Maximal nighttime electrical power generation via optimal radiative cooling

Pang

et al. 2021

EcoMat

Passive daytime radiative cooling (PDRC) dissipates terrestrial heat to the extremely cold outer space without using any energy input or producing pollution. It has the potential to simultaneously alleviate the two major problems of energy crisis and global warming. In this review, we summarize general strategies implemented for achieving PDRC and various applications of PDRC technologies. We first introduce heat transfer processes involved in PDRC, including radiative and nonradiative heat transfer processes, to evaluate the PDRC performance. Subsequently, we summarize the general material designs used for controlling PDRC performance, such as tuning the thermal mid-infrared emittance and solar reflectance. Finally, we discuss the diverse applications of PDRC technologies to overcome problems in space cooling, solar cell cooling, water harvesting, and electricity generation.

Section: Electricity Generationmentioning

confidence: 62%

Section: Electricity Generationmentioning

confidence: 99%

See 1 more Smart Citation

Passive daytime radiative cooling: Fundamentals, material designs, and applications

Pang

et al. 2021

EcoMat

“…Generally, the power generated by the 0.04 m 2 prototype is low, the maximum value is only 10 mW/m 2 , which is much lower than the power in [21,23], even though the environments are different. Secondly, the prototype did not have an external protective layer, meaning that the winds could affect heat convention.…”

Section: Limitationsmentioning

confidence: 96%

“…Recently, Fan et al [21] reached more than 2 W/m 2 via a vacuum chamber connected with radiative cooling, while the cost is much higher than previous studies. Technological progress has allowed TEG to have more applications in buildings.…”

Section: Introductionmentioning

confidence: 92%

An experiment on full-day power generation building fabric component for zero-energy buildings

Li¹

2021

Preprint

Thermal electricity generation (TEG) is a potential method to utilize energy emitted from the built environment. This work presents a prototype of the low-cost full-day power generation solar building component, which can be integrated as the building fabric or as a part of the solar panels. The size of the prototype is 0.04 m2. The overall cost is less than 25 USD. The prototype is tested in various environments to validate its performance. The first experiment tests its performance under the radiation of a high-temperature source, the prototype can generate the highest voltage of 0.8 V. In onsite experiments, it can reach a maximum value of 10 mW/m2 under sunlight. It can also work at night depending on the thermal radiation of the environment. It can also be used in different weather; the performance is even better than the nighttime. The experiments indicate that radiation heat transfer has a stronger influence on energy conversion than the convective heat transfer. The relative humidity has a certain influence on its performance, but there is no obvious effect of radiation heat transfer. Although the prototype has great potential, there are still limitations, and this article also discusses the problems. Meanwhile, this article also points out possible directions for improving design in the future. The results in this article might be helpful for zero-energy buildings and low-carbon buildings.

Maximizing Electric Power through Spectral‐Splitting Photovoltaic‐Thermoelectric Hybrid System Integrated with Radiative Cooling

Guo

Huai

2023

Advanced Science

As zero-emission technologies, a daytime radiative cooling (RC) strategy developed recently, and photovoltaic (PV) and thermoelectric (TE) technologies have aroused great interest to reduce fossil fuel consumption and carbon emissions. How to integrate these state-of-the-art technologies to maximise clean electricity from the sun and space remains a huge challenge, and the limit efficiency is still unclear. In this study, a spectral-splitting PV-TE hybrid system integrated with RC is proposed to maximise clean electricity from the sun and space without any emissions. For the sun acting as a typical constant heat-flux heat source, the current thermoelectric theory overestimates the thermoelectric efficiency highly since the theory is based on constant temperature-difference conditions. A new theory based on heat-flux conditions is employed to achieve maximum thermoelectric efficiency. The PV-TE hybrid system with RC is superior to the conventional hybrid system, not only in terms of higher efficiency but also in its 24-h operation capacity. In a system with a single-junction cell, the total efficiency with 30 suns (39.4%) is higher than the theoretical PV efficiency at 500 suns (38.2%). In a hybrid system with four-junction cells, total efficiency is over 65% which is superior to most current photoelectric and thermal power systems.