Solar Energy

Radiative cooling and solar heating from one system, no electricity needed

Published

4 years ago

February 9, 2021

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Radiative cooling and solar heating from one system, no electricity needed

Passive cooling, like the shade a tree provides, has been around forever. Recently, researchers have been exploring how to turbo charge a passive cooling technique – known as radiative or sky cooling – with sun-blocking, nanomaterials that emit heat away from building rooftops. While progress has been made, this eco-friendly technology isn’t commonplace because researchers have struggled to maximize the materials’ cooling capabilities.

New research led by University at Buffalo engineers makes significant progress in this area.

A study published Feb. 8 in the journal Cell Reports Physical Science describes a uniquely designed radiative cooling system that:

+ Lowered the temperature inside a test system in an outdoor environment under direct sunlight by more than 12 degrees Celsius (22 degrees Fahrenheit).

+ Lowered the temperature of the test box in a laboratory, meant to simulate the night, by more than 14 degrees Celsius (25 degrees Fahrenheit).

+ Simultaneously captured enough solar power that can be used to heat water to about 60 degrees Celsius (140 degrees Fahrenheit).

While the system tested was only 70 centimeters (27.5 inches) squared, it could eventually be scaled up to cover rooftops, engineers say, with the goal of reducing society’s reliance on fossil fuels for cooling and heating. It also could aid communities with limited access to electricity.

“There is a great need for heating and cooling in our daily life, especially cooling in the warming world,” says the study’s lead author Qiaoqiang Gan, PhD, professor of electrical engineering in the UB School of Engineering and Applied Sciences.

The research team includes Zongfu Yu, PhD, University of Wisconsin-Madison; Boon Ooi, PhD, King Abdullah University of Science and Technology (KAUST) in Saudi Arabia; and members of Gan’s lab at UB, and Ooi’s lab at KAUST.

System design and materials key to success

The system consists of what are essentially two mirrors, made of 10 extremely thin layers of silver and silicon dioxide, which are placed in a V-shape.

These mirrors absorb incoming sunlight, turning solar power from visible and near-infrared waves into heat. The mirrors also reflect mid-infrared waves from an “emitter” (a vertical box in between the two mirrors), which then bounces the heat they carry into the sky.

“”Since the thermal emission from both surfaces of the central thermal emitter is reflected to the sky, the local cooling power density on this emitter is doubled, resulting in a record high temperature reduction,” says Gan.

“”Most radiative cooling systems scatter the solar energy, which limits the system’s cooling capabilities,” Gan says. “Even with a perfect spectral selection, the upper limit for the cooling power with an ambient temperature of 25 degrees Celsius is about 160 watts per square meter. In contrast, the solar energy of about 1000 watts per square meter on top of those systems was simply wasted.””

Spinoff company aims to commercialize technology

Gan co-founded a spinoff company, Sunny Clean Water LLC, which is seeking partners to commercialize this technology.

“One of the key innovations of our system is the ability to separate and retain the solar heating and radiative cooling at different components in a single system,” says co-first author Lyu Zhou, a PhD candidate in electrical engineering in the School of Engineering and Applied Sciences. “During the night, radiative cooling is easy because we don’t have solar input, so thermal emissions just go out and we realize radiative cooling easily. But daytime cooling is a challenge because the sun is shining. In this situation, you need to find strategies to separate solar heating from the cooling area.”

The work builds upon previous research Gan’s lab led that involved creating a cone-shaped system for electricity-free cooling in crowded cities to adapt to climate change.

“The new double-sided architecture realized a record local cooling power density beyond 280 watts per square meter. Under standard atmospheric pressure with no vacuum thermal isolation, we realized a temperature reduction of 14.5 degrees Celsius below the ambient temperature in a laboratory environment, and over 12 degrees Celsius in an outdoor test using a simple experimental system,” says the other co-first author, Haomin Song, PhD, a research assistant professor of electrical engineering in the School of Engineering and Applied Sciences.

“Importantly, our system does not simply waste the solar input energy. Instead, the solar energy is absorbed by the solar spectral selective mirrors, and it can be used for solar water heating, which is widely used as an energy efficient device in developing countries,” says Gan. “It can retain both the solar heating and radiative cooling effects in a single system with no need of electricity. It’s really sort of a ‘magic’ system of ice and fir.”

The research team will continue to investigate ways to improve the technology, including examining how to capture enough solar power to boil water, making it suitable for drinking.

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Solar Energy

New system offers early warning of dust storms to protect solar power output

Published

3 days ago

April 16, 2025

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New system offers early warning of dust storms to protect solar power output

by Simon Mansfield

Sydney, Australia (SPX) Apr 10, 2025

A new predictive platform called iDust is poised to transform dust storm forecasting and improve solar energy output in dust-prone regions. Developed by researchers at the Chinese Academy of Sciences, iDust offers high-resolution, fast-turnaround dust forecasts that could help mitigate power losses across solar farms, particularly in arid zones.

The tool was created under the leadership of Dr. Chen Xi from the Institute of Atmospheric Physics and detailed in the Journal of Advances in Modeling Earth Systems (JAMES).

“Dust storms not only block sunlight but also accumulate on solar panels, decreasing their power output.” said Chen, outlining the motivation behind the project. With China’s rapid expansion of solar installations in desert areas, the need for precise and timely dust forecasts has become increasingly urgent to avoid operational disruptions and revenue shortfalls.

Traditional systems like those from the European Centre for Medium-Range Weather Forecasts (ECMWF) often lack the spatial resolution and processing speed needed for optimal solar planning. iDust addresses these limitations by embedding dust-related dynamics directly into its forecast engine. This allows the system to generate forecasts with 10-kilometer resolution-a fourfold improvement over previous models-while maintaining near-parity in computational load. Crucially, iDust can deliver 10-day forecasts within six hours of initial observations.

The effectiveness of iDust was put to the test on April 13, 2024, when it successfully tracked a severe dust storm over Bayannur in northern China. Such storms can distort solar energy projections by as much as 25% if unaccounted for, underscoring the value of integrating dust modeling into energy planning.

Designed for practical deployment, iDust aims to assist solar facility operators and grid managers in optimizing power production and reducing losses due to airborne particulates. As China pushes toward its carbon neutrality goals, innovations like iDust will be central to achieving sustainable energy reliability.

Researchers plan to expand the system for global application, allowing other countries with desert-based solar assets to benefit from enhanced dust forecasting.

Research Report:The Efficient Integration of Dust and Numerical Weather Prediction for Renewable Energy Applications

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Solar Energy

Going green with fluoride-enhanced perovskite solar cells

Published

4 days ago

April 15, 2025

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Going green with fluoride-enhanced perovskite solar cells

by Simon Mansfield

Sydney, Australia (SPX) Apr 15, 2025

A team of scientists from Queensland University of Technology (QUT) has unveiled a sustainable method for fabricating perovskite solar cells (PSCs) by using a fluoride-based additive in a water-only solution. This innovation replaces hazardous solvents typically used in PSC production, achieving a notable power conversion efficiency exceeding 18%.

Perovskite solar cells have emerged as a promising technology for the future of solar energy, thanks to their high efficiency and cost-effectiveness. Yet, their commercial scalability has been hindered by the environmental and health hazards posed by conventional toxic solvents used during manufacturing. While water-based methods offer a more sustainable route, they have so far underperformed in delivering high-efficiency devices.

To overcome this barrier, QUT researchers introduced lead(II) fluoride (PbF2) into the aqueous precursor mix. This additive plays a dual role: it speeds up the formation of the light-absorbing phase and aligns the crystallization process to optimize light conversion. The fluoride ions also passivate surface defects in the perovskite grains, minimizing charge loss and improving conductivity.

“With the PbF2 additive, we achieved a power conversion efficiency of 18.1%, compared to 16.3% in the control device,” said Dr. Minh Tam Hoang, a postdoctoral researcher at QUT and lead author of the study. “Even more exciting is the improved operational and environmental stability, which brings us closer to scalable, green manufacturing of PSCs.”

This advancement signals a meaningful shift in perovskite solar cell development, offering a pathway to produce efficient and durable solar modules through eco-friendly processes. The results demonstrate the value of fluoride-based chemistry in advancing both performance and sustainability in solar technologies.

The findings were published in the journal Materials Futures, underscoring the growing role of green additives in next-generation clean energy solutions.

Research Report:Lead (II) fluoride additive modulating grains growth of water-processed metal halide perovskites for enhanced efficiency in solar cells

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Solar Energy

Launch of AI-powered solar diagnostics platform boosts PV asset performance

Published

4 days ago

April 15, 2025

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Launch of AI-powered solar diagnostics platform boosts PV asset performance

by Simon Mansfield

Sydney, Australia (SPX) Apr 15, 2025

The Solar Energy Research Institute of Singapore (SERIS) at the National University of Singapore (NUS) has launched a commercial spin-off called the “PV Doctor,” marking a significant leap forward in managing and optimizing solar photovoltaic (PV) system performance. Officially unveiled on April 2, 2025, the platform leverages 15 years of R and D into the behavior of PV systems in diverse climates and aims to restore and maintain peak energy output for solar installations worldwide.

The PV Doctor combines AI-based analytics with routine monitoring and benchmark comparisons to ensure that solar assets operate at maximum efficiency. In addition to diagnostics, the service provides corrective action plans and hands-on rectification, helping system owners recover lost energy output and maximize returns on investment.

“Our mission is to ensure that every PV system under our care performs at its peak potential,” the founders stated. “By integrating deep expertise with real-time diagnostics, we can prevent losses before they escalate.”

Many PV systems are sold under the misleading premise of being maintenance-free, despite the reality that even minor oversight can result in substantial inefficiencies. Global preventable losses from underperforming systems are estimated at $10 billion annually. PV Doctor targets this gap by offering root-cause analysis and active management for both healthy and ailing systems. Its Smart O&M algorithm tracks performance in real-time, detecting anomalies before they degrade output.

Initially trialed by SERIS across Asia, the Smart O&M services quickly proved their value. In just under a year, PV Doctor systems reached over 200 MWp of assets under management, covering 400 sites in 10 countries. In Singapore, more than 3% of all PV installations are already being managed by the platform.

PV Doctor’s capabilities are structured around six core services:

1. Smart O&M – This foundational offering provides real-time performance monitoring, automatic issue detection, and root-cause analysis. The system integrates seamlessly with inverter portals, using a combination of sensor inputs, satellite data, and machine learning to pinpoint losses from pollution, shading, grid disruptions, and component failures.

2. Preventive O&M – For owners seeking a passive role, this service delivers scheduled maintenance, inspections, and early fault resolution, ensuring systems remain operational without owner involvement.

3. Rectification and Special Investigations – PV Doctor tackles complex issues such as potential-induced degradation or mechanical defects, especially common in low-tilt systems near the equator. Thorough diagnostics precede tailored interventions to restore full performance.

4. Repowering – Older or obsolete systems can be upgraded with the latest high-efficiency modules and inverters. Repowering revitalizes aging assets, increases output, and prolongs operational lifespan.

5. Audits and Performance Assessments – Independent third-party assessments support transactions and compliance needs. PV Doctor uses thermal imaging, satellite-derived irradiance, and electrical testing to deliver objective performance evaluations.

6. Technical Support – Beyond system operations, the platform assists stakeholders across the solar value chain with project planning, risk analysis, component selection, and due diligence for acquisitions.

PV Doctor positions itself as an essential partner for solar developers, asset managers, EPC firms, and investors, offering scalable solutions from residential systems to large-scale solar farms.