Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.

Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.

Modern reservoir management typically involves simulations of geological models to predict future recovery estimates, providing the economic assessment of different field development strategies. Integrating reservoir data is a vital step in developing reliable reservoir performance models. Currently, most effective strategies for traditional manual history matching commonly follow a structured approach with a sequence of adjustments from global to regional parameters, followed by local changes in model properties. In contrast, many of the recent automatic history matching methods utilize parameter sensitivities or gradients to directly update the fine-scale reservoir properties, often ignoring geological inconsistency. Therefore, there is need for combining elements of all of these scales in a seamless manner. We present a hierarchical streamline-assisted history matching, with a framework of global-local updates. A probabilistic approach, consisting of design of experiments, response surface methodology and the genetic algorithm, is used to understand the uncertainty in the large-scale static and dynamic parameters. This global update step is followed by a streamline-based model calibration for high resolution reservoir heterogeneity. This local update step assimilates dynamic production data. We apply the genetic global calibration to unconventional shale gas reservoir specifically we include stimulated reservoir volume as a constraint term in the data integration to improve history matching and reduce prediction uncertainty. We introduce a novel approach for efficiently computing well drainage volumes for shale gas wells with multistage fractures and fracture clusters, and we will filter stochastic shale gas reservoir models by comparing the computed drainage volume with the measured SRV within specified confidence limits. Finally, we demonstrate the value of integrating downhole temperature measurements as coarse-scale constraint during streamline-based history matching of dynamic production data. We first derive coarse-scale permeability trends in the reservoir from temperature data. The coarse information are then downscaled into fine scale permeability by sequential Gaussian simulation with block kriging, and updated by local-scale streamline-based history matching. he power and utility of our approaches have been demonstrated using both synthetic and field examples.

Atmospheric convection is sensitive to the nature of the surface and its temperature. Both dry (without cloud) and moist (with cloud) convections depend on the surface temperature. Surface temperature is of critical importance in several practical applications like human comfort and crop cultivation. In the climate change scenario too, variations in the surface temperature take the center stage. Therefore, prediction of surface temperature is important. The evolution of the temperature is governed by the energy equation and the surface temperature by the surface energy balance. Important components of the surface energy balance are radiation (incoming solar radiation, reflected solar radiation, incoming and outgoing longwave radiation), sensible and latent heat fluxes and heat flux into the ground (called ground heat flux). A large number of individual and collective observations have been carried out in the past to understand the atmospheric boundary layer and the surface energy budgets. However a major share of the observations is from mid-latitudes. There have been few experiments carried out in India, for example, MONTBLEX, LASPEX, etc. One common drawback among these experiments is that the data time series is discontinuous and continuous measurements covering an entire season are lacking. Moreover these measurements were not comprehensive and hence did not allowed to calculate complete surface energy balance – in some cases radiation data is not available while in some humidity data. Therefore, continuous time series of sufficient duration and covering all variables needed to look at the seasonal energy balance based on measurements alone is missing in the Indian context. New programmes with the main objective of predicting convection are being planned in India. For example, PROWNAM (Prediction of Regional Weather with Observational Meso-Network and Atmospheric Modeling) is aimed at predicting the short term weather at SHAR and STORM (Severe Thunderstorms – Observations and Regional Modeling) aims to predict the occurrence of severe thunderstorms in the northeastern India. In both these programmes, measurement of all components of surface energy balance is one of the main objectives. However, the minimum configuration and data accuracy requirements for the flux towers, sensitivity of computed fluxes on data accuracy have not been carefully evaluated. This thesis is aimed at filling this gap. As a part of my work, a 10 m high micrometeorological tower was installed in an open area within the Indian Institute of Science (IISc) Air Field. Temperature, relative humidity and wind speed and direction instruments were mounted at two levels, 2 m and 8 m. All components of radiation were measured. Data, sampled every 5 s and averaged for 2 minutes were continuously stored, starting May 2006 onwards. Soil temperature was measured at 4 depths, 5 cm, 10 cm, 15 cm and 20 cm. In addition, a sonic anemometer capable of measuring 3 components of velocity and air temperature was installed at 2 m height, and data was collected for more than a month to enable the calculation of momentum and buoyancy fluxes using the Eddy correlation method (ECM). The present work evaluated the sensitivity of the fluxes for small calibration errors and quantified the minimum data accuracies and configuration needed for flux measurement with the Profile method (PM). After applying corrections, the comparison of fluxes from PM and ECM are in good agreement. The complete long-term surface energy balances is calculated in terms of source and sink. One aspect that emerges from the observation is that the seasonal variation in the sink term is relatively small (150-170 Wm-2) whereas the source term shows much larger variation from 180-250 Wm-2. A method has been implemented by which the ground surface temperature can be estimated by using the subsurface temperature timeseries by the method of Fourier decomposition and using the Fourier heat conduction equation. In addition we can compute the thermal diffusivity of the soil by using the amplitude and phase information of the sub-surface soil time series. The estimated temperatures from this method and one that estimated from radiation method are in good agreement with the maximum difference being less than 0º C.

EDF souhaite utiliser la technologie de mesure de température répartie par capteur à fibre optique utilisant l’effet Raman pour réaliser des cartographies de température de certains composants de centrales nucléaires. Les conditions environnementales auxquelles le capteur à fibre optique est soumis sont particulièrement agressives (température de 350 °C et rayonnements gamma ionisants). Les rayonnements ionisants sont responsables de la création de défauts structurels au cœur de la fibre, qui atténuent sa transmission lumineuse, et dont les effets engendrent une erreur de mesure de température pouvant aller jusqu'à l’interruption totale de la mesure. La haute température, quant à elle, dégrade le revêtement protecteur de la fibre optique, ce qui la fragilise mécaniquement. Des irradiations gamma in situ sur des fibres optiques multimodes commerciales à revêtement or protégées par une gaine en acier inoxydable ont été réalisées, à l’aide de deux sources de rayonnements différentes, pour observer l'atténuation radio-induite du capteur à fibre optique en fonction du débit de dose et de la dose cumulée. Les effets du rayonnement à température ambiante, puis à haute température, ont été observés. Ce travail expérimental démontre que la haute température peut être maîtrisée grâce à une fibre à revêtement or, et que la haute température est bénéfique contre l’atténuation de la fibre engendrée par l’irradiation. La mise en œuvre de capteur de température à fibre optique en environnement sévère devient possible, ainsi que l’estimation des incertitudes sur la mesure associée. / EDF is working on Raman distributed temperature sensing using optical fiber sensors in order to map temperature of nuclear power plants big components. The sensor has to sustain harsh environmental conditions (temperatures up to 350 °C and gamma ionizing radiations). Ionizing radiations can create structural defects inside the fiber’s core, which attenuate the light transmission. This phenomenon can lead to temperature measurements errors until no measurement is possible. As for high temperature, it can affect the fiber coating, which mitigate the fiber mechanical resistance.Gamma rays in situ irradiations have been carried out over commercial off-the-shelf multimode gold coated fibers protected with a stainless steel metal tubing, with two different radiation sources, in order to observe radiation-induced attenuation over dose rate or cumulated dose. Effects of gamma rays over gold coated optical fiber sensors have been observed at both room anhigh temperature.This experimental work enlightens that high temperature can be controlled with gold coated fibers, and that the radiation-induced attenuation downsides can efficiently be balanced with high temperature. Implementation of a Raman distributed temperature optical fiber sensor in such harsh environments becomes possible, as well as the associated estimation of measurement uncertainty.

La Thèse a été réalisée en cotutelle entre l’Université Jean Monnet de Saint Etienne (France) et l’université de Palerme (Italie) et en collaboration avec l’Agence nationale pour la gestion des déchets radioactifs (ANDRA). Le travail de recherche concerne l'étude des capteurs répartis à fibres optiques (utilisant la lumière rétrodiffusée Raman et Brillouin) destinés à l’observation et à la surveillance des ouvrages dédiés au stockage géologique de déchets radioactifs de haute activité et moyenne activité à vie longue (projet CIGEO : centre industriel de stockage géologique). Dans ce contexte, les fibres optiques sont envisagées en tant qu’élément sensible de capteurs pour la mesure de paramètres environnementaux tels que la température ou la déformation. Les conditions environnementales extrêmes d’exploitation entrainent la dégradation des propriétés de la fibre optique et des performances du capteur. La réponse des capteurs Brillouin et Raman est influencée par la présence de rayonnement y et d’hydrogène dans l’atmosphère Cigéo. Dans les deux cas, une diminution de la transmission linéique de la fibre optique est observée. Ce phénomène est dû à l’atténuation induite par radiation (RIA) ou par hydrogène (HIA) réduisant ainsi la portée de la mesure. En outre le rayonnement y et l’hydrogène provoquent des erreurs sur la mesure de température ou de déformation pour les deux types de capteurs. L’étude a permis d’établir les lignes directrices pour la sélection et le développement des capteurs repartis à fibre optique appropriés pour travailler dans l’environnement Cigéo / This PhD thesis is conducted in the joint supervision of both the University Jean Monnet of Saint Etienne (France) and the University of Palermo (Italy) in collaboration with the French national agency for the management of radioactive wastes (ANDRA). The aim of the Thesis is to evaluate the performances of distributed optical fiber sensors (based on Raman and Brillouin scattering technologies) that will be employed for monitoring industrial site for deep geological disposal for high and long-lived intermediate level activity radioactive waste (HL-W and LL/IL-W, respectively), called Cigéo. In this context, the distributed optical fiber sensors will provide a time and spatial cartography of the strain and temperature inside the disposal cell. The severe environment of Cigéo requires the sensor evaluation taking into account the resulting degradation of the sensing optical fiber. The sensor response is affected by y-rays and hydrogen presences inside the storage cells. In both cases a decrease of the optical fiber transmission, due to the radiation or hydrogen induced attenuation (RIA or HIA) is observed and limits the sensing distance range of the sensor. Moreover, the two different environment constraints lead to errors in the temperature or strain evaluation for both sensor technologies. This Thesis work establishes the guidelines to select and design distributed optical fiber sensors suitable to operate in radiation environment such as Cigéo one

Immersion heaters are used by industries to heat fluids. The element of an immersion heater need to be fully immersed into the heated liquid, otherwise it could be subject to overheat. The main purpose of this thesis is to find a temperature sensor, which could signal in case the immersion heater is at risk to suffer from overheat due to low liquid level. A comparison of accuracy, size and cost between an analog and a digital sensor is held, to conclude whether either one is at an advantage for this application.An immersion heater with ceramic element and quartz glass tube and a water tank, both provided by Scandymet, is used during experiments. First, the position for the sensor inside the heater was examined, by placing the sensor at different positions. Next, measurements of the operating temperature of the immersion heater were made at different liquid levels. This resulted in a placement for the sensor near the head of the immersion heater and an approximate temperature range from 41 ℃ to 58 ℃. Both the analog and digital sensors is chosen with measurable ranges to match the result from previous experiments. A thermistor along with a linearizing series resistor make the analog design and a DS18B20+ with a pull-up resistor the digital design. The microcontroller for both designs is Adafruit Feather Adalogger M0, which is programmed in C/C++ using Arduino IDE software. It is concluded that it is possible to signal in case liquid level decrease below minimum level, by inserting a temperature sensing device into the immersion heater. The sensor should be placed above the maximum liquid level mark, close to the head of the heater. The analog design would be recommended as overheat protection, due to its smaller size, less expensive and, with further calibration, accurate response.

This thesis describes basic concepts, principles and properties of optical fibers. Considerable part is devoted to fiber gratings that are created by a change in the refractive index in the optical fiber core. In this work is described description, principle, method od production and distribution of gratings on Bragg gratings, gratings with long period and chirped gratings. In this thesis are also presented different types of lasers and their advantages over other lasers. A large part deals with the description of the femtosecond laser, with which the structures will be later made into the material. In addition, the laser modes are differentiated, this is a mode of micro-machining and modification or a change in refractive index of the material. The last part deals with change the refractive index in planar technology, the creation of a groove for fastening the fiber and attempts to write the gratings into the optical fiber. Created fiber sensor are tested for temperature and tensile changes. Finally, the practical use of sensors made by femtosecond laser and the advantages over UV laser and phase mask techniques are presented.

Diploma thesis was dealing with design of the device for measuring the mean temperature in a channel of any cross-section. First, the theory of heat, heat transfer and fluid flow was summarized. Theory was focused specially on the uneven temperature distribution in the flowing medium. Furthermore, a general overview of commercially used temperature sensors and developed sensors with applicability to the investigated problematics was elaborated. Then, a device for sensing mean temperature in a flow channel for several different diameters has been fully designed and developed. The device included the temperature sensor itself, the necessary measurement electronics and its programming, and a simple measurement data application.

Master's thesis deals with a design of the thermostat for biological experiments considering 2l of volume, with capability of setting up required temperature between 20-40 degree Celsius and related accuracy of measurement +/- 1 degree Celsius. Following chapters are one by one described and properly explained from possible ways of measuring temperature to final implementation. Result of the thesis presents necessarily calculations, discussion of module's performance modeling, schematics together with PCB's design and the list of components. Neither the question of software nor possibilities of realization is neglected.