The present paper investigated the seasonal solar thermal energy storage (SSTES) using solid-gas thermochemical sorption technology that has inherently combined function of heat pump and energy storage. The thermochemical reactions that can discharge heat at a higher temperature usually requires a relatively higher desorption temperature during charging process, which could be problematic to efficiently recover solar energy in high-latitude regions like the UK when using the most mature and economic solar thermal collector (flat-plate or evacuated tube type). The present work studied two hybrid concepts where an electric-driven compressor or an electric heater was introduced to supplement the thermochemical desorption process in terms of pressure rise and temperature lift, respectively, when the available solar heat was not sufficiently high. The SrCl2-8/1NH3 chemisorption was selected from 230 ammonia-chemisorption reactions due to its suitable adsorption/desorption temperature and large energy storage density. The performance of two hybrid systems using SrCl2-8/1NH3 chemisorption were evaluated and compared to determine the optimal solution. The results revealed that the hybrid thermochemical sorption with a compressor substantially improved the storage capacity compared to that with electric heater. With a compression ratio of 4, the SSTES system with 20 m2 solar collector under the weather condition of Newcastle upon Tyne can store 3226.8 kWh chemisorption heat in summer by charging 4465.4 kWh solar heat and 848.2 kWh electricity, indicating 60.7% storage efficiency; the corresponding energy density based on the overall system volume is 147.3 kWh/m3. Because of using the renewable solar heat and low carbon intensity electricity in summer, the proposed hybrid SSTES system has noteworthy reduction on carbon emission compared to gas boiler and conventional heat pump.

中文翻译：

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用于季节性太阳能存储的电辅助热化学吸附系统

本文研究了使用固气热化学吸附技术的季节性太阳能热能储存（SSTES），该技术具有热泵和储能的固有组合功能。可以在较高温度下释放热量的热化学反应通常在充电过程中需要相对较高的解吸温度，这可能会成为英国等高纬度地区使用最成熟、最经济的太阳能集热器有效回收太阳能的问题。平板型或真空管型）。目前的工作研究了两种混合概念，当可用太阳能热量不够高时，引入电动压缩机或电加热器以分别在压力升高和温度提升方面补充热化学解吸过程。SrCl2-8/1NH3化学吸附因其合适的吸附/解吸温度和较大的储能密度而从230个氨化学吸附反应中选出。对使用 SrCl2-8/1NH3 化学吸附的两种混合系统的性能进行了评估和比较，以确定最佳解决方案。结果表明，与电加热器相比，压缩机的混合热化学吸附显着提高了存储容量。在压缩比为4的情况下，在泰恩河畔纽卡斯尔的天气条件下，SSTES系统配备20平方米太阳能集热器，可在夏季储存3226.8千瓦时的化学吸附热量，充电4465.4千瓦时的太阳能和848.2千瓦时的电能，存储效率为60.7%；基于整个系统体积的相应能量密度为 147.3 kWh/m3。