Solar thermal tanks: Energy solution in terminals and docks

Introduction

Seeking clean and sustainable energy sources is not just an option: it is an urgent necessity. The energy transformation nowadays is not limited to large cities or visible industries, it also touches lesser-thought-of places such as docks and port terminals. Docks and terminals, so essential to trade and logistics, of course have considerable energy demands. From hot water for staff showers in these spaces to cleaning equipment, energy is used daily, in every corner of the port.

In this context, solar thermal tanks, also known as Top Tanks Solar, can make a difference. But what would be the idea behind the need for these installations? The answer lies in replacing, at least in part, the use of fossil fuels used for these requirements with solar thermal energy, reducing costs and emissions, while giving the planet a break on CO₂ emissions.

The sun’s potential in ports

If one stops to look at a port, the first thing that jumps out is its wide roofs, large structures, and unshaded surfaces. All that wasted space could be turned into a huge “sun trap” thanks to thermal collectors, which capture the sun’s energy to heat a fluid that is then stored in tanks.

These systems, which look like panels, but instead of generating electricity to heat water, capture solar radiation -direct and even diffuse- and then store it in well-insulated tanks or vice versa. That is, from the tanks to the heaters or panels and from there to the sanitary distribution system. In tropical countries such as those of the Caribbean Sea basin, where the sun is not exactly scarce, the potential of this installation and service is enormous.

The coastal location of many ports can offer favorable solar conditions for much of the year. So solar radiation can be efficiently harnessed by well-designed solar thermal systems.

Having hot water without relying entirely on electricity or gas is not only efficient, it can also be a lifesaver when the supply fails, as is often the case in these countries. A solar water heating system performs the vital function of storing the heat captured by the solar collectors for later use. Unlike a conventional water heater that produces heat on demand (or keeps it constantly warm by means of a resistance or flame), the solar thermal system collects the energy during the hours of sunshine.

In some cities where there are cold temperatures, but there is also radiant sunshine during the day, the use of these heaters is for homes and industries. They are used to heating water in homes and workshops, and this has worked successfully. The physics behind this is simple: solar collectors (usually flat panels or vacuum tubes on coils in the manner of a radiator) absorb solar radiation and transform it into heat, which is then transferred to a fluid (water or a mixture of water and antifreeze).

This hot fluid circulates to the storage tank, where, through a heat exchanger (or by direct contact in thermosyphon systems), it transfers its thermal energy to the sanitary water contained in the tank.

So why not think that this also works in other infrastructures where CO₂ emissions are critical such as docks and terminals?

Practical applications of solar thermal tanks in dockside applications

Solar tanks are not just a practical and useful idea; they have concrete and very varied uses. Here are some examples:

Hot water for port personnel

The use of showers, sinks and kitchens in offices, workshops or rest areas require constant hot water. With the installation of these solar thermal systems and storage tanks, a significant part or all of this demand can be covered, helping to reduce the associated energy costs and improving the life quality of personnel. This is especially true in contexts where access to reliable energy is not guaranteed.

General cleaning of equipment and vessels

Contrary to what one might think, docks and harbors require water. It is commonly used for cleaning equipment and for maintenance tasks on smaller vessels. A solar thermal system would be contributing to the efficiency and hygiene of these operations.

Sensitive industrial processes

It should be noted that docks and terminals handle sensitive products – such as food, pharmaceuticals, or chemicals – and require hot water for cleaning, sterilization or preheating. A solar tank can complement or even replace other sources, with clear benefits in terms of sustainability and savings.

Indirect heating systems

In tropical climates there are certain cooler port regions, and it is not uncommon for hot water to circulate through heating systems in offices or warehouses.

Defrosting of equipment in winter

For the most extreme latitudes in ports, it can be used in de-icing systems, keeping cranes, ramps and metal structures operational during the winter.

What are the keys to a successful installation in marine areas?

Not everything is so simple when installing a Top Tanks in this area. Ports, being in coastal areas, present challenges to consider:

• Corrosion is a silent enemy. Given the environmental conditions and the location of the ports, brackish air deteriorates metals in a short time. Therefore, one of the recommendations is to use high quality stainless steel or plastics resistant to UV radiation and salt water.
• Strong and frequent winds, so the supports to be used must be firm, well anchored, and designed to withstand considerable wind loads or rainfall that can be storm-rated.
• Space must be well evaluated. Although ports seem to have a lot of land, not all space is suitable for installing collectors: good solar orientation and maintenance facilities and accessibility are required.
• Integrating the system with the existing infrastructure is vital. The connection to the hot water network must minimize heat losses and avoid technical complications.

Profitability, suitability, and future

Understanding that the future is different requires making executive decisions in favor of the continuous improvement of operations. That is why investing in projects such as solar thermal energy is not only an ecological decision. It is also a smart financial strategy:

• Operating costs are reduced. For every liter of water heated with the sun is a liter that does not depend on gas or electricity. It is imperative to establish the reduction of electricity or fuel consumption for water heating, which translates directly into significant savings in the port’s energy bills.
• It increases energy independence, which is also particularly valuable in locations where supply may be irregular. Reduced dependence on grid or fossil fuel supplies should be considered to increase the operational resilience of the port, especially in regions with potential supply disruptions.
• The port’s environmental image is improved, something that increasingly weighs more heavily in tenders, international relations and environmental regulations. In Europe, for example, there are already ports that must report their CO₂ emissions and demonstrate annual improvements (European Maritime Safety Agency, 2023). In both European ports and harbors, the adoption of solar thermal energy has been shown to reduce greenhouse gas emissions and demonstrates the port’s commitment to environmental sustainability, improving its public image and complying with increasingly stringent environmental regulations.

The service life of the system is long. Properly maintained, these systems can operate efficiently for more than 20 years. With proper maintenance and the use of materials resistant to marine conditions, solar thermal systems can have a desirable service life, providing long-term economic and environmental benefits.

Conclusions

Harnessing the sun’s heat to heat water is a futuristic idea for net-zero. It is certainly a viable, useful and multi-beneficial reality. With space available, good solar radiation and above all, recognizing that there is a growing need for sustainable solutions, solar thermal tanks fit perfectly into the energy map of docks and terminals.

These systems Top Tanks can make a significant contribution to reducing operating costs, improving environmental sustainability and increasing the energy independence of these important maritime infrastructures. In short: they heat water, save money, care for the planet and – if done right – will work for decades.

References

1. European Maritime Safety Agency (2023). Sustainability in European Ports. https://emsa.europa.eu
2. Ministerio del Poder Popular para la Energía Eléctrica. (2022). Informe Nacional de Consumo Energético. Caracas, Venezuela.
3. International Renewable Energy Agency (IRENA). (2021). Solar Heat for Industrial Processes: Technology Brief. https://www.irena.org