Gurveer Singh

Bio: Gurveer Singh is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Thermal & Heliostat. The author has an hindex of 4, co-authored 15 publications receiving 50 citations. Previous affiliations of Gurveer Singh include Government College & University College of Engineering.

Dealing with dust – Some challenges and solutions for enabling solar energy in desert regions

Abstract: In India, the desert regions of Rajasthan and Gujarat are preferred for installation of solar photovoltaic (PV) and concentrated solar thermal (CST) systems because of a high level of both DNI and GHI components of solar radiation. However, such regions pose substantial challenges in terms of dust, a high ambient temperature and scarcity of water. This paper is an attempt to address issues related to the deposition of dust (a) on a mirror with stand depicting PV panel or heliostat in the wake of a similar geometry and (b) in the porous absorber of an open volumetric air receiver (OVAR). A detailed insight to the wake-region behind an inclined flat-plate or heliostat is provided based on analysis and experiment. These indicate possible measures such as modification of the geometry of collectors to mitigate the problem of dust deposition. Also, the use of a cyclone separator with defined parameters based on a decision variable has been suggested for reliable operation of an OVAR. These problems being generic in nature, similar strategies are expected to be applicable in other desert regions subject to their specific conditions.

Dust Deposition Mechanism and Cleaning Strategy for Open Volumetric Air Receiver Based Solar Tower Sub-systems☆

Abstract: Desert regions like Rajasthan and Gujarat in India receives abundant solar energy At the same time these regions are blessed with dust or sand Solar thermal systems are one of the ways to harness this available energy Open Volumetric Air Receiver based concentrated solar tower systems are being investigated for applications, like, metal processing The dust deposition on sub-systems like, heliostat, porous receiver will hinder smooth operation of such a system Considering this fact, aspects of dust deposition in porous absorber of the receiver and in heliostat are presented In this direction, experiments and analyses are performed This revealed that dust deposition on heliostat will be affected by its location among other parameters The presented analysis shows the required free-stream air velocity for cleaning of such a mirror depending on particle size and location Experiments on dust deposition in a single pore of an absorber, simulated by a thin and long glass tube of 13 mm diameter is presented Furthermore, experiments on dust deposition in one porous absorber reveal its severe consequence Finally, a strategy for collection of the removed dust particles from these pores is presented to avoid their passage to internals

On the evaluation of a cyclone separator for cleaning of open volumetric air receiver

Abstract: Rajasthan and Gujarat on being located at the equatorial belt receive almost the highest solar irradiation in India. At the same time, such arid desert regions are blessed with dust. This energy can be harnessed using, for instance, solar thermal technology. The recovered heat can be employed for applications, like, heat treatment of metal. For this purpose, an open volumetric air receiver based solar tower technology concept is adopted. In this receiver concentrated solar irradiation is focused onto porous absorber, which is open to atmosphere. The atmospheric air is used as heat transfer fluid with suction. The suspended dust particles in atmosphere will deposit in the pores of the open absorber and even pass to the internals of the complete systems. This is expected to damage the receiver and prevent continuous operation of such a system. In this paper, design and evaluation of a cyclone separator for cleaning and collection strategy of dust from open volumetric air receiver is described. In particular, this paper presents (a) an experiment demonstrating the dust deposition in porous absorber (b) evaluation of the designed cyclone separator and (c) proposed modification in Lapple model for prediction of pressure-drop in cyclone separator including the effect of operating temperature.

Reprint of: Dealing with dust – Some challenges and solutions for enabling solar energy in desert regions

Abstract: In India, the desert regions of Rajasthan and Gujarat are preferred for installation of solar photovoltaic (PV) and concentrated solar thermal (CST) systems because of a high level of both DNI and GHI components of solar radiation. However, such regions pose substantial challenges in terms of dust, a high ambient temperature and scarcity of water. This paper is an attempt to address issues related to the deposition of dust (a) on a mirror with stand depicting PV panel or heliostat in the wake of a similar geometry and (b) in the porous absorber of an open volumetric air receiver (OVAR). A detailed insight to the wake-region behind an inclined flat-plate or heliostat is provided based on analysis and experiment. These indicate possible measures such as modification of the geometry of collectors to mitigate the problem of dust deposition. Also, the use of a cyclone separator with defined parameters based on a decision variable has been suggested for reliable operation of an OVAR. These problems being generic in nature, similar strategies are expected to be applicable in other desert regions subject to their specific conditions.

Design of a Cyclone Separator for Cleaning of Dust from Volumetric Air Receiver

Abstract: Arid regions, like Rajasthan, receive abundant solar energy and are prone to dust/sand storms. Line and point focusing technologies are used for harnessing this energy. At IIT Jodhpur, open porous volumetric air receiver based point focusing technology is considered for process heat application. This system uses air as heat transfer fluid and is expected to achieve a temperature as high as 800 °C. This receiver on account of volumetric heating, is exposed to a high heat flux, even, up-to 1000 suns (1sun = 1 kW/m2). As this receiver is open to atmosphere, the dust storms in these regions can block the absorber pores and enter the system. Due to lower thermal conductivity of sand in comparison to absorber material, high temperature gradients and thermal stresses are expected on the absorber. It can result in failure of the system. In view of this the current activity aims at cleaning and collection of the removed dust from pores of receiver. A 2D2D geometry of cyclone separator is proposed for deposited dust collection. The experiments on collection efficiency and pressure drop are performed and compared with empirical model. Pressure drop is estimated using CFD and experimentally validated for an improved relation for pressure drop coefficient.

Solar and wind energy: Challenges and solutions in desert regions

Abstract: In desert regions, several environmental challenges have the potential to reduce solar energy production. These are the formation of thinly crusted mud and/or carbonates coatings caused from deposited dust aerosols during humid conditions and other weather conditions. These challenges that profoundly affect photovoltaic panel surfaces as well as wind turbines were delineated to conclude the potential feasibility to establish solar and/or wind energy systems in Kuwait. The study concluded that photovoltaic (PV) cells are not the most suitable energy source for Kuwait due to the above mentioned environmental challenges; therefore, alternative renewable energy sources are considered more feasible. After one year of operation at solar units and wind farms in Kuwait, the results clearly show that wind energy records energy production numbers that exceed the industry average. This was associated with high capacity factors throughout the year, resulting in an annual power production that is 2.3 times higher than that of PV; powering 450 homes compared to 199 homes for PV. West of the state of Kuwait and the Bubiyan Island are the recommended potential sites for wind farm establishment.

A review study on the modeling of high-temperature solar thermal collector systems

Abstract: Concentrated solar power technologies are gaining more attention in the last two decades in order to replace the conventional power technologies and reduce their environmental impact. Among the developed concentrating technologies, parabolic trough solar collector and solar tower are the most mature and dominant technologies. As part of the continuous development of these technologies, significant efforts have been deployed to predict and improve their performance, and therefore reduce their cost and make them more competitive. In this context, numerous analytical and numerical studies have been developed and presented in the literature. This review aims to summarize the state-of-the-art modeling approaches used to simulate, predict and evaluate the optical, thermal and dynamic performance of high-temperature solar thermal collectors. The review includes the different analytical and ray tracing models used to determine the non-uniform flux on the receiver aperture. Energy balance models are also presented as simple and easy computational models suitable to predict the thermal performance at a reasonable time and computational cost, whereas Computational Fluid Dynamic models are more convenient to study the details of the coupled fluid flow and heat transfer in the internal and external flow. The review also includes dynamic models such as the lumped capacitance models which are used to simulate the dynamic characteristics of the heat transfer fluid and interaction with the solar receiver under transient conditions. The dynamic behavior of the whole solar plant using different codes is examined. Furthermore, different features and capabilities of those approaches are also analyzed and compared. Finally, the use of numerical modeling in the development of new designs and assessment of the use of nanofluids is discussed. In summary, this work presents a comprehensive review of the existing numerical models and could serve as a guideline to develop new models for future trends in concentrating solar technologies.

Spatial and temporal variations of dust concentrations in the Gobi Desert of Mongolia

Abstract: Dust mass concentrations of PM 10 and PM 2.5 from four monitoring stations in the Gobi Desert region of Mongolia were analyzed for a 16-month period in 2009–2010. Annual averaged PM 10 concentration ranged from 9 μg m − 3 to 49 μg m − 3 at these stations during 2009. Concentrations were high in winter owing to air pollution and in spring owing to dust storms; the monthly mean concentrations of PM 10 (PM 2.5 ) at the three stations except for Sainshand reached yearly maxima in December and January, ranging from 60 (38) μg m − 3 to 120 (94) μg m − 3 . Diurnal variations of PM 10 and PM 2.5 concentrations at two sites, Dalanzadgad and Zamyn-Uud, included two maxima in the morning and evening and two minima in the afternoon and early morning. However, at Erdene PM 10 maxima occurred in the afternoon and evening. Both PM 10 and PM 2.5 concentrations were enhanced from March to May by dust storms. Dust storms raised huge amounts of fine dust particles in the Gobi of Mongolia. Maximum daily mean PM 10 (PM 2.5 ) concentrations reached 821 (500) μg m − 3 at Dalanzadgad, 308 (129) μg m − 3 at Zamyn-Uud, and 1328 μg m − 3 at Erdene. Hourly maximum PM 10 (PM 2.5 ) concentrations were as high as 6626 (2899) μg m − 3 at Dalanzadgad during a dust storm.

Self-cleaning of a hydrophobic surface by a rolling water droplet.

Abstract: A water droplet behavior on a hydrophobic surface is examined relevant to the dust particles removal from the surface. Surface crystallization of polycarbonate is realized in acetone bath and the resulting surface is coated by the functionalized nano-size silica particles towards reducing contact angle hysteresis. This arrangement provides droplet rolling/sliding on the hydrophobic surface. Droplet translational velocity is formulated and predictions are compared with those resulted from the high speed recorded data. Influence of surface inclination angle on droplet dynamics is investigated and the dust removal mechanism on the inclined surface is analyzed. It is found that predictions of droplet translational velocity agree well with those obtained from the experiment. Droplet rolling dominates over sliding on the inclined surface and droplet sliding velocity remains almost 10% of the droplet translational velocity. The main mechanism for the dust particles removal is associated with the droplet fluid cloaking of the dust particles during its transition on the hydrophobic surface. Droplet acceleration, due to increased surface inclination angle, has effect on the rate of dust particles removal from the surface, which is more apparent for large droplet volumes. Increasing droplet acceleration improves the coverage area of the clean surface.

Performance of solar photovoltaic modules under arid climatic conditions: A review

Abstract: Arid and semi-arid climates are blessed with abundant sunshine, and photovoltaic (PV) modules are now widely used under these climatic conditions. The aim of this paper is to put into perspective the recent uses of solar PV installations under arid climates with the evolution of PV technologies. The novelty of this review is to present up-to-date experimental results under such climates, and to plot results of experiments running for about one year or more. The effect of environmental parameters such as weather or dust are analyzed depending on different locations and technologies. These parameters have a tremendous impact on PV modules performance and degradation, and it is critically important to consider them carefully when implementing a PV installation under such conditions. From this review, general conclusions and guidelines are presented.