the mechanical vibrations and acoustic noise resulting from the compressor still remain as a serious problem. This paper presents the development and implementation of an online disturbance state-filter for the suppression of multiple unknown and time-varying vibrations of air conditioning systems. The proposed design has a form of the state-filter based on a Luenburger-style closed-loop speed observer. An active vibration decoupling strategy with an estimated disturbance is provided, which manipulates a motor torque command. Since the proposed estimation does not require any additional transducers or hardware for obtaining real-time information upon disturbances, it is suitable for retrofitting industrial air conditioners.

Calculation methods for a complete air conditioning study

PurposeThe purpose of this paper is to describe and categorize calculation methods for conducting a complete air conditioning study. More specifically, this paper is a general review of cooling loads calculation methods, psychrometric calculations for installing a central air conditioning unit, ways of fan coil units connection and air duct calculation methods.Design/methodology/approachThis paper was based on two pillars: a dissertation for an industrial facility and technical information found after methodical research.FindingsAfter a brief reference of the calculation methods and the air conditioning systems installed in this industrial facility, this paper concludes with the most appropriate calculation methods for this industrial facility.Research limitations/implicationsThis study describes some calculation methods. Thus, future research could be addressed toward the analysis of more methods.Practical implicationsThis paper includes implications for choosing the most appropriate calculation method according to the air conditioning system installed.Originality/valueThe originality of this paper lies in the fact that, except for the theoretical part, there are some examples taken from a case study, thus it can be used as a future guide for selecting methods and systems of industrial air conditioning.

Analysis of control system for industrial air-conditioner with desuperheater

The industrial air-conditioner is a complex device, which can not operate in manual mode. The existing approaches to automation assume the decomposition of conditioning technology at intermediate portions with their subsequent automation. In this case, the control system does not take into account the mutual influence of the equipment. The article analyzes the artificial climate system as technological complex with an integrated control system. This approach permits to take into account the effect of external perturbations and technological interaction of the equipment in the control system. Applying the methods of structural analysis of the theory of control we obtained the parametric scheme of the industrial air-conditioner with desuperheater. To improve the quality of control it is recommended to apply the program-parameter setting of temperature and humidity regulators of the air-conditioner, depending on the season. The suggested parametric scheme can be used by specialists occupied with the design of industrial computer-integrated technological complex of air conditioning. This will bring the control system of the air conditioner to a higher level and will ensure the efficient consumption of energy for the artificial climate control system

Mathematical model of an industrial central air conditioner having a humidifier with irrigated packing

This article describes the specific features of the mathematical model of an industrial central air conditioner having a humidifier with irrigated packing. The complexity of heat and mass transfer processes in the irrigation chambers makes it difficult to obtain their unambiguous dynamic and static characteristics, and, moreover, different researchers get not only different calculated dependencies for determining transfer coefficients and time constants but also different forms of transfer functions. The control object in a two-link (two-channel) system is represented in P-canonical form. The convenience of such representation consists in that all transfer functions along the respective channels can be determined by active experiment.

AN APPLICATION OF ACTIVITY BASED COSTING IN THE AIR CONDITIONER MANUFACTURING INDUSTRY

AIRCO is a manufacturer of industrial air conditioner units whose management is concerned that their current traditional cost accounting (TCA) system is not accurately representing their product cost behavior. Under certain operating conditions, an activity based costing (ABC) system can provide relevant and accurate indirect cost information that assists in making customer, product, and process improvement decisions. An ABC system was successfully developed for AIRCO that indicated that their products do not consume overhead costs on a volume basis as represented by their current TCA system. Valuable product and process information were obtained. This case study details the development process that was used and the results that were obtained during the ABC analysis.

Keeping Things Cool: Air-Conditioning in the Modern World

What would we do without air-conditioning? It has become such an important part of every summer that most of us do not give it a second thought—that is, until the power goes out in the middle of August. In summer 2002, OAH's weekly radio program Talking History celebrated the one hundredth anniversary of the first industrial air-conditioner. Talking History's Fred Nielson interviewed Marsha Ackerman, author of Cool Comfort: America's Romance With Air-Conditioning (2002), about how air-conditioning truly revolutionized American culture. From increasing productivity in factories to creating the “cool comfort” of American malls and movie theaters on hot days, air-conditioning changed the ways in which people lived their lives and the locations in which they chose to live, work, and play. Because students probably take air-conditioning—and the mall—for granted, discussing the impact it has on their lives is a pedagogical device that might jolt them into new ways of...

Effects of Additional Vortices on Pulsating Flows with Free Convection in Horizontal Rectangular Ducts.

On duct system in industrial plants and air conditioners, free convection is produced by buoyancy forces in the fluid because of the temperature differences between the duct wall and the fluid. In previous papers (1997, 1998), a numerical analysis was shown on influences of free convection for steady laminar flows is horizontal rectangular ducts. As a result, it was indicated that secondary flow vortices in a cross section of the duct occur, and counter-rotating additional vortices arise in a region near the bisector of the bottom wall at high ReRa. The above phenomenon is also shown for pulsating flows in duct system with fluid machineries. For this pulsating flows with free convection, there is a few report in horizontal pipes, while there are few reports in horizontal rectangular ducts arising additional vortices. Therefore, pulsating laminar flows with free convection in horizontal rectangular ducts are studied numerically for air (Pr=0.73) at ReRa=106 with no additional vortex and ReRa=2×106 with additional vortices on steady flows. The effects of pulsating frequency ω on axial velocities, temperatures, stream lines of secondary flow, friction losses, Nusselt numbers and intensities of additional vortices are presented. Furthermore, the influences of ω and ReRa on amplitudes and phase lags of axial velocities and temperatures are also calculated, and these results are compared with the numerical data at ReRa=0 reported by Yakhot et al. (1999).

Active noise control of a duct using robust control theory

In this paper the control of sound propagation in an air-handling duct using a feedback active noise control (ANC) system is investigated both from a theoretical and from a practical point of view. Using identified discrete-time models of the duct, robust linear controllers are designed by means of the combined pole placement/sensitivity function shaping method. The specific features of the harmonic sources of noise and the study of the effect of model uncertainty on the ANC performance are taken into account in order to avoid the classical stochastic adaptive and the reference noise-based methods. As a consequence, our solutions are easy to implement in real-time applications. As an illustration, we give detailed results for the control of the noise in an industrial air conditioner propagating through a duct.

Major problems involved in creation of low-power-consuming turbocompressors for consumer and industrial air conditioners

A series of computation-theoretical studies are carried out concerneing the effect of the power indices of air conditioners having turbocompressors of the following factors : porperties of the coolants, type of thermodynamic cycle with single or double throttling, temperature regimes of operation, schemes of cooling of the built-in electric motor by boiling coolant with an intermediate cycle pressure and with boiling pressure, geometric and gas-dynamic characteristics of the centrifugal stages, efficiency of the electric drive and cooling power of the air conditioner

An experimental study for cold end orifice of vortex tube

Vortex tube is a simple device which splits a compressed gas stream into a cold stream and a hot stream without any chemical reactions. The phenomena of energy separation taking place in a vortex tube has been investigated experimentally. Recently, vortex tube is widely used to local cooler of industrial equipments and air conditioner of special purpose. In this study, experimental study on vortex tube efficiency was performed with various cold end orifices and nozzles type. The experimental results indicate that there is an optimum diameter of cold end orifice and nozzle type for the best cooling performance. The variation of the maximum wall temperature along the vortex tube surface provides useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. The similarity relation for the prediction of the temperature of the cold exit air was obtained.