Ramesh C. Chawla

Fuzzy Neural Network-Based Health Monitoring for HVAC System Variable-Air-Volume Unit

For indoor smart grids, the proper operation of building environmental systems is essential to energy efficiency, so automatic detection and classification of abnormal conditions are important. The application of computational intelligence tools to a buildings environmental systems that include the building automation system (BAS) and heating ventilating and air conditioning (HVAC) loads is used to develop automatic building diagnostic tools for health monitoring, fault detection, and diagnostics. A novel health monitoring system (HMS) for a variable air volume (VAV) unit is developed using fuzzy logic (FL) to detect abnormal operating conditions and to generate fault signatures for various fault types. Artificial neural network classification technique is applied to fault signatures to classify the fault type. The HMS is tested with simulated data and actual BAS data. The system created was demonstrated to recognize faults and to accurately classify the various fault signatures for test faults of interest.

An experimental and theoretical study of the nonlinear heat conduction in dry porous media

Heat transfer in porous media is important in various engineering fields, including contaminated soil incineration. Most heat transfer models are theoretical in nature. Consequently, this study was undertaken to perform both theoretical and experimental studies of heat transfer in two different sand matrices. A mathematical model based on Fouriers law of heat conduction for a one-dimensional system with the variable thermal conductivity was developed. The experimental part included heating sand samples placed in a small reactor within an infrared furnace. The transient temperature profiles of the sand layers were monitored by thermocouples. The bulk thermal conductivity was estimated to be linearly proportional to the temperature. The temperature profiles predicted by the model of heat conduction with a variable bulk thermal conductivity was compared by the observed temperatures in Quartz and Sea sands matrices up to 1300 K. Copyright

Contaminant removal from dry and wet sands by thermal desorption

Infrared heating was used to determine the effects of temperature and moisture on the removal of selected organic compounds from contaminated sand matrices. Quartz sand was used as a chemically inert surrogate for soil to isolate the heat transfer and mass transfer effects without any chemical contribution from soil. The selected organic contaminants were 3-nitrobenzene sulphonic acid, sodium salt (NBSS) and naphthalene (NAPH). The results of the weight loss data and concentration analyses of the contaminants in the sand showed that at similar concentrations and operating temperatures, a short period of time was required for NAPH, compared to the time required for NBSS, for achieving the same removal level. Temperature profiles in dry quartz sand were determined experimentally and predicted by a one-dimensional conduction model with variable thermal conductivity. The results from the wet sand experiments indicate that the presence of small moisture content can help the removal process by providing an additional convective heat transfer mechanism.

Pollutant Transfer Between Air, Water and Soil: Criteria for Comprehensive Pollution Control Strategy

Large amounts of pollutants are continuously discharged into air, water or soil — the three domains of the Ecosystem. These domains have mutual interactions in terms of mass transfer, which affect the concentration of these pollutants both temporally and spacially in all domains. The intra-domain interactions that influence the pollutant transfer between air, water and soil may be either due to the bulk phase transfer (e.g., acid rain) or due to interfacial transfer (e.g., pesticide evaporation from soil to air). The mathematical equations based on the general principles of mass transfer such as Ficks Law of Diffusion and Raults Law, and equilibrium relationships can quantitatively predict the pollutant transfer from one phase to another. Thus far, our pollution control efforts have been directed at each individual domain without much regard to their effect on the other domains. This has, in some cases, merely shifted the problem instead of solving it. A basic understanding of transfer processes is presented here. The problem of trihalomethanes in water is discussed to support the case for a comprehensive pollution control strategy which makes both technical and economic sense.

Organic products of incomplete combustion of colored bags and inks

The goal of this study was to identify and trace the possible sources of organics emitted during the laboratory incineration of colored paper bags. An infrared incinerator was used to separately burn segments of colored paper bags and each ink component of the bags at a temperature of 300°C. Chemical analyses were performed to characterize the Products of Incomplete Combustion (PICs) emitted during the combustion process. A gas chromatograph/mass spectrometer (GC/MS) was used to identify organic groups ranging from alkanes to aromatics and polycyclic compounds. PICs identified and traced to their sources include: benzaldehyde, ethenylbenzene, furfural, naphthalene, and phenol.