Daylighting has emerged as a prominent strategy for elevating indoor environments by harmonizing visual comfort and energy efficiency. This paper introduces a louver system crafted for energy simulations, specifically tailored to address lighting and cooling requirements in office spaces. Louvers, acknowledged for their exceptional efficiency in providing daylight, are integrated as a pivotal energy-saving technique. Adopting a quantitative research approach facilitated by building information simulation tools, DIALUX evo and Rhino were employed for modeling and simulating the building’s daylighting performances. The simulation outcomes reveal substantial energy savings, particularly in the realms of lighting and cooling. Notably, a 50% louver opening in office spaces results in an impressive 27.0% reduction in energy consumption. The study explores various louver configurations, providing insights into both lighting and cooling energy savings. The overall system performance excels in sustaining consistent daylight, significantly contributing to enhanced energy efficiency.

We have proposed a fruitful design principle targeting a concentration ratio (CR) >1000× for a typical high concentrating photovoltaics (HCPV) system, on account of a two-concentrator system + homogenizer. The principle of a primary dual-lens concentrator unit, completely analogous basic optics seen in the superposition compound eyes, is a trend not hitherto reported for solar concentrators to our knowledge. Such a concentrator unit, consisting of two aspherical lenses, can be applied to minify the sunlight and reveal useful effects. We underline that, at this stage, the CR can be attained by two orders of magnitude simply by varying the radius ratio of such two lenses known from the optics side. The output beam is spatially minimized and nearly parallel, exactly as occurs in the superposition compound eye. In our scheme, thanks to such an array of dual-lens design, a sequence of equidistant focal points is formed. The secondary concentrator consists of a multi-reflective channel, which can collect all concentrated beams from the primary concentrator to a small area where a solar cell is placed. The secondary concentrator is located right underneath the primary concentrator. The optical characteristics are substantiated by optical simulations that confirm the applicability of thousands-fold gain in CR value, ~1100×. This, however, also reduced the uniformity of the illumination area. To regain the uniformity, we devise a fully new homogenizer, hinging on the scattering principle. A calculated optical efficiency for the entire system is ~75%. Experimentally, a prototype of such a dual-lens concentrator is implemented to evaluate the converging features. As a final note, we mention that the approach may be extended to implement an even higher CR, be it simply by taking an extra concentrator unit. With simple design of the concentrator part, which may allow the fabrication process by modeling method and large acceptant angle (0.6°), we assess its large potential as part of a general strategy to implement a highly efficient CPV system, with minimal critical elaboration steps and large flexibility.

Agricultural land is increasingly under pressure from expanding solar energy infrastructure, leading to a growing conflict between food and energy production. Conventional photovoltaic (PV) systems often reduce crop yields due to shading and suboptimal light conditions for photosynthesis. This study introduces a Red Spectrum Splitting Concentrated Agrivoltaic (RSSCA) system designed to overcome these limitations by selectively directing specific wavelengths of sunlight to serve both agricultural and energy needs. The system uses a Fresnel lens and dichroic mirror to concentrate solar radiation and split the spectrum: red light (around 630 nm), essential for rice growth, is transmitted to the crops, while the remaining wavelengths are directed to high-efficiency multi-junction solar cells. We employed optical simulations and analytical modeling to assess system performance. Results show a photoelectric conversion efficiency of 31.2% and adequate Daily Light Integral (DLI) levels for rice cultivation in high-sunlight regions such as Hanoi and Ho Chi Minh City. For instance, DLI values in Hanoi range from 14.3 to 32.2 mol/m²/day and in Ho Chi Minh City from 24.3 to 37.8 mol/m²/day, compared to 6.6–16.1 and 14.4–18.2 mol/m²/day under conventional PV systems, respectively. Electricity production with RSSCA peaks at 2790 W/m²/day in Ho Chi Minh City and 2577 W/m²/day in Hanoi, outperforming traditional PV setups by 3–5 times. Compared to conventional PV systems, the RSSCA offers improved light uniformity, better land-use efficiency, and significantly higher electricity generation. However, in regions with limited direct sunlight, such as Seoul in winter, system performance decreases. These findings suggest the RSSCA system is well-suited for tropical and subtropical areas where direct sunlight is abundant. It presents a viable solution for enhancing both food production and renewable energy generation on shared land.

Daylighting has been widely adopted in recent years due to its potential to improve the indoor environment in terms of visual comfort and energy-saving. One of the energy-saving techniques for energy-efficient buildings is the integration of louver systems. Louvers are considered more efficient for providing daylight in the interior as compared to other daylighting systems. Here, this paper presents the design of a louver system for conducting energy simulations for lighting and cooling requirements in office spaces. The simulation results indicate that the use of louvers in different opening configurations can lead to energy savings, particularly in the lighting aspect. The louver system in office spaces with a 50% louver opening leads to 27.0% energy savings. Further, the results are presented for different louver openings to calculate the lighting and cooling energy savings. The overall performance of the system is better in terms of providing consistent daylight, which eventually improves energy saving.