With a fleet of more than 250 vehicles, it is one of the largest providers of crane services and heavy load transports in North Rhine-Westphalia. With a fleet of more than 250 vehicles, it is one of the largest providers of crane services and heavy load transports in North Rhine-Westphalia. Because of the steady growth of the business, a new large shop with a truck wash for vehicles with a length of up to 23 metres was built. Since a solar thermal plant had been considered in the planning period already, building the collector field and components took less than two months. The components were delivered ready to use and directly integrated to the system.
The company is located in an industrial park in which an obligatory use of solar energy had been considered. Furthermore, specific requirements for the preservation of ground water have to be met because the location is inside a water protection area. For these reasons, a PV-plant has been built already several years before, which now was extended by vacuum-pipe collectors for the thermal use of solar energy.
168 collectors with an area of 205 m² convert the incoming solar radiation to thermal energy, which is stored in three buffer tanks of 2,500 litres volume. The heat is used for two high-pressure washers with a water demand of 1,200 l/h at 70 °C and a brushing wash system with under carriage washing using 250 l/min. The brushing wash system is operated three hours a day and needs around 1000 litres hot water per vehicle. In sum 15 m³ hot water at 70 °C are used for cleaning purposes each day. Warm water production via a fresh water station, air conditioning, and heating are additional heat consumers. When solar radiation is insufficient, a cascade of four condensing gas-boilers with a total thermal power of 380 kW, integrated by a hydraulic switch, can be used for reheating. In order to be able to meet the great water demand, a peak load store with 1,000 litres volume has been installed.
To avoid the system from stagnating even at sunny days with little heat demand, an underground cold water tank with a volume of 130 m³ provides a very large heat sink. In order to be able to react quickly to technical faults, the system is constantly supervised automatically. Planners, installers and customer service can be contacted on demand via SMS or email.
Because the design allows a heat supply at a relatively low temperature level, the solar system achieves a specific collector yield of more than 480 kWh/m², which equals to a system utilisation ratio of 48 %. With the funding from the market incentive programme, an amortization period of less than 10 years is possible.
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