paper

ARCHITECTURAL INTEGRATION of PV MODULES
in STRUCTURES of DWELLINGS

THERMIE SE 102/95/NL/DE

Keywords: Building Integration - 1; Facade - 1.

1. Introduction

2. The building project

3. The integrated PV system

4. The PV-system

5. Monitoring

6. Innovations

7. Results and prospects

REFERENCES

PARTICIPANTS

1. Introduction

In the Oudelandshoek area of Dordrecht, De Rietlanden, 22 new dwellings provided with PV systems were built by Stam+de Koning, Zwijndrecht. The dwellings are situated in a line, south of a roundway of the city. The south facade is open for passive and active solar use. The north facade is nearly closed. In the shading device of the south facade 10 m2 PV module is integrated with a tilt of 60 0. The total capacity per dwelling amounts to about 1 kWp.
The PV systems of eight dwellings will be monitored. One of them is extensively monitored. On behalf of the individual demand in dwellings a standard, relatively low-cost monitoring device is developed. In two dwellings a monitoring device as such is mounted that measures the actual energy production of the system and compares the results with the expected production. In a central location a PC with a display will be situated, which presents the most important results of both parts of the monitoring program.

2. The building project

The houses are located along a noisy highway. Because of the noise the houses are almost closed along the road and opened to the other, sunny side (SW) of the location. The living, with its large windows, faces south.
Passive and active solar can be used in this way. To prevent overheating in summer, a solar shading device is used. In figure 1 a photograph of the project-model is shown.

The aim of the housing project is to develop environmental and energy-conscious housing. This means that the houses are well-insulated, Low-E glazing, high efficiency stove, an electrical heat-pump for ventilation combined with a hot water boiler and PV-modules for electricity. Water-saving equipment is a standard in the houses. Building materials are selected according to environmental aspects. The houses are called 'Milieu +' or 'Environment extra'. This means that the houses will become a (future) new standard for housing in the Netherlands.
The municipality of Dordrecht uses checklists on environmental aspects for new building plans. To increase the realisation of environmental aspects in the building industry this plan is supported as an example or demonstration for new standards in Dordrecht. (Which will be followed by other municipalities).

On the site along a highway of the city the dwellings are designed with aspects to the high noise
level. For that reason the dwellings are almost without doors and windows on the north (noise)side and opened to the sunny south side. This specially designed house can be used in a lot of noise-sites along highways with heavy traffic.

Special attention is paid to the architectural integration of the chosen constructions. There is a big need for good examples of solar dwellings where photo-voltaic, passive and active solar energy are combined.
This demonstration is a good example and will be followed in future projects with integrated PV-modules in housing design.

fig.2 PV construction detail

fig.3 South-east side along the water 

3. The integrated PV system

Because of the specific situations the houses are also a good example of passive-solar housing. Because of the heat load in summer, a passive-solar house needs shading. Part of the shading is fixed and part of the shading must be removable for use in summer-conditions only. For this reason a special shading-device is designed to integrate both functions together with the possibility of integrating PV-modules in the facade.
For substantial electricity production by PV in Europe, grid connected systems in the built environment will become important. For the introduction of these systems, further cost reduction is essential. In this project, several ways of further cost reduction by integrated PV will be explored.In the first place, integration of PV systems in the built environment can result in considerable cost reduction. The PV system has, besides the energy production function, also the function of a building part like a shading device.
In the second place, there is no essential difference between a panel and an unframed solar module. This means that the extra cost for integrating unframed solar modules in a panel construction will be low.
This is quite a difference to normal roofs where mostly a watertight skin under the solar modules is necessary. The extra skin increases the price of the normal roof.
In the third place PV panels in architectural facades are more and more accepted and implemented.
This project combines all three statements in the facade/shading device integrated PV system. Experiences will be now be achieved.

4. The PV system

The applied PV panels (with Siemens cells) make GSS, with an area of about gross 10 m2, are JRC ISPRA tested. The net capacity amounts to 1037 Wp. The PV system is grid-connected. Due to the requirements of this integration the PV modules can not be delivered as a total factory-made system. The typical specifications in relative normal architectural design involve the design and the manufacturing of custom-built PV modules. The mounting construction is strongly emphasized to minimise the total costs and to perform mounting smoothly. The inverter is a recently developed, high efficient instrument provided with a micro-processor and a MPPT. The instrument is especially designed and demonstrated for the PV systems with low capacities in dwellings as applied in this project. Results of the system can be easily read out. For the monitoring program results are received with a PC via a RS 232 connection. The architectural integrated PVmodules in the facade are fabricated in laminates. The dimensions, the thickness and the colour of the background are choosen in accordance with the facade design. The module is divided in several pieces (subarrays). The solar panels are mounted on a specific structure and can be easily removed (exchanged) when needed. An important item in this demonstration project is to think solar and to apply it architectural justifiably. The total PV system is delivered by GSS Gebaude - Solarsysteme GmbH, GERA Germany together with the BST Group, Terheijden, the Netherlands.

5. Monitoring

The measurements to be performed within the monitoring program concern: ambient climate (solar radiation, temperature), temperature of the PV panels, the amount of energy (voltage, current) by the system, the amount of energy given back to the grid, the amount of energy purchased from the utility. The monitoring program consists of 2 parts: an extensive part for two selected dwellings and a restricted part for other dwellings. All data are logged in a central computer system via a datalogger. With a modem connection results will be gained, analysed and presented at the work place. On this basis a standard monitoring device will be developed and validated. In two dwellings this monitoring device is mounted that measures the actual energy production of the system and compares the results with the expected production. In figure 2 the principle is presented. In a central location a PC with a display will be situated, which presents the most important results of both parts of the monitoring program.

6. Innovations

Innovative aspects.
The innovative aspects are:
- PV-modules integrated in shading devices in (passive) solar dwellings;
- The integration of structural and electrical details of the total system;
- The low-cost standard monitoring instrument for dwellings.

The optimised hanging and mounting constructions together with the PV integrated shading emphasize a new development for a wide-spread field of applications.
New structural and electrical details in the facade and in the installation are optimised and applied. That means that primarily based on the experiences from previous projects and secondly on behalf of new components on the market the total system is emphasized, e.g. electric connections, earthing, inverter including controls, grid interface unit. The standard monitoring device can be used in the so-called Guaranteed Solar Results (GSR) projects in the field of photo-voltaics [2].

7. Results and prospects

In different ways applications of PV systems for the building sector are emphasized. Constructions, designs, producttypes, etc. are tuned with the consumer demands. Results now are a demonstration of 22 dwellings with integrated, cost-effective PV-systems. The total capacity amounts to 22 kWp. The project is a demonstration of a prototype PV-dwelling for future designing.

The resulting knowledge and experience are used to improve the possibilities of applications on a large scale.
The results of the energy measurements of the project will be evaluated by comparing with measured results of equivalent projects and with calculated results by the use of simulation programs. Reference yields will be emphasized. These measurements wille start about the beginning of 1997.

The aim of this project is to encourage the commercialisation of PV-systems demonstrated in a PV-integrated solar project of dwellings.
With this demonstration project proposers and subcontractors will try to generate more activities in the field of energy saving technics and to promote the sense of energy saving by the use of solar energy. The project significantly contributes to achieve the final goals of CO2 reduction and the related market, estimated by the EC and the government.
The participants aim and ensure a fully commercial exploitation of technological knowledge acquired during the project.
The participants expect cost savings of further replication of this project first of all in the integration technics (replaced costs). Besides, in PV-cells and lamination, mounting materials and inverters. Together with the tendency of decreasing costs in PV-cells, solar projects as such will meet a promising economic viability and an important reduction of CO2 and NOx emissions.
The results will be disseminated in branche organisations.

8. References

1. G. Brouwer, W.J. van Beek. Integration of photo-voltatic solar energy in the facade of the office buiding EnergieNed, Arnhem, NL. 1994.
2. G. Brouwer, J.H. Liefting. Guaranteed solar results of collective solar hot water installations. DG XVII, EG Altener 93.
3. T. H. Reijenga. Glass roof integrated PV system at the national environmental education centre 'De Kleine Aarde', Boxtel, NL. Thermie EG project. 1995.

PARTICIPANTS

·European Commission, Directorate-General XVII (Energy)
·NOVEM (Netherlands agency for energy and the environment)
·ENECO Dordrecht (utility company)
·BST Group; Benelux Solar & Technical Systems B.V., Terheijden (NL)