*4.1. Optimizing the Operation through the Installation Mode*

The technical water generator is very easy to install, as Figure 5 demonstrates. Since the time required for repairs or maintenance work is limited (and this is a positive aspect, taking into account the limitations onboard ships), the installation is very compact. The heating medium in which the still operates is hot water, such as water coming from the main engine, but it can also be steam. The cooling liquid of the condenser is sucked directly into the cooling system of the main engine, to which it is also returned after passing through the distiller system. The feed water is sent by means of a pump or an ejector, this being necessary for the evaporation process, as well as the water that must reach the ejector of brine combined with air. This water can be drawn from the condenser discharge, or it can come from an alternative source.

**Figure 5.** The arrangement of the AQUA Blue S-type technical water generator in the framework of the cooling water installation [drawn by the authors].

The technical water generated is pumped to a storage tank. The control panel provides electrical power to the feed pump, to the ejector, to the water pump and to the metering pump and also provides the control voltage to the hallometer and the drain valve. The components of the diagram above are as follows:


#### *4.2. Optimization of Electricity and Water Consumption*

The technical water generator has an optimized technology that allows it to convert a higher percentage of technical water from salt water. More than that, it cuts the amount of salt water needed for cooling in half. This means that a halved amount of electricity is consumed for pumping, representing half of the electricity consumption dedicated to the operation of the entire system. For cooling, it is possible to opt for the still to be cooled directly by the open cooling circuit of the main engine, and this would further reduce electricity consumption [30]. This difference is highlighted in the diagram in Figure 6.

#### *4.3. Optimization through the Use of Membranes with Special Construction*

As mentioned, the system is composed of titanium plates with a 3-in-1 design, the main differences between these plates being marked in Figure 7. They are provided with two types of gaskets, and the whole configuration allows evaporation, separation and condensation in a single package uncovered by the plates. At the same time, this specific configuration enhances the evaporation process and allows the conversion of a larger amount of salt water.

**Figure 7.** Model of titanium plates used in the configuration of the freshwater generator [drawn by the authors].

In the figure above, the colors associated with the areas of the titanium plates denote the following processes:


The constructive elements of the plates, as they are numbered in the figure above, are:


The salt water passes through the lower part of the plate pack, where it is evaporated at a temperature of 40–60 ◦C in a vacuum process of 85–95% [32]. As the steam increases its pressure and density between the plates, it passes through the separation zone, which locks the brine and makes it fall into the pool at the base of the technical water generator. Thus, only technical water vapor reaches the upper part, which is cooled and condensed into fresh water. The result of the whole process is the generation of good quality water with a maximum salinity of 5 ppm [33]. Due to the optimized flow distribution along the plates, any form of calcareous deposit is avoided.

#### *4.4. Optimizing by Ensuring Correct Exploitation and Compliance with the Installation Maintenance Schedule*

Although the technical water generator does not require a high level of maintenance, its operation depends in many ways on the way the installation it serves is maintained. For these reasons, the maintenance of these types of devices is closely related to the maintenance technical water installation onboard the ship [34]. In general, the maintenance and upkeep of the installations onboard ships must focus on the following directions:



The control and checks of the installation have a permanent character, being part of the current follow-up regarding the technical condition of the construction, which, correlated with the maintenance and repair activity, has as its objective the maintenance of the installation at the designed parameters. The control and verification of the installation is performed by the operating personnel on the basis of a program. The program will include provisions regarding the entire installation, the categories of installation elements and functional operations, recorded in the operating instructions of the installation.

#### **5. Conclusions**

Desalination of ocean water requires a huge amount of energy and of course produces greenhouse gases. Moreover, desalination plants endanger marine ecosystems. In a report dedicated to ocean water desalination plants, representatives of the environmental organization WWF were quite concerned about this issue. Seawater desalination is far from the ideal solution. This technology is a potential threat to the environment and will only make climate change worse [36]. The recourse to these new technologies, which are increasingly accessible, will not remain without consequences for the environment.

Technical water systems or plants can also have a negative impact on coastal areas, amplifying the destruction of marine ecosystems specific to these areas. In addition, the risk of disturbing the balance of these wetlands and the purification and protection functions against catastrophes increases greatly.

Specialists in marine pollution and ecotoxicology have also sounded the alarm about the dire consequences that could occur after the commissioning of the desalination unit onboard the ships [37]. The process of desalination and drinking water production plays a critical role when it comes to navigation and making long-distance and long-duration journeys.

At the same time, the desalination process plays an important role in many other fields, totally different from maritime transport. Many countries in arid areas use seawater as a source of drinking water for their coastal cities, subjecting it to expensive desalination processes. Obviously, the oldest and largest desalination plant is nature itself through evaporation from the seas. More than 30 water desalination processes are known, including condensation, freezing, extraction, electrodialysis, reverse osmosis, ion exchangers, etc.

**Author Contributions:** Conceptualization, C.F. and E.R.; methodology, E.R.; software, Microsoft Office Word; validation, C.F. and E.R.; formal analysis, E.R.; investigation, E.R.; resources, C.F.; data curation, C.F.; writing—original draft preparation, C.F.; writing—review and editing, C.F. and E.R.; visualization, C.F. and E.R.; supervision, E.R.; project administration, E.R.; funding acquisition, C.F. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by PROINVENT – POCU Programme grant number PN-III-P4- ID-PCE-2020-0008 And The APC was funded by Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding—UEFISCDI.

**Data Availability Statement:** Further data on author work can be studied by accessing the following links, for additional information: https://iopscience.iop.org/article/10.1088/1757-899X/1182/1/0 12024/meta, https://iopscience.iop.org/article/10.1088/1757-899X/1182/1/012023/meta, https: //www.gup.ugal.ro/ugaljournals/index.php/mtd/article/view/4028, https://www.gup.ugal.ro/ ugaljournals/index.php/mtd/article/view/4028.

**Acknowledgments:** The work of Faitar Catalin was supported by the project "PROINVENT", Contract no. 62487/03.06.2022—POCU/993/6/13—Code 153299, financed by The Human Capital Operational Programme 2014–2020 (POCU), Romania, the work of E.R. was carried out in the framework of the research project DREAM Dynamics of the Resources and technological Advance in harvesting Marine renewable energy), supported by the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding—UEFISCDI, grant number PN-III-P4-ID-PCE-2020- 0008.

**Conflicts of Interest:** The authors declare no conflict of interest.
