{"id":6961,"date":"2014-09-04T20:18:26","date_gmt":"2014-09-05T01:18:26","guid":{"rendered":"https:\/\/greenbugenergy.com\/?page_id=6961"},"modified":"2022-05-30T12:24:45","modified_gmt":"2022-05-30T17:24:45","slug":"archimedes-screw-generators","status":"publish","type":"page","link":"https:\/\/greenbugenergy.com\/how-we-do-it\/archimedes-screw-generators","title":{"rendered":"Archimedes Screw Generators"},"content":{"rendered":"\t\t
To reclaim land as with this windmill pump in Holland.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
To irrigate land \u2013 past and present day.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t To pump sewage.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t To pump fish in the aquaculture industry.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t Our preference is to install beside the main existing water control concrete structure and not install on it because while installation on an existing weir is possible, it raises engineering questions about the weir\/dam structure itself and there is also the issue about potentially decreasing the flood flow capacity of the weir structure which has to be studied. We prefer to bypass these extra costs because micro hydro does not have the scale to withstand these types of costs.<\/p> Usage and refurbishment of existing channels and intakes is possible to reduce site disruption and civil construction as it was at the\u00a0Fletcher site.<\/a>\u00a0We utilized the old existing turbine intake and refurbished it, cleaned out the old channel and simply added an addition on the end. In this case we did not utilize the old mill tail race, but instead turned the screw 90 degrees to have the water exit for the screw enter the watercourse immediately below the weir, in order to eliminate any depleted reach that would have been caused by using the old tail race. All the work on the addition was done on dry ground, and when completed the earth between the screw exit and the watercourse was removed.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t Small 500 Watt capacity Archimedes Screw generator of the Open Complete model type sitting on small weir spillway.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t The Archimedes Screw has been used for pumping water for over 2000 years. Applying the principle in reverse, the same equipment now offers a new method for generating power from water, providing a fish friendly and highly efficient alternative to a conventional turbine. Each Archimedean Screw hydropower system is manufactured to be site-specific, with a choice of designs depending on which is the most appropriate and cost-effective for each individual site.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t The power that we can be derived from a hydro site is a function of the head, or height, of the vertical drop and the volume of water in the river. The bigger the head and the bigger the volume of water the more power can be generated.<\/p> Hydro turbines at any specific site are designed to capture the greatest possible head and the greatest possible volume of water \u2013 Turbines are designed to turn when water goes through them and it is the turning motion which generates electricity.<\/p> There are several types of hydro electric turbines. All the turbines have a gearing mechanism that drives the generator, but they differ in the manner by which the energy is extracted from the fall of water and converted into mechanical rotation. The mechanical rotation is then converted into electrical energy.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t \u2013 Slow rotation \u2013 No blade strike damage to fish. \u2013 Fast blade rotation = High rate of injury to fish. Although widely in use throughout Europe and the U.K. for some time now, the Screw is a newcomer in North America.<\/p> On the basis of previous studies carried out in Europe which supported the claims to fish-friendliness, the first Ontario Screw installation was installed in 2013.<\/p> Literally thousands of fish passages have been monitored and recorded using underwater cameras at the intake, inside the chamber of the Screw itself and at the outflow to assess the effect of the Screw on salmonids (including smolts and kelts), brown trout and eels. The trials looked at fish passage across a broad spectrum of sizes and turbine speeds, possibly the most impressive of which was the safe passage of a kelt measuring 98cm in length and weighing 7.6kg.<\/p> The European studies conclude that the Archimedean Screw turbine is indeed fish- friendly with no adverse physical effect on fully grown fish or kelts; at most 1.4% of smolts sustaining limited and recoverable scale loss (NB \u2018at most\u2019 because these were wild fish and quite likely to have sustained some scale damage prior to entry into the turbine) and just 1 out of 160 eels (0.64%) suffered minor and recoverable pinching Fish safely entering the top of screw as the screw turns slowly.<\/p> this is measured as the distance between where the water leaves a river to enter a hydro system and where the water goes back into the river. Clearly by taking a given volume of water out of a river, there will be an impact upon the natural ecology of the river bed. A large depleted distance may therefore compromise the ecology of the river bed. The smaller the depleted distance, the less impact there will be upon the fish and wildlife ecology. The Archimedean Screw has the lowest depleted reach because it is placed alongside a river weir \u2013 the water enters the system from just above the weir and returns to the river just below the weir. While more traditional turbines such as the Kaplan can also be placed alongside the weir, the Kaplan does not have the advantage of being considered \u2018fish friendly\u2019.<\/p> because the Archimedean Screw is visible, there is an educational benefit to this type of turbine. It can be readily viewed while in operation and the turning motion and the generation of electricity is immediately obvious.The educational aspect of the Archimedean Screw ought not to be underestimated.<\/p> The Archimedean Screw is the most cost efficient option. A report funded by Yorkshire Forward (Archimedes\u2019Screw:Copley Hydro Power Generator) showed that the costs of installing a Kaplan turbine in relation to an Archimedean Screw are higher per kW installed.<\/p> The Archimedes Screw has a high level of overall efficiency which is maintained across a huge range of flows, resulting in a single speed screw continuing to generate power down to approx. 30% of the maximum flow capacity.<\/p> The Archimedes Screw generator is a simple, robust machine with low maintenance requirements because it has only a few wear parts. Due to the simple and robust design. Screw generator installations require minimum maintenance.<\/p> Only a simple 120mm(6\u2033) bar screen is used to prevent large items from entering the screw generator. This saves costs, prevents head loss and allow fish passage.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t Coarse intake grate allows fish and small debris to pass while safely keeping out larger objects.<\/p> The screw generator is capable of handling flows from 100l\/s \u2013 10m3\/s each.<\/p> Any head from 1m to 10m<\/p> Cleaning of the screw generator is not necessary. The need to make sure that no fish or debris enters into the Kaplan system requires a fine mesh screen at the water inlet channel. This has to be regularly cleaned and is recommended to be accompanied by an automatic trash cleaning device. This will increase the capital cost and maintenance of a Kaplan turbine project. In contrast, floating objects, debris and fish simply pass through an Archimedes Screw with no need for expensive fine screening. There is a coarse intake grate with 6\u2033 x 6\u2033 openings on the Archimedes Screw which can require periodic cleaning to remove large debris but can be minimized with proper placement of a floating boom<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\tThe Archimedes Screw as a generator \u2013 Technology Overview<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
At least 400 Archimedes screw generators (ASGs) have already been installed in Europe since 1993 (Lashofer et al., 2012) and more are under construction, however there are currently few installations outside Europe. GreenBug connected the first ASG to the North American power grid in September, 2013, near Waterford, Ontario.<\/blockquote>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
We now have 2 different \u201cOff grid\u201d or stand-alone systems for remote areas.<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\tHow the screw can be used at existing water control structures<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Cold weather performance of the Archimedes Screw System<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Technical issues that make the Archimedes Screw generator environmentally attractive.<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
1 cubic Meter\n= 1000 liters\n= 264 U.S. Gallons<\/blockquote>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
Economics<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Old Technology \u2013 New Application<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Why we use Archimedes Screw Generators<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
We use Archimedes Screws because of these features;<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Fish Friendly \u2013<\/strong><\/h3>\nIt, and the Waterwheel are the least harmful to fish of all the turbine types. Scientific evidence (Fish Monitoring and Live Fish Trials Phase 1, Sept 2007 and Phase 2, April 2008, Fishtek Consulting) shows the safe passage of fish down the screw while it is operational. The Archimedean Screw and the Waterwheel operate at normal atmospheric pressure while other turbines, for instance the Kaplan, operate by forcing water at high pressure into the system. In addition, the screw turns at a low velocity of approx 28 rpm. This, together with the operation of the turbine under normal atmospheric pressure, enables the safe passage of fish through the system.\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
ACHIMEDEAN SCREW<\/h6>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\u2013 Normal water pressure = No fish swim bladder damage.
\u2013 Large water chambers = Safe passage for fish of all sizes.
\u2013 Smooth flow = No disorientation of fish.
\u2013 No fish screening is required.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\tCONVENTIONAL TURBINE<\/h6>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\u2013 Pressure changes in water = High rate of injury to fish.
\u2013 Fine fish screening required = increase installation & running costs.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
to the tail. In addition, behavioural and migrational patterns across the species have been shown to be entirely unaffected by the turbine.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\tNo Depleted Reach \u2013<\/strong><\/h3>
Visibility \u2013<\/strong><\/h3>
Cost efficiency \u2013<\/strong><\/h3>
Overall efficiency \u2013<\/strong><\/h3>
Low Maintenance \u2013<\/strong><\/h3>
No fine screen necessary \u2013<\/strong><\/h3>
Wide range of flows \u2013<\/strong><\/h3>
Wide range of heads \u2013<\/strong><\/h3>
Minimal Cleaning necessary \u2013<\/strong><\/h3>
Operational Range of an Archimedes Screw System<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Overhead View of Typical an Archimedes Screw Generator Installation<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Advantages of Archimedes Screw Small Hydropower Systems<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Archimedes Screw Generator Applications<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t