Life Cycle Assessment of Solar-Driven Post-Combustion Carbon Capture Systems: The Way Forward to Slash the Energy Penalty

Post-combustion carbon capture (PCC) technique has been extensively investigated over the past two decades to mitigate the effects of greenhouse gas (GHG) emissions. Nowadays, integrating solar energy with a PCC retrofit has become an active area of research due to its potential to slash the energy penalty on power plants. The economic aspects of both solar-assisted PCC (SA-PCC) and solar-powered PCC (SP-PCC) counterparts have already been studied in literature. Therefore, this paper aims at analysing and comparing the environmental footprints of SA-PCC and SP-PCC systems throughout their life cycle using the ReCiPe 2016 method. A cradle-to-grave framework is employed to specify the life cycle inventories in OpenLCA software for capturing one carbon capture unit (tonne of CO2) over the project’s lifespan. Results showed that SP-PCC significantly reduces environmental burdens (>10%) in various midpoint categories compared to SA-PCC counterpart. Furthermore, the endpoint assessment of SA-PCC revealed that particulate matter formation, global warming, land use, and mineral scarcity have substantial damaging impacts on the endpoint areas of protection, accounting for 37.29%, 49.48%, 76.18%, and 13.49% of the total impact, respectively. As a result, they are classified as critical impact categories that should receive priority attention for improvements. Further categorization of critical categories showed that the key difference between the examined systems lies in the contributions of nitrate salts and mono-ethanolamine (MEA) production. Furthermore, MEA contributions in SP-PCC are considerably lower than those of nitrate salts in SA-PCC across the critical categories. This demonstrates the superiority of SP-PCC over the SA-PCC in mitigating the environmental burdens when incorporating solar energy in carbon capture proces

Solar Hot Water Systems Using Latent Heat Thermal Energy Storage: Perspectives and Challenges

Domestic water heating accounts for 15% to 27% of the total energy consumption in buildings in Australia. Over the past two decades, the latent heat thermal energy storage (LHTES) system has been widely investigated as a way to reduce fossil fuel consumption and increase the share of renewable energy in solar water heating. However, the research has concentrated on the geometric optimisation of the LHTES heat exchanger for the past few years, and this might not be sufficient for commercialisation. Moreover, recent review papers mainly discussed the development of a particular heat-transfer improvement technique. This paper presents perspectives on various solar hot water systems using LHTES to shift focus to on-demand performance studies, as well as structure optimisation studies for faster commercialisation. Future challenges are also discussed. Since the topic is an active area of research, this paper focuses on references that showcase the overall performance of LHTES-assisted solar hot water systems and cannot include all published work in the discussion. This perspective paper provides directional insights to researchers for developing an energy-efficient solar hot water system using LHTES.</jats:p

Solar Hot Water Systems Using Latent Heat Thermal Energy Storage: Perspectives and Challenges

Domestic water heating accounts for 15% to 27% of the total energy consumption in buildings in Australia. Over the past two decades, the latent heat thermal energy storage (LHTES) system has been widely investigated as a way to reduce fossil fuel consumption and increase the share of renewable energy in solar water heating. However, the research has concentrated on the geometric optimisation of the LHTES heat exchanger for the past few years, and this might not be sufficient for commercialisation. Moreover, recent review papers mainly discussed the development of a particular heat-transfer improvement technique. This paper presents perspectives on various solar hot water systems using LHTES to shift focus to on-demand performance studies, as well as structure optimisation studies for faster commercialisation. Future challenges are also discussed. Since the topic is an active area of research, this paper focuses on references that showcase the overall performance of LHTES-assisted solar hot water systems and cannot include all published work in the discussion. This perspective paper provides directional insights to researchers for developing an energy-efficient solar hot water system using LHTES

Investigation of an Energy Source Temperature for NH3 + NaSCN and NH3 + LiNO3 Absorption Refrigeration Systems

Abstract This paper evaluates the energy source temperature for novel salts based ammonia/sodium thiocyanate (NH3 + NaSCN) and ammonia/lithium nitrate (NH3 + LiNO3) absorption refrigeration systems. Minimum energy source temperature (cutoff) required to initiate the cooling, critical energy source temperature for optimized thermodynamic performance and possible maximum energy source temperature to avoid crystallization have been determined, and empirical correlations are developed to facilitate continuous operation of the system. A comparison of cutoff energy source temperature depicts that the NH3 + NaSCN pair requires averagely 6 –7 °C higher cutoff temperature compared with the NH3 + LiNO3 pair. Contradictory to this, the maximum coefficient of performance (COP) of the NH3 + NaSCN pair is 7.02% higher than that the NH3 + LiNO3 pair. However, NH3 + NaSCN pair operates in a very narrow range of energy source temperature. From the P − T − X diagram, the crystallization phenomenon is clarified and the maximum energy source temperature has been determined beyond which the system would not function due to crystallization problems. For −10 °C evaporator temperature, the energy source temperature should be controlled between 87 °C and 115 °C for the NH3 + NaSCN pair and between 80 °C and 147 °C for the NH3 + LiNO3 pair.</jats:p