SOLARGE

Dom starejsih obcanov Tezno

Maribor, Slovenia

Pension house | 100 sqm installation

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Project summary · Technical description · Financing · Development · Downloads

Project Summary

Description

Solar system is built at Elderly home TEZNO in Maribor. Elderly home is a company financed by state concession. 80 employees take care for 200 elderly peoples. Solar system is used for heating of hot tap water. There are 100 sqm of selective flat solar collectors placed on flat roof. Four buffer heat storages, each with a volume 900 litres, are placed in a boiler room at the top floor of the building. Two low-temperature gas boilers are used for heating of the building and additional heating of hot tap water. System was built in 2003. The investment cost was 500 Euro per sqm of solar collector. Half of the investment was paid by the owners of the elderly home, the other half was paid by municipality of Maribor in form of non-refundable funds.



 


Building

Type of building

Pension house

Number of dwellings, floors

200 residents
+80 employees
99 rooms
P+3 floors

Year of construction

2003

Total effective area (heated)

4,805 m2

Hot tap water consumption (measured/estimated)

not available

Whole energy consumption for heating purpose after CSTS implementation

1,297,350 kWh/a


System engineering

Year of construction of CSTS

2003

Type of collectors

Flat plate collectors

Thermal power

70 kWtherm.

Aperture area of collectors*)

100 m2

Buffer storage

3.6 m3

Hot tap water storage

2.0 m3

Total capacity of boilers with energy source

570+× kW,
Natural gas

Type of hot tap water heating

Centralised

Type of heating system

Centralised


Costs

Total cost solar system

50,000 Euro

Cost of the CSTS/gross area of collectors

455 Euro/m2

Subsidies

50 %


Output

Output of solar heat**)

29,390 kWh/a

Reduction of final energy***)

29,390 kWh/a

CO2-emissions avoided

5.9 t CO2/a

Solar performance guarantee

No


*) 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

 

 


N. N.:

"Construction of such large solar system on public building is a unique challenge in Slovenia. Company Viessmann cooperated in this project not only as equipment supplier, but also as designer and supervisor. During the process of argumentation, planning, construction and operation of large solar system a lot of experience was gained. First two years of operation showed that the system is accurately designed and well constructed. The experience is successfully used in new projects."

 

 


Owner

Dom starejših obcanov TEZNO (Elderly home TEZNO)
Jasna Cajnko, M. Sc. director
Panonska ulica 41
2000 Maribor, Slovenia
Phone: +386 2 4602602
Jasna.cajnko(at)dso-tezno.si


Operator

see Owner

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Technical description

 


Description of the CSTS

Year of construction of CSTS

2003

Thermal power

70 kWtherm.

Gross area of collectors

110 m2

Aperture area of collectors

100 m2 

Type of collectors

Flat plate collectors

Type of assembly

On flat roof

Orientation of collectors

South-West (+15°)

Inclination angle to horizon

not available

Freezing protection

Glycol

Overheating protection

Expansion vessel

Operation mode

Low flow

Use of CSTS for

Hot tap water heating

Buffer storage

3.6 m3

Hot tap water storage

2.0 m3

Control of backup-system/CSTS

Separated control


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

2×1.0 m3

Specification (if necessary)

./.


Space heating system

Type of heating system

Centralised

Number of boilers

2

Total capacity (power output) of boilers

570 kW

Capacity of each boiler (year of construction)

No. 1: 285 kW (2003)
No. 2: 285 kW (2003)

Energy source

Natural gas

Type of boiler system

Low temperature


Type of operation

Operator of the CSTS system

Self-operation

CSTS monitoring

Yes (operating hours of solar system pumps. Only the operating hours of solar system pumps are measured, but the counter was reset several times and no one takes the notes. The new series of measurements started in August 2005 for SOLARGE project purposes.)

Data accessible via internet

No

Scientific monitoring & follow up

No

Maintenance contract

No

Visualisation of the solar heat output

No


Yield of CSTS plant

Output of solar heat

29,390 kWh/a

Origin of data

Design

Measuring point

not available

Reduction of final energy

29,3690 kWh/a

Origin of data

estimated

Solar performance guarantee

No


Heat consumption

Whole energy consumption for heating purposes after CSTS implementation

1,297,350 kWh/a

Origin of data

Measured

Energy used for heating of

Hot tap water heating,
space heating,
laundry and kitchen

Whole energy consumption for heating purposes before CSTS implementation

./.

Total tap water consumption

6,912 m3/a

Hot tap water consumption

not available

Hot tap water temperature

60 °C

Cold water temperature

10–12 °C

 

 


Summary

The solar system, which is used for heating of tap hot water, is composed from two fields of flat selective solar collectors with total area of 100 sqm. There are four heat storages, each with a volume 900 litres, which serve as buffer storages. Two of them are connected parallely forming the battery. Two batteries are connected in sequence. In such a way a better temperature distribution in storages is achieved. Heat from the buffer solar heat storages is transferred over a plate heat exchanger into two additional storages where the tap water is heated. Each of them has a volume of 1,000 litres. Cold tap water flows through the first to the second storage and is additionally heated with a spiral exchanger integrated into the last storage and gas boiler.


 

 


Planner & Producer

Viessmann d. o. o.
Slavko Može, M. Sc
Cesta XIV divizije 116a
2000 Maribor, Slovenia
Phone: +386 2 4805550
Fax: +386 2 4805560
viessmann(at)viessmann.com

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Financing and investment

Introduction

Accurate costs are not known. The investment cost was approximately 500 € per sqm of solar collector. Half of the investment was paid by local community in the frame of elderly help programme. In the first two years of operation there were no significant costs with system maintenance.


 


Financing of the CSTS

Form of financing

Purchase

Distribution in percentage

50 %


Costs of solar materials

Total cost of solar system

50,000 Euro


Operation costs of heating system

Increase of the operation cost after CSTS implementation

not available

 

 

 


Addresses

Ministry of Labour, Family and social affairs
City community of Maribor


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Development & experiences

Qualitative aspects of the CSTS

 

The solar system for tap water heating is built with two equally large solar collector fields with total net area 100 sqm. Four heat storages with total volume 3,600 l is used as buffer storages. Two additional heat storage (each with volume 1,000 l) is used for tap water backup heated by gas boiler. Every day hot tap water is heated up to 60 °C for a short period of time because of sanitary requirements.

Summary of experiences / Notices to the project performance

The system, as well as the building, was financed from Ministry of Labour, Family and Social Affairs and City community of town Maribor. Present users took over completed building, therefore there are no data about solar system projecting and installing. Supplier of the solar system manages and maintains the system free of charge. There were no breakdowns in the first two years of operation.

 


Experiences management

Experienced problems or failures?

No

Found solutions to these problems or failures?

not available


Financial effects / project performance

Project economically efficient?

not available

Fiscal or other financial effects?

not available

Effects on rental fees?

not available


Experiences technical staff

Experienced problems or failures?

No

Found solutions to these problems or failures?

not available

 

 


Architect

Lucka Kamenik, B. Sc.
Slovenia



Installer

IMP Montaža
Maribor
(not existing after 2004)

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Downloads

SOLARGE_goodpractice_si_domstarejsihobcanovtezno.pdf

this datasheet in printable PDF-format

1.5 M

Dom-starejsih-obcanov-Te_sl.gif

the hydraulic scheme

1.2 M

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