DC Thermal Energy Flexibility Model for Waste Heat Reuse in Nearby Neighborhoods

More than 30 international research and pilot seasonal thermal energy stores (TESs) were realized within the past 30 years. Experiences with operation of these systems show that TES are technically feasible and work well. Seasonal storage of solar thermal energy or of waste heat from heat and power cogeneration plants can significantly contribute to substitute fossil fuels in future energy systems. However, performance with respect to thermal losses and lifetime has to be enhanced, while construction costs have to be further reduced. This paper gives an overview about the state-of-the-art of seasonal thermal energy storage with the focus on tank and pit TES construction. Aspects of TES modeling are given. Based on modeled and measured data, the influence of construction type, system configuration, and boundary conditions on thermal losses of large-scale TES is identified. The focus is on large-scale applications with tank and pit thermal energy stores and on recent investigations on suitable materials and constructions. Furthermore, experiences with the operation of these systems with respect to storage performance are discussed.

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Design and Optimization of Integrated Distributed Energy Systems for Off-grid Buildings

Journal of Energy Resources Technology ◽

10.1115/1.4052619 ◽

2021 ◽

pp. 1-27

Author(s):

Jian Zhang ◽

Heejin Cho ◽

Pedro Mago

Keyword(s):

Energy Storage ◽

Optimal Design ◽

Power Systems ◽

Thermal Energy ◽

Waste Heat ◽

Carbon Dioxide Emission ◽

Energy Systems ◽

Solar Thermal ◽

Solar Thermal Energy ◽

Distributed Energy

Abstract Off-grid concepts for homes and buildings have been a fast-growing trend worldwide in the last few years because of the rapidly dropping cost of renewable energy systems and their self-sufficient nature. Off-grid homes/buildings can be enabled with various energy generation and storage technologies, however, design optimization and integration issues have not been explored sufficiently. This paper applies a multi-objective genetic algorithm (MOGA) optimization to obtain an optimal design of integrated distributed energy systems for off-grid homes in various climate regions. Distributed energy systems consisting of renewable and non-renewable power generation technologies with energy storage are employed to enable off-grid homes/buildings and meet required building electricity demands. In this study, the building types under investigation are residential homes. Multiple distributed energy resources are considered such as combined heat and power systems (CHP), solar photovoltaic (PV), solar thermal collector (STC), wind turbine (WT), as well as battery energy storage (BES) and thermal energy storage (TES). Among those technologies, CHP, PV, and WT are used to generate electricity, which satisfies the building's electric load, including electricity consumed for space heating and cooling. Solar thermal energy and waste heat recovered from CHP are used to partly supply the building's thermal load. Excess electricity and thermal energy can be stored in the BES and TES for later use. The MOGA is applied to determine the best combination of DERs and each component's size to reduce the system cost and carbon dioxide emission for different locations. Results show that the proposed optimization method can be effectively and widely applied to design integrated distributed energy systems for off-grid homes resulting in an optimal design and operation based on a trade-off between economic and environmental performance.

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Waste-Heat Recovery And Thermal Energy Storage In Food Processing Facilities

Energy Efficiency and Management in Food Processing Facilities ◽

10.1201/9781420063394.ch8 ◽

2008 ◽

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Food Processing ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat

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Thermal Energy Requirements of Air-Conditioning Systems

Journal of Engineering for Power ◽

10.1115/1.3445548 ◽

1971 ◽

Vol 93 (2) ◽

pp. 172-176

Author(s):

M. E. Lackey

Keyword(s):

Thermal Energy ◽

Air Conditioning ◽

Waste Heat ◽

Energy Requirements ◽

Absorption Refrigeration ◽

Refrigeration System ◽

Fast Breeder Reactors ◽

Breeder Reactors ◽

Absorption Refrigeration System ◽

Air Conditioning Systems

The thermal energy requirements for air conditioning by compressive and absorption methods were determined for light-water, thermal-breeder, and fast-breeder reactors. The energy required to produce a ton-hour of refrigeration varied from 5100 Btu to 13,100 Btu by absorption and from 5600 to 8800 Btu by compression. The amount of waste heat dissipated to the environment at the reactor site as a consequence of producing a ton-hour of air conditioning ranged from an increase of 21,000 Btu for the electric-motor-driven refrigeration system to a decrease of 6000 Btu for the absorption refrigeration system.

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Experimental Investigation of Thermoacoustic-Piezoelectric Energy Harvesters and Refrigerators With Dynamic Magnifiers

Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting ◽

10.1115/smasis2013-3030 ◽

2013 ◽

Author(s):

M. Nouh ◽

O. Aldraihem ◽

A. Baz

Keyword(s):

Temperature Gradient ◽

Thermal Energy ◽

Acoustic Waves ◽

Waste Heat ◽

Mechanical Impedance ◽

Acoustic Resonator ◽

Critical Threshold ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Theoretical Results

Conventional Thermoacoustic-Piezoelectric (TAP) energy harvesters convert thermal energy, such as solar or waste heat energy, directly into electrical energy without the need for any moving components. The input thermal energy generates a steep temperature gradient along a porous medium. At a critical threshold of the temperature gradient, self-sustained acoustic waves are developed inside an acoustic resonator. The associated pressure fluctuations impinge on a piezoelectric diaphragm, placed at the end of the resonator. The reverse phenomenon results in piezo-driven thermoacoustic refrigerators (PDTARs). A pressure wave driven by a piezo-speaker induces a temperature gradient across the porous body. In this study, the TAP harvester and the PDTAR are coupled with auxiliary elastic structures in the form of simple spring-mass systems to enhance their performance. The proposed addition is referred to as a dynamic magnifier and has been shown in different areas to amplify significantly the deflection of vibrating structures. A comprehensive model of the dynamically magnified thermoacoustic-piezoelectric (DMTAP) system has been developed earlier that includes equations of motions of the system’s mechanical components, the harvested voltage, the mechanical impedance of the coupled structure at the resonator end as well as the equations necessary to compute the self-excited frequencies of oscillations inside the acoustic resonator. Theoretical results confirmed significant amplification of the harvested power is feasible if the magnifier’s parameters are properly chosen. The performance of experimental prototypes of a DMTAP harvester and a PDTAR with a dynamic magnifier are examined here. The obtained experimental findings are validated against the theoretical results. Dynamic magnifiers serve as a novel approach to enhance the effectiveness of thermoacoustic energy harvesting and refrigeration.

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