The criterion was that the output of the PV-systems must be at least 95% of the estimated feasible maximum. Studies showed that, provided the angle of pitch of the PV roof was not too great, the
roofs could face anywhere from south-east to south-west. This gives sufficient scope for an urban planner to design a highly attractive residential area.
The architectural design shows a pent-roof with a
vertical 'step' providing space for windows, which enables the use of passive solar energy. The lower roof area is covered with conventional roofing tiles, while the top area is the energy-producing roof containing
solar cells and thermal solar collectors. In this project, frameless PV panels mounted in aluminium profiles constitute the waterproof layer. Shell Solar Energy (former R&S Renewable Energy Systems) has installed a
total of 110 kWp of turn-key PV systems on the roofs of 50 rented houses. Through conduits in the cavity wall, the (dc) power is conducted from the panels in the roof to seven small inverter rooms, containing 5 kW dc/ac
The PV systems will remain the property of the electricity company REMU, which has established legal rights on the houses in this respect. In the rental agreements with the householders, the housing
corporation has included provisions allowing REMU access to the houses and obliging the householders to prevent shadow.
Because all the parties involved the municipality, the housing corporation, the architect,
the contractor, the supplier and REMU were enthusiastic about the project from the start, it got off to a quick start and proceeded smoothly. The project has already demonstrated that the use of PV on houses is
compatible with an attractive estate layout and architecture, and that there is wide public support specifically for the use of PV in the built environment.
A much larger project is being prepared as a
follow-up. A total of 1.3 MWp will be installed on about 500 homes, a primary school, school dwellings, a day care centre, a
sports hall and a community centre.
'NIEUW SLOTEN' PROJECT
The Energy Company of
Amsterdam, now part of ENW, wished to investigate how PV could best be integrated in part of a new residential area called 'Nieuw Sloten'. An added difficulty in this project is that Amsterdam has to build high-density
housing. Apart from south-facing roofs, east and west-facing roofs were also admissible to a limited extent, provided they had a low angle of pitch. The PV systems have been installed on the roofs of 70 homes designed
for owner occupation, both low and high-rise. The PV panels have a total capacity of 250 kWp, with Shell Solar Energy supplying 140 kWp and BP Solar 110 kWp. The project is partly financed by the EC THERMIE programme.
The project was aimed at a high level of integration with:
- the ac electricity grid;
- urban planning, architecture and the building construction;
- the usual organisational processes of a house-building project, including contracts involved.
The electricity from the panels is conducted to a separate inverter room via an underground dc network. Surprisingly, detailed calculations showed that the output of the system would be maximised by connecting most
of the arrays to a single inverter. The losses due to mismatch would be partially compensated by the greater yield of a large inverter. In addition, a large inverter would be cheaper. On the other hand, the varying
orientations of the PV arrays meant that the size of the inverter could be reduced. This aspect will be monitored particularly closely over the next few years. The centralised design will make it easier to manage and
maintain the system.
For more information contact the CADDET Dutch National Team in Sittard.