SOLARGE

WG Merkur

Berlin, Germany

Multi-family house | 56 sqm installation

 


Project summary · Technical description · Financing · Development · Downloads

Project Summary

Description

Before the installation of the solar system in this residential building with district heating connexion, the hot tap water was provided by decentralised gas boilers.The building dates back to 1963. Already in 1998, the building received an overall refurbishment including new insulation of the facades, the basement and the top floor ceiling. In the framework of this measures, the tap water heating was switched to centralised district heating. The decision for a centralised tap water heating was made because of high repairing and maintenance costs till then. Furthermore, obligations were raised by the chimney sweep concerning the renovation of the flue pipes. On top of that, the gas boilers needed to be overhauled. The solar system is used for both tap water heating and support of the space heating.

 


 

 


Building

Type of building

Multi-family house

Number of users / dwellings, floors

70–80 users
50 dwellings
5 floors

Year of construction

1963

Total effective area (heated)

2,910 m2

Hot tap water consumption (measured/estimated)

733 m3/a

Whole energy consumption for heating purpose after CSTS implementation

212,430 kWh/a


System engineering

Year of construction of CSTS

2000

Type of collectors

Flat plate collectors

Thermal power

35kWtherm.

Aperture area of collectors*)

50.16m2

Buffer storage

2.0 m3

Hot tap water storage

0.6 m3

Total capacity of boilers with energy source

not available,
district heating

Type of hot tap water heating

Centralised

Type of heating system

Centralised


Costs

Total cost solar system

77,000 Euro

Cost of the CSTS / gross area of collectors

1,373 Euro/m2

Subsidies

30 %


Output

Output of solar heat**)

23,575 kWh/a

Reduction of final energy***)

189,150 kWh/a

CO2-emissions avoided

not available
(district heating)

Solar performance guarantee

Yes

*) Aperture area = light transmitting area of the front glass
**) measured, between storage and piping to taps (solar system output)
***) related to the measured output mentioned before

 

 


Andrea Schulz, Board member:

"With a stock of 1,567 dwellings the building society Merkur e. G. belongs to the rather smaller building companies in Berlin. The residential houses of our society with mostly three to five floors were built between 1958 and 1965.
As early as 1998, the building society Merkur e. G. successfully finished the overhauling and modernisation of all its property. Refurbished roofs, new heating systems, modernised windows, a comprehensive insulation of facades, cellar and top floor ceilings as well as refurbished stairways and house entrance areas guarantee a modern quality of living.
The new developed operating costs management of the building society affects our tenants noticeably in a positive way. Due to this management, the operating costs could be reduced by 10 % below the average of Berlin in the last years. Along this way, Merkur e.G. also changed to innovative and trend-setting developments. In the years 1996 to 2000 already 21 % of the complete dwelling stock was equipped with solar energy centres. These solar thermal systems allow a cost-effective and environmental friendly living, due to their energy efficient and sustainable operation."

 

 


Owner

WG MERKUR e. G.
Andrea Schulz
Volkradstr. 9e
D-10319 Berlin, Germany
Phone: +49 30 515887-44
Fax: +49 30 515887-66
info(at)wg-merkur.de
www.wg-merkur.de


Operator

See owner

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Technical description

 


Description of the CSTS

Year of construction of CSTS

2000

Thermal power

35 kWtherm.

Gross area of collectors

56.1 m2

Aperture area of collectors

50.16 m2 

Type of collectors

Flat plate collectors

Type of assembly

On flat roof

Orientation of collectors

South (0 °)

Inclination angle to horizon

45°

Freezing protection

Glycol

Overheating protection

Expansion vessel

Operation mode

Low flow

Use of CSTS for

Hot tap water heating, space heating

Buffer storage

2.0 m3 (2 × 1 m3), solar stratified storage with external heat exchanger and internal ramrod (special concept of Solvis)

Hot tap water storage

0.6 m3 (2 × 0.3 m3), standard stainless steel storage

Control of backup-system / CSTS

Shared control:
RIEcon R36SEM


Hot tap water system

Type of hot water heating

Centralised

Recirculation system

Yes

For decentralised systems:
The installation on the consumer site

./.

Size of storage for hot tap water

0.6 m3

Specification (if necessary)

./.


Space heating system

Type of heating system

Centralised

Number of boilers

not available

Total capacity (power output) of boilers

not available

Capacity of each boiler (year of construction)

not available

Energy source

District heating

Type of boiler system

./.


Type of operation

Operator of the CSTS system

Self-operation

CSTS monitoring

No

Data accessible via internet

No, solar energy output and hot tap water consumption are read by the caretaker every two months

Scientific monitoring / follow up

No

Maintenance contract

Yes: twice a year

Visualisation of the solar heat output

No


Yield of CSTS plant

Output of solar heat

23,575 kWh/a

Origin of data

Measured

Measuring point

Between collector and storage

Reduction of final energy

189,150 kWh/a

Origin of data

Measured: billing notes

Solar performance guarantee

Yes


Heat consumption

Whole energy consumption for heating purposes after CSTS implementation

212,430 kWh/a

Origin of data

Measured

Energy used for

Hot tap water heating, space heating

Whole energy consumption for heating purposes before CSTS implementation

401,580 kWh/a

Total tap water consumption

2,200 m3/a

Hot tap water consumption

733 m3/a

Hot tap water temperature

54 °C

Cold water temperature

10 °C

 

 


Summary

Solar Control Centre with directing control computer RIEcon R36SEM.
The system described corresponds – in its design and its set-up – to advanced conventional house connection units. For the first time however, a complex control centre was installed for monitoring and controlling all components including the solar system.
The Solar Control Centre monitors the integrated heating circuit, a conventional and a domestic water heating and support of space heating.
The Solar Control Centre is a complete prefabricated unit, including cabling, with the following connections:

flow

-->

district heating / boiler

flow

-->

solar circuit

return

-->

district heating/ boiler

return

-->

solar circuit

flow

-->

space heating

connection charging / discharging

return

-->

space heating

solar buffer storage

hot water

-->

building feed-in

hot water

-->

circulation

feed-in of cold water

The Control Centre and the directing computer RIEcon MR C 20 are integrated into the unit. These components are similar to those used for conventional house connexion units. Only components established in the heating installation are being used. Thanks to the compactness, the Control Centre requires only marginal space and its assembly of single components makes it easy to maintain.
All functions for domestic hot water and supplementary space heating mentioned above are accessible via the buffer storages in case of compliance of the regulation criteria.



 


Planner, Engineering company

Plan_E GmbH
Herr Jurisch
Parkstraße 7–9
D-13187 Berlin, Germany
Phone: +49 30 481601-90
Fax: +49 30 481601-99
b.jurisch@planen-energie.de
www.planen-energie.de

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Financing and investment

Introduction

For the refurbishment of the residential building and the equipment with a solar thermal system, specific subsidies have been applied for. At the very beginning it was clear for Merkur e. G. that the solar system should not be financed with a loan, but with equity capital.

 


 


Financing of the CSTS

Form of financing

Purchase

Distribution in percentage

30 %


Costs of solar materials

Total cost of solar system

77,000 Euro

Detailed costs for

Collectors

15,600 Euro

Elevation / mounting structure

1,800 Euro

Planning / Engineering

12,720 Euro

Others (SEZ, Solar Control Centre)

20,886 Euro


Operation costs of heating system

Maintenance cost

817 Euro/a

 

 

 

Investitionsbank Berlin (Investment Bank of Berlin): 15,286 EUR
Due to the directive for granting subsidies for energy efficient modernisation of housing, use of renewable energy sources as well as for training and employment (ModInstRL 99 of 30th June 1999).

 


Investitionsbank Berlin 

www.ibb.de


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Development & experiences

Qualitative aspects of the CSTS

The system Solar Energy Centre was already installed in four other buildings before (Sewanstr. 166, Sewanstr. 154, Michiganseestr. 12, Salzmannstr. 9). In this case, an overall refurbishment of the building was implemented. The roof was modernised, new windows installed, the facade, the basement and the top floor ceiling were insulated. An average energy saving of 40 % was achieved with these measures alone and were further reduced by an average of 33 % due to the solar system. The reduction of operating costs coming along with this, was the decisive argument for the installation of the Soler Energy Centre in Michelangelostr. 77.


Summary of experiences / Notices to the project performance

Particularly favourable conditions for a comprehensive evaluation concerning the energy savings are provided in those houses, which already were equipped with a centralised heating system before the refurbishment. The solar yield of those systems amounted to 460 kWh/(m²·a) on average. Thus cost savings of about 100 EUR per year were achieved for tenants in a dwelling with a size of 60 m².

The following overview shows how the energy consumption in these objects has developed during the last years. The consumption before and after the refurbishment are compared as well as the consumption after the installation of the solar system.

The refurbishment of the buildings involved the exchange of the windows, the modernisation of the heating system and the insulation of the facades, the cellar and the top floor ceilings.
The savings due to the overall refurbishment measures in the six objects mentioned amounted to an average of 103 kWh/m² of living space per year, i.e. 41 %. After the installation of the solar systems, the energy consumption on this basis could be reduced by another 52 kWh/(m²·a), i.e. 37 %. 30–45 % of the total hot tap water consumption per year is supplied by the solar systems.

The object in Michelangelostraße 63–71 was one of the first buildings ever to receive the “seal of approval for large scale solar thermal systems in the house building with several floors” in 2001 by the German Solar Energy Association (Deutsche Gesellschaft für Sonnenenergie, DGS).

The yearly energy saving has been effecting our operating costs very favourably for years. The operating costs (all additional costs included) in the billing year 2001 for the six objects only amounted to 0.58 EUR per square meter living space, including the costs for heating and hot tap water, the registration and the billing of the consumption, as well as the rental fees for the meters.

Along with the expected raise of energy prices this advantage will increase for our members and tenants. Low operating costs and the implementation of innovative technologies also have very positive effects on the image of our society and therefore represent a positive aspect for the renting of our flats.

 


Experiences management

Experienced problems or failures?

Yes: 6 times failure of solar energy centre
- partly lacking provision and failures respectively, due to grid annoyance
- overvoltage of up to 800 V of electric feed-in lead to failure of the solar energy centre

Found solutions to these problems or failures?

Yes: Even if the problem solving with BEWAG was an exhausting process with shifting of blame, the problem finally could definitely be solved.


Financial effects / project performance

Project economically efficient?

Yes

Fiscal or other financial effects?

No

Effects on rental fees?

No


Experiences technical staff

Experienced problems or failures?

not available

Found solutions to these problems or failures?

not available

 

 










Top of page Project summary · Technical description · Financing · Development · Downloads

Downloads

SOLARGE_goodpractice_de_merkur.pdf

this datasheet in printable PDF-format

1.3 M

merkur_scheme.pdf

the hydraulic scheme

539 K

merkur_scheme_bw.pdf

the hydraulic scheme (for monochrome printers)

534 K