A hybrid solar power generation system integrating a solar photovoltaic (PV) module and a solar thermochemical module is proposed based on methanol thermochemistry. Sunlight is concentrated by trough mirror collectors and partially converted to electricity by PV cells overlain on the surface of a solar thermochemical reactor. An endothermic chemical process of methanol (e.g., decomposition) within the reactor then absorbs the ‘‘waste heat” of the PV cells and simultaneously cools the cells. During this process, the low-level thermal energy from the sunlight is upgraded to high-level chemical energy in syngas, which is stored and burned to generate electricity when necessary. Analysis indicates that the theoretical net solar-electric efficiency of the hybrid system could be as high as 45% and relatively insensitive to operation temperature and pressure. Additionally, the system exhibits a good potential in solar energy storage, and capable of providing stable electricity supply around the clock. The PV–thermochemical hybrid system might suggest a promising approach for efficient and stable power generation from solar energy.
A novel hybridization between solar PV and solar thermochemical power generation modules integrating methanol decomposition has been proposed and analyzed. Theoretical net solar electric efficiency of the hybrid system (after taking all major losses into account) reaches up to 45.4% at operating temperature of 225°C and pressure of 7 bar. Compared with conventional PV-only systems, PVT systems and thermochemical-only systems (e.g., the reference system), such a combination significantly enhances the efficiency for two major reasons. The first reason is the ‘‘cascaded” utilization of solar energy, which results in the decrease of exergy losses during solar energy collection and conversion by way of both the power generation of solar cells and endothermicity of methanol decomposition. The second reason is the ‘‘leverage” effect of energy levels between high energy level fossil fuel (i.e., methanol) and low energy level thermal energy from solar cells; the latter is upgraded to the energy level of syngas chemical energy, at the cost of the decrease of methanol energy level during methanol decomposition. The hybrid system also exhibits its capability of uninterrupted and stable electricity supply due to the combination of solar PV cells (for daytime power generation) and solar energy storage through syngas (for nighttime power generation). Sensitivity analysis of key operation parameters of the hybrid system indicates its relative insensitivity to the operation pressure and temperature, which brings tremendous benefits in system design and system operation, due to opposite responses of PV cells and methanol thermochemistry to temperature. Based on all above-mentioned advantages, the PV–thermochemical hybrid system proposed in this work could provide a promising approach for effective solar energy utilization in the near future.
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Efficient solar power generation combining photovoltaics and mid-/low temperature methanol thermochemistry
Mar 18, 2019 / Author by Li Wenjia Text SizeDBSA hybrid solar power generation system integrating a solar photovoltaic (PV) module and a solar thermochemical module is proposed based on methanol thermochemistry. Sunlight is concentrated by trough mirror collectors and partially converted to electricity by PV cells overlain on the surface of a solar thermochemical reactor. An endothermic chemical process of methanol (e.g., decomposition) within the reactor then absorbs the ‘‘waste heat” of the PV cells and simultaneously cools the cells. During this process, the low-level thermal energy from the sunlight is upgraded to high-level chemical energy in syngas, which is stored and burned to generate electricity when necessary. Analysis indicates that the theoretical net solar-electric efficiency of the hybrid system could be as high as 45% and relatively insensitive to operation temperature and pressure. Additionally, the system exhibits a good potential in solar energy storage, and capable of providing stable electricity supply around the clock. The PV–thermochemical hybrid system might suggest a promising approach for efficient and stable power generation from solar energy.
A novel hybridization between solar PV and solar thermochemical power generation modules integrating methanol decomposition has been proposed and analyzed. Theoretical net solar electric efficiency of the hybrid system (after taking all major losses into account) reaches up to 45.4% at operating temperature of 225°C and pressure of 7 bar. Compared with conventional PV-only systems, PVT systems and thermochemical-only systems (e.g., the reference system), such a combination significantly enhances the efficiency for two major reasons. The first reason is the ‘‘cascaded” utilization of solar energy, which results in the decrease of exergy losses during solar energy collection and conversion by way of both the power generation of solar cells and endothermicity of methanol decomposition. The second reason is the ‘‘leverage” effect of energy levels between high energy level fossil fuel (i.e., methanol) and low energy level thermal energy from solar cells; the latter is upgraded to the energy level of syngas chemical energy, at the cost of the decrease of methanol energy level during methanol decomposition. The hybrid system also exhibits its capability of uninterrupted and stable electricity supply due to the combination of solar PV cells (for daytime power generation) and solar energy storage through syngas (for nighttime power generation). Sensitivity analysis of key operation parameters of the hybrid system indicates its relative insensitivity to the operation pressure and temperature, which brings tremendous benefits in system design and system operation, due to opposite responses of PV cells and methanol thermochemistry to temperature. Based on all above-mentioned advantages, the PV–thermochemical hybrid system proposed in this work could provide a promising approach for effective solar energy utilization in the near future.