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Pulmonary disease due to Mycobacterium chelonei subspecies abscessus: A report of four cases
13 Space heating and cooling W/O0574
Tubular ceramic supports
Rodriguez, C. M. Hernandez, L. R. T. Rev, Mex. Fir., 1999,45,61-63. (In Spanish) The employment of ceramic supports in the heterogeneous chemical and technological areas is spread in continuous form. For example; the multi-channel monolithic for motor car catalysts, the pilaread clay, the permeable membrane, and so forth. In this paper the results of five ceramic tubular supports are presented. The supports were composed from alumina-a, feldspar and mud. An assembling system with a machine of universal mechanic testing for direct and cold extrusion was designed. Moreover, dates of the monolithic micastructural characterization are shown, these sustain their possibilities for use as catalytic supports in reactive/permeable membranes and supports in anaerobic reactors.
13
SPACE HEATING AND COOLING
A model of the thermal transient state of a wall of a room during the heating by a heating system Massouros, P. er al. Int. J. Energy Res., 2000, 24, (9), 779-789. W/W575
After turnmg on a room heating system (e.g. central heating) a thermal transient phenomenon takes place on the wall-room system, until it reaches a final thermal equilibrium state. The temperature profiles on the wall cross-section, starting from an initial profile, corresponding to the initial thermal equilibrium state, come gradually through successive intermediate temperature profiles, to a final temperature profile corresponding to the final thermal equilibrium state. These intermediate, non-linear and time-dependent temperature profiles characterize the wall thermal transient state and describe the dynamic thermal behaviour of the wall-room system. The mass of the air in the room is negligible, compared to the mass of the surrounding walls, so the dynamic behaviour of the room-wall system is imposed by the corresponding thermal dynamic behaviour of the walls. The influence of this thermal transient state is important for the room heating behaviour because it acts as a thermal flywheel attenuating and smoothing the room temperature variations. In the present work, using the integral method, analytical expressions yielding the temperature profiles, and the duration of the transient state as a function of thermal and structural characteristics have been developed. Conclusions were drawn on the dynamic thermal behaviour of the room-wall system. A three-dimensional non-equilibrium model for an intermittent adsorption cooling system
W/W576
Zhang, L. Z. Solar Energy, 2000, 69, (I), 27-35. Intermittent adsorption cycles, driven by low temperature heat, like solar heat, instead of electricity or natural gas, can achieve substantial fossil energy savings. In this paper, the mathematical model for the coupled heat and mass transfer in the adsorber of an intermittent adsorption cooling system is set up. The model includes four submodels: heat transfer in heating/cooling fluids, heat transfer in the metal tube, heat transfer in the fins and heat and mass transfer in the adsorbent. The model for the heat and mass transfer in the adsorbent is a three-dimensional non-equilibrium model which takes into account both the internal and the external mass transfer resistance in the adsorbent. An experiment has been carried to validate the model. With some modifications, the model can be used in system optimization and design of adsorption cycles driven by solar energy or waste heat.
Ada tive control of multivariable thermal processes in l$VAC systems
00100577
Singh, G. et al. Energy Conversion & Managemenr, 2000,41, (15), 16711685. The application of adaptive control for a class of multivariable processes in heating, ventilating and air conditioning (HVAC) systems is studied. As an example, a two zone fan-coil heating (FCH) system is considered. The thermal dynamics of the FCH system and environmental zones are simulated by a non-linear model. The environmental zones are acted upon by multiple disturbances, such as changes in outdoor temperature, solar radiation fluxes and dynamic disturbances due to the thermal inertia of the enclosure elements. The control objective is to hold the zone temperatures and the boiler temperature close to their respective set-points irrespective of the changes in disturbances acting on the system. A multivariable adaptive controller based on LQR (Linear Quadratic Regulator) theory is designed. Simulation results showing the closed loop response of the system to changes in operating points, external disturbances, changes in system parameters and unmodelled dynamics are presented. It is shown that 60
Fuel and Energy Abstracts
January 2001
the adaptive controller is able to adapt to a wide range of operating conditions and is able to maintain the zone temperatures and the boiler temperature close to their respective set-points. 00100576 Analysis of thermal performance and energy savings of membrane based heat recovery ventilator Zhang, Y. er al. Energy, 2000, 25, (6), 515-527. The heat and mass transfer characteristics of a water permeable membrane were studied to determine appropriate selection criteria for such a membrane in a heat recovery ventilator (HRV). A general physical model was developed to analyse the performance of various types of membrane based HRVs. The theoretical results obtained using the model were validated experimentally. The advantages of such a system are: simultaneous recovery of the sensible and latent heat, high heat and moisture exchange effectiveness, no mechanical components and year-round energy savings in air-conditioning systems. The model and results can be used to develop membrane based heat recovery ventilators.,
Effects of shingle absorptivity, radiant barrier emissivity, attic ventilation flowrate, and roof slope on the performance of radiant barriers Medina, M. A. Znr. J. Energy Res., 2000, 24, (8), 665-678. 00100579
This paper presents a parametric study of the effects that shingle absorptivity, radiant barrier emissivity, attic ventilation flow-rate and roof slope have on the performance of radiant barriers in symmetrical residential attics. A heat balance model was developed to investigate these effects. The model was validated against experimental data and was found to predict with good accuracy. Of the four parameters investigated, only emissivity of the radiant barriers had first-order effects on their performance. Variations in the performance of the horizontal radiant barrier (HRB) configuration were minimal in the other three parameters. The truss radiant barrier (TRB) configuration showed slightly more variations because of the presence of uncovered end-gables. This paper presents a brief description of the heat balance model, the parametric studies and conclusions.
00100560 Energy conservation and potential of a sunspace: sensitivity analysis Mihalakakou, G. and Ferrante, G. Energy Convers. Manage., 2000, 41, (12), 1247-1264. The influence of different main design parameters on the heating/ cooling potential of a sunspace connected with a building has been investigated in the present paper. The sunspace consists of a glazed enclosure, usually on the south side of a building and it is regarded as one of the most popular solar systems because of its potential as an energy collecting system and also because of its pleasant appearance. The dynamic thermal performance of the system for the winter and summer periods of the year and its operational limits have been calculated using an accurate transient thermal model environment. The simulated results showed that sunspaces can be an appropriate and effective system during the cold period of the year. However, they are, very often, responsible for overheating during the warm period of the year. An extensive sensitivity investigation is performed in order to analyse the impact of various main system’s parameters, such as orientation, boundary conditions and glazing material on the energy potential of the system. 00100561 Feasibility of lowering the condenser’s inlet water temperature of a chiller using thermal water storage Asrael, J. er al. Applied Energy, 2000, 66, (4), 339-356. A novel approach is proposed for applying cool thermal storage to reduce the on-peak demand of a water-cooled chiller. By charging the store at night via a cooling tower and using this water to supply the condenser of a chiller during on-peak hours, cooler than normal water is supplied to the chiller. A feasibility study of this system was conducted using TRNSYS - a transient simulation modelling program examining varying capacities of cooling tower and thermal store volumes. These systems were tested using geographic weather data that demonstrated conducive diurnal changes in wet-bulb temperature (T,,,). Results suggest that the use of cool water thermal storage in this way can reduce both on-peak energy demand and on-peak power use by as much as 35%. System optimization is dependent on the thermal storage efficiency, the capacity of the cooling tower and the diurnal change in T,,,. 00100562 Interactions between lighting and space conditioning energy use in US commercial burldings Sezgen, 0. Koomey! J. G. Energy, 2000, 25, (8) 793-805. Reductions in lightmg energy have secondary effects on cooling and heating energy consumption. In general, lighting energy reductions increase heating and decrease cooling requirements of a building. The net change in a building’s annual energy requirements, however, is difficult to quantify and depends on the building characteristics, operating conditions, and climate. This paper characterizes the effects
Tubular ceramic supports
Rodriguez, C. M. Hernandez, L. R. T. Rev, Mex. Fir., 1999,45,61-63. (In Spanish) The employment of ceramic supports in the heterogeneous chemical and technological areas is spread in continuous form. For example; the multi-channel monolithic for motor car catalysts, the pilaread clay, the permeable membrane, and so forth. In this paper the results of five ceramic tubular supports are presented. The supports were composed from alumina-a, feldspar and mud. An assembling system with a machine of universal mechanic testing for direct and cold extrusion was designed. Moreover, dates of the monolithic micastructural characterization are shown, these sustain their possibilities for use as catalytic supports in reactive/permeable membranes and supports in anaerobic reactors.
13
SPACE HEATING AND COOLING
A model of the thermal transient state of a wall of a room during the heating by a heating system Massouros, P. er al. Int. J. Energy Res., 2000, 24, (9), 779-789. W/W575
After turnmg on a room heating system (e.g. central heating) a thermal transient phenomenon takes place on the wall-room system, until it reaches a final thermal equilibrium state. The temperature profiles on the wall cross-section, starting from an initial profile, corresponding to the initial thermal equilibrium state, come gradually through successive intermediate temperature profiles, to a final temperature profile corresponding to the final thermal equilibrium state. These intermediate, non-linear and time-dependent temperature profiles characterize the wall thermal transient state and describe the dynamic thermal behaviour of the wall-room system. The mass of the air in the room is negligible, compared to the mass of the surrounding walls, so the dynamic behaviour of the room-wall system is imposed by the corresponding thermal dynamic behaviour of the walls. The influence of this thermal transient state is important for the room heating behaviour because it acts as a thermal flywheel attenuating and smoothing the room temperature variations. In the present work, using the integral method, analytical expressions yielding the temperature profiles, and the duration of the transient state as a function of thermal and structural characteristics have been developed. Conclusions were drawn on the dynamic thermal behaviour of the room-wall system. A three-dimensional non-equilibrium model for an intermittent adsorption cooling system
W/W576
Zhang, L. Z. Solar Energy, 2000, 69, (I), 27-35. Intermittent adsorption cycles, driven by low temperature heat, like solar heat, instead of electricity or natural gas, can achieve substantial fossil energy savings. In this paper, the mathematical model for the coupled heat and mass transfer in the adsorber of an intermittent adsorption cooling system is set up. The model includes four submodels: heat transfer in heating/cooling fluids, heat transfer in the metal tube, heat transfer in the fins and heat and mass transfer in the adsorbent. The model for the heat and mass transfer in the adsorbent is a three-dimensional non-equilibrium model which takes into account both the internal and the external mass transfer resistance in the adsorbent. An experiment has been carried to validate the model. With some modifications, the model can be used in system optimization and design of adsorption cycles driven by solar energy or waste heat.
Ada tive control of multivariable thermal processes in l$VAC systems
00100577
Singh, G. et al. Energy Conversion & Managemenr, 2000,41, (15), 16711685. The application of adaptive control for a class of multivariable processes in heating, ventilating and air conditioning (HVAC) systems is studied. As an example, a two zone fan-coil heating (FCH) system is considered. The thermal dynamics of the FCH system and environmental zones are simulated by a non-linear model. The environmental zones are acted upon by multiple disturbances, such as changes in outdoor temperature, solar radiation fluxes and dynamic disturbances due to the thermal inertia of the enclosure elements. The control objective is to hold the zone temperatures and the boiler temperature close to their respective set-points irrespective of the changes in disturbances acting on the system. A multivariable adaptive controller based on LQR (Linear Quadratic Regulator) theory is designed. Simulation results showing the closed loop response of the system to changes in operating points, external disturbances, changes in system parameters and unmodelled dynamics are presented. It is shown that 60
Fuel and Energy Abstracts
January 2001
the adaptive controller is able to adapt to a wide range of operating conditions and is able to maintain the zone temperatures and the boiler temperature close to their respective set-points. 00100576 Analysis of thermal performance and energy savings of membrane based heat recovery ventilator Zhang, Y. er al. Energy, 2000, 25, (6), 515-527. The heat and mass transfer characteristics of a water permeable membrane were studied to determine appropriate selection criteria for such a membrane in a heat recovery ventilator (HRV). A general physical model was developed to analyse the performance of various types of membrane based HRVs. The theoretical results obtained using the model were validated experimentally. The advantages of such a system are: simultaneous recovery of the sensible and latent heat, high heat and moisture exchange effectiveness, no mechanical components and year-round energy savings in air-conditioning systems. The model and results can be used to develop membrane based heat recovery ventilators.,
Effects of shingle absorptivity, radiant barrier emissivity, attic ventilation flowrate, and roof slope on the performance of radiant barriers Medina, M. A. Znr. J. Energy Res., 2000, 24, (8), 665-678. 00100579
This paper presents a parametric study of the effects that shingle absorptivity, radiant barrier emissivity, attic ventilation flow-rate and roof slope have on the performance of radiant barriers in symmetrical residential attics. A heat balance model was developed to investigate these effects. The model was validated against experimental data and was found to predict with good accuracy. Of the four parameters investigated, only emissivity of the radiant barriers had first-order effects on their performance. Variations in the performance of the horizontal radiant barrier (HRB) configuration were minimal in the other three parameters. The truss radiant barrier (TRB) configuration showed slightly more variations because of the presence of uncovered end-gables. This paper presents a brief description of the heat balance model, the parametric studies and conclusions.
00100560 Energy conservation and potential of a sunspace: sensitivity analysis Mihalakakou, G. and Ferrante, G. Energy Convers. Manage., 2000, 41, (12), 1247-1264. The influence of different main design parameters on the heating/ cooling potential of a sunspace connected with a building has been investigated in the present paper. The sunspace consists of a glazed enclosure, usually on the south side of a building and it is regarded as one of the most popular solar systems because of its potential as an energy collecting system and also because of its pleasant appearance. The dynamic thermal performance of the system for the winter and summer periods of the year and its operational limits have been calculated using an accurate transient thermal model environment. The simulated results showed that sunspaces can be an appropriate and effective system during the cold period of the year. However, they are, very often, responsible for overheating during the warm period of the year. An extensive sensitivity investigation is performed in order to analyse the impact of various main system’s parameters, such as orientation, boundary conditions and glazing material on the energy potential of the system. 00100561 Feasibility of lowering the condenser’s inlet water temperature of a chiller using thermal water storage Asrael, J. er al. Applied Energy, 2000, 66, (4), 339-356. A novel approach is proposed for applying cool thermal storage to reduce the on-peak demand of a water-cooled chiller. By charging the store at night via a cooling tower and using this water to supply the condenser of a chiller during on-peak hours, cooler than normal water is supplied to the chiller. A feasibility study of this system was conducted using TRNSYS - a transient simulation modelling program examining varying capacities of cooling tower and thermal store volumes. These systems were tested using geographic weather data that demonstrated conducive diurnal changes in wet-bulb temperature (T,,,). Results suggest that the use of cool water thermal storage in this way can reduce both on-peak energy demand and on-peak power use by as much as 35%. System optimization is dependent on the thermal storage efficiency, the capacity of the cooling tower and the diurnal change in T,,,. 00100562 Interactions between lighting and space conditioning energy use in US commercial burldings Sezgen, 0. Koomey! J. G. Energy, 2000, 25, (8) 793-805. Reductions in lightmg energy have secondary effects on cooling and heating energy consumption. In general, lighting energy reductions increase heating and decrease cooling requirements of a building. The net change in a building’s annual energy requirements, however, is difficult to quantify and depends on the building characteristics, operating conditions, and climate. This paper characterizes the effects