1. Solar cells

The roof of the main hull and parts of the floats protruding out from under it are fitted with solar cells. Solar cells that are able to be walked on are planned to be used on the sun deck. A total surface area of 939 sq ft can thus be obtained.
    The wind turbine poses something of a problem as it periodically casts a shadow, which reduces the production of electricity. The reason for this is that each individual solar cell has only a low voltage and thus several need to be connected in series. Thus, electricity production is interrupted in the entire series of cells if just a single cell drops out. This problem is mitigated in the Eco-Trimaran by keeping the series short, as the amount of voltage required for the electro­lyser does not need to be very high. With the solar power generator there is also no need for an inverter or voltage converter, since the electrolyser operates on direct current. This
reduces energy loss,
allowing  us to assume an efficiency rate of 12 %. In the end on account, 20 % is deducted for the shadow of the wind turbine as well as other losses (connecting lines, unfavourable operating temperatures).

2. Electricity yield

Solar energy is available on the earth’s surface partially in the form of direct sunlight and, when it is cloudy, partially as diffuse radiation. Both types are subsumed under the term “global radiation”. It is the strongest near the equator and is weaker with increasing proximity to the poles and in frequently cloudy areas. For our calculations, we require average values for many years for all possible areas of operation and all possible moorings. These are obtained from special maps or tables available on the web. In this case the System ”Meteonorm" was used. The calculations presented in the following are based on the standard operating scenario, described more fully in the section “Energy”, using the ratio: mooring time

without crew : mooring time with crew : travel time = 50 : 273 : 42 and a motor operating time of 6 hours per day of travel.
    Worst-case scenario: the longstanding average for global radiation on the North Sea north of Scotland is approx. 800 kWh/sqm (74 kWh/sq ft). We will assume that the ship is both moored and operates within this area In this case the amount of energy produced by the solar cells would be 6.71 MWh per year or 18.37 kWh per day.
    Best-case scenario: average annual global radiation of 1850 kWh/sqm (172 kWh/sq ft) is measured for the area south of Sicilia.* If the ship is both moored and operates in this area, the amount of energy produced by the solar cells would be 15 MWh per year or 42 kWh per day.
    Standard scenario: as global radiation is strongly dependent on the degree of latitude, a basic decision needs to be taken as to whether
Note: Here the “best-case scenario” was sought within the Mediterranean Sea. Yet better radiation conditions by far are found in other areas of the globe, for example near the Canary Islands or the California coast.
sun energy
                during mooring times
sun energy during travel times
the Eco-Trimaran will operate mostly in bodies of water in the north (North and Baltic Sea or North Atlantic) or in the Mediterranean. The standard scenario thus needs to be further differentiated to include a “northern and a “southern” scenario. These scenarios are presented in the tables at left and above, with
the rows giving the radiation data (“Rad.” column in kWh/sqm per year). Values for radiation, while determined arbitrarily, are approximate representative for the regions as depicted in the global radiation maps in each case. Under standard conditions the amount of energy produced by the solar cells would be 12 MWh per year or 33 kWh per day while moored or travelling in northern areas. At southern latitudes, 21 MWh per year or 58 kWh per day would be obtained.

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