Analysis of Hybrid Electric/Thermofluidic Control for Wet Shape Memory Alloy Actuators

2009 ◽  
Author(s):  
Leslie Flemming ◽  
Stephen Mascaro
Keyword(s):  
Control Strategies ◽  
Fluid Dynamic ◽  
Thermal Response ◽  
Electric Heating ◽  
Electrical Heating ◽  
Linear Contraction ◽  
Heating And Cooling ◽  
The Wire ◽  
Temperature Strain ◽  
Strain Model

A wet SMA actuator is characterized by an SMA wire embedded within a compliant fluid-filled tube. Heating and cooling of the SMA wire produce a linear contraction and extension of the wire. Thermal energy can be transferred to and from the wire using combinations of resistive heating and free/forced convection using hot and cold fluid. The goal of this paper is to analyze the speed and efficiency of wet SMA actuators using a variety of control strategies involving different combinations of electrical and thermofluidic inputs. A computational fluid dynamic model is used in conjunction with a temperature-strain model to simulate the thermal response of the wire and compute strains, contraction/extension times and efficiency. The simulations produce cycling rates of up to 5 Hz for electrical heating and fluidic cooling, and up to 2 Hz for fluidic heating and cooling. The results demonstrate efficiencies up to 0.5% for electric heating and up to 0.2% for fluidic heating.

A review of flexible electric heating element and electric heating garments

2020 ◽  
pp. 152808372096827
Author(s):  
Shu Fang ◽  
Rui Wang ◽  
Haisu Ni ◽  
Hao Liu ◽  
Li Liu
Keyword(s):  
Electric Heating ◽  
Review Article ◽  
Electrical Heating ◽  
Cold Environment ◽  
Passive Heating ◽  
Future Perspectives ◽  
Advantages And Disadvantages ◽  
Smart Garments ◽  
Material Preparation ◽  
Electric Heating Element

Electric heating garment can improve the thermal comfort for people living and working in cold environment. Compared with passive heating materials, electrical heating shows dominant advantages on reusability, controlled temperature, safety and so on. This review article systematically introduced the material preparation, electric-thermal properties, advantages and disadvantages of the existing flexible heating elements, and elaborated the research and application progress of smart garments in detail, providing reference for the research of flexible heating elements and smart garments. And the existing challenges and the possible future perspectives were also discussed.

Modeling and Design of Building-Integrated Thermoelectrics

2011 ◽  
Author(s):  
Leon M. Headings ◽  
Gregory N. Washington
Keyword(s):  
Thermal Response ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Net Energy ◽  
Arbitrary Boundary ◽  
Heating And Cooling ◽  
Temperature Oscillations ◽  
Wall Structures ◽  
And Control

The goal of this research is to develop a framework for replacing conventional heating and cooling systems with distributed, continuously and electrically controlled, building-integrated thermoelectric (BITE) heat pumps. The coefficient of performance of thermoelectric heat pumps increases as the temperature difference across them decreases and as the amplitude of temperature oscillations decreases. As a result, this research examines how thermal insulation and mass elements can be integrated with thermoelectrics as part of active multi-layer structures in order to minimize net energy consumption. In order to develop BITE systems, an explicit finite volume model was developed to model the dynamic thermal response of active multi-layer wall structures subjected to arbitrary boundary conditions (interior and exterior temperatures and interior heat loads) and control algorithms. Using this numerical model, the effects of wall construction on net system performance were examined. These simulation results provide direction for the ongoing development of BITE systems.

Thermal Modeling of the Cavity in Pulsed Excimer Laser Calorimeters

2000 ◽  
Author(s):  
D. H. Chen ◽  
Z. M. Zhang
Keyword(s):  
Laser Heating ◽  
Average Power ◽  
Pulsed Laser ◽  
Thermal Response ◽  
Element Model ◽  
Electrical Heating ◽  
Deep Ultraviolet ◽  
Simplified Finite Element Model ◽  
193 Nm ◽  
Pulsed Laser Heating

Abstract A simplified finite element model is built to study the thermal response of the 193-nm pulsed-laser calorimeter. The nonequivalence between pulsed-laser heating and electrical heating is estimated to be 0.46% at the thermocouple locations by comparing the calibration factors for average-power laser heating and electrical heating. This study should help the development of calibration and measurement standards in pulsed energy measurements for deep ultraviolet excimer lasers that are important for photolithographic and materials processing applications.

A numerical study on the thermal response in multi-layer of skin tissue subjected to heating and cooling procedures

2022 ◽  
Vol 137 (1) ◽  
Author(s):  
Rajneesh Kumar Chaudhary ◽  
Vikas Chaurasiya ◽  
Mohamed M. Awad ◽  
Jitendra Singh
Keyword(s):  
Numerical Study ◽  
Thermal Response ◽  
Skin Tissue ◽  
Heating And Cooling

scholarly journals Proposed Strategies for Improving Poor Hygrothermal Conditions in Museum Exhibition Rooms and Their Impact on Energy Demand

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 620 ◽  
Author(s):  
Joanna Ferdyn-Grygierek ◽  
Krzysztof Grygierek
Keyword(s):  
Relative Humidity ◽  
Energy Demand ◽  
Air Conditioning ◽  
Control Strategies ◽  
Internal Heat ◽  
Current Method ◽  
Dramatic Improvement ◽  
Precise Control ◽  
Heating And Cooling ◽  
Microclimate Conditions

In museums, poor microclimate conditions, especially large changes in relative humidity and temperature, can lead to serious deterioration of the exhibits. Properly designed heating, ventilation, and air conditioning (HVAC) systems for precise control of the air parameters are required. However, due to the financial restrictions of museums, complex air-conditioning systems are often not feasible. In this study, we tested and propose novel methods to reduce the short- and long-term fluctuations in the relative humidity in exhibition rooms of a Polish museum. The methods only include indoor temperature and ventilation airflow control strategies, without the use of (de)humidification equipment. The analysis is based on simulations using EnergyPlus software. A multi-zone thermal model of the museum building was validated and calibrated with measured data. A full calendar year was simulated for five control cases (including the current method used) and two internal heat gain schedules. The energy demand for heating and cooling for each case was calculated. The combination of temperature control and adequate ventilation using ambient airflow allows for dramatic improvement in the microclimate conditions. The proportion of the year when the instantaneous indoor relative humidity is ±5% from set point decreased from 85% to 20%. A significant effect was obtained over the summer months.

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