China Solar Hot Water Design Achieves 75 Percent Home Energy Savings

By Staff
article image
Photo by Himin Solar
The Utopian Garden Project in Dezhou, China, utilizes a unique metal casing to house 504 vacuum tube collectors that creates the attractive and futuristic form of a wave and covers the entire roof of the building. 

The following article
is reposted with permission from the author from the

The solar
installations above the apartment blocks of the “Utopia
Garden” Project in the Chinese city of
Dezhou attract
attention even from a distance. The 504 vacuum tube collectors have been placed
horizontally in a massive metal casing that has the form of a wave and covers
the entire roof of the building. The solar fields, with a gross collector area
of around 1,400 square meters [15,070 square feet], consist of pressurized,
heat pipe vacuum tubes, which harness the sun on the roof and feed it into a
central heating and cooling system that runs through the entire building

The design and construction of the eco-friendly houses, as
well as the marketing of the apartment units is completely in the hands of
Himin Solar Energy Realty, a subsidiary of the Himin Solar Group. The company
has already sold out four blocks with a total of apartments at the waterfront
of an artificial lake, and the new owners started to move in at the end of
2011. Two more blocks are now under construction.

“Seeing what modern living standards will be like in the
future persuades people to buy the 300 to 600 square meter [3,229 to 6,458
square feet] big flats,” explains Chen Ping from the Brand Management
Department of Himin Solar, one of the largest solar water heater manufacturers
in China.
“The price of the flats is around 12,000 Chinese Renminbis per square meter of
living space ($180/square foot), which is around 50 percent more than for
comparable flats. Advanced renewable energy technology and intelligent home
technologies make the difference.” Still, apartment owners save up to 75 percent
of annual energy costs in their new accommodations.

In summer, the solar field above the roof powers the
absorption chillers for the apartments’ air conditioning. Any excess solar heat
is stored in a seasonal storage area below the building complex. The size of
the storage area – which includes 1,800 bore holes – has been constructed large
enough to also supply the entire Utopia Garden Project, which is said to
include, in all, 10 blocks of apartment units.

Electric compression chillers, as well as gas absorption
chillers, have been installed to serve as backup systems when the solar heat
does not reach a high enough temperature to run the solar chillers. The space
heating demand in winter is primarily covered by the seasonal storage’s ground
source heat pumps. If they do not prove sufficient, the buildings will get the
rest of their energy from the district heating system.

Each apartment also includes a vacuum tube collector, which
has been integrated into the façade, and a 300-liter [79-gallon] tank, which
has been mounted to the balcony and supplies a family with hot water. These
solar systems represent a totally new way of using residential solar hot water
in China.
They are pressurized, indirect systems that include U-pipe collectors and a
closed loop solar circuit filled with glycol. Whenever the façade collector does
not reach the required 60 degrees Celsius, an electrical element will take over
the heating process. In these buildings, the apartments’ solar hot water is
kept separate from the central heating and cooling system.

Bärbel Epp is the
founder of
Solrico, a market research agency focusing on solar thermal