25.12.2020 | 15:18
smayoo kaže:
Djuro genijalac kaže:
Smayoo, molim te, nemoj selektivno pamtiti. Vozila s fuel cell pogonom (vodikove ćelije) nisu više prototipovi, nego (malo)serijski proizvodi koji se mogu normalno kupiti. Ne kod nas, jer nema infrastrukture koja bi to podržala, ali u naprednijim dijelovima EU mogu.
Evo, jedan konkretan primjer:
www.hyundai.de/modelle/nexo/
Dakle, problemi skladištenja vodika su riješeni, stvar normalno fercera, samo je zasad odvratno skupa. Da, u načelu je to elektroauto, samo ne koristi kemijsku bateriju, nego ajmo reći, vodikovu protočnu.
Zabavno mi je kako potenciraš problem požarnog rizika liijskih baterija, a bagateliziraš problem eksplozivnosti vodika.
Smayoo, uporno izvrćeš moje riječi. Ne banaliziram ništa. Ti si rekao si da su to sve prototipovi. NISU. To je serijski proizvod. Iza njega stoji multinalcionalna korporacija koja je za taj auto dala jamstvo od 5 godina bez ograničenja kilometara. Vozilo je maloserijsko samo zato jer košta koliko košta i ljudi ga ne kupuju hrpimice ili im je cijena vodika neodgovarajuća, ili je mreža punionica nedovoljno izgrađena da ispuni njihove potrebe/očekivanja.
Vodik u Njemačkoj možeš kupiti NAJNORMALNIJE na nekim pumpama koje prodaju i benzin/dizel. Prije više od 10 godina smo u Münchenu tankali vodik u BMW serije 7 koji je bio dual fuel. ICE motor je radio i na benzin i na vodik. Priključak je bio donekle sličan onom za LPG. Spojio je navojno, ako se dobro sjećam, onda je bila faza izjednačavanja tlakova i onda je počelo punjenje. Nisam više siguran, ali čini mi se da nije bilo moguće dopunjavanje tipa za 100 kn, nego da je sustav mogao samo napuniti spremnik do kraja. No, i opet, poanta je da se vodik skladišti, da se normalno puni spremnik u autu i da auto na to normalno vozi.
Vodik je eksplozivan. Je. Ti auti, kao i oni s LPG ili CNG instalacijama ne smiju u podzemne garaže. I benzin može sasvim lijepo grunuti. Ali, ponavljam, sustav je razrađen i serijski se koristi.
Još jednom te molim da provjeriš činjenice. Ili ostani u svojem uvjerenju. Evo, samo zato da dokažem da nisi u pravu, osmislio sam web stranicu na kojoj pogrešno i lažno navodim da postoji mreža punionica vodika u Europi.
h2.live/en
Dakle, evo, sad u sat vremena sam postavio ovu stranicu, jer skladištenje i korištenje vodika nije moguće. Ovo je sve laž. Samo NASA koristi vodik da bi poslala nešto u svemir, pa i to ponekad grune, jer je vodik, kako smo rekli eksplozivan.
Hyundai NEXO nije serijski model koji se može kupiti. To je maketa s velikim disclaimerom: ako ga kupite, do odredišta se nećete odvesti nego ćete odletjeti u zrak kao Challenger.
To je zapravo radni prototip, jer njegove prodajne količine nisu 27134 dnevno što je granica da se neki proizvod više ne smatra prototipom i postaje serijskim.
I evo, ovo sam napisao, ali to je sve laž!
Is hydrogen safe?
Hydrogen (H2) safety
Fuel-cell vehicles are characterised by short refuelling times, long ranges, and powerful acceleration. They enable zero-emissions mobility for the purposes of a sustainable energy transition. Mobility powered by hydrogen and fuel cells is not only a safe bet when it comes to climate protection. It’s clear that handling hydrogen requires responsible handling — after all, it contains sufficient energy to propel a vehicle at high speed.
Properties of Hydrogen
Hydrogen is a gas with a long history. Discovered in 1766 by the English chemist Henry Cavendish, it has been used as an industrial gas for over 100 years. Today, it is used in many industrial and technical processes.
When it comes to safety, hydrogen is often the subject of prejudices. In fact, hydrogen even has safety advantages over other fuels. Hydrogen (H2) is the lightest known element – about 14 times lighter than air. H2 forms an ignitable mixture with oxygen in a wide range (4 vol. % to 77 vol. %) –an explosive mixture with oxygen (oxyhydrogen gas) forms at a concentration of 18 % and above.
Hydrogen is non-toxic and cannot contaminate soils, the atmosphere or humans. In the event that hydrogen catches fire, the rate of combustion is relatively high. No smoke or fumes are produced unless other substances are burned.
Safety during transport and storage
Hydrogen is transported in specially designed hydrogen trailers, using pressure levels of 200 bar, 300 bar or 500 bar. hydrogen is subject to the regulations for the transport of dangerous goods (ADR). This means that the transport vehicles used, as well as the drivers, must meet specified requirements. Alternatively, hydrogen can also be transported in cryogenic, liquid form in special, highly insulated tank trucks. In some parts of Germany, there are also hydrogen pipelines through which large quantities of hydrogen gas are transported to the customer.
There are various ways of storing hydrogen at the filling station, depending on the design of the hydrogen filling station, and the volume dispensed daily. Today’s facilities most commonly store hydrogen in a gaseous state at pressures of 45 bar or 200 bar. Storage in a cryogenic, liquefied state (-253°C) is also possible.
Safety during refuelling
The hydrogen fuel pump communicates with the vehicle via an infrared interface. The vehicle has a communication interface directly next to the tank nozzle, which provides the filling station with data on pressure and temperature in the tank. This data is compared with the measurements taken at the filling station. If there are certain deviations, the service station interrupts or stops refuelling in order to check the reason for the deviation. In addition, the vehicle can stop the refuelling process – an additional safety feature that does not exist for any other fuel.
The refuelling line connection to the car is a so called ‘closed connection’ meaning: No hydrogen escapes during the refuelling process – otherwise the vehicle could not be refilled. It’s very similar with bicycle tyres: if you don’t have a good seal and the air blows past the valve, the tyre doesn’t fill up. To prevent this happening at the hydrogen filling station, the filling station first checks the fit of the nozzle and the tightness of the line. If one of the two is not right, the refuelling process will not start. The filling station uses a control system to ensure that the car is full, but not overfilled. As an additional safety measure, overpressure valves are installed in the vehicle tank to reliably limit the pressure.
After refuelling, the nozzle and the tank hose are “depressurised”: The hydrogen is fed back to the station. Only a very small and therefore harmless amount of hydrogen remains at the nozzle – about one third of a shot glass.
Safety in the vehicle
In terms of safety, hydrogen-powered vehicles are no different from conventional means of transport. This has been demonstrated by independent test services such as Germany’s TÜV in various crash tests and test series. Even if hydrogen is highly flammable, there is no increased risk in the event of an accident. Rather, hydrogen-powered vehicles are safer than conventional gasoline engines – because hydrogen doesn’t explode.
A leak in the hydrogen tank is very unlikely. And even if a leak should occur, the sensors detect the escaping hydrogen. The vehicle is automatically switched off and all safety valves are closed. The hydrogen tank is tested at 2.25 times the permitted operating pressure – i.e. a 700 bar tank must withstand a pressure of at least 1,400 bar and has high safety reserves in the event of an accident. The hydrogen tank is extremely resistant to internal and external pressure as well as to fire.