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MODELING AND INVESTIGATION OF A HYBRID THERMAL ENERGY HARVESTER
Last modified: 2017-12-04
Abstract
MODELING AND INVESTIGATION OF A HYBRID THERMAL ENERGY HARVESTER
T. Todorov1*, N. Nikolov1, G. Todorov2 Y. Ralev1
1: Dept. of Theory of Mechanisms and Machines, Technical University of Sofia, Bulgaria
2: Dept. of Technology of Machine Tools and Manufacturing, Technical University of Sofia, Bulgaria
* Correspondent author: tst@tu-sofia.bg
Keywords: Energy harvester, Shape memory alloy, Piezoelectric layer, Thermoelectric generator, Rotational oscillations
ABSTRACT
The paper deals with a new thermal energy harvester comprising piezoelectric cantilever, shape memory alloy (SMA) thermal actuator, and piezoelectric transducer. This energy harvester is designed to convert heat energy into electrical energy. The operational principle of the combined thermoelectric generator is based on the rotational oscillations of a hot plate. When the hot plate is in touch with a strained SMA wire it heats and compresses. The compression of the SMA wire rotates the hot plate and the contact between SMA wire and hot plate brakes. Then SMA wire cools and returns the hot plate in contact and all processes are repeated. The SMA wire strains under the action of elastic force of a cantilever with piezoelectric layer. The compression of SMA wire deforms the piezoelectric cantilever. The rotation of the hot plate and the deformation of the piezoelectric cantilever are similar to oscillations, which depend on mechanical, electrical, and thermal properties of the system.
The energy harvester is designed to transform the energy of source with constant heat into non-continuous heat for the SMA wire. The longitudinal contractions and stains of the SMA wire deform a piezoelectric transducer, which produces electricity.
A dynamical model is built in order the behavior of the temperature and the deformation of the shape memory alloy wire, the stress of the piezoelectric beam, and the generated voltage to be investigated.
Series of experiments with the combined device are conducted. I figure 1 the experimental setup of the thermal energy harvester is shown.
Fig. 1 Experimental setup for thermal energy harvester investigations
The dynamical model is investigated by series of simulations. The obtained experimental results prove the theoretical investigations validate the model appropriateness and determine the capability of the device.
The parameters of energy harvester for maximum energy delivering and for optimal performance are investigated and described.
The considered in the paper energy harvester disclosure new approach for converting energy of constant heat source through mechanical oscillations into electric energy.
The investigations show that the possibilities for miniaturization of this type of device are promising.
T. Todorov1*, N. Nikolov1, G. Todorov2 Y. Ralev1
1: Dept. of Theory of Mechanisms and Machines, Technical University of Sofia, Bulgaria
2: Dept. of Technology of Machine Tools and Manufacturing, Technical University of Sofia, Bulgaria
* Correspondent author: tst@tu-sofia.bg
Keywords: Energy harvester, Shape memory alloy, Piezoelectric layer, Thermoelectric generator, Rotational oscillations
ABSTRACT
The paper deals with a new thermal energy harvester comprising piezoelectric cantilever, shape memory alloy (SMA) thermal actuator, and piezoelectric transducer. This energy harvester is designed to convert heat energy into electrical energy. The operational principle of the combined thermoelectric generator is based on the rotational oscillations of a hot plate. When the hot plate is in touch with a strained SMA wire it heats and compresses. The compression of the SMA wire rotates the hot plate and the contact between SMA wire and hot plate brakes. Then SMA wire cools and returns the hot plate in contact and all processes are repeated. The SMA wire strains under the action of elastic force of a cantilever with piezoelectric layer. The compression of SMA wire deforms the piezoelectric cantilever. The rotation of the hot plate and the deformation of the piezoelectric cantilever are similar to oscillations, which depend on mechanical, electrical, and thermal properties of the system.
The energy harvester is designed to transform the energy of source with constant heat into non-continuous heat for the SMA wire. The longitudinal contractions and stains of the SMA wire deform a piezoelectric transducer, which produces electricity.
A dynamical model is built in order the behavior of the temperature and the deformation of the shape memory alloy wire, the stress of the piezoelectric beam, and the generated voltage to be investigated.
Series of experiments with the combined device are conducted. I figure 1 the experimental setup of the thermal energy harvester is shown.
Fig. 1 Experimental setup for thermal energy harvester investigations
The dynamical model is investigated by series of simulations. The obtained experimental results prove the theoretical investigations validate the model appropriateness and determine the capability of the device.
The parameters of energy harvester for maximum energy delivering and for optimal performance are investigated and described.
The considered in the paper energy harvester disclosure new approach for converting energy of constant heat source through mechanical oscillations into electric energy.
The investigations show that the possibilities for miniaturization of this type of device are promising.