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Through analyzing the control effect of three different controllers, such as PID, fuzzy control and fuzzy-PID, it was proved that fuzzy-PID parameters self-tuning controller can make central air-conditioning system get well dynamic and steady performance, Simulation results showed that the fuzzy-PID method can restrain its time delay,high inertia and non-linearity. Using fuzzy-PID parameters self-tuning...
Task conditioning aims to provide each occupant with personalized clean air direct to the breathing zone. Microenvironment of a typical office workplace consisting of different task air conditioning system, such as CMP (computer monitor panel), MP (movable panel), horizontal desk grill (HDG) and vertical desk grill (VDG) are studied by numerical simulation. Numerical simulation by k-epsiv 3-D turbulent...
The environment of room temperature is complicated and it is difficult to get precise mathematics model for the control of air-condition with frequency change. It is difficult using conventional PED or general fuzzy control way to control air-condition to get good control performance. A new fuzzy controller is designed to control air-condition based on fuzzy reasoning system and genetic algorithm...
In this paper, the attribute recognition model was used to identify indoor air quality evaluation. The objective weighting method of variation coefficient and entropy method were also used to determine the weights of evaluate indicators. Then this model was used in four buildings, the evaluate result was in line with the actual situation. This attribute recognition model is fully applicable and feasible,...
The authors conduct the experimental study andsimulation for the automobile air conditioning parallel flow condenser, especially study the properties of heat transfer and flow at the side of air when using louver fin. This model used a finite volume method to predict the condenser performance. The properties of air and refrigerant at outlet of each element were determined by the effectiveness-NTU...
This paper describes the design of a liquid desiccant air conditioning system using low-grade heat resource, which employs environmental-friendly, ozone-safe working substance - LiCl solution as the desiccant and is able to treat the ambient air at a high temperature 35degC to the air conditioning supply air at a low temperature 18degC. It can handle both latent and sensible heat load of the room...
By the steady state incompressible Reynolds-averaged Navier-Stokes equations, turbulence model, the finite volume method with interlacing of discretization, the three-dimension airflow and temperature fields inside a passenger vehicle are calculated numerically. The solar radiation and body heat are additional source term of energy equation, the influence of passenger and solar radiation on airflow...
This paper presents the results of simulating and evaluating an under-voltage protection scheme, which takes stalled air-conditioner (a/c) units offline so that the slow voltage recovery phenomena can be prevented in areas heavily loaded with AC motors during summer peak periods. First, a three-feeder test-bed was used to quantify the effectiveness of the protection scheme and the sensitivity of the...
Designed the fuzzy controller of the automobile air-conditioner and built the simulation frame of automobile air-conditioner compartment temperature, established fuzzy membership, fuzzy outputs and translated fuzzy outputs to precise value, simulated which under summer environment, the temperature in the automobile can be controlled in the expected scope.
PID control has been widely used for air-conditioning system but there still remain a lot of possibilities. It will be then natural desire to try to eliminate the effects of disturbances before they have created control errors. An example is a certain system for an air-conditioning system in which an outdoor thermometer detects sudden weather changes and the supply air flowrate can be appropriately...
This paper investigates how to use robust model prediction control in air-conditioning systems. Air-conditioning processes are described using a first-order plus time-delay model associated with uncertainties in process gain, time constant and time-delay. An uncertainty polytope is developed to describe the corresponding uncertainties when the continuous model is sampled into a discrete one and further...
In order to cut down air-condition energy consumption in the communication room and reduce the heat island effect partially, through the use of CFD (computational fluid dynamics), we have a study on airflow characteristics in communication engine-room. On the basis of established mathematical and physical equation about airflow characteristics, we try to get the numerical solution, and analyze the...
This paper presents our study in designing a 700 acre low-energy community on the Island of Hawaii. This study was an interdisciplinary collaboration among engineering, architecture, landscape architecture and business management. We took an integrated approach, which encompasses reducing energy demand, optimizing on-site renewable energy generation, implementing an efficient energy distribution system...
Full-scale model of a representative data center was developed, with the arrangement of bringing outside air under suitable conditions. Four different world cities were considered to evaluate the energy savings over the entire year. Results show a significant saving in chiller energy (up to 70%), and even the possibility of switching off chillers for certain months of the year. The details of relative...
The improved control algorithm in central air conditioning control system is discussed in this paper. Based on a number of practical projects, a primary theory model of expert fuzzy logic controller is established. The expert control ideal is applied in the framework design process of the air conditioning control system. The boundaries of membership function are decided by expert experience, and the...
The performance of multi-split air conditioning system is very complex because of the interaction among different evaporators. An optimal control method and a two-stage fuzzy proportional integral derivative (FPID) controller for room temperature control are proposed. The salient feature of the two-stage FPID controller is that it has a simple structure and is easy to implement. The controllability...
The paper has studied features of a regional air conditioning mechanism (RACM) and CFD model to predict the comfort properties in a certain area of a workroom. The paper described the constructs of RACM, the use of computational fluid dynamics software Fluent to analyze turbulent airflow and setting up the heat transfer parameters of a certain area with RACM. As the numerical simulation of many cases...
This paper presents a set of pedagogical solutions, their analysis, test and improvement, for an autonomous computer aided learning module. The content of the module is an introduction to digital control, based on a real (but simulated) industrial system: the automatic air conditioning system inside a modern car. The rather theoretical contents are presented without any mathematics to our non specialist...
Since variable air volume (VAV) systems become more economical than other alternative systems, the building industry nowadays has widely adopted VAV systems in the building engineering to maintain the cooling and heating demands. However, because VAV system is multivariable, strongly coupled, nonlinear, and time variant, it is more difficult in design, performance and management than constant air...
According to the recent newsletter on energy efficiency and related matters, No. 8 published by electrical & mechanical services department, it was recommended the air-conditioned room temperature in summer be set to 25.5degC. It was admitted by E.M.S.D. that 25.5degC might not be everyone's most preferred temperature, but it is a temperature that can save a substantial amount of energy. An estimation...
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