Field Tests of a Wind-Electric Controller for Parallel Stock Water Pumping and Heating

2002 ◽  
Author(s):  
Scott A. Morton ◽  
John E. Nydahl
Keyword(s):  
Pulse Width Modulation ◽  
Field Tests ◽  
Field Studies ◽  
High Plains ◽  
Variable Load ◽  
Water Heater ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Water Pumping ◽  
State Relay

Many of the improvements in wind-electric stock water pumping systems are attributable to advanced controller strategies and hardware that maximize performance over a range of wind speeds. The cost of the early and more complex controllers was of the order of one quarter of the whole system. Sophisticated yet inexpensive-programmable micro-controllers are now being introduced that enhance both performance and reliability. This study utilized a micro-programmable logic controller (PLC) to place a variable auxiliary load in the form of a stock water heater in parallel with the pump motor. This improves the system’s economic viability on the Northern High Plains by mitigating stock tank freezing to help extend the grazing season. For the variable auxiliary load, the PLC uses long period pulse width modulation to drive a 3-phase solid-state relay. This continuously variable load strategy was designed to both increase the power factor when the pump is operating, and to extract resistive heating power in wind regimes not suitable for operating the pump. This paper reports on the preliminary but encouraging field studies directed toward optimizing the low wind speed water heating performance of this multi-tasking controller when the pump motor is inoperable.

scholarly journals Study on wind energy potential for agricultural water pumping system in the middle part of Thailand

2018 ◽  
Vol 192 ◽  
pp. 03058
Author(s):  
Chamlong Prabkeao ◽  
Akapot Tantrapiwat
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Water Discharge ◽  
Middle Part ◽  
Energy Potential ◽  
Wind Speeds ◽  
Pumping System ◽  
Low Wind Speed ◽  
Water Pumping ◽  
Wind Energy Potential

A study on wind powered water pumping system aimed for agriculture was carried out in the middle part of Thailand. In this alluvial plain, wind energy potential was determined by making a survey on 21 observation sites. The survey was made in a period of one year, and it has shown that this region locates in a clam climate zone with average wind speeds at about 2 m/s. A wind turbine-water pumping system was installed and evaluated for its performance and efficiency. The result has shown a linear relationship between water discharge capability and the wind speeds. Due to the type of turbine and low wind speed in this region, the system efficiency turned out to be minimal, yet it was practical because the wind power was free. A simple cost analysis from the survey data also has shown that using a wind turbine in this region will be worthwhile when it can be operated for about two decades.

Cold acclimatization and finger numbness

1955 ◽  
Vol 143 (912) ◽  
pp. 392-407 ◽  
Keyword(s):  
Human Performance ◽  
Hand Function ◽  
Field Tests ◽  
Cumulative Effect ◽  
Field Studies ◽  
Linear Increase ◽  
Tactile Discrimination ◽  
Wind Speeds ◽  
Cold Room ◽  
Skin Temperatures

Evidence is scarce on the alterations in human performance that follow repeated exposure to cold climates. These experiments have therefore attempted to establish whether people show any measurable changes in hand function when they live in cold environments. The investigations started as field studies in Canada and continued as cold-room researches later in England. The field tests in the sub-Arctic were mostly in terms of tactile sensitivity of the fingers. The volunteers for these tests were termed either indoor or outdoor men, according to the amount of time they usually worked outside. Their fingers were chilled for 6 min, and it was found that air temperatures of — 16 to — 25° C at wind speeds of about 4 m.p.h. had a much greater numbing effect on the indoor men. One criterion used for numbness estimation was the two-point tactile discrimination threshold. The increase in this threshold was seven times greater for the indoor men, although both groups had equally sensitive fingers before cold exposure. A definite but smaller difference was also found after exposure as regards their vibration-detection thresholds. Over a large range of wind-chill conditions the indoor men gave a marked and linear increase in their two-point thresholds. But with the same changes in environmental severity the outdoor men showed no such alteration in sensitivity. Extremely severe exposures, however, did give equally marked numbness in both groups. The higher the skin temperatures after exposure, the less were the numbness scores in either group. [Other workers have shown that Eskimos have higher skin temperatures and resting hand blood flows than white men (Brown & Page 1952).] The outdoor men had higher finger-skin temperatures before and particularly after the experimental cold exposures. Possibly, then, the outdoor men might have developed a greater resting finger blood flow which more effectively maintained their finger warmth and tactile discrimination. This suggestion needs study by further cold-room research. Cold-room experiments have shown so far that short daily exposures have a cumulative effect during the winter-time; the increase in the two-point threshold after chilling was halved within 2 to 5 weeks. But an English summer prevented this adaptation taking place. Would either recent tropical experience or concurrent hot-room exposure also hinder acclimatization to cold?

scholarly journals Comparison of Weibull Estimation Methods for Diverse Winds

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ferhat Bingöl
Keyword(s):  
Wind Farm ◽  
Study Data ◽  
Distribution Functions ◽  
Likelihood Method ◽  
Estimation Methods ◽  
Weibull Function ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Low Wind Speeds ◽  
Wind Distribution

Wind farm siting relies on in situ measurements and statistical analysis of the wind distribution. The current statistical methods include distribution functions. The one that is known to provide the best fit to the nature of the wind is the Weibull distribution function. It is relatively straightforward to parameterize wind resources with the Weibull function if the distribution fits what the function represents but the estimation process gets complicated if the distribution of the wind is diverse in terms of speed and direction. In this study, data from a 101 m meteorological mast were used to test several estimation methods. The available data display seasonal variations, with low wind speeds in different seasons and effects of a moderately complex surrounding. The results show that the maximum likelihood method is much more successful than industry standard WAsP method when the diverse winds with high percentile of low wind speed occur.

scholarly journals Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivation

2015 ◽  
Vol 4 (3) ◽  
pp. 89 ◽  
Author(s):  
Heikki M. T. Hokkanen ◽  
Ingeborg Menzler-Hokkanen ◽  
Marja-Leena Lahdenpera
Keyword(s):  
Crop Protection ◽  
Field Tests ◽  
Weather Conditions ◽  
Field Studies ◽  
Field Trials ◽  
Marketable Yield ◽  
Dissemination Activity ◽  
Grey Mold ◽  
Commercial Farms ◽  
Disease Pressure

<p>Targeted precision biocontrol and improved pollination were studied Europe-wide in the EU ERA-NET CORE ORGANIC 2 project BICOPOLL (Biocontrol and Pollination). A case study was conducted on the management of strawberry grey mold <em>Botrytis cinerea</em>, with the biocontrol fungus, <em>Gliocladium catenulatum</em>, vectored by honey bees or bumble bees. A joint field trial carried out in five countries targeted strawberry cultivations in open field, and included four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical and biocontrol combined. In organic fields, no pesticide treatments were included. The proportion of moldy berries, and/or the marketable yield of healthy berries were recorded from each treatment, along with other parameters of local interest. A pilot study was started in Finland in 2006, and, by 2012, large commercial farms were using entomovectoring. In 2012, field trials were started in Estonia and in Italy, and in 2013-14, these experiments were expanded to Slovenia and Turkey. In total, 26 field tests were conducted using entomovectoring and <em>Gliocladium catenulatum</em> (Prestop<sup>®</sup> Mix) on strawberry, with five additional trials on raspberry. Efficacy results have been excellent throughout the field studies. The results show crop protection equalling or exceeding that provided by a full chemical fungicide program, under all weather conditions, and over a wide geographical range (from Finland to Turkey). Under heavy disease pressure, entomovectoring provided on average a 47% disease reduction, which was the same as multiple fungicide sprays. Under light disease pressure, biocontrol decreased grey mold by an average of 66%, which was greater than fungicide sprays. The concept has proven to be effective on strawberries, raspberries, pears, apples, blueberries, cherries, and grapes. A conservative estimate for Finland is that over 500 ha of strawberry cultivation currently use the technique (≈15% of the strawberry growing area). To make full use of the entomovectoring technique, organic berry and fruit growers are encouraged to (i) keep bees, or to hire the service from local beekeepers for entomovectoring; and (ii) manage vegetation within and around the target crop to support the activity of bees and other pollinators, which can help to disseminate the beneficial microbial populations within the crop. Beekeepers are encouraged to (i) market pollination and biocontrol services to fruit and berry growers, and (ii) ensure that all operations are effective in mananging bees and their microbe dissemination activity. Biocontrol product manufacturers are encouraged to further develop products and their formulations specifically for entomovectoring, because current formulations are suboptimal as they are initially optimized for other uses (e.g., mixing into the soil).</p>

Into the wild: developing field tests to examine the link between elasmobranch personality and laterality

Behaviour ◽  
2016 ◽  
Vol 153 (13-14) ◽  
pp. 1777-1793 ◽  
Author(s):  
Evan E. Byrnes ◽  
Catarina Vila Pouca ◽  
Sherrie L. Chambers ◽  
Culum Brown
Keyword(s):  
Personality Traits ◽  
Field Tests ◽  
Animal Personality ◽  
Field Studies ◽  
Individual Level ◽  
In The Wild ◽  
Port Jackson ◽  
The Relationship

The field of animal personality has received considerable attention in past decades, yet few studies have examined personality in the wild. This study investigated docility, a measure of boldness, in two Port Jackson shark (Heterodontus portusjacksoni) populations using field tests, and if laterality differences explained docility levels. We developed a struggle test as an assay for docility, which is particularly amenable to field studies. The struggle test was effective, and repeatable inter-individual docility differences were observed. Sex, but not population, influenced docility scores, with male sharks being less docile than females. This difference is likely due to the contrasting role each sex plays during mating. We also found individualized lateralization. However, no individual-level relationship between lateralization and docility was detected. Despite reported links between laterality and some personality traits, the relationship between laterality and boldness remains inconclusive in sharks. Further studies will prove essential to clarify the mechanisms behind personality traits in vertebrates.

Field tests and numerical modeling of INVELOX wind turbine application in low wind speed region

Energy ◽  
2019 ◽  
Vol 181 ◽  
pp. 745-759 ◽  
Author(s):  
Freshteh Sotoudeh ◽  
Reza Kamali ◽  
Seyed Mahmood Mousavi
Keyword(s):  
Numerical Modeling ◽  
Wind Speed ◽  
Wind Turbine ◽  
Field Tests ◽  
Low Wind Speed

scholarly journals Strategies for Enhancing the Low Wind Speed Performance of H-Darrieus Wind Turbine—Part 1

2019 ◽  
Vol 1 (1) ◽  
pp. 185-204 ◽  
Author(s):  
Palanisamy Mohan Kumar ◽  
Krishnamoorthi Sivalingam ◽  
Teik-Cheng Lim ◽  
Seeram Ramakrishna ◽  
He Wei
Keyword(s):  
Wind Speed ◽  
Poor Performance ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Viable Solution ◽  
Speed Performance ◽  
Low Wind Speeds ◽  
Starting Characteristics

Small wind turbines are key devices for micro generation in particular, with a notable contribution to the global wind energy sector. Darrieus turbines, despite being highly efficient among various types of vertical axis turbines, received much less attention due to their starting characteristics and poor performance in low wind speeds. Radically different concepts are proposed as a potential solution to enhance the performance of Darrieus turbine in the weak wind flows, all along the course of Darrieus turbine development. This paper presents a comprehensive review of proposed concepts with the focus set on the low wind speed performance and critically assessing their applicability based on economics, reliability, complexity, and commercialization aspects. The study is first of its kind to consolidate and compare various approaches studied on the Darrieus turbine with the objective of increasing performance at low wind. Most of the evaluated solutions demonstrate better performance only in the limited tip speed ratio, though they improve the low wind speed performance. Several recommendations have been developed based on the evaluated concepts, and we concluded that further critical research is required for a viable solution in making the Darrieus turbine a low speed device.

scholarly journals The Transition from Downward to Upward Air–Sea Momentum Flux in Swell-Dominated Light Wind Conditions

2018 ◽  
Vol 75 (8) ◽  
pp. 2579-2588 ◽  
Author(s):  
Ulf Högström ◽  
Erik Sahlée ◽  
Ann-Sofi Smedman ◽  
Anna Rutgersson ◽  
Erik Nilsson ◽  
...  
Keyword(s):  
Wind Speed ◽  
Momentum Flux ◽  
Water Surface ◽  
Sea Waves ◽  
Progressive Wave ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Light Wind ◽  
Wind Sea ◽  
Almost All

Abstract Fifteen hours of consecutive swell data from the experiment Flux, État de la Mer, et Télédétection en Condition de Fetch Variable (FETCH) in the Mediterranean show a distinct upward momentum flux. The characteristics are shown to vary systematically with wind speed. A hysteresis effect is found for wave energy of the wind-sea waves when represented as a function of wind speed, displaying higher energy during decaying winds compared to increasing winds. For the FETCH measurements, the upward momentum transfer regime is found to begin for wind speeds lower than about U = 4 m s−1. For the lowest observed wind speeds U &lt; 2.4 m s−1, the water surface appears to be close to dynamically smooth. In this range almost all the upward momentum flux is accomplished by the peak in the cospectrum between the vertical and horizontal components of the wind velocity. It is demonstrated that this contribution in turn is linearly related to the swell significant wave height Hsd in the range 0.6 &lt; Hsd &lt; 1.4 m. For Hsd &lt; 0.6 m, the contribution is zero in the present dataset but may depend on the swell magnitude in other situations. It is speculated that the observed upward momentum flux in the smooth regime, which is so strongly related to the cospectral peak at the dominant swell frequency, might be caused by the recirculation mechanism found by Wen and Mobbs in their numerical simulation of laminar flow of a nonlinear progressive wave at low wind speed.

MAJOR FIELD TEST EVALUATES A SHORELINE CLEANER TO SAVE OILED MARSH GRASS

1997 ◽  
Vol 1997 (1) ◽  
pp. 397-402 ◽  
Author(s):  
S. R. Pezeshki ◽  
R. D. DeLaune ◽  
A. Jugsujinda ◽  
G. P. Canevari ◽  
R. R. Lessard
Keyword(s):  
Spartina Alterniflora ◽  
Field Test ◽  
Field Tests ◽  
Field Studies ◽  
Test Site ◽  
Field Conditions ◽  
Marsh Vegetation ◽  
Beneficial Effects ◽  
Live Biomass ◽  
South Louisiana

ABSTRACT Extensive greenhouse studies using intact cores of marsh vegetation including Spartina alterniflora demonstrated the potential of a shoreline cleaner (Corexit 9580) to remove oil from plant canopy. Because of these positive results, a permit to conduct a full-scale field test was obtained by Louisiana State from regulatory agencies in June 1995. Field tests were conducted in a Louisiana marsh at a wildlife refuge in August 1995. The test site contained replicated 8 ft X 8 ft test plots that included the following treatments: oiled with South Louisiana crude oil, oiled and chemically cleaned after 2 days using Corexit 9580, and control. Significant initial reductions in plant stomatal conductance, transpiration, and CO2 fixation rates in response to the “oil” and “oil + Corexit 9580” treatments were noted, which were followed by substantial recovery in the “oil + Corexit 9580” treatment. Use of the cleaner improved the survival and regeneration capability of treated plots because of the low initial mortality rates and the rapid restoration of plant gas exchange activities. Plots treated with “oil + Corexit 9580” had a significantly greater number of live shoots throughout the measurement period in 1995. Biomass harvests conducted at the end of the 1995 growing season revealed that live biomass per unit area of marsh was significantly reduced under all treatments. The second harvest in 1996 indicated that live biomass had recovered to levels close to those of control plots. Our field studies demonstrated that oil can be removed using Corexit 9580 in the field without any detectable adverse effects on plants, In addition, the beneficial effects of Corexit 9580 in rapidly restoring plant transpiration pathways under field conditions was evident. However, plants under all treatments recovered, showing that Spartina alterniflora, given adequate time, can recover from oiling with South Louisiana crude. Additional studies using more stressful oil types such as Bunker C are needed to examine the effectiveness of Corexit 9580 in cleaning plant canopies under field conditions.

Sign in / Sign up

Export Citation Format

Share Document