Photo: Solareast Arcon-Sunmark
 Second Arcon-Sunmark SDH system up and running in Tibet

Second Arcon-Sunmark SDH system up and running in Tibet

In the middle of November, Chinese-Danish joint venture Solareast Arcon-Sunmark Large-Scale Solar Systems Integration started up its second solar district heating system in Tibet. Now, its 35,000 m² solar field is supplying the thermal energy needed for heating rooms in thousands of households across Zhongba County. In the photo, taken during an inspection visit in early October, the team who worked on the project can be seen standing in front of the storage tank that is part of the new installation. The first SDH plant put up by the joint venture was completed last year and came online in December 2018.
Photos: Solareast Arcon-Sunmark
The company’s second system is 4,700 metres above sea level and was put up in Zhongba, near the border between China and Nepal, where winter temperatures reach minus 30 °C and the heating season lasts around 250 days. The investment in the solar installation including the new district heating network added up to around Renminbi (RMB) 173 million, or EUR 22.3 million. All of the money came from China’s central government.


First SDH plant, built in Langkazi

Second SDH plant, in Zhongba

Construction time

April to December 2018

April to November 2019

In operation since

December 2018

November 2019

Situated at a height of



Solar field

22,000 m²

35,000 m²

Flat plate collector supplier

Arcon-Sunmark, made in Vietnam

Arcon-Sunmark, made in Vietnam

Storage tank

15,000 m³ of seasonal storage

15,000 m³ seasonal storage

Storage tank

Pit heat storage

Steal tank

Heated floor area

82,600 m²

118,000 m²

Solar fraction

90 %


Total investment of solar system including district heating network

RMB 120 million (EUR 15.4 million)

up to RMB 173 million (EUR 22.3 million)

Specific investment

701 EUR/m²

637 EUR/m²

Backup system

3 MW electric boiler

Two 1.4-MW oil boilers and 200 kW photovoltaics

Supply temperature

65 °C

63 °C

Return temperature

35 °C

38 °C

Key data on two SDH systems installed in Tibet
Source: Solareast Arcon-Sunmark
Management staff from the joint-venture partners toured both SDH sites at the beginning of October (see the photo below). The Danish side of the venture was represented at the event by Arcon-Sunmark’s Managing Director Thomas Karst and Torben Sørensen, Group Executive Officer at parent company VKR Holding. Karst became head of Danish-based Arcon Sunmark, a supplier of solar thermal turnkey systems and collectors, after Ole Dalby stepped down last November. Its Chinese venture partner was represented by Xinjian Xu, Founder and Chairman of the Board of Solareast Holding, which trades under the brands Sunrain and Micoe, as well as Solareast Arcon-Sunmark’s Managing Director Aaron Feng Gao.
Pleased with the success of the first SDH project in Langkazi (from right): Aaron Feng Gao, Managing Director of Solareast Arcon-Sunmark (China), Torben Sørensen, Group Executive Officer at VKR Holding (Denmark), Thomas Karst, Managing Director of Arcon-Sunmark (Denmark) and Jason Zhang, Technical Coordinator of Solareast Arcon-Sunmark.
Solareast Arcon-Sunmark operates the SDH systems on behalf of their owners, which are the local municipalities. Feng Gao estimates annual operation and maintenance costs to be EUR 515,000 in Langkazi, or 3 % of the initial investment. In Denmark, owners of SDH installations usually expect to pay 1 % for O&M: “We have employed eight operators for the first year, to guarantee safe operation. In Europe, we would need only two employees for the same job at a plant of this size. Moreover, the plant is in a remote location, far away from any bigger city, so labour and transport costs are high.” Still, Feng Gao expects “significantly lower operating expenses in the future, after operators have gained more experience.”
Organisations mentioned in the news article:
Solareast Arcon-Sunmark Large-Scale Solar Systems Integration:


Baerbel Epp

Bärbel Epp is Founder and Director of the German communication and market research agency solrico and editor-in-chief of