Temperature control is widely sought after in regards to optical systems as their optical parameters often show dependence on temperature. Examples include diode lasers, multiplexing systems, optical amplifiers, and filters all of whom have a high sensitivity to temperature. This thesis presents a temperature controlled environment chamber actuated by a thermoelectric cooler. The design of which provides a simple, multi-applicable solution for temperature control in optical devices. The final device is comprised of three sub-areas of design. Each subsystem was custom built and applied in the final assembly -- including a digitally implemented signal generator, an error correction controller, and the environment chamber heat sink structure. The signal generator is used as input for a switched-mode based Peltier driver found commercially. A feedback error controller compensates the driver for temperature control. Both systems are implemented with microcontroller units. The environment chamber heat sink assembly is designed specifically to handle the thermal energy generated by the thermoelectric cooler. All of the systems were tested collectively for functionality. The input signal generator achieved its design goals and is capable of creating specific profiles in the temperature response. Error controller performance was reasonable in set-point tracking for continuous input signals. Step input responses are tuned for minimal settling time and overshoot. Temperature resolution in the thermistor response is around 0.1•C after digital filtering. The thermal design achieved its goal of operating in an ambient environment up to 54°C. Low temperature ambient environment operation has been confirmed to 8°C. / Master of Science

It is well known that the seats in a parked vehicle become very hot and uncomfortable on warm days. A new self-powered thermoelectric car seat cooler is presented to solve this problem. This study details the design and optimization of such a device. The design relates to the high level layout of the major components and their relation to each other in typical operation. Optimization is achieved through the use of the ideal thermoelectric equations to determine the best compromise between power generation and cooling performance. This design is novel in that the same thermoelectric device is utilized for both power generation and for cooling. The first step is to construct a conceptual layout of the self-powered seat cooler. Using the ideal thermoelectric equations, an analytical model of the system is developed. The model is validated against experimental data and shows good correlation. Through a non-dimensional approach, the geometric sizing of the various components is optimized. With the optimal design found, the performance is evaluated using both the ideal equations and though use of the simulation software ANSYS. The final design consists of a flat absorber plate embedded into the car seat with a thermoelectric attached to the back. A finned heat sink is used to cool the thermoelectric. The device is shown to generate enough power to provide a reasonable temperature drop in the seat. / Master of Science

This paper presents an integrated column-type micro thermoelectric cooler (£g-TEC) constructed with serial connected p-type antimony-tellurium (Sb2Te3) and n-type bismuth-tellurium (Bi2Te3) micro pillars deposited by electrochemical deposited technology. To optimize the power factor, density and uniformity of the TE films and to enhance the reproducibility of £g-TEC device, a cathode with tunable rotary speed and with accurate current controller has been designed in the electroplating system of this research. The electroplating deposited Bi2Te3 and Sb2Te3 with an average thickness of 8 £gm, are connected using Cr/Au layers at the hot junctions and cold junctions. The measured Seebeck coefficient and electrical resistivity are -86 £gV/K and 16 £g£[-m for Bi2Te3 films after annealed at 250¢XC, and are 68 £gV/K and 30 £g£[-m for Sb2Te3 films after annealed at 200¢XC. The optimized power factors of the n-type (2.64¡Ñ10-4 W/K2m) and p-type (2.64¡Ñ10-4 W/K2m) telluride compounds have been demonstrated in this paper. Under 5 volts driven, the integrated £g-TEC device shows average cooling achieved is about 1.3 ¢XC.

The main goal for this project was to design, manufacture and evaluate a thermoelectric cooler, TEC, prototype. One of the biggest challenges with TECs is that they need to be very reliable and have a long lifetime. The two biggest contributing factors to degradation and breakdown stem from thermal expansion mismatch, resulting in cracks, and from material diffusion between the thermoelectric material and connecting materials. The thermoelectric material in this case is Bismuth telluride, Bi2Te3, obtained from two suppliers. The thermoelectric cooler prototype was successfully manufactured. The prototype, which consisted of 38 thermoelectric elements, showed a maximum temperature difference of 65.1 degrees Celsius. A commercial TEC of the same size had a maximum temperature difference of 68 degrees Celsius. The figure of merit and grain size of p- and n-doped Bismuth Telluride from two different suppliers have been measured as means of testing the thermoelectric material prior to manufacturing, and to compare the suppliers. In this report, the figure of merit is a measure of how well a material converts electrical current to a heat gradient. The figure of merit for bismuth telluride, Bi2Te3, from both suppliers was found to be between 0.4 and 0.8 through the Harman method. Since studies show that smaller grains for Bi2Te3 result in a more durable material, the morphology was investigated. However, no grains could be observed with light optical microscopy with an applied etchant, or scanning electron microscopy. A cohesion tape test showed that Bismuth telluride from one of the suppliers is more fragile than the other.

The state of the art in artificial micro self assembly concepts are reviewed. The history of assembly is presented with a comparison to macro assembly, which has been widely studied, and micro self assembly. Criteria were developed and tested to show that macro assembly is more complex in ways that micro self assembly is not. Self assembly requirements for successful and complex self assembly, which evolved from the macro and micro comparison, are also established and tested. A method to assemble complex structures in the micro scale is proposed and demonstrated at the meso scale. The basic concepts of self assembly and a novel approach to complex multi layer self assembly is analyzed.

Today many processes generate a lot of waste heat, for example industries or cars. One way to make this thermal energy useful is to transform it into electrical energy with a thermoelectric generator (TEG) or thermoelectric cooler (TEC). This technology is not used in any large scale today, but a lot of research is being done on the subject. The technology is based on the Seebeck effect and uses a temperature difference between two sides of an element to generate an electrical current. The reason that the research has gained more attention in recent years is because of the increasing electricity prices and the diminishing natural resources. Other benefits are that they run quietly and do not demand much maintenance.Another area where this technology could be useful is in off-grid cabins where it is easy to generate a lot of thermal energy by burning wood, but electrical energy is in high demand.In this thesis two different types of TEGs and one type of TEC are tested to investigate how much power they generate at different temperature differences, how well they meet the specified values in their respective data sheet and what their power per euro value is. For this, an experimental setup was made with:- An induction plate to increase the temperature on the hot side.- A CPU-fan, to reduce the temperature on the cold side.- Two temperature sensors (one for measuring the hot temperature and one for the cold one).- An electric circuit featuring a voltmeter, an amperemeter and an adjustable resistor (rheostat).The results show that, for this experiment the highest received power (6,38 W) comes from the medium-priced element but the highest power per euro comes from the lowest priced element (1,16 W/€). A quality problem for the lowest priced element was that parts of the solder melted when the temperature exceeded 225 °C. Another problem was that the induction plate was unable to provide enough heat for the most expensive of the elements to reach the temperature for which the retailer supplies their measured data.

In order to reliably test thermoelectric modules, it is necessary to have a adequate measuring apparatus. The presented diploma thesis deals with the design of measuring apparatus capable of performing both long-term testing of thermoelectric modules at a constant high temperature and thermal cycling extension has been designed. Both types can be changed in a short time.

nÃo hà / O uso racional de recursos à pauta recorrente nas discussÃes acerca do desenvolvimento sustentÃvel e tem estimulado o projeto de equipamentos mais eficientes quanto ao consumo de energia elÃtrica. Agentes regulamentadores e certificadores estabelecem regras para o funcionamento e para a classificaÃÃo de eletrodomÃsticos quanto ao consumo de energia elÃtrica a fim de formalizar a relaÃÃo entre o desempenho dos mesmos e a manutenÃÃo indefinida dos recursos. Nesse contexto, lanÃa-se mÃo do projeto de um controlador preditivo baseado em modelo aplicado à regulaÃÃo da temperatura do reservatÃrio de Ãgua gelada de um refrigerador termoelÃtrico obedecendo as especificaÃÃes da norma internacional ANSI18 que determina condiÃÃes funcionais para bebedouros com refrigeraÃÃo mecÃnica incorporada, concomitantemente buscando atender aos requisitos para a certificaÃÃo ENERGY STAR quanto ao critÃrio de eficiÃncia energÃtica. Para tanto foram realizadas as etapas de i) Modelagem e IdentificaÃÃo do Processo: foi desenvolvido um modelo em termos de funÃÃo de transferÃncia do sistema de refrigeraÃÃo termoelÃtrico de fluidos atravÃs de modelagem fenomenolÃgica; foram realizados experimentos para a identificaÃÃo de parÃmetros de modelos discretos pelo mÃtodo caixa branca; foi desenvolvido critÃrio de seleÃÃo de modelo baseado na capacidade de simulaÃÃo e caracterÃsticas do resÃduo de simulaÃÃo; ii) Estudo do Controlador Preditivo Baseado em Modelo: foi projetado e implementado na planta um controlador preditivo baseado em um dos modelos parametrizados para regulaÃÃo da temperatura do reservatÃrio interno; foi analisado o desempenho do controlador segundo a norma regulamentadora; iii) Estudo da EficiÃncia do Controlador: foi analisado o desempenho do controlador quanto a capacidade do protÃtipo em atender aos requisitos que o qualificam à obtenÃÃo de certificado segundo critÃrio de eficiÃncia energÃtica para regulaÃÃo da temperatura interna do reservatÃrio e, por fim, realizado um estudo comparativo entre a estratÃgia de controle biestÃvel aplicada atualmente ao processo e a estratÃgia proposta. / The rational use of resources is a recurring theme in sustainable development discussions and has stimulated the development of more efficient electrical power consumption appliances. Regulators and Certifiers agencies set standards for the functionality requirements and for the electric power consumption classification of devices in order to formalize the relationship between performance and maintenance of these resources indefinitely. Thus a model based predictive controller was applied to a thermoelectric cooler to attain the international standard ANSI18 specifications for water cooler dispensers and to meet ENERGY STAR$ iny^{ extregistered}$ energy efficiency requirements. A phenomenological linear model was obtained and the respective parameters were identified by using least squares algorithm; experiments were performed to identify the parameters of the discrete transfer functions; a model criterion selection based on simulation capabilities and residue characteristics was developed; a model based predictive controller was designed and applied using one of the models identified; the controller performance was analyzed attending to the ANSI18 standard and according to energy performance certificates; a comparative study between the bistable control and the proposed strategy was made for performance analysis. Simulation and experimental tests have shown compromise between the simulation capability and residue characteristic criterion. The closed loop system behavior allowed energy saving in standby temperature regulating compared to thermostat control mode. The new control strategy achieved ENERGY STAR energy-efficiency criteria certification requirements infeasible for traditional regulation.