With modest dimensions, sensors often can make the difference in many applications. One example of this is the Blue Battery from AquaBattery. The Blue Battery is an electrical energy storage system that uses membrane technology, water and kitchen salt. In order to measure the height of liquids in several tanks, tests were done in their own workshop with ultrasonic sensors from elobau. The robust ultrasonic sensors were selected because they provide the necessary reliability, accuracy, IP rating and are compatible with the control system.
Aquabattery was founded a few years ago by five young men who had specific ideas about a cheap but effective way to store electrical energy. An important theme at a time when there is a risk of a surplus of energy as a result of over-production of PV panels, and supplying back is not always possible or lucrative (anymore).
There are many options for storing energy, of which the regular “battery” – which works with lead or lithium cells – is the best known. A major disadvantage of these types of batteries is that the materials used are partly toxic, expensive and flammable, up to the risk of explosion. How could this be changed?
With everyone having a background in “water”, the solution for Blue Battery was to store energy by making use of the potential difference that exists between salt and fresh water. “The technology for producing electricity by allowing salt and fresh water to flow past membranes is already known from the 1960s,” says COO Emil Goosen. “However, by reversing the principle, it is also possible to save energy with the same membrane technology, and that is exactly what happens in our Blue Battery. A system that consists of two or three tanks connected with pipework, pumps and the membrane sets. Based on the conductivity of the media, the level in the tanks and the pressure and direction which liquids have to flow in order to charge or discharge the battery is determined by the controlsystem. ”
Many tests have been carried out in our own workshop in Leiderdorp with membrane packages and capacities up to approximately 1 kW. This has resulted in a setup which will be tested in our first pilot in “the Green Village” in Delft. Emil Goosen: “This project was mainly carried out within the framework of “scaling up”. An important step because such a pilot must show that the successful operation on a laboratory scale also works well and reliably in larger systems. This first pilot uses 10 cubic meters of fresh water, spread over different tanks. At this point everything is working satisfactorily, leading to the start of a second and third pilot, where we are moving to even larger capacities. ”
Level measurement
In order to measure the level in the tanks, experiments were initially conducted with capacitive sensors. However, these were not accurate enough and, more importantly, gave too many fluctuations… (continue reading)
