Polyvinylpyrrolidone (PVP)-enabled significant suppression of supercooling of erythritol for medium-temperature thermal energy storage

Distributed thermal energy storage (DTES) provides specific opportunities to realize the sustainable and economic operation of urban electric heat integrated energy systems (UEHIES). However, the construction of the theory of the model and the configuration method of thermal storage for distributed application are still challenging. This paper analyzes the heat absorption and release process between the DTES internal heat storage medium and the heat network transfer medium, refines the relationship between heat transfer power and temperature characteristics, and establishes a water thermal energy storage and electric heater phase change thermal energy storage model, considering medium temperature characteristics. Combined with the temperature transmission delay characteristics of a heat network, a two-stage optimal configuration model of DTES for UEHIES is proposed. The results show that considering the temperature characteristics in the configuration method can accurately reflect the performance of DTES, enhance wind power utilization, improve the operation efficiency of energy equipment, and reduce the cost of the system.

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Flexible Electricity Dispatch of an Integrated Solar Combined Cycle through Thermal Energy Storage and Hydrogen Production

Thermo ◽

10.3390/thermo1010008 ◽

2021 ◽

Vol 1 (1) ◽

pp. 106-121

Author(s):

Miguel Ángel Reyes-Belmonte ◽

Alejandra Ambrona-Bermúdez ◽

Daniel Calvo-Blázquez

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Hydrogen Generation ◽

Combined Cycle ◽

Medium Temperature ◽

Cost Of Electricity ◽

Demand Curves ◽

Hydrogen Plant ◽

Demand Coverage

In this work, the flexible operation of an Integrated Solar Combined Cycle (ISCC) power plant has been optimized considering two different energy storage approaches. The objective of this proposal is to meet variable users’ grid demand for an extended period at the lowest cost of electricity. Medium temperature thermal energy storage (TES) and hydrogen generation configurations have been analyzed from a techno-economic point of view. Results found from annual solar plant performance indicate that molten salts storage solution is preferable based on the lower levelized cost of electricity (0.122 USD/kWh compared to 0.158 USD/kWh from the hydrogen generation case) due to the lower conversion efficiencies of hydrogen plant components. However, the hydrogen plant configuration exceeded, in terms of plant availability and grid demand coverage, as fewer design constraints resulted in a total demand coverage of 2155 h per year. It was also found that grid demand curves from industrial countries limit the deployment of medium-temperature TES systems coupled to ISCC power plants, since their typical demand curves are characterized by lower power demand around solar noon when solar radiation is higher. In such scenarios, the Brayton turbine design is constrained by noon grid demand, which limits the solar field and receiver thermal power design.

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An experimental investigation of composite phase change materials of ternary nitrate and expanded graphite for medium-temperature thermal energy storage

Solar Energy ◽

10.1016/j.solener.2019.11.102 ◽

2020 ◽

Vol 195 ◽

pp. 573-580 ◽

Cited By ~ 6

Author(s):

Wei Lu ◽

Guizhi Liu ◽

Zhibo Xiong ◽

Zhigen Wu ◽

Guanhua Zhang

Keyword(s):

Experimental Investigation ◽

Energy Storage ◽

Phase Change ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Phase Change Materials ◽

Expanded Graphite ◽

Medium Temperature ◽

Composite Phase Change Materials

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Thermal Characterization of Medium-Temperature Phase Change Materials (PCMs) for Thermal Energy Storage Using the T-History Method

Materials ◽

10.3390/ma14237371 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7371

Author(s):

Paulina Rolka ◽

Roman Kwidzinski ◽

Tomasz Przybylinski ◽

Adam Tomaszewski

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Thermophysical Properties ◽

Phase Change Materials ◽

Experimental Tests ◽

Stored Energy ◽

Medium Temperature ◽

Heating Systems ◽

Selection Of

To reduce energy consumption and increase energy efficiency in the building sector, thermal energy storage with phase change materials (PCMs) is used. The knowledge of the thermophysical properties and the characteristics of PCMs (like their enthalpy changes and the distribution of stored energy over a specified temperature range) is essential for proper selection of the PCM and optimal design of the latent thermal energy store (LHTES). This paper presents experimental tests of the thermophysical properties of three medium-temperature PCMs: OM65, OM55, RT55, which can be used in domestic hot water installations and heating systems. Self-made test chambers with temperature control using Peltier cells were used to perform measurements according to the T-history method. In this way the temperature range of the phase transition, latent heat, specific heat capacity, enthalpy and the distributions of stored energy of the three PCMs were determined. The paper also presents measurements of the thermal conductivity of these PCMs in liquid and solid state using a self-made pipe Poensgen apparatus. The presented experimental tests results are in good agreement with the manufacturers’ data and the results of other researchers obtained with the use of specialized instruments. The presented research results are intended to help designers in the selection of the right PCM for the future LHTES co-working with renewable energy systems, waste heat recovery systems and building heating systems.

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