Tibet’s first solar district heating plant made up of parabolic trough collectors was put into operation in late October, confirmed Vicot Solar Technology, the turnkey solar field supplier based in Dezhou, China. The 20,000 m2 system supplies heat to 1,800 households in the town of Shenzha, in the Naqu prefecture in northern Tibet. The long winter in this mountainous area caused delays in construction, which took 1.5 years.
“The system in Shenzha has been completed and is in good working order,” Ouyang Cheng, Marketing Manager at Vicot confirmed in November, when he returned the filled-out table below. The same sort of table, which lists key data about individual installations, had already been used to publish information on two other SDH systems in operation in Tibet. In contrast to the other systems, the recently completed SDH plant includes a high-temperature, 900 m3 storage tank with molten salt, currently the most common and cost-effective way to store heat from large CSP plants.
Heat can be stored in the molten salt tank after raising the temperature of the heat transfer medium inside the receivers to about 140 °C. Via a heat exchanger, water at around 70 °C is later fed into the district heating network to supply thermal energy to the new radiators or floor heating systems in connected residential units.
A report posted on sohu.com in October 2018 confirms that the connected households previously used coal, cow dung or firewood for heating. All three energy sources, however, cause air pollution and offer little thermal comfort. According to Vicot, solar heat will now meet 75 % of the heat demand in connected households, while the remainder will be supplied by electric boilers. The sohu report also underlines the contribution of Wilo China, the local subsidiary of a German pump manufacturer, which delivered the pumps for the district heating circuit and the heat exchanger stations.
One row of Vicot parabolic trough collectors in Shenzha. The photo was published in a report on www.sohu.com, a Chinese news portal on HVAC equipment, and shows the system in October 2018, when it was still under construction.
Key data on the solar district heating field in Shenzha
|SDH installation in Tibet|
|Construction time||May 2018 to October 2019|
|In operation since||October 2019|
|Situated at a height of||4,900 m|
|Solar field||20,000 m2 of aperture area|
|Collector type||Parabolic trough|
|Solar field supplier||Vicot Solar Technology, China|
|Storage tank||900 m3 of molten salt|
|Solar fraction||75 %|
|Funding source||Central government of China|
|Backup system||Electric boilers|
|No. of households to be connected to the district heating network||1,800|
|Supply temperature||70 °C|
|Return temperature||50 °C|
|Organisation that owns and operates the SDH solar field||Municipality of Shenzha, Naqu, Tibet|