GUARANTEED RESULTS OF SOLAR THERMAL SYSTEMS IN GERMANY

Objective

The project will introduce in Germany the Guaranteed Results of Solar thermal installation (GRS-Approach) which was first applied in France, Northern Italy and Catalania. The partners are town utilities in Germany, which are already active in the field of energy distribution. The GRS approach is a dissemination activity. The town utilities should gain confidence and experience with the different solar plants and in future should be able to apply solar technology without EC or national funding, either with performance contracting or selling heat from solar plants to customers.
It was proved that and it is possible to guarantee the results of thermal solar plants, hence to apply the GRS approach not only in Southern France but also in Germany.
The difficulties found in managing this project can be summed up as follows :
- SITES : Not all buildings chosen were "solar friendly". The additional construction especially on flat roofs were very cost intensive.
-USER BEHAVIOUR : Some of the chosen application had peak demands only during the week or were closed during summer time which limited or made it difficult to use solar energy efficiently.
- MODELLING THE GRS-VALUE : When starting the project the available simulation programmes were either too simple or very complicated to use. It was very difficult to recalculate a detailed simulated plant because of the numerous factors which were not always know in reality. It may be sufficient in the future to take a set GRS-value e.g. for DHW-systems 300 kWh/m²year, even if this value is not very satisfactory.
- MONITORING THE GRS-VALUE : The cost of monitoring equipment was high, about 5000-6000 ECU. Additionally the man power involved for the control and data analysis comes to the same sum, so that 10000-12000 ECU have to be financed to have a detailed follow up. Such sums can only be financed for large solar plants above investment cost of at least 50000 ECU
- LACK OF EXPERIENCE WITH LARGER SOLAR PLANTS : It was found that there are not enough proven systems known by the consulting engineers how to connect the collectors, thanks and auxiliary heating and what control strategies to apply for systems larger than those of individual houses.
The positive points found are :
- Reliable Material : except for one soldering problem the involved material, especially the collectors, was reliable and no material failure occured.
- Benefit from monitoring
- Exchange of experience
1. INNOVATIVE TECHNOLOGY
Solar plants are a young technology bearing technical risk for the owner such as less energy delivered to the user or non reliable systems. The GRS approach minimises these risks by providing remote supervision and maintenance together with a guaranty of the annual thermal output.
2. CONTEXT
The town utilities involved are already working in the field of energy distribution. Long term investments are their day to day business. Solar energy itself is known as a technology but few utilities are running their own plants, most of them have little experience or none.
Different applications are included in the project, such as open air swimming pools, heating of shower water in sport facilities and domestic hot water in dwellings.
3. ECONOMIC ASPECTS
The burden of the investment is transfered from the individual household to the utility company. The technical risk is taken by the consultant together with the installer and the manufacturer. The thermal cost are still higher than with fossile energy, however the long term prospectus are favorable if write-off periods are shorter than the life cycle of solar installations. Experience of the last 15 years of solar installation in Germany show, that the maintenance and running cost are very small for good quality solar thermal installations compared with fossile installations. As the specific cost for larger installation drop considerably, the economical aspects are better than generally believed. However experience on a larger scale is still missing.
4. MONITORING
All the Installation will be equipped with identical remote monitoring system used already in Prance by the third proposer TECSOL. All the plants will be linked to the investigating office IST by modem. The results are registered once per week as dayly averages and the last two days as ten minute averages. If abnormalities are noticed, the last two days can be investigated more closely. The monthly results are sent to the differentutilities.
In the case of failure of the guaranteed results, which is based on one off the well known models such as f-Chart or TRNSYS, which are based the load and the long term weather conditions, the guaranteeing consortium, lead by the consultant, has to pay back a percentage of the investment cost equal to the performance missing. The performance is defined on an annual basis. If the actual annual solar radiation differs from the long term average, the calculation is revised with the annual data, obviously the plant's performance can be guaranteed and not the annual weather conditions.

Programme(s)

ENG-THERMIE 1 - Programme (EEC) for the promotion of energy technology in Europe (THERMIE), 1990-1994

Topic(s)

6.2 - THERMAL

Call for proposal

Data not available

Funding Scheme

DEM - Demonstration contracts

Coordinator

ASEW

EU contribution

No data

Address

VOLKSGARTENSTRAßE 22
50677 Köln
Germany

Total cost