Shotcrete Solar Racking[edit | edit source]
This literature review covers the concept of using shotcrete as a PV racking material it supports the following publication:
Why Shotcrete supports[edit | edit source]
Residential, Commercial, and Utility-Scale Photovoltaic (PV) System Prices in the United States: Current Drivers and Cost-Reduction Opportunities[edit | edit source]
https://www.nrel.gov/docs/fy12osti/53347.pdf
- Drop in PV module prices but high installation, component, and system cost
- Market price vs bottom-up analysis are very different
- Installation costs are reason for having low PV cost but low application
Shotcrete[edit | edit source]
Shotcrete: Methods and Compositions[edit | edit source]
Dr. Anwar Khitab Shotcrete: methods and Compositions
https://www.researchgate.net/publication/281443236_Shotcrete_Methods_and_Compositions
- Introduction to shotcrete technology and its application methods
- Dry mix applied at rate of 1-2 yards^3 /hr and wet mix at a rate of 7-8 yards^3 /hr
- Proper drainage and rock bolts are essential on slopes
- Fibers are the best option for reinforcement
Types of shotcrete and its applications[edit | edit source]
https://www.engr.psu.edu/ce/courses/ce584/shotcrete/C2-Types.pdf
- Helps in identifying which shotcrete methods to be used for different applications
- Slope and surface protection and thin sections over large areas are covered
- Wet mix is more frost resistant and seals water leaks
- Fiber reinforcement is essential
Shotcrete application for different conditions[edit | edit source]
https://www.rocscience.com/assets/resources/learning/hoek/Practical-Rock-Engineering-Chapter-15-Shotcrete-Support. https://www.shotcrete.org/media/Archive/2002Sum_Ballou.pdf.
- Helps in identifying which shotcrete methods to be used for different applications.
- Water removal options: weep holes, geocomposite drainage board, and drains horizontal
- Added silica fumes improve adhesion but reduce strength
Comparative evaluation of steel mesh, steel fibre and high-performance polypropylene fibre reinforced shotcrete[edit | edit source]
O Cengiz L Turanli "Comparative evaluation of steel mesh, steel fibre and high-performance polypropylene fibre reinforced shotcrete in panel test" Cement and Concrete Research Volume 34, Issue 8, August 2004, Pages 1357-1364
https://www.sciencedirect.com/science/article/pii/S000888460400002X
Abstract In this study, experimental investigations were performed on steel mesh (SM), steel fibre (SF) and high-performance polypropylene fibre (HPPF) reinforced shotcrete (HPPFRS) panels to evaluate performance characteristics such as toughness, flexural ductility, energy absorption and load capacity. The panel tests, in accordance with European specification for sprayed concrete (EFNARC), were made on 18 prismatic specimens having the same mix designs and were cured for 28 days but reinforced with various fibres. In addition, the rebound characteristics of these mixes were determined to compare the actual in situ fibre contents.
Test results show that all reinforcements, including HPPFs that are low-modulus fibres, greatly improved the flexural ductility, toughness, and load-carrying capacity of the brittle matrix. It was seen that there was a positive synergy effect between steel and polypropylene fibre in hybrid fibre usage from a performance point of view. According to results, it can be concluded that a hybrid polypropylene-SF can be used alternatively instead of SM and monosteel fibre as a reinforcement in shotcrete applications to get better efficiency in mechanical properties of composite.
- compares which type of Shotcrete application is better
- most common options provide ample strength for this type of design
Projects using Shotcrete technology[edit | edit source]
http://web.archive.org/web/20160909114950/http://www.shotcrete.org:80/media/Archive/2014Win_Underground.pdf http://web.archive.org/web/20160705055416/http://shotcrete.org:80/media/Archive/2014Win_Architecture.pdf http://web.archive.org/web/20160804094059/http://shotcrete.org:80/media/Archive/2014Win_PoolRec.pdf http://web.archive.org/web/20160705055638/http://shotcrete.org:80/media/Archive/2014Win_Infrastructure.pdf http://web.archive.org/web/20160909114545/http://www.shotcrete.org:80/media/Archive/2014Win_International.pdf
- Helps in understanding Shotcrete technology better and the difficulties that can occur while performing.
- In slope stabilization it proven to be cost effective and sustainable using a soil nail wall system.
- Pools are an example of precision and water-curing capabilities
- Used to stabilize drilling operations
Mechanism of wet shotcrete interacting with rock in support systems[edit | edit source]
LI Li, WU Ai-xiang, WANG Yi-ming, HAN Bin, WANG Hong-jiang, WANG Chun-lai "Mechanism of wet shotcrete interacting with rock in support systems"
Abstract: In order to have a good understanding of the behavior of wet shotcrete as a support element interacting with the rock mass, mechanism of wet shotcrete interacting with rock in support systems was analyzed through theoretical, numerical study and analytical analysis. A new model of distribution of rock stress state after wet shotcrete was applied, which includes shotcrete layer, composite layer, strengthening layer, plastic layer and elastic layer, and a full illustration of the rock mass stress state was given after shotcrete interacting with rock mass. At the same time, numerical analysis with FLAC gives a stress distribution along the monitor line, respectively, at the sidewall and roof of the tunnel. The displacement obviously decreases with the depth of rock, the tangential stress for tunnel supported by shotcrete is lower than that without shotcrete, and radial stress for tunnel supported by shotcrete is higher than that without shotcrete. It has been demonstrated by AIRY’S stress function, which gives a reasonable solution. Finally, the application of wet shotcrete in Jinfeng Gold Mine shows that the displacement of tunnel decreases obviously in sidewall and roof.
Fibre reinforced shotcrete[edit | edit source]
DESIGN OF FIBRE REINFORCED SHOTCRETE LININGS WITH MACRO-SYNTHETIC FIBRES[edit | edit source]
E. S. Bernard "DESIGN OF FIBRE REINFORCED SHOTCRETE LININGS WITH MACRO-SYNTHETIC FIBRES" https://www.researchgate.net/publication/241804218_DESIGN_OF_FIBRE_REINFORCED_SHOTCRETE_LININGS_WITH_MACRO-SYNTHETIC_FIBRES
ABSTRACT Fibre Reinforced Shotcrete (FRS) reinforced with macro-synthetic fibres has now been used to stabilize ground in underground mines and tunnels, and for slope stabilization, for over 10 years. Experience has demonstrated that macro-synthetic fibres are capable of exhibiting very high levels of performance and are a highly effective form of reinforcement for both temporary and permanent ground support. Engineering data also exists showing that macro-synthetic fibres excel with regard to corrosion resistance and embrittlement in shotcrete, and are very effective in ground subject to high deformation. Despite this, the design of FRS linings using this type of reinforcement lags behind that of linings incorporating alternative forms of reinforcement. There is a lack of appreciation within the engineering construction community that methods of design exist for this material and that these have been proven satisfactory. This paper will attempt to summarize generic approaches to the design of temporary and permanent ground support based on macro-synthetic FRS.
- Can know about fibre reinforced shotcrete strength
- Fiber reinforcement effects corrosion, post crack energy absorption, post fire accacity, and rigidity.
- Permanent ground support on soft vs firm ground
Embrittlement of fiber-reinforced shotcrete[edit | edit source]
Erik Bernard Embrittlement of fiber-reinforced shotcrete https://www.researchgate.net/publication/284099980_Embrittlement_of_fiber-reinforced_shotcrete
- To know about the environmental effects on shotcrete
- Long term testing
- Loss of ductility is esential to be aware of
- Macro-synthetic fibers absorb energy best with age
Age-dependent changes in post-crack performance of fibre reinforced shotcrete linings[edit | edit source]
Erik StefanBernard "Age-dependent changes in post-crack performance of fibre reinforced shotcrete linings" https://www.sciencedirect.com/science/article/pii/S0886779815000899
Abstract It is commonly assumed that when a mix achieves satisfactory performance in Quality Control tests at 28 days this result will translate into satisfactory performance throughout the design life of the corresponding concrete structure. While this is generally true of the compressive strength of concrete it is not necessarily true for other parameters. The post-crack performance of fibre reinforced concrete (FRC) differs from that of conventionally reinforced concrete in that the post-crack performance of fibres is related in a complex manner to the characteristics of the concrete matrix. Age-dependent changes in the characteristics of the concrete matrix can effect changes in the post-crack behaviour of fibres. The present investigation has examined how the post-crack energy absorption of fibre reinforced shotcrete (FRS) changes with aging and has found that some types of fibre exhibit dramatically different performance characteristics at late age compared to that displayed at 28 days. This change can have significant consequences for the design of ground support based on fibre reinforced shotcrete. Tunnel linings required to resist sustained ground stresses, or which may be subject to deformation associated with seismicity or ground movement at later ages, should be designed with consideration of a possible long-term loss of ductility exhibited by some types of fibre reinforced shotcrete.
- To know the effect of age on the shotcrete
- Ductility standard of 400 J energy absorption at 40 mm deflection
- Ground movement such as freezing requires adequate ductility to avoid collapse
FIBER REINFORCED WET-MIX SHOTCRETE UNDER IMPACT[edit | edit source]
y P. Gupta, N. Banthia, and C. Yan "FIBER REINFORCED WET-MIX SHOTCRETE UNDER IMPACT" https://ascelibrary.org/doi/pdf/10.1061/%28ASCE%290899-1561%282000%2912%3A1%2881%29
ABSTRACT: As a result of excavation blasting, traffic, sudden ground movements, rock bursts, and seismic activity, shotcrete is often subjected to impact and other dynamic loads. Limited data exist, however, with regard to the resistance of shotcrete to such dynamic loads. Impact resistance of wet-mix shotcrete reinforced with 10 different types of fibers was investigated using instrumented drop weight impact tests. A direct comparison was made with the quasi-static response. Both beam and plate specimens were tested and the data were correlated. Fiber reinforcement was found to be highly effective in improving the fracture energy absorption and toughness under impact loading, but the improvements under impact loading were found to be substantially different than those seen in quasi-static tests, and were also highly dependent on the type of fiber used. When beams and plates were compared, the relative improvements between fiber types were found not necessarily in agreement.
- To know why Fibre reinforced wet mix shotcrete is better
- Dynamic load testing and loading axis for surface coating
- Synthetic fibers advised
- Fiber recommendation varies depending on static or dynamic load. Static loads improve more greatly from fiber addition.
Accelerating admixtures for shotcrete[edit | edit source]
Luiz Roberto Prudêncio Jr. "Accelerating admixtures for shotcrete" https://www.sciencedirect.com/science/article/pii/S0958946598800073
Abstract A variety of additives and admixtures are added to shotcrete to improve strength, adhesiveness, cohesiveness, freezing/thawing and abrasion resistance characteristics, and reduce rebound. Accelerators are being used increasingly in both dry- and wetprocess applications. Accelerators are common in the dry process to increase early strength and reduce dust and rebound and in the wet process are used to achieve rapid set and early strength. The choice of a particular accelerator and its dosage is largely governed by the setting time required for the shotcrete application. Various watersoluble salts of the alkali metals can be used to accelerate the setting of cement. Most of the set accelerators used today are based on alkali aluminates in combination with carbonates and hydroxides and produced in both liquid and powder form. The performance of these accelerators depends on the cement chemical composition and fineness, and the presence of mineral additions such as flyash, and blastfurnace slag. This performance is generally evaluated using setting tests on cement/ accelerator pastes despite the belief of some researchers that this procedure can produce misleading results. This paper describes the main accelerators used in shotcrete and presents some results of field tests performed on shocrete panels evaluating the behavior of different accelerators. Particular attention is given to a new liquid alkalifree shotcrete accelerator that showed a very interesting behavior at very early ages and no strength loss at later ages. The early strengths were evaluated using non-destructive tests (Constant Depth Penetrometer and Constant Energy Penetrometer).
- May be used for shotcrete knowledge but not necessary
- Accelerating admixtures reduce strength significantly and results are temperature dependant
- Limited use to special applications
slope stabilization using soil nails: design assumptions and construction realities[edit | edit source]
Tan,Yean-chin and Chow Chee-Meng "slope stabilization using soil nails: design assumptions and construction realities" http://gnpgeo.com.my/download/publication/2004_11.pdf
- May be useful if racking is to be done on on slope.
- Soil nail placement is important for structural integrity but location dependant
Detachment of shotcrete lining due to long terminteraction with ground water[edit | edit source]
Dr. Michael Romer "Detachment of shotcrete lining due to long term interaction with ground water" https://www.sheffield.ac.uk/polopoly_fs/1.142959!/file/10.pdf
- useful if shotcrete solar racking is done in a location where land is wet.
- Main idea of leaching can pertain to erosion and degradation due to rain and dirt buildup
Soil and rock slope stabilization using fiber-reinforced shotcrete in North America[edit | edit source]
Mike Ballou and Matt Niermann"Soil and rock stabilization using shotcrete in north america" https://www.shotcrete.org/media/Archive/2002Sum_Ballou.pdf
- useful for shotcrete application at any location
Thermal properties of lightweight dry-mix shotcrete containing expanded perlite aggregate[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0958946514000936
- Thermal diffusivity and mechanical performance assessed
- The thermal diffusivity and conductivity of the shotcrete was able to be dropped without losing performance up to 75% sand additive
Optical Design and Characterization of Solar Concentrators for Photovoltaics[edit | edit source]
J. Nilsson, "Optical Design and Characterization of Solar Concentrators for Photovoltaics"
- optics of concentrators
- optical efficiency of the concentrators
- Models to estimate output
- Assess azimuth angle, incomplete illumination, adjustable inclination, and dip at noon
- Better efficiency in winter due to reduced change in angle
- Reflectors improve efficiency particularly in morning and evening
Effects of low concentration planer concentrators on array-scale solar photovoltaic systems performance[edit | edit source]
- Open circuit voltage and short circuit current
- Greater efficiency in winter
- Monthly tilt angle adjustment
Photovoltaic system performance enhancement with non-tracking planar concentrators: Experimental results and BDRF based modelling[edit | edit source]
https://ieeexplore.ieee.org/document/7293585
- Non-tracking is more affordable and improves output by 35-45%
- In depth angle assessment
Model of Loss Mechanisms for Low Optical Concentration on Solar Photovoltaic Arrays with Planar Reflectors[edit | edit source]
Rob Andrews, Nabeil Alazzam, and Joshua M. Pearce, “Model of Loss Mechanisms for Low Optical Concentration on Solar Photovoltaic Arrays with Planar Reflectors”, 40th American Solar Energy Society National Solar Conference Proceedings, pp. 446-453 (2011).
- Losses involved in using flat plate concentrator theoretically.
Design Procedure of V-trough Cavities for Photovoltaic Systems[edit | edit source]
- Experimentally shows use of concentrator increases energy output.
- Trough angle and concentration ratio finite ranges and plateau maximization
- Cost analysis
OPERATION OF STANDARD PV MODULES IN V-TROUGH CONCENTRATORS[edit | edit source]
- Overview of double reflectors to reduce cost and increase efficiency
- Wider trophs reduce error and better circulation
- Synthesis of which factors affect angle calculations and efficiencies
PERFORMANCE OF A V-TROUGH PHOTOVOLTAIC/THERMAL CONCENTRATOR[edit | edit source]
https://core.ac.uk/download/pdf/56364165.pdf
- Aluminum instead of stainless steel are more cost effective, made equally durable, but need to improve thermal effects
- V trough is feasible but needs cooling
Concentrating solar module with horizontal reflectors[edit | edit source]
Toshio Matsushima, Tatsuyuki Setaka, SeiichiMuroyama https://www.sciencedirect.com/science/article/pii/S0927024802001563
- Helpful in constructing a Solar module with concentrators
- Sun altitude analysis
- Concentrating module at 20 degrees to horizontal and 90 degrees to solar panel with high reflector rating
- Lesser angles create greater efficiencies in winter months
The enhancement of energy gain of solar collectors and photovoltaic panels by the reflection of solar beams[edit | edit source]
M.D.J Pucarab, A.R Despicb https://www.sciencedirect.com/science/article/pii/S0360544201000810
- Can be used for optimal positioning of concentrators
Models to estimate output
- Assess azimuth angle, incomplete illumination, adjustable inclination, and dip at noon
- Better efficiency in winter due to reduced change in angle
- Reflectors improve efficiency particularly in morning and evening
Performance evaluation of photovoltaic modules at different tilt angles and orientations[edit | edit source]
https://www.sciencedirect.com/science/article/pii/S0196890403003571
- Tilt angle range calculations with southern orientation
Comparative study of PV modules with and without a tilted plane reflector[edit | edit source]
https://www.sciencedirect.com/science/article/pii/S0196890400001394
- Open circuit voltage and short circuit current
- Greater efficiency in winter
- Monthly tilt angle adjustment
Optimization of operational and design parameters of plane reflector-tilted flat plate solar collector systems[edit | edit source]
https://www.sciencedirect.com/science/article/pii/S0360544200000037
H.M.S. Hussein, G.E. Ahmad, H.H. El-Ghetany
- Useful in construction of solar modules along with concentrators, and for there positioning
Booster ReØectors for PVModules in Sweden[edit | edit source]
- Ueful in designing the module
- 30% performance increase with 10% cost increase
- 0.4-0.5% reduction in efficiency per degree C
- Reduce thermal effect by increasing mass
- Angle analysis
- Low resistance is key to performance with boosters
- Parallel vs series analysis
Flow and heat transfer in the air gap behind photovoltaic panels[edit | edit source]
https://www.sciencedirect.com/search/advanced?docId=10.1016/S1364-0321(98)00005-7
- Useful in temperature reducing of the panels.
- 0.4-0.6% reduction in efficiency per degree C therefore 20*change = 0.6-1% difference in efficiency
- Turbulent and laminar flow observed
- Reducing emissivity of the rebound surface decreases flow through the gap, therefore a high emissivity is recommended
- Heat is radiated to back surface then heats the air by convection
A review of solar photovoltaic systems cooling technologies[edit | edit source]
- Assess 9 heat removal techniques with many pros and cons
- Many use and waste water
- Transparent cooling and hybrid solar photovoltaic/thermal system
V-TROUGH CONCENTRATOR ON A PHOTOVOLTAIC FULL TRACKING SYSTEM IN A HOT DESERT CLIMATE[edit | edit source]
https://www.sciencedirect.com/science/article/pii/096014819500055O
- Separation angle and concentration ratio to increase efficiency and reduce cost
- Rays: direct, incident, diffused
- open voltage and closed current
PERFORMANCE OF A V-TROUGH PHOTOVOLTAIC/THERMAL CONCENTRATOR[edit | edit source]
https://www.sciencedirect.com/science/article/pii/S0038092X13005057
- Water cooled to increase heat transfer on back surface of PV
- Suggested concentrator: mirror finished stainless steel
- Equations that take into account reflectance
- Latitude is equal to absorber mount angle
A Combined Optical, Thermal and Electrical Performance Study of a V-Trough PV System—Experimental and Analytical Investigations[edit | edit source]
- Reduce temperatures with low concentration and low cost reflectors
Snow Removal[edit | edit source]
An Experimental investigation of snow removal from photovoltaic solar panels by electrical heating[edit | edit source]
https://services.lib.mtu.edu:2072/science/article/pii/S0038092X18306789?via%3Dihub
- Thermal snow removal from electrical heater and reverse current
- Frameless panels advised
- Meltwater refreeze warning and upper/lower half frame melt addressed
- Tilt angel and back insulation
Modified vacuum tubes for overheating limitation of solar collectors: A dynamic modeling approach[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0038092X18306832
- Assess solutions for thermal overheating
Design and low energy ventilation solutions for atria in the tropics[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S2210670711000606
- Uses dynamic thermal model (DTM)
- Pressure mechanical ventilation explained
Drainage[edit | edit source]
Roof and rain gutter ice melt system and assembly[edit | edit source]
- Two heat cables: at edge and in gutter
New landscape-orientated PV system, offset seismic reinforcement, environmental education at NIT[edit | edit source]
http://dx.doi.org/10.1080/01430750.2003.9674902
- Solar panel waterproofing function
Comparison of Pavement Drainage Systems[edit | edit source]
https://journals.sagepub.com/doi/abs/10.1177/0361198196151900101
- Water leakage into pavement is bad
- Evaluates the performance of cement drainage systems
- Base layer is significant
- Geocompostingand open grade remove water fastest
- Reduce panel length and to reduce cracking
Enhanced Parking Lot Design for Stormwater Treatment[edit | edit source]
https://ascelibrary.org/doi/abs/10.1061/40644(2002)12
- Reduce runoff retaining on site
- Swales and deep rooted vegetation greatly improve drainage
- Assess nutrient and mineral transport
Paint as reflector[edit | edit source]
Investigating performance prediction and optimization of spectral solar reflectance of cool painted layers[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0378778815301122
- Isotropic scattering properties of paints
- Particles, particle diameter, and paint thickness
Acrylic white paint of industrial sector for cool roofing application[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0038092X18304547
- Solar reflectance, infrared emittance, albedo
- Reduction in surface temperature
- Degradation over time assessment
Cement based superhydrophobic coating with excellent robustness and solar reflective ability[edit | edit source]
- Solar reflectance coating durability
- Self cleaning with rainfall, mechanical durability, and temperature variance resistance
- Optimum Ti02 30%
- Comprehensive conclusion
Passive cooling techniques through reflective and radiative roofs in tropical houses in Southeast Asia: A literature review[edit | edit source]
https://www.sciencedirect.com/science/article/pii/S2095263514000399
- Increasing urban population causes increasing energy consumption
- Passive cooling: reduce heat, modify thermal gain, dissipate internal heat (due to reflectance and emittance)
- Colored paint is effective because the majority of sun rays are visible light
- Limitations in weathering, dirt, and visual obscurity
- 2 facing surfaces of different temps will have radiant flux
Estimating thermal performance of cool colored paints[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0378778809001546
- Cool pain of darker colors are effect but not as much as white
- Pigment aspect of paint effects: gloss, hiding power, strength, permeability of film, and albedo
- Complex inorganic colored pigments (CICPs) have greater reflectance and emissivity thus reducing infrared radiation
- CICPs are very effective and have similar absorption but higher reflectance
- Cost is up to $1/m^2 more but increases durability but has low cost/easy application
Row walkways[edit | edit source]
The science behind codes and standards for safe walkways[edit | edit source]
https://www.sciencedirect.com/science/article/abs/pii/S0003687015300508?via%3Dihub
- Level and slip reinforced walkways
Effective Width of Pedestrian Corridors[edit | edit source]
https://ascelibrary.org/doi/10.1061/%28ASCE%290733-947X%281984%29110%3A1%2880%29
- Clearance from walls based off boundary conditions
- 5.5 -7.8 in clearance needed
OSHA 1910.73[edit | edit source]
https://www.osha.gov/laws-regs/standardinterpretations/1982-03-09
- Walkways must be at least 18in in width
Grading feasibility[edit | edit source]
Partially Automated Grading: Construction Process Innovation[edit | edit source]
https://ascelibrary.org/doi/abs/10.1061/(ASCE)0733-9364(1988)114:1(19)
- Fine grading necessary for construction on grades
- Automation is time efficient, accurate, and consistent
Estimated Costs of Precision Land Grading With On-Farm Labor[edit | edit source]
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.623.3534&rep=rep1&type=pdf
- Long term investment
- Erosion control
- $0.51/yard^3 to move soil
====Estimated Costs of Precision Grading Sugarcane Fields, 2017==== https://www.lsuagcenter.com/~/media/system/8/7/5/a/875a105c7fdf9bc07be233b1281d12ae/2017%20sugarcane%20precision%20grading%20cost%20reportpdf.pdf
- Precise slope effects draining drastically
- Cost analysis in cubic yards of dirt not square yards
Landform Grading and Slope Evolution[edit | edit source]
https://ascelibrary.org/doi/abs/10.1061/(ASCE)0733-9410(1995)121:10(729)
- Long term slope stability and settling
- Strategic runoff concentration
- More complex shapes and grading do not cause significant increase in cost or feasibility but can be done with conventional equipment
- Cost driven by volume of earth moved
