On-board energy-food sustainability

Our aim: 100% on-board sustainability

This might seem to be utopic but this aim is taken as a challenge and an experiment. Our goal is to be as close as possible to an energy-food sustainable boat, allowing to move goods and people accross the world with no impact on eco-systems and environments.

On-board energy sustainability can be achievable with today’s technology. Electricity for the navigation instruments, the pumps and the lights can be obtained using solar panels, wind turbines and water propellers systems when sailing the ship. The systems needs to be tested, adjusted, calibrated with time, to obtain the best yield with the less material possible.

If the ship is to go North, a proper clean heating system is needed for the cargo and the crew. Heat pumps systems will be experimented on-board, taking advantage of the sea-water temperature perpetually available. The system will convert the energy from the sea into heat for the ships mess room and cabins. Our partner DTU Technical University will help us to obtain a stable system that could inspire other ships.

Our preliminary strategy to obtain energy sustainability (not yet confirmed in simulation or calculation software).

  • Heating and cooling low exergy concept.

The main idea is to exploit the sea water’s temperature and turn it as the heating and cooling source for Hawila.

Heat pumps convert the renewable energy, in this case the sea temperaturesea water temperature, and electricity directly into heat. In the winter, it transfers heat from outdoors to indoors in order to heat the occupied space, and in the summer, it removes heat in the opposite direction from the occupied space to the sea. Here the Carnot Circle is going to be studied.

The heat pump will perform with a high COP (Coefficient of Performance), which expresses the energy efficiency of the heat pump. The COP of the heat pump for heating means the ratio of heat delivered to energy input (electricity). In the market 3 types of heat pumps can be found, water to water, earth to water, air to air. In this design a water to water heat pump is going to be used.

The heat pump is considered to be a reversible one, so that can work either thermal direction in order to provide heating or cooling to the internal space. This is done by a reversing valve to reverse the flow of refrigerant (R134, Freon) from the compressor through the condenser and evaporation coils (note: this is a close circuit).

In the market it can be found open and close circle of water to water heat pumps. The former requires a large surface while the later an inlet and an outlet. In our case the second is suitable. This type of heat pump takes in directly the sea water , and after well filtering it (since big particles till shrimps and fishes can stuck), the temperature is taken by a heat exchanger and then exhausting it back to the sea.

The radiant ceiling is performing at temperatures close to the room temperature (approximately 30 – 35 C for heating and 16 C for cooling) and therefore high temperatures are not required.

Domestic Hot Water (DHW) will use the generated heat by a heat exchanger and distribute it to shower and sanitary warm water uses. The shower can use the preheated water and worm it to the desired temperature with an electric heater by getting an advantage of the low ΔT.

  • Radiant ceiling panels

Why to use radiant panels?
Advantages of radiant ceilingsradiant ceiling
– With comfortable, uniform distribution of warmth
– With long term durability, practically maintenance free
– Heating and cooling emissions guaranteed
– Free of draughts, noise or forced air movement with dust disturbance
– With all possibilities for applications with alternative energies.
– No energy waste from high temperature gradients (hot roof – cold floor)
– Unrestricted use of wall and floor space
– Good regulation and short heat-up time due to low inertia of the system
– Efficient and cost effective installation by use of pre-fabricated modular construction with optimum fixing centers.
– Optimum heat emission by use of high quality material (precision steel tubes 1˜ and radiant plates 1.25 mm are close fitted by a patented double point welding method giving an unbreakable thermal conducting bond).
– Special production i.e. angled, sound absorbing, and interrupted radiant plates (below roof-lights).

The most important advantage of a radiant ceiling system is that the medium circulating (water)  has to be around 30-35 degrees Celcius. The old conventional radiators (as they are currently) are performing with a medium’s temperature of 75 degrees! By changing the system to the introduced one, the energy consumption is expected to be dramatically diminished.

The potential available ceiling can host the amount of panels that are needed, plus the weight of each panel is not going to cause any problem. (25kg/m2, including the water in it and the installations).

  • Solar power

The current technology allows us to use new type PV panels, flexible, durable and corrosion resistant. pvThe Solar power engineer is already working on it in order to examine whether it is feasible to sew ultra thin film-type panels on the sails. The maximum potential sail area is up to 250m2. Of course not all is available, however, both sides of the sails could be exploited, with a half active system each time. Another option (perhaps could work simultaneously) is to install this kind of panels on the site of the boat, where the sun is striking both direct and indirect from the water’s reflection.

As far Hawila stays in Denmark or sails close to the Baltic sea, there is no need to install PV panels on horizontal positions (deck or top of the kitchen) since the Sun’s position is very low and it will strike on a oblique and inefficient angle.

  • Wind power

Here the strategy is to install 4 wind turbines. The idea is to install 2 on the top of the masts and 2 on thwind turbinee back of the ship. The consideration so far is to use wind turbines without a tail in order to be more resistant to sudden wind changes, concerning it’s direction. Those wind turbines are facing always the dominating wind without changing drastically position each time there is a wind change. The system here is rather complicated, due to the wind velocities and movement of the boat. An algorithm is going to express this irregular movements, and later by simulating with the weather data, predictions for worst case scenarios under certain energy load can be shown.


The real challenge: on-board food sustainability

The biggest experiment will be around this field. Some considerations are for instance a solar fruit-vegetable dryer, waterless or hydroponic plant grow systems. Many questions are rising, such as:

  • Is it possible to grow vegetables while at sea?          hydroponic tomato systemSolar Dryer
  • Is it possible to embark animals on-board for long trips?
  • How much can we fish while sailing?
  • Can we sustain a reduced crew with such amount of food?


These are the questions we will try to answer in the near future, stay tuned!


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