Simulation and analysis of thermochemical seasonal solar energy storage for district heating applications in China

Li, Zhanchao; Xu, Min; Huai, Xiulan; Huang, Caifeng; Wang, Kejian

doi:10.1002/er.6295

Cited by 13 publications

(5 citation statements)

References 49 publications

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“…Donkers et al [32] reviewed 563 salt hydrates as sorbent materials and discussed screening methods for DHW applications. Li et al [33] discussed the feasibility of using MgO/H 2 O as the working pair for a TCHS for district heating in northern China. Compared with conventional sensible storage, the proposed system can reduce the need for concentrated collectors by two-thirds.…”

Section: Introductionmentioning

confidence: 99%

Two-Stage Solar–NaOH Thermochemical Heat Pump Heating System for Building Heating: Operations Strategies and Theoretical Performance

Su,

Yang,

et al. 2024

Energies

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Heating buildings with solar energy is challenged by the seasonal mismatch between solar availability and heating demand. Thermochemical energy storage is a promising technology to overcome this challenge because of its high energy density. In building applications, space requirement is also an important consideration. Therefore, both the storage space and collector areas are important considerations, with only the latter often being neglected in previous studies. This paper proposes a novel two-stage thermochemical heat pump heating system based on the working pair of NaOH/H2O. We demonstrate that this system can work with a concentration difference (70% wt–30% wt) for the climate in hot summer and cold winter regions in China. The energy storage density based on the discharged solution is 363 kWh/m3. With this solar-driven thermochemical heat pump heating system, 35.13 m2 of collectors and 10.48 tons of 70% wt NaOH solution are sufficient to complete a full charge–discharge cycle and meet the heating demand of a single-family house (winter space heating + DHW: 9370 kWh, summer DHW: 2280 kWh). The theoretical maximum storage for solution (discharged + water tank) is 32.47 m3. Compared with the sensible seasonal storage alternative, the collector area is reduced by 12.5% and the storage space is reduced by 59%, with a possible further reduction through optimization. With the potential to be further optimized for space saving, the two-stage solar–NaOH heat pump heating system is an energy-efficient and space-efficient heating system for buildings in the hot summer and cold winter regions of China.

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Section: Introductionmentioning

confidence: 99%

Two-Stage Solar–NaOH Thermochemical Heat Pump Heating System for Building Heating: Operations Strategies and Theoretical Performance

Su,

Yang,

et al. 2024

Energies

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“…Solar energy is a clean and renewable energy source . Concentrated solar power (CSP) plants convert solar energy into electricity through thermal conversion .…”

Section: Introductionmentioning

confidence: 99%

“…Solar energy is a clean and renewable energy source. 1 Concentrated solar power (CSP) plants convert solar energy into electricity through thermal conversion. 2 This technology holds significant importance in mitigating climate change and ensuring energy security.…”

Section: Introductionmentioning

confidence: 99%

Calcium Looping Energy Storage Characteristics of Mn-Impregnated Limestone in Fluidization under Direct Solar Irradiation

Fang,

Li,

Zhang

et al. 2024

Energy Fuels

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The directly irradiated reactor is suitable for the solar calciner in calcium looping energy storage technology. However, the low optical absorption performance of CaCO 3 is disadvantageous for its decomposition under direct irradiation. In this work, a directly irradiated fluidized-bed reactor was designed for calcium looping energy storage. The top of the fluidized-bed reactor can receive the simulated solar irradiation from the xenon lamp with a maximum irradiation intensity of 260 kW/m 2 . The energy storage characteristics of CaCO 3 under fluidization and static conditions were compared. The effect of the irradiation intensity on the solar−thermal conversion efficiency was investigated. Furthermore, the energy storage characteristics of Mn-impregnated CaCO 3 were also studied. The results indicate that direct irradiation leads to a high temperature difference in the bed. The temperature difference in the fluidization state is 30% lower than that under the static condition. Increasing the irradiation intensity enhances the decomposition efficiency of CaCO 3 . However, a high radiation efficiency exacerbates irradiation reflection, reducing the solar−thermal conversion efficiency. Mn impregnation enhanced the optical absorption performance of CaCO 3 . The optical absorbance of Mn-impregnated CaCO 3 with a CaCO 3 /Mn mass ratio of 100:3 is 0.83, which is 6 times higher than that of CaCO 3 . The solar−thermal conversion efficiency of Mnimpregnated CaCO 3 increases by 25% compared with CaCO 3 at 200 kW/m 2 . This work further promotes the application of directly irradiated fluidized-bed reactors in calcium loop energy storage.

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“…Such a scheme would increase the energy and resource efficiencies not only of regional energy systems (including the DH networks) but also of the national energy system (because the transportation of energy could be carried out without relying on the electricity transmission network) while boosting the penetration of VRE. The idea of combining TCES and DH is attractive because a large share of the available infrastructure of the DH system can be adapted to use a reduced metal as fuel [16,17]. DH plants based on solid fuels (fossil and nonfossil) in the Nordic countries typically use fluidized bed (FB) combustors (either bubbling or circulating), which can be retrofitted to process metal powders [18].…”

Section: Introductionmentioning

confidence: 99%

Thermochemical Energy Storage with Integrated District Heat Production–A Case Study of Sweden

et al. 2023

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The implementation of electricity-charged thermochemical energy storage (TCES) using high-temperature solid cycles would benefit the energy system by enabling the absorption of variable renewable energy (VRE) and its conversion into dispatchable heat and power. Using a Swedish case study, this paper presents a process for TCES-integrated district heating (DH) production, assesses its technical suitability, and discusses some practical implications and additional implementation options. The mass and energy flows of a biomass plant retrofitted with an iron-based redox loop are calculated for nine specific scenarios that exemplify its operation under electricity generation mixes that differ with respect to variability and price. In addition, the use of two types of electrolyzers (low-temperature and high-temperature versions) is investigated. The results show that for the Swedish case, the proposed scheme is technically feasible and capable of covering the national DH demand by making use of the existing DH plants, with an estimated process energy efficiency (electricity to heat) of 90%. The results also show that for a retrofit of the entire Swedish DH fleet, the required inventories of iron are approximately 2.8 Mt for the intermediate scenario, which represents 0.3% and 11.0% of the national reserves and annual metallurgical production rates of the national industry, respectively. In addition to the dispatchable heat, the process generates a significant amount of nondispatchable heat, especially for the case that employs low-temperature electrolyzers. This added generation capacity allows the process to cover the heat demand while decreasing the maximum capacity of the charging side computed herein.

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Simulation and analysis of thermochemical seasonal solar energy storage for district heating applications in China

Cited by 13 publications

References 49 publications

Two-Stage Solar–NaOH Thermochemical Heat Pump Heating System for Building Heating: Operations Strategies and Theoretical Performance

Two-Stage Solar–NaOH Thermochemical Heat Pump Heating System for Building Heating: Operations Strategies and Theoretical Performance

Calcium Looping Energy Storage Characteristics of Mn-Impregnated Limestone in Fluidization under Direct Solar Irradiation

Thermochemical Energy Storage with Integrated District Heat Production–A Case Study of Sweden

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