Award Date

August 2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

First Committee Member

Biswajit Das

Second Committee Member

Yingtao Jiang

Third Committee Member

Emma E. Regentova

Fourth Committee Member

Frank Van Breukelen

Number of Pages

150

Abstract

Accumulation of dust on solar panels poses a serious problem as it can significantly reduce light absorption and electrical energy output. Several factors affect the dust accumulation such as location, dust properties, wind velocity, system orientation, ambient temperature, humidity, and panel surface properties. Experimental and theoretical studies show that short circuit current and maximum power output of photovoltaic panels reduce approximately linearly with dust concentration. Incidentally, the locations with higher solar energy concentrations are also arid or semi-arid regions with higher dust concentrations. In order to avoid loss in power output, most PV installations perform periodic panel cleaning with water. Such water cleaning, in addition to added cost, can be challenging in arid areas that are otherwise ideal for solar power generation. In addition, the effectiveness of water cleaning varies with the proximity of the installations to the dust source/location as well as the time of the year.

There have been many efforts to reduce (or eliminate) water cleaning requirements for solar panels, focusing primarily on dust control and dust remedy many of these are based on techniques that originated from NASA efforts to develop dust control and remedy systems for lunar and Mars missions. In these techniques, dust control was typically achieved by making the solar panel surface more hydrophobic or hydrophilic through surface modification; dust removal is typically achieved using electromagnetic wave, acoustic wave, airflow or combinations thereof. Unfortunately, many of these techniques are expensive and may not be cost-effective for PV energy generation.

Researchers are looking for low-cost technology for solar panel dust control/remediation using micro- and nanotechnologies. The use of such low dimensional technologies can provide significant enhancement in dust control and remediation at very low cost. The Nevada Nanotechnology Center at UNLV has developed non-lithographic ways of generating such nanostructures as a demonstration of feasibility. In addition, such low dimensional structures are also suitable for low-cost spray or dip-coating processes. The objective of this thesis is to study, investigate and develop a nanotechnology-based technique for water-less dust mitigation on solar panels.

Firstly, in this dissertation, the chemical and physical properties of dust were examined, the variation of airborne or aeolian dust seasonally for the southwestern US. Secondly, to resolve the issues related to enhanced cleaning, a cost-effective spray coated, or dip coated hydrophobic layer of transparent conductive oxide can be applied to modify the solar panel surface. A low-cost nanostructure-based technology for control and remedial of dust on PV panels that can be applied through spray or dip coating was developed and studied. With further studies, this approach can be applied to utility-scale solar plants for effective and low-cost dust control and remedial system for PV panels.

The dust studies and their seasonal data analysis were reported in chapter 2 and 3. Statistical analysis exhibits that the trend in dust deposition varies seasonally and geographically. The experimental studies and characterizations form the last two chapters of this dissertation. FESEM data shows clustering of nanoparticles due to coalescing. The data confirms the presence of both undoped and doped ZnO respectively. Different tests were being conducted to test the hydrophobicity and transparency of coated glass panels. The XRD scan pattern for the ZnO nanoparticles shows preferential (0 0 2) plane growth. The samples were tested for electrical conductivity, resistivity, and sheet resistance using Van Der Pauw method. The transparent conductive oxide was doped in order to alter the properties, such as band gap to further enhance the conductivity and transparency.

Keywords

Aeolian dust; cost effective; Dust mitigation; Solar Panels; transparent conductive oxides; waterless

Disciplines

Engineering | Geology | Nanoscience and Nanotechnology

Language

English

Available for download on Sunday, August 15, 2021


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