Multi-zone Space Research Articles

Dynamics of state of former agricaltural lands taken out of agricatrure after the Chernobyl accident, according to remote sensing data

Results of assessment of condition (overgrowth of woody and shrubby vegetation), for example, of former agricultural land, taken out of agriculture, in western area of the European part of the Russian Federation (Bryansk region) using algorithms for automated detection of changes in multi-time multi-zone space images are presented. To perform the work, data from TM radiometers (Landsat 5) were selected from available data for study area, and two images of different times (2011 and 2018) were formed. Automated processing included following stages: preliminary processing of satellite images; determination of difference vegetation index (NDVI) based on index images assessment of changes in multi-time images by principal component method (РСА) based on formation of more informative combinations of source images obtained in different spectral zones and reduction of set of analyzed data; identification of changes by difference method based on difference in brightness of each pixel of first image and brightness of corresponding pixel of second image combined with first. Evaluation of use of algorithms for automated detection of changes in multi-time satellite images has shown that joint image processing makes it much better to assess the processes of changes that have occurred on former agricultural land, derived from agricultural turnover.

Control-Oriented, Data-Driven Models of Thermal Dynamics

We investigate data-driven, simple-to-implement residential environmental models that can serve as the basis for energy saving algorithms in both retrofits and new designs of residential buildings. Despite the nonlinearity of the underlying dynamics, using Koopman operator theory framework in this study we show that a linear second order model embedding, that captures the physics that occur inside a single or multi zone space does well when compared with data simulated using EnergyPlus. This class of models has low complexity. We show that their parameters have physical significance for the large-scale dynamics of a building and are correlated to concepts such as the thermal mass. We investigate consequences of changing the thermal mass on the energy behavior of a building system and provide best practice design suggestions.

Remote sensing as a method of predicting PGM mineralization based on the results of the study of the Eastern Sector Bushveld complex

In this paper, a study of the differentiated Bushveld complex (South Africa) is carried out on the basis of remote cosmic and gravimagnetic methods. The article shows the possibility of using Landsat 7 ETM+ multi-zone space imagery and brightness characteristics to predict platinum mineralization in new promising areas. Analysis of the values of the gravitational field showed that in the area under study, platinum mineralization is concentrated in a fairly narrow range of values, which makes it possible to use this data as a search feature. The main conclusions have been formulated and the possibilities of the Landsat 7 ETM + multi-zone space survey to forecast platinum mineralization in new promising areas have been clearly demonstrated. The conducted studies prove the efficiency of the integration of remote (space and geophysical) to improve the approach to prospecting for platinum-coppernickel mineralization.

Application of remote sensing for detection of zones of cataclastic and metasomatic rocks on the area of the Uvatsky ore cluster (Eastern Sayan)

Interpretation materials of the Russian space survey «Resource-P» (Geotone) in the visible and infrared bands made it possible to identify crush belts and faults of the northeastern, sublatitudinal and submeridional strike that determine the structural position of uranium mineralization within the Uvat ore cluster in the East Sayan. The principal possibility of using a high-resolution multi-zone space survey (3 m) for detecting metasomatically altered ore-bearing rocks of the Lower Proterozoic and Riphean-Paleozoic carbonate-terrigenous deposits was determined.

Characterizing transport and deposition of particulate pollutants in a two-zone chamber using a Markov chain model combined with computational fluid dynamics

• Markov chain model combined with CFD for multi-zone space proposed. • Exposure levels and deposition rates of particulate pollutants analyzed. • Proposed model may be of practical use for obtaining real-time predictions. Understanding the distribution and spread of indoor airborne contaminants between rooms in a multi-zone space is crucial for protecting human health and indoor environmental control. Predicting the transmission of suddenly released particulate pollutants from one room to another in a rapid and precise manner is important for reducing or even eliminating the risk of cross contamination between occupants. In this study, we developed a modified Markov chain model that considers the effect of gravity to predict the dispersion and deposition of aerosol particles in a two-zone chamber. To perform particle phase simulations, the proposed model couples the data obtained from a steady-state flow field using the computational fluid dynamics (CFD) software Fluent with some codes that we developed in the MATLAB environment. Two examples based on previously reported experimental data were used to validate the proposed model. The results indicate that the proposed model is suitable for modeling the dynamic processes where airborne particles are released from constant and pulsed contaminant sources in multi-zone spaces with reasonable accuracy and computational efficiency. After analyzing particle exposure in the two-zone chamber, we found that the accumulated exposure level in the zone with the constant contaminant source always had a higher rate of increase than the other zones. However, the accumulated exposure level for the pulsed (instantaneous) source was inversely proportional to the air exchange rate for all zones. Compared with traditional CFD models and multi-zone models, our proposed model can balance the accuracy and efficiency when predicting the spread of particulate contaminants in multi-zone spaces by choosing appropriate grid resolution (s).

Investigation of the dynamics of ephemeral gully erosion on arable land of the forest-steppe and steppe zone of the East of the Russian Plain from remote sensing data

Spatio-temporal estimation of the erosion of arable soils is still an urgent task, in spite of the numerous methods of such assessments. Development of information technologies, the emergence of high and ultra-high resolution images allows reliable identification of linear forms of erosion to determine its dynamics on arable land. The study drew attention to the dynamics of the most active erosion unit – an ephemeral gully. The estimation of the dynamics was carried out on the basis of different space images for the maximum possible period (from 1986 to 2016). The cartographic method was used as the main research method. Identification of a belt of ephemeral gully erosion based on materials of multi-zone space surveys and GIS-technology of their processing was carried out. In the course of work with satellite imagery and subsequent verification of the received data on the ground, the main signs of deciphering the ephemeral gully network were determined. A methodology for geoinformation mapping of the dynamics of ephemeral gully erosion belt was developed and a system of indicators quantitatively characterizing its development on arable slopes was proposed. The evaluation of the current ephemeral gully network based on the interpretation of space images includes the definition of such indicators of ephemeral gully erosion as the density of the ephemeral gully net, the density of the ephemeral gullies, the area and linear dynamics of the ephemeral gully network. Preliminary results of the assessment of the dynamics of the belt erosion showed an increase in all quantitative indicators of ephemeral gully erosion for the observed period.

Multi-zone outdoor air coordination through Wi-Fi probe-based occupancy sensing

As most urban residents spend an average 90% of their time in buildings, it is crucial for building residents to monitor and maintain a comfortable indoor environment and air quality. Controlling the indoor carbon dioxide (CO2) concentration level is the major objective of mechanical ventilation systems to ensure healthy indoor air quality (IAQ). Current methods utilize proportional–integral–derivative (PID) controllers and multi-zone equations to operate ventilation systems in large spaces based on ASHRAE Standard 62. However, this approach suggests to determine the fresh air supply rate primarily based on CO2 level without considering occupancy. This often results in insufficient fresh air or energy waste in unnecessary mechanical operations in unoccupied building zones. Therefore, this study proposes a ventilation strategy based on occupancy profiles that captured by a Wi-Fi probe enabled occupancy sensing system. Based on the detected occupancy profiles, the proposed ventilation strategy and other two conventional strategies were compared in a two-day experiment conducted a multi-zone space. The comparison results in the experiment show that the proposed approach could maintain a CO2 concertation level lower than 1000 ppm for 94% (weekday) and 80% (weekend day) of day time for all zones. At the same time, the proposed strategy saved about 44.26% (weekday) and 55.5% (weekend day) of ventilation energy consumption when compared to the fixed rate ventilation strategy and saved about 23.6% (weekday) and 46.1% (weekend day) of ventilation energy consumption when compared to the multi-zone equation strategy.

MODELLING AND EXPERIMENT OF BUILDINGS THERMO-AERAULIC BEHAVIOR ACCORDING TO THE LEVEL-COMPACTNESS IN SAHARAN CLIMATE CONDITIONS

A large number of studies of building energy simulation neglect the humidity, or well represented, with a very simplified method. It is for this reason that we have developed a new approach to the description and modelling of multizone buildings in Saharan climate. The concept of the form factor and index compactness “quotient of external walls area and volume of the building” are two of the key elements for analyzing the building geometry. We can introduce it’s as validation tools in some cases. In this paper, governing equations of physical phenomena allow to build a model of the thermo-aeraulic behavior. The primary objective is the validation of numerical results able to determine the humidity and temperature in a multizone space. The calculated results were compared with firstly, experimental values, and secondly with simulated results using TRNSYS software. We check if the results change radically for an invariable compactness index. The comparison shows that the found results are to some extent satisfactory. For buildings of similar thermal properties, especially, the used construction materials, the thermal insulation and thermal inertia level, orientation, etc., the result proves that temperature and specific humidity varie slightly when the compactness index is constant.

Decentralized [formula omitted] controller design for a multi-zone space heating system

The multi zone space heating system (MZSH) is an interconnected dynamical system subject to external disturbances and input saturation. In this paper, the problem of temperature control design in MZSH is investigated. The design of decentralized H∞ controllers are tackled using an iterative-procedure based on the homotopy method. Numerical simulation are presented and compared with an improved decentralized method based on linear quadratic theory to show the efficacy of the developed approach.

Forecasting simulations of indoor environment using data assimilation via an Ensemble Kalman Filter

Data assimilation is widely used in weather forecasting and other complex forecasting problems such as hydrology, meteorology, and fire dynamics. Among various data assimilation methods, the Ensemble Kalman Filter (EnKF) is one of the best solutions to large-scale nonlinear problems while the computational cost is relatively less intense than other forecasting methods. In this paper, a new application of EnKF to forecast indoor contaminant concentrations is presented. The first part of the paper introduces the fundamental theories of data assimilation. The second part is a case study of forecasting the concentrations of a tracer gas in a multi-zone manufactured house by using a mass balance model with an EnKF. The benefits of EnKF and several important parameters for EnKF were discussed including numbers of ensemble members and observations, time step of observations, and forecasting lead time. The EnKF method presented is one of the first studies applied to the indoor environment field. It was shown that by using EnKF, the predictability of the simple indoor air model for the multi-zone space was improved significantly.

Optimization of a liquid desiccant based dedicated outdoor air-chilled ceiling system serving multi-zone spaces

A liquid desiccant based dedicated outdoor air-chilled ceiling (DOAS-CC) system is proposed to serve a multi-zone space. The outdoor airflow rate and the supply air humidity ratio are two crucial variables in such a system, which significantly influence indoor thermal comfort, indoor air quality and energy consumption. Two strategies are presented to optimize these two variables in the study. They are the demand-controlled ventilation (DCV) strategy and the supply air humidity ratio set-point reset strategy. To evaluate the performances of these two strategies, a basic control strategy, i.e., the strategy adopting constant ventilation flow rate and constant supply air humidity ratio, is selected as the benchmark. Performances of the two strategies in terms of indoor air temperature, relative humidity and CO2 concentration as well as energy consumption are analyzed using simulation tests. The results show that the supply air humidity ratio set-point reset strategy is effective for the indoor air humidity control. It can save about 19.4% of total energy consumption during the whole year. The DCV-based ventilation strategy can further reduce about 10.0% of energy consumption.

Model-based optimal control of a dedicated outdoor air-chilled ceiling system using liquid desiccant and membrane-based total heat recovery

This study presents a model-based control strategy for a novel dedicated outdoor air-chilled ceiling (DOAS-CC) system with the aim of optimizing the overall system performance. The DOAS-CC system incorporates liquid desiccant dehumidification and membrane-based total heat recovery technologies. Simplified but reliable models of major components in the DOAS-CC system are firstly developed to predict the system performance. A cost function is then constructed to minimize total energy consumption while properly maintaining thermal comfort reflected by indoor air temperature and relative humidity. Genetic algorithm is used to search for optimal set-points of the supply air temperature and humidity ratio of the dedicated outdoor air subsystem as well as the supply water temperature. The performance of this strategy is tested and evaluated with different control settings in a simulated multi-zone space served by the DOAS-CC system under various weather conditions. The results show that optimized control variables produced by the optimal strategy can improve the system energy performance and maintain indoor thermal comfort.

Study on the all-coefficient adaptive sequential decoupling control

Multi-zone space crystal furnace is the key equipment to produce excellent crystal materials. But it is difficult to implement the decoupling control among multi-zone due to the constraints in transient power dissipation and working time. In this paper, according to the working modes of the multi-zone space crystal furnace in China, an all-coefficient adaptive sequential decoupling control method is proposed, which combines the all-coefficient adaptive theory with the idea of sequential decoupling. There is no need to design performance index function and solve complex Diophantine equation in this method. Furthermore, this approach has the character of strong robustness. Finally, an example of a two zones space crystal furnace is provided and an all-coefficient adaptive sequential decoupling control system is designed to simulate the running process based on the working mode in our country. The simulation results show that the proposed method is effective and suitable for more zones crystal furnace.

Adaptive neuro-fuzzy based inferential sensor model for estimating the average air temperature in space heating systems

The heating systems are conventionally controlled by open-loop control systems because of the absence of practical methods for estimating average air temperature in the built environment. An inferential sensor model, based on adaptive neuro-fuzzy inference system modeling, for estimating the average air temperature in multi-zone space heating systems is developed. This modeling technique has the advantage of expert knowledge of fuzzy inference systems (FISs) and learning capability of artificial neural networks (ANNs). A hybrid learning algorithm, which combines the least-square method and the back-propagation algorithm, is used to identify the parameters of the network. This paper describes an adaptive network based inferential sensor that can be used to design closed-loop control for space heating systems. The research aims to improve the overall performance of heating systems, in terms of energy efficiency and thermal comfort. The average air temperature results estimated by using the developed model are strongly in agreement with the experimental results.

Development and Validation of a Multizone Model for Overall Indoor Air Environment Prediction

Many factors can affect the indoor air environment of residential buildings. The most important factors are airflow, air temperature, air humidity, and air contaminant concentration. An indoor air quality analysis that includes the important factors (temperature, humidity, airflow, and concentration) simultaneously, is appropriately entitled ‘overall indoor air environment analysis’. A dynamic model to describe the overall indoor air environment and to determine its variations in a multizone space is proposed. The model analysis was applied to a typical apartment with five rooms on the campus in Yunlin, Taiwan, to compare the overall indoor air environment inferred from experimental data with simulated results in multizone spaces. There was an average agreement between the model and the measurements to within 8% variation.

The Evaluation of Total Indoor Air Quality in a Multizone Model of a Building

Many factors affect the indoor environment of residential buildings. Among those factors are airflow, temperature, humidity and concentration. A total indoor air quality model which can simultaneously simulate the above four important factors in a multizone space is proposed. A case study of a typical six-room apartment is presented to demonstrate the total indoor air quality in a multizone space as well as the effect of thermal comfort. This is discussed using PMV and PPD indices.

Optimal Tracking Control of Multi-Zone Indoor Environmental Spaces

Optimal control of indoor environmental spaces is explored. A physical model of the system consisting of a heating system, a distribution system and an environmental zone is considered and a seventh order bilinear system model is developed. From the physical characteristics and open-loop response of the system, it is shown that the overall system consists of a fast subsystem and a slow subsystem. By including the effects of the slow subsystem in the fast subsystem, a reduced order model is developed. An optimal control law is designed based on the reduced order model and it is implemented on the full order nonlinear system. Both local and global linearization techniques are used to design optimal control laws. Results showing the disturbance rejection characteristics of the resulting closed-loop system are presented. The use of optimal tracking control to implement large changes in setpoints, in a prescribed manner, is also examined. A general model to describe environmental zones is proposed and its application to multi-zone spaces is illustrated. A multiple-input optimal tracking control law with output error integrators is designed. The resulting closed-loop system response to step-like disturbances is shown to be good.

222 Temperature control of multi-zone space heating systems using decentralized robust controllers: M. Zaheer-uddin, R.V. Patel, S..A.K, Al-Assadi, pp 1073–1076

222 Temperature control of multi-zone space heating systems using decentralized robust controllers: M. Zaheer-uddin, R.V. Patel, S..A.K, Al-Assadi, pp 1073–1076

Temperature Control of Multi-Zone Space Heating Systems Using Decentralized Robust Controllers

In this paper, temperature control of multi-zone environmental spaces is studied. Decentralized and centralized controllers are designed based on solving constrained servomechanism problems for a bilinear system. Simulation results are presented which show the regulation properties of the decentralized and centralized controller designed for the bilinear model. A decentralized controller is also designed for the bilinear model based on minimizing not only the output error and input energy but also a measure of sensitivity to parameter variations. Simulation results for the corresponding bilinear closed-loop system are presented.

The dynamic modelling of air humidity behaviour in a multi-zone space

Single-zone dynamic modelling of air humidity can fairly account for most moisture transfer processes in single-zone buildings. However, such models cannot truly represent air humidity behaviour in most building since they have distinct interior partitioning of their volumes. A dynamic model to describe the air humidity behaviour and to determine its variations in a multi-zone space is proposed. The model accounts for boundary conditions variation from one zone to another, the different zonal interaction with the outdoor environment and the individual zonal functional and physical characteristics. The model accounts for both diffuse moisture transfer and convective moisture transfer due to inter-zonal air movement. A multi-cell air flow model that accounts for individual zone air flow, air flow through the envelope in each zone and the inter-zonal air flow is incorporated. Air humidity within each zone is determined through a simultaneous solution of a set of linear algebraic equations using time dependent humidity parameters. A discrete time interval approach was used since most moisture transfer processes are not continuous in nature. A case study on a six-zone building space is presented to demonstrate the air humidity behaviour in a multi-zone space as well as to examine the effect of the influencing parameters such as wind speed and direction, air leakage characteristics, indoor moisture generation, surface condensation, inter-zonal air temperature variation, and building materials absorption and desorption. The results also showed the uniqueness of individual zones air humidity behaviour and its dependence on its relative location along the building air humidity flow path.