Soft robotic fabric design, fabrication, and thermoregulation evaluation

2021 ◽  
pp. 004051752098590
Author(s):  
Yan Cui ◽  
Xiaogang Liu ◽  
Jintu Fan ◽  
Dahua Shou
Keyword(s):  
Air Conditioning ◽  
Low Cost ◽  
Hvac Systems ◽  
Trapped Air ◽  
Fabric System ◽  
Fabric Design ◽  
Pneumatic Structures ◽  
Compression Resistance ◽  
Insulation Performance ◽  
Resistance Value

Usually, traditional insulation materials have a constant thermal resistance value that cannot change within the ambient temperature and will decrease as ambient humidity or external stress increases. Humans heavily rely on heating, ventilation, and air conditioning (HVAC) systems to meet the thermal comfort requirements of their bodies, giving rise to energy waste and global warming. As an infinitely available natural resource, air is one of the most efficient thermal retaining substances known to science. Inspired by soft pneumatic robotics, we propose an architecture for air-driven thermoregulation fabrics called soft robotic fabrics (SRF). By changing the thickness of trapped air layer in fabric system through SRF, wearers could modify garments’ thermal insulation performance. A fabrication method is introduced to rapidly manufacture low-cost pneumatic structures using various types of construction and dimensions. With excellent ductility, elasticity, and compression resistance, the thickness of SRF increases by 12 times or more after inflation, and the fabric even can lift an object 270 times heavier than its weight. The excellent deformability can effectively increase stable air layer between clothing and skin. Based on the Predicted Mean Vote–Predicted Percentage of Dissatisfied model, the thermoregulation capability of SRF helps HVAC expand the temperature setpoint range by 3–8 times when compared with traditional fabrics, and has far-reaching significance in saving energy.

A Time-series Rank Ordering Control-system Data-driven Fault Detection Approach for HVAC Systems in Buildings

2021 ◽  
pp. 1-12
Author(s):  
James Shia ◽  
David M. Auslander
Keyword(s):  
Control System ◽  
Fault Detection ◽  
Air Conditioning ◽  
Low Cost ◽  
Hvac Systems ◽  
Fault Detection And Diagnosis ◽  
Machine Learning Algorithms ◽  
Total Energy Consumption ◽  
Model Free ◽  
System Data

Abstract About 41% of total energy consumption in the U.S. of year 2014 is used for heating and air conditioning, that is about 40 quadrillion (40×1015) British thermal units (BTU). Despite the fact that people have been working on on fault detection and diagnosis (FDD) for Heating, Ventilation, and Air Conditioning (HVAC) systems for a long time, very few publications have focused on scalability and low cost. In order to address this challenge, we will propose an approach which focuses on control-system data. Several machine learning algorithms are introduced for data exploration and analysis, a control-system data focused model free approach is presented as well, and finally, FDD is carried out by implementing anomaly algorithms. A simulation model is used to evaluate the performance of the various algorithms.

scholarly journals A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 400 ◽  
Author(s):  
Zelin Nie ◽  
Feng Gao ◽  
Chao-Bo Yan
Keyword(s):  
Optimization Model ◽  
Air Conditioning ◽  
State Of The Art ◽  
Hvac Systems ◽  
Practical Significance ◽  
Hvac System ◽  
Bilinear Model ◽  
Optimization And Control ◽  
And Control ◽  
Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

Performance evaluation and design considerations for a split air-conditioner with built-in thermal energy storage

2018 ◽  
Vol 40 (5) ◽  
pp. 560-575
Author(s):  
Jehanzeb Ahmad ◽  
M Najam Ul Islam ◽  
Jawwad Sabir
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Low Cost ◽  
Hvac Systems ◽  
Air Conditioner ◽  
Widespread Application ◽  
Air Conditioners

The benefits of thermal energy storage using phase change materials are well documented in the literature. Despite all the potential benefits of thermal energy storage, its commercial and widespread application remains limited. This is due to the high initial cost of phase change materials, extensive rework required in buildings, major modifications in HVAC systems, and the potential for leakage, fire and toxicity hazards. There is a strong need for a simple thermal energy storage solution which can be adopted by large number of consumers. Ductless split air-conditioners are portable, low cost, efficient and account for 70% of all air-conditioning systems sold worldwide each year. The present research provides a novel and low cost solution that incorporates thermal energy storage in these air conditioners, allowing them to run without electricity for 3 h. The paper deals with the detailed design aspects and engineering challenges that arise when incorporating thermal energy storage in these small units. A prototype air-conditioner with in-built thermal energy storage was developed, and all performance parameters presented have been validated through data obtained from the prototype. Our results indicate that thermal energy storage can be incorporated in split units in low cost and with minimal drop in overall energy efficiency of the system. Practical application: Incorporating thermal energy storage in split air-conditioners which enables them to run without grid for many hours has immense practical applications. Since around 50% power in any building is consumed by HVAC systems, being able to provide cooling during peak hours without using grid can significantly reduce load on the grid without compromising user comfort. For developing countries where load shedding is frequent, the users can run these air-conditioners without the use of generators or batteries thus saving costs and the environment.

scholarly journals Some Aspects of HVAC Design in Energy Renovation of Buildings

2021 ◽  
Author(s):  
Taghi Karimipanah
Keyword(s):  
Renewable Energy ◽  
Air Conditioning ◽  
Distribution Systems ◽  
Energy System ◽  
Building Energy ◽  
Hvac Systems ◽  
Heat Losses ◽  
Energy Sources ◽  
Air Distribution ◽  
Building Energy System

It is well-known fact that air conditioning systems are responsible for a significant part of all energy systems in building energy usage. In EU buildings, the building HVAC systems account for ca 50% of the energy consumed. In the U.S., air-conditioning accounts on average about 12% of residential energy expenditures. The proper choice of air distribution systems and sustainable energy sources to drive the electrical components have a vital impact to achieve the best requirements for indoor climate including, hygienical, thermal, and reasonable energy-saving goals. The building energy system components that have a considerable impact on the demand for final energy in the building are design, outdoor environment conditions, HVAC systems, water consumption, electrical appliances, indoor thermal comfort, and indoor human activities. For calculation of the energy balance in a building, we need to consider the total energy flows in and out from the building including ventilation heat losses, the perimeters transmission heat loses, solar radiation, internal heat from occupants and appliances, space and domestic water heating, air leakage, and sewage heat losses. However, it is a difficult task to handle the above time-dependent parameters therefore an energy simulation program will always be used. This chapter aims to assess the role of ventilation and air-conditioning of buildings through the sustainability approaches and some of the existing renewable energy-based methods of HVAC systems are presented. This comprehensive review has been shown that using the new air distribution systems in combination with renewable energy sources are key factors to improve the HVAC performance and move toward Nearly Zero Carbon Buildings (NZCB).

scholarly journals Dynamic simulation of indirect air conditioning systems with optimized computational time

2019 ◽  
Vol 111 ◽  
pp. 04042
Author(s):  
Nicolás Ablanque ◽  
Santiago Torras ◽  
Carles Oliet ◽  
Joaquim Rigola ◽  
Carlos-David Pérez-Segarra
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Control Strategies ◽  
Model Potential ◽  
Hvac Systems ◽  
Object Oriented Programming ◽  
Computational Time ◽  
Air Conditioning System ◽  
Numerical Resolution ◽  
Air Conditioning Systems

The simulation of HVAC systems is a powerful tool to improve the energy efficiency in buildings. The modelling of such systems faces several obstacles due to both the physical phenomenology present and the numerical resolution difficulties. The present work is an attempt to develop a robust, fast, and accurate model for HVAC systems that can interact with the other relevant systems involved in buildings thermal management. The whole system model has been developed in the form of libraries under the Modelica language to exploit its advantageous characteristics: object-oriented programming, equationbased modelling, and handling of multi-physics. The global resolution is carried out dynamically so that not only steady-state predictions can be conducted but also control strategies can be studied over meaningful periods of time. This latter aspect is crucial for optimizing energy savings. The libraries include models for all the system individual components such as pumps, compressors or heat exchangers (operating with twophase flows and/or moist air) and also models assemblies to account for vapour compression units and liquid circuits. An illustrative example of an indirect air conditioning system is detailed in the present work in order to highlight the model potential.

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