<figure class="image"><img style="aspect-ratio:751/747;" src="/uploads/images/solarshowerupdate1.png" width="751" height="747"></figure><p>Now that the winter has subsided, we decided it was time to turn on our solar shower again.<br>The system was turned on during the April working weekend, and two WOTters actually enjoyed a (still very cold) shower, a very welcome surprise after all the mud that was picked up at the other activities 🙃.</p><p>At an association night (Wednesday the 10th of April) we noticed two problems with the system.<br>-The water temperature was rising unexpectedly fast on Saturday and Sunday (for the sun intensity those days) and dropping too fast at nights.<br>-The pump failed to switch on on Monday and Tuesday. The system thinks it switched on the pump but the return-line temperature was not following the collector temperature. Which also meant the tank-temperature was not increasing on those days.So that Wednesday we checked the water level of the tank and sure enough the tank was almost empty, during dinner we let the tank fill up. And we used the bottom flush of the tank to try to flush some rust out of the system, which might have been blocking the pump.</p><p>We were hoping this would work, but during the following days, we noticed that the pump still was not switching on correctly. On some days it was (like Saturday the 12th of April), but on other days it was not. We can however see that the tank now heats up and cools down slower than it did when it was not completely filled.</p><figure class="image"><img style="aspect-ratio:770/332;" src="/uploads/images/solarshowerupdate2.png" width="770" height="332"></figure><p><a target="_blank" rel="noopener noreferrer" href="https://web.archive.org/web/20250121214527/https://www.wot.utwente.nl/senslog/?Object=BV&amp;Sensor=T&amp;VSObject=BV&amp;VSSensor=H">Here</a> you can find a graph displaying the data that is measured live from the solar shower system. This graph shows the temperatures of various sensors and the time the pump was on for every 10 minutes.<br>-The pink line shows how long the pump was on, the pump cycles on automatically when the collector temperature is higher than the tank temperature.<br>-The dark-blue line shows the temperature of the collectors, it quickly rises if the sun is shining.<br>-The red line shows the temperature of the water flowing out of the collectors and into the tank.<br>(This means it follows the collector temperature while the pump is on but the temperature quickly drops towards ambient once the pump has shut off)<br>-The light-blue and yellow line show the actual water temperatures in the isolated storage vat this is the water that is used to heat the shower water through a heat exchanger.</p><figure class="image"><img style="aspect-ratio:801/337;" src="/uploads/images/solarshowerupdate3.png" width="801" height="337"></figure><p>On Monday the 14th of April we flushed more rust out of the pump, this time by actually manually disconnecting the pump and running it with some clean water. This did not seem to work, because on the 18th the pump was jammed. On the 23th a small hole was found in a pipe and had been welded shut, this explains why the tank was as good as empty during the working weekend. The pump was replaced with another one on the 24th and this seemed to have helped, because the pump has been functioning every day up to the day of writing (the 3th of May). Since the 29th of May the days kept getting warmer and on the 1th of May the tank was at a temperature of 45°C and someone had a nice and warm shower 😊.</p><figure class="image"><img style="aspect-ratio:416/418;" src="/uploads/images/solarshowerupdate4.png" width="416" height="418"></figure>

<p>It’s finally spring and at the working weekend we were busy like bees. This time the focus was on fixing the windmills on our terrain. The crankshaft of the Oasis needed to be placed back. The mystery of the ripped sails of the Cretan windmill had to be solved and the ripped sail needed to be repaired. The Diever needed a new breaking pin and we also wanted to install an underground power line to the Diever so we can put our praised windmill in the spotlight 🌟. Besides fixing the windmills, the Breurram was going to be tested at the PTB tower to see how much flow it produces on different heights.</p><p>We started the working weekend off with some pancakes, but soon after we all started on our projects. The crankshaft of the Oasis was temporarily removed. The Wednesday before the working weekend it was hardened to make it more sturdy, this morning it was placed back. The breaking pin in the Diever was replaced so she could pump again. Meanwhile the dig for the trench towards the Diever started. At the back of the terrain the PTB was cleaned using a pressure washer and prepared for the Breurram test.</p><p>The Cretan windmill had a ripped sail that needed to be repaired by gluing pieces of pvc sheets over the tear lines. After a while it was decided that the edge of the wing could be used to cover these tears and still have it look white. Towards the end of Saturday the wing was fixed and put back into the Cretan windmill, which started pumping soon after. The suspected reason why the blade ripped is because the ropes that hold the blades open were too loose.</p><p>During the working weekend the Kijito was still waiting on new parts so we could not repair her pump. In the meantime it was suggested that the reason the old pump did not work was because it sucked sand from the bottom of the well. The sand probably made the old pump wear out quicker. Therefore the well was deepened such that when the new pump is installed it will wear out slower.</p><figure class="image"><img style="aspect-ratio:4032/3024;" src="/uploads/images/wwapr420241.jpg" width="4032" height="3024"></figure><p>At the end of the day we finished with a BBQ 😋, celebrating our achievements halfway into the working weekend. And even after this the people who were eager to dig finished the trench and layed the cables towards the new power supply at the Diever. In the afternoon of Sunday the trench with the cables was filled again and the new socket was installed at the Diever.</p><p>On Sunday the first test for the 2” Breurram took place. With the water pressure provided by the ferro-cement tank it pumped water up the PTB. The flow of the Breurram at 5 different heights along the PTB was measured by measuring the volume of water displaced up the tower in 15 minutes. The pump itself ran without interruption for more than 1 hour despite a somewhat irregular pulse frequency. The data of this test will be processed and soon you can read the elaborate results in another blogpost, here.</p><p>We also appreciate all the smaller maintenance that was done on the terrain, namely that a large portion of the lawn was mown. So the terrain and her windmills can once again be appreciated in their full glory.</p><figure class="image"><img style="aspect-ratio:3024/4032;" src="/uploads/images/wwapr420244.jpg" width="3024" height="4032"></figure>

<p>We are thrilled to announce that the board of the WOT has been awarded the “best part-time board of the year 2023”</p><p>This price was awarded at the MTAD award, the event with which the student union of the university of Twente aims to thank students who achieve “More Than A Degree” by spending their time on running the different student associations and organisations that fuel the student culture in Enschede.</p><p>Great thanks go out to the jury and all our fellow students who voted for us. ❤</p><figure class="image"><img style="aspect-ratio:761/569;" src="/uploads/images/MTAD.png" width="761" height="569"></figure>

<p>The WOT is hosting introduction activities every Wednesday and Thursday throughout the month of September.<br>Yes, that is a lot of intro activities.<br>The intro activities are easy to follow and well prepared, you need no prior knowledge and can come by to have a look what the WOT is all about. Interested? Use the signup form below to let us know that you are coming and to join the free dinner (If you so wish).</p><p>The evening starts at about 17:45 and we have dinner together (which you can join), or come by later in the night for the activity, to help with a project or to join us around the campfire.</p><p>&nbsp;</p><p>Wednesday the 6th of September<br>Terrain tour and marblepump workshop.<br>This Wednesday we will be giving tours of our terrain, multiple members will be walking around to explain what each contraption or building is and answer any questions you might have.|</p><p>After the tours (and dinner) we will be starting construction on marble pumps, each course taker can make their own marblepump and take it home with them afterwards.<br>Here (Dutch, English) is the manual we will be following, but you don’t need to prepare anything.</p><p>Thursday the 7th of September<br>Lecture on well drilling.<br>We will host a lecture on well drilling, and in particular manual well drilling. Different techniques and concepts will be introduced and discussed and of course there will be time for all your questions.</p><p>Wednesday the 13th of September<br>EMAS drilling!<br>Today we will put some of the learned theory in practice. (or give you a very quick catch up course if you missed last Thursday)<br>We will be drilling a well by hand using the EMAS method, last year we got to 6,5 meters. Will we be able to beat that?</p><p>Thursday the 14th of September<br>Fix your bike for free, (repareer je fiets voor niets)<br>This night you will get the chance to fix your own bicycle! we will provide parts and expertise to help you (within reason), you bring a bicycle and your unbridled enthusiasm.</p><p>Wednesday the 20st of September<br>Workshop course<br>We will be giving a workshop course, you can get experience with different techniques like welding, grinding, cutting, reading technical drawings etc.</p><p>Thursday the 21th of September<br>Working on “the Diever” the Diever<br>Today we will be working on WOT projects, one of which is our big steel windmill at the front of the terrain: the Diever.<br>If the weather allows us we will be repairing the tail.</p><p><br>Wednesday the 27th of September<br>Working on “the Diever” the Diever<br>Continuing work on projects.</p><p>Thursday the 28th of September<br>Working on “the Diever” the Diever<br>Continuing work on projects.</p><p>Please sign up for an activity if you are interested, it is always possible to withdraw but this helps us estimate how many people (and thus food and materials) to expect.</p>

<p>Since we already installed a number of rope pumps in the Netherlands, we were looking for a safety brake that is reliable and stultifies the appearance of the rope pump not too much. As users of rope pumps know, the wheel and handle swing back firmly when they stop pumping. In developing countries the user gets instructions to use the hook to prevent turning back of the handle. For public places where anyone can use the pump, the blocking hook will not be used and there is a chance of injuring the user.</p><p>Therefore, we searched for an automatic device that prevents the reversal movement.</p><figure class="image"><img style="aspect-ratio:366/272;" src="/uploads/images/brakeflamingo.png" width="366" height="272"></figure><p>We have already been experimenting with a kind of rattle that inserts in the spokes of the wheel. Tests showed that the forces were too high resulting in bending the rattle pin. Another solution might be a band brake. This is also tested. These solutions do not look very pretty and they are susceptible to vandalism. Also, the braking power is not sufficient and reliable enough. A third type of a one-way brake with a nail into a wedge-shaped space in the bearing bushing gave good results. Better than expected. <a target="_blank" rel="noopener noreferrer" href="https://web.archive.org/web/20250618175909/https://youtu.be/yhyIM7kU5lU">The video</a> below shows the principle operation, construction, and testing of the one-way brake.</p>

<p>It’s Christmas time! Like many buildings, the WOT site got a makeover too last week. Thousands of Christmas lights bring magic to the place.<br>No doubt about it: all lights are LED’s!</p><p>It’s worth watching it, especially in snow.</p><figure class="image"><img style="aspect-ratio:373/279;" src="/uploads/images/wwl.png" width="373" height="279"></figure>