Background

Aizkraukle Gymnasium in Latvia was interested to get financial support regarding the installation of solar thermal collectors at the school. The school wishes to raise its profile as a "green school". Among other "green projects" the school has put forward an idea of preparing hot water and space heating from solar energy. The purpose of installing solar thermal collectors was not only to demonstrate the concept at the school, but also the possible use of solar heating in connection with district heating. Further, the purpose was to demonstrate the technology as well as the economic and financial feasibility and viability of a general use of solar thermal collectors in Latvia.

The objective of the overall project was to analyse the technical and financial possibilities to implement solar thermal heating systems in general in Latvia, primarily in public buildings and with focus on the combination with local district heating.

Furthermore the objective was to demonstrate the analysed concept at a concrete building: Aizkraukle Gymnasium, which has installed a solar thermal system for domestic hot water and space heating connected to the local district heating system.

The results and the experiences both from the general analysis and from the installed solar system at the school are disseminated carefully via a homepage on the Internet and via a national seminar.

It is a good idea to connect the solar system to the district heating plant, because the heating and domestic hot water demand at the school is very low in the summer months, where the output from the solar system is high. The surplus from the solar system, therefore, can be transferred to the district heating system and distributed to other buildings connected to the net.

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Project outline

Two solar heating systems for Aizkraukle in Latvia have been installed in the start of 2003. One of the systems is a domestic hot water system for the school including the sport facilities; the other system is a solar heating plant connected to Aizkraukles district heating network.

The solar domestic hot water system is a low flow system with 15 solar collector panels with a total area of 32.9 m, with a vertical hot water tank with stratification inlet pipes as heat storage and with an external heat exchanger as part of the solar collector loop. The external heat exchanger is used to transfer heat from the solar collector fluid to the domestic water. The domestic water is pumped from the bottom of the hot water tank to the heat exchanger and back to the hot water tank through the stratification inlet pipes. The tank design ensures good thermal stratification in the tank and therefore a high thermal performance of the solar heating system.

The 120 m solar heating plant consists of 5 parallel connected rows of solar collector panels. Each row has two serial connected panels.

The design of the solar heating systems was determined by means of experience from the operation of similar solar heating systems and by means of calculations of the thermal performance and costs of differently designed solar heating systems.

The solar heating systems are equipped with monitoring equipment. The systems as well as the experience from the operation of the systems are presented on this homepage.

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General study on implementing solar thermal systems in Latvia

The study comprises following issues, and is divided into two parts:

Part I) including:

Technical description of thermal solar collectors for use in Latvia including an appraisal of the possibilities of Latvian production of the components.

Integration of solar collectors into local district heating network

Use of solar collectors in combination with individual boilers (coal, gas, and electricity), including accumulating tanks

and Part II) including:

Financial and economic analysis of thermal solar collector systems

Design, marketing, installation and maintenance organisation

Impact on heat prices

Environmental benefits

Description of technical, financial and economic viability of utilisation of thermal solar systems in Latvia

The study will be shown here at a later stage!

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Solar Atlas / Reference year for Latvia

A reference year contains a number of weather parameters, making it possible to carry out technical calculations in connection with design of HVAC systems. In connection with design of solar heating systems, the reference year can for instance be used for the determination of:

expected performance of the solar system,
necessary supplement from supplementary heating source,
the course of temperature in the system,
expected solar fraction of the solar heating system,
statistics for periods with solar fractions or temperatures in the storage tank above a given level.

The data sets can also be used in connection with the estimation of energy consumption for heating of buildings.

In the reference year, in contradistinction to an average year, natural courses of outside temperature, global radiation on horizontal, and diffuse radiation on horizontal are described on annual basis. This makes it possible to use the reference year for detailed calculations by means of electronic data processing programs that require weather data on an hourly basis.

In this project a reference year for Latvia has been worked out from data from "The European Solar Radiation Atlas" (ESRA). ESRA contains 10 years monthly mean values of for instance minimum and maximum outside temperatures and global radiation.

With the program METEONORM, a reference year based on hour values has been generated from the ESRA data.

Even though the data sets of the reference year are based on observations from the neighbourhood of Riga, they are generally usable for calculations over the whole of Latvia. At a few positions, as e.g. areas near the coast, at the centre of Riga, and in the forest areas situated high in the middle of Latvia, deviations in the weather occur. It is considered, however, that for Latvia in general there is no deviations owing to the position that are larger than deviations between the single years and the reference year.

Hour values for outside temperature, global radiation, and diffuse radiation are reproduced graphically in the report. Corresponding data can be obtained in electronic form.

Click here to open full report (PDF, 630kb)

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Feasibility study for the solar thermal systems on Aizkraukle Gymnasium and on the District Heating Plant

The thermal performance of three different solar heating systems in Latvia was calculated with simulation models. The systems are:

A solar domestic hot water system for Aizkraukle Gymnasium including the sports facilities.
A solar domestic hot water system for the kindergarten in Aizkraukle.
A solar heating plant connected to the district-heating network of Aizkraukle.

The two solar domestic hot water systems are designed as low flow systems with a hot-water tank with a large thermal stratification. The heat is transferred from the solar collector loop to the domestic water by means of an external heat exchanger. Domestic water from the bottom of the hot-water tank is circulated to the external heat exchanger where the water is heated and back to the hot-water tank either through a fixed inlet or through a stratification inlet pipe securing that the water enters the tank in the "right" level. Simulations are carried out for both designs.

Further, the simulations are carried out for different hot-water consumption with different solar collector types and collector areas. The calculated thermal performance of the systems is a good basis to determine the design and dimensions of the systems, which are built in Aizkraukle.

Click here to open the full report (PDF, 2.220kb)

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Sketches of the solar systems

Schematic illustration of the Solar system for the school

Schematic illustration of the Solar District Heating Plant

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Photos of the installed solar systems

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Guidelines how to calculate the feasibility of solar systems in Latvia

Simple Design Rules

Domestic Hot Water Consumption: Eastern Europe: Often 100 l/day per person

Collector Area for DHW supply: 1 m² for each 50 l/day of consumption

Collector Area for District Heating: No simple rules, but as much as possible

Storage volume for DHW supply 50 litres per m² of solar collector

Heat Exchanger area: 35 W/⁰C per m² of Collector Area

Flow rate in Collector arrays: Traditional Systems: 1 litre/min per m² of Collector Area

Low Flow Systems: 0.2 litre/min per m² of Collector Area

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Public solar Seminar

A national seminar was held on September 8, 2003 in Aizkraukle with the programme shown below.

The invitation- and the particiant list is also shown below together with photos from the seminar.

To explore the presentations from the individual speakers, please "click" on the paper heading.

09.30	Welcome Vilnis Plume, Mayor of Aizkraukle, Latvia
09.45	Introduction Introduction by the Danish partner. Anders Hasselager, Danish Energy Authority Introduction by the Latvian partner. Einars Zebergs, Aizkraukle Municipality Overview of the Solar Thermal Project in Latvia. Torben Esbensen, Esbensen Consulting Engineers A/S, Denmark
10.30	Possibilities for Solar Thermal Energy in Latvia Solar Atlas for Latvia. Dr. Simon Furbo, Technical University of Denmark Solar Heating Systems for Latvia. Dr. Galina Kashkarova, ENERGI-R, Ltd., Riga Investments and feasibility of solar energy. Professor Peteris Shipkovs, ENERGI-R, Ltd., Riga
11.30	Coffee Break
11.50	Solar Demonstration Plants in Aizkraukle Solar Heating Systems for Aizkraukle Gymnasium and for District Heating Plant in Aizkraukle. Mads Lange, Esbensen Consulting Engineers A/S, Denmark Practical experiences from the installation of Solar Heating Systems. Ivars Bekmanis, Bek-Konsult, Riga
12.45	Lunch at Aizkraukle Gymnasium
13.30	Visit to the Solar Demonstration Plants at Aizkraukle Gymnasium and the District Heating Plant
15.00	Experiences from operation Experiences from the Operation of the Solar Plant at Aizkraukle Gymnasium. Leons Lidums. Headmaster of Aizkraukle Gymnasium Measurements from the Solar Heating Systems. Simon Furbo, Technical University of Denmark
16.00	Coffee Break
16.20	Information The internet www.SolarAizkraukle.com. Leon Lidums, Headmaster of Aizkraukle Gymnasium Aizkraukle as Brundtland Solar City. Torben Esbensen, Esbensen Consulting Engineers A/S
17.00	Discussion of the future of solar energy in Latvia
17.30	Closing of the Seminar

Invitation list:

Name From Latvia	Organisation	Address
Vilnis Plume	Mayor in Aizkraukle	Lacplesa 1a, Aizkraukle, LV-5101
Einars Zebergs	Managing Director, Aizkraukle Municipality	Lacplesa 1a, Aizkraukle, LV-5101
Aivars Aldermanis	Director of Aizkraukle District Heating Company	Rupniecibas str. 2, Aizkraukle, LV-5101
Bruno Bebris	Director of Aizkraukle SPMK	Jaunceltnes 3, Aizkraukle, LV-5101
Valdis Kregers	Director of Energy Department Latvian Development Agency	Perses 2-615, Riga, LV-1011
Inguna Ozolina	Energy Department Latvian Development Agency	Perses 2-615, Riga, LV-1011
Ugis Sarma	Director of Energy Department LR Ministry of Economy	Brivibas str.55, Riga, LV-1010
Andris Kreslins	Riga Technical University, Department of Building	Azenes 16, Riga, LV- 1048
Dagnija Blumberga	Riga Technical University	Kronvalda b. 1 Riga, LV-1010
Ivars Veidenbergs	Ekodoma Ltd.	Noliktavas 3-3, Riga, LV-1010
Valdis Egle	Ministry of Education and Science, Latvia	Valnu str.2, Riga, LV-1050
Inita Stikute	Riga Meteorological Institute	Maskavas str.165, Riga, LV-1019
Martins Gedrovics	Latvian Gas, Riga	Vagonu 20, Riga, LV-1009
Agnese Meijre	Latvian Gas, Riga	Vagonu 20, Riga, LV-1009
Ivars Bekmanis	Bek-Konsult, Riga	Aizkraukles str. 21, Riga, LV-1006
Aija Karlevica	Bek-Konsult, Riga	Aizkraukles str. 21, Riga, LV-1006
Modris Spugis	Bek-Konsult, Riga	Aizkraukles str. 21, Riga, LV-1006
Peteris Shipkovs	Energi-R, Ltd. Riga	Aizkraukles str.21, Riga, LV-1006
Galina Kashkarova	Energi-R, Ltd, Riga	Aizkraukles str.21, Riga, LV-1006
Juris Ekmanis	Director of the Institute of Physical Energetics (IPE)	Aizkraukles str.21, Riga, LV-1006
Gunta Shlihta	Deputy director of the Institute of Physical Energetics (IPE)	Aizkraukles str.21, Riga, LV-1006
Kristina Lebedeva	Institute of Physical Energetics (IPE)	Aizkraukles str.21, Riga, LV-1006
Maris Malahovskis	Architectural Company – NAMS Ltd.	Palasta 7, Rīga, LV-1050
Artis Glazers	Engineering Consultant Company - Viessmann, Latvia	Araisu str.37, Riga, LV-1039
Rolands Bebris	Director of Environmental Protection Department, Ministry of Environment	Peldu str .25, Riga, LV-1494
Armands Plate	Environmental Protection Department, Ministry of Environment	Peldu str .25, Riga, LV-1494
Ilze Purina	Director of Latvian Environmental Investment Found	Pils str.6, Riga, LV-1050
Martins Jirgens	Environmental Projects Ltd.	Pils str. 17, Rīga, LV-1050
Vilnis Gulbis	Latvia University of Agriculture	Akademijas str. 19, Jelgava, LV-3001
Ansis Grundulis	Latvia University of Agriculture	Akademijas str. 19, Jelgava, LV-3001
Lauma Rode	Chief Referent of the Investment Department. Ministry of Environment	Peldu str. 25, Riga, LV-1494
Juris Letinskis	Chief Architect, Aizkraukle Municipality	Lacplesa 1a, Aizkraukle, LV-5101
A. Akermanis	Association of Heat Suppliers	Antenas str. 3, Riga, LV-1004
A. Zjutauts	Association of Heat Suppliers	Antenas str. 3, Riga, LV-1004
Edmunds Biela	JSC “Rīgas siltums”	Cēsu str. 3 a, Riga, LV-1012, Latvija
Igors Gushchins	JSC"Latvijas Finieris"	Bauskas str. 59 Riga, LV-1004, Latvija
Medias from Latvia
Andrejs Vasiljevs	Editor-in-chief of journal “Enerģētika un automatizācija”	Vilandes str. 13-6, Riga, LV-1010
Maruta Osane	Journal “Enerģētika un automatizācija”	Vilandes str. 13-6, Riga, LV-1010
Edite Kalnina	Journal “Enerģija un pasaule”	Vilandes str. 13-12, Riga, LV-1010
Mirdza Tupina	TV 1	Zakusalas krastmala 3, Riga, LV - 1509
Operator	TV 1	Zakusalas krastmala 3, Riga, LV - 1509
From Denmark
Anders Hasselager	Danish Energy Authority	Amaliegade 44, DK-1256 København K, Denmark
Simon Furbo	Technical University of Denmark	Brovej - Bygning 118 DK-2800 Kgs. Lyngby Denmark
Ole Hansen	Batec Solar Heating A/S	Danmarksvej 8 DK-4681 Herfølge Denmark
Mads Lange	Esbensen Consulting Engineers A/S	Moellegade 54, DK-6400 Soenderborg, Denmark
Torben Esbensen	Esbensen Consulting Engineers A/S	Moellegade 54, DK-6400 Soenderborg, Denmark

Participant List:

Vārds/Uzvārds No Latvijas	Organizācija	Adrese
Vilnis Plūme	Aizkraukles novada domes priekšsēdētājs	Lāčplēša 1a, Aizkraukle, LV-5101
Einārs Zēbergs	Aizkraukle domes izpilddirektors	Lāčplēša 1a, Aizkraukle, LV-5101
Aivars Aldermanis	"Aizkraukles siltums", direktors	Rūpniecības str. 2, Aizkraukle, LV-5101
Bruno Bebris	Aizkraukles SPMK direktors	Jaunceltnes 3, Aizkraukle, LV-5101
Valdis Krēgers	Latvijas attīstības aģentūras Enerģētikas departamenta direktors	Pērses 2-615, Rīga, LV-1011
Dagnija Blumberga	Rīgas Tehniskā Universitāte	Kronvalda b. 1 Rīga, LV-1010
Mārtiņš Gedrovičs	Latvijas gāze	Vagonu 20, Rīga, LV-1009
Agnese Meijre	Latvijas gāze	Vagonu 20, Rīga, LV-1009
Ivars Bekmanis	SIA "Bek-Konsult"	Aizkraukles 21, Rīga, LV-1006
Aija Karleviča	SIA "Bek-Konsult"	Aizkraukles str. 21, Rīga, LV-1006
Modris Spuģis	SIA "Bek-Konsult"	Aizkraukles 21, Rīga, LV-1006
Peteris Šipkovs	SIA "Energi-R"	Aizkraukles 21, Rīga, LV-1006
Galina Kaškarova	SIA "Energi-R"	Aizkraukles 21, Rīga, LV-1006
Juris Ekmanis	Fizikālas Enerģētikas Institūts, direktors	Aizkraukles 21, Rīga, LV-1006
Gunta Šlihta	Fizikālas Enerģētikas Institūts, direktora vietniece	Aizkraukles 21, Rīga, LV-1006
Kristina Ļebedeva	Fizikālas Enerģētikas Institūts	Aizkraukles 21, Rīga, LV-1006
Edmunds Bieļa	A/S “Rīgas siltums”	Cēsu 3 a, Rīga, LV-1012, Latvija
Igors Guščins	A/S"Latvijas Finieris"	Bauskas 59, Rīga, LV-1004, Latvija
Pauls Krieviņš	SIA "Ekodoma"	Noliktavas 3-3, Rīga, pauls@ekodoma.lv, fax.732310
Karīna BARNAŠA	RTU, Vides zinātnes maģisratūra, EEF, studente	Carnikava, Jūras iela 5-4, wiral@navigator.lv, fax. 7993363
Marta SMITA	Latvijas Hidrometeoroloģijas aģentūra	Maskavas ielā 165, Rīgā, LV 1019,Marta.Smita@meteo.lv, fax: 7145154
Inese BOŽE	RTU, Vides zinātnes maģisratūra, EEF, studente
Anastasija PETROVA	RTU
Pāvels PALAMARČUKS	RTU
Līga STRODE	RTU
Marika BLUMBERGA	SIA "Ekodoma"
Claudio ROCHAS	SIA "Ekodoma"
Iveta BINOVSKA	BO SIA "Vides projekti"
Vilnis GULBIS	Latvijas Lauksaimniecības universitāte
Poļina PONAMARJOVA	Olaines pilsētas dome
Ingūna KĀRNUPA	RTU , studente
Ivars BĪBERS	SIA "VIESSMANN"
Daina OZOLA	Vides ministrija
Latvijas masu mēdiji
Andrejs Vasiljevs	“Enerģētika un automatizācija”	Vilandes 13-6, Rīga, LV-1010
Maruta Osāne	“Enerģētika un automatizācija”	Vilandes 13-6, Rīga, LV-1010
Edīte Kalniņa	“Enerģija un pasaule"	Vilandes 13-12, Rīga, LV-1010
Zaiga Kipere	“Zinātnes vēstnesis”
Mirdza Tupina	LTV 1	Zaķusalas krastmala 3, Rīga, LV - 1509
Operators	LTV 1	Zaķusalas krastmala 3, Rīga, LV - 1509
No Dānijas
Simon Furbo	Dānijas Tehniskā universitāte
Ole Hansen	Batec Solar Heating A/S
Mads Lange	Esbensen Consulting Engineers A/S	Moellegade 54, DK-6400 Soenderborg, Dānija
Torben Esbensen	Esbensen Consulting Engineers A/S	Moellegade 54, DK-6400 Soenderborg, Dānija

Photos from the seminar:

Opening of the seminar by a local saxophone performance

Presents to the project partnes - here Prof. Peteris Sipkovs - presented by the Mayor of Aizkraukle, Mr. Vilnis Plume

The Danish project leader, Mr. Torben Esbensen, interviewed by the Latvian National Radio, during one of the breaks

Presentations of the demonstartion project by the consulting engineers Mr. Mads Lange (Denmark) and Mr. Ivars Bekmanis (Latvia)

Viewpoints on utilisation of solar thermal energy in Latvia, presented by Mr. Ivars Bekmanis

Coffee and soft drinks in the breaks

Results of the contest "Make a drawing of the solar heating plant at the Gymnasium. Viewed by Dr. Simon Furbo (Denmark) and Mr. Leons Lidums, Headmaster of Aizkraukle Gymnasium

Technical installation in the basement located in the heat exchanger room.

The installation in the front are used for space heating and in the rear the installation for the solar heating plant is located

Aizkraukle Gymnasium. Examination of the solar collector temperature by Dr. Simon Furbo (Technical University of Denmark)

Operation control equipment and energy meters located in the basement. The energy meters are connected to a datalogger and data are transferred to Denmark for monitoring and presentation at the Internet

Solar collector array at the roof of Aizkraukle Gymnasium

Solar collectors at the roof of the District Heating Boiler House - 120 m² of collectors

Collectors at the District Heating Plant just before sunset

Preinsulated flexible hose, covered with a flexible aluminium duct connects two solar panels

Heat exchanger connections at the District Heating Boiler House, including the control unit, energy meter and datalogger for transmitting data to Denmark

Site visit for the seminar participants. Director of Aizkraukle District Heating Company, Mr. Aivars Aldermanis explains the functioning of the solar system

End of the seminar and time for evaluation at the Headmasters office at Aizkraukle Gymnasium

Programme: "Open Solar Heating Seminar in Latvia" on May 24, 2004

9:30 am	Registration of participants
10:00 am	Welcome. I. Knets, Rector and Dagnija Blumberga, RTU
10:15 am	Nordic Energy Research, Mikael Forss, Nordic Energy Research
10:45 am	Nordic Energy Research project: Competitive solar heating systems for residential buildings, Simon Furbo, Technical University of Denmark
11:05 am	Coffee break
11:25 am	Glazed polymer collectors, system design – building integration - applications, Michaela Meir, University of Oslo
11:55 am	Pellets and solar – a logical combination, Frank Fiedler, SERC
12:25 pm	Development of concentrating collectors for building integration, Björn Karlsson, Lund University
12:55 pm	Lunch
2:10 pm	Solar/natural gas heating systems, Alexander Thür, Technical University of Denmark
2:40 pm	REBUS activities in Latvia, Ilmars Piebalgs, RTU
3:10 pm	Coffee break
3:30 pm	Solar heating possibilities in Latvia, Torben Esbensen , Esbensen Consulting Engineers Ltd
4:00 pm	Aizkraukle solar heating project, Leons Lidums
4:30 pm	Solar energy use in Latvia, round table discussion

Photos from the seminar "Open Solar Heating Seminar in Latvia" on May 24, 2004

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Partners

Please find here the names, addresses etc. on the partners involved in the project.

Main Partners of the Project

Position

Organisation and contact persons

Phone / fax

Web

Finance

Country co-ordinator

Danish Energy Authority

Amaliegade 44

DK- 1256 Copenhagen K

Mr. Anders Hasselager

Phone:

+45 33 92 67 00

Fax:

+45 33 11 47 43

Direct:

+ 45 33 92 75 66

www.ens.dk

Partner in Latvia

National Beneficiary

Latvian Development Agency

Brivibas 55,

LV-1010, Riga

Latvia

Ms. Inguna Ozolina

Phone:

+371 70 13257

Fax:

+371 73 15203

Partner in Latvia

Local Beneficiary

Municipal Council of Aizkraukle

Lacplesa iela 1a

LV-5101, Aizkraukle

Latvia

Mr. Einars Zebergs

Mr. Juris Letinskis

Phone:

+371 51 81282

Fax:

+371 51 81 326

Phone:

+371 51 81293

www.adc.lv/aizkraukle

Partner in Latvia

Local Beneficiary

Aizkraukle Gymnasium

Lacplesa iela 21,

LV-5101, Aizkraukle

Latvia

Mr. Leons Lidums

Phone:

+371 51 81816

Fax:

+371 51 81817

www.adc.lv/skola

Partner in Latvia

Local Beneficiary

Aizkraukle District Heating Company

Rupniecibas iela 2

LV-5101, Aizkraukle

Latvia

Mr. Aivars Aldermanis

Phone:

+371 51 81 627

Fax:

+371 51 21858

www.adc.lv/STU

Partner in Latvia

Local consultant

ENERGI-R, Ltd.,

Aizkraukles iela 21,

LV-1006, Riga

Latvia

Prof. Peteris Shipkovs

Dr. Galina Kashkarova

Phone:

+371 75 53537

+371 75 58620

Fax:

+371 7 553 537

Partner in Latvia

Local consultant

BEK-KONSULT,

Aizkraukles iela 21,

LV-, Riga

Latvia

Mr. Ivars Bekmanis

Mrs. Aija Karlevica

Phone:

+371 7 540 697

Fax:

+371 7 550 839

Www.bekkonsult.lv

Project Holder

Project Manager

Senior expert

Consultant

Esbensen Consulting Engineers A/S

Moellegade 54

DK-6400 Soenderborg

Mr. Torben Esbensen (*)

Mrs. Lotte Gramkow

Mr. Mads Lange (*)

Phone:

+45 73 42 31 00

Fax:

+45 73 42 31 01

Phone:

+45 46 36 08 44

Fax:

+45 46 36 08 40

www.esbensen.dk

Sub-consultant

Senior expert

Technical University of Denmark

Department of Civil Engineering, Solar Energy Group,

Building 118

DK- 2800 Lyngby

Dr. Simon Furbo

Phone:

+45 45 25 17 00

Fax:

+45 45 93 17 55

Sub-consultant

Expert in District Heating Technology

Association of Danish District Heating

Mr. Viktor Jensen

M.Sc, Civil eng.

Sundvanget 4

DK-6400 Soenderborg

Phone:

+45 76 30 80 23

Fax:

+45 75 52 89 62

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