How to keep
the district cool?
Siemens Refrigeration Compressor Package
The environmentally compatible chiller
Answers for energy.
Targeting Zero Emission Through Siemens
Compressor Chiller Packages
Big cities present many obvious environmental problems, but the challenge of energy-efficient housing
is actually easier to tackle in compact urban areas than in loosely structured, low-density communities.
The growth of cities will be a dominant
demographic trend of coming decades.
The current proportion of the world‘s
population living in urban areas just
passed the halfway mark. The United
Nations expect to rise to almost 60 %
by 2025, and to reach 70 % around 2050.
As cities grow, personal living conditions
in cities become more important.
Energy supply, whether electricity,
steam, hot water or chilled water, will,
in the future, place major challenges
on infrastructure.
Modern architectural design generates a
rapidly growing cooling demand.
Global population
Constantly growing floor space
Billion inhabitants
6.5
8.0
There are many reasons, including
people‘s increasing expectations of
more living space corresponding to
the spacious public areas
construction of new buildings with
huge window areas to provide sunlight
buildings containing more heat-generating equipment such as computers.
A survey among 522 stakeholders in
25 large urban agglomerations world­
wide indicates the willingness to invest
in an improved environment.
There‘s a strong interest in megacities
to reduce greenhouse-gas emissions
and other air pollutants – megacities
already emit roughly 10 % of global
CO2 emissions.
Commitment to investment for environment
= 100 %
25 %
Rural
51 %
43 %
Urban
49 %
57 %
2005
2025
Source: UN
District Cooling
A district cooling plant offers a perfect
alternative to conventional Window A/C,
since the cooling capacity is generated
in an effective and efficient manner. A
central district cooling plant generates
cool water and distributes it through a
network of piping system to individual
customer buildings.
District cooling has been implemented in
a variety of structures, both private and
government-owned utilities, universities
and airports. The district cooling systems
serve a wide variety of types of buildings,
including commercial offices, residential,
hotels, sport areas.
17 %
Disagree
Undecided
58 %
Agree
Source: Siemens Megacity Report (2007)
The benefits of district cooling are
Comfort and convenience for
customers as there is no noisy
equipment in the window or on
the roof
Improved energy efficiency
Enhanced environmental protection
System reliability
Decreased building capital costs
Improved architectural design
flexibility
1
Siemens Refrigeration Compressor Package (SRCP)
Optimized for 10,000 tons of refrigeration (RT)
SRCP 10, a chiller generating 10,000
tons of refrigeration, is equipped with
two highly efficient compressors, inlet
guide vanes using high efficient tubes
in the optimized heat exchangers. The
system is completed with all required
chiller auxiliaries including the control
and protection system.
This new system technology provides an
overall efficiency improvement of 7 %,
compared to conventional chiller equipment. This is thanks to the implementation of turbocompressor equipment design
typically used in petrochemical plants and
the phenomenal size of the 10,000 RT
chiller system itself.
This capacity, and the use of one electrical
motor to drive the compressors without
a gear, leads to minimum losses.
The new 10,000-ton design requires
approximately 40 % less space compared
to 4 chillers of 2,500 RT. Space is money,
especially when the district cooling plant
is located in the middle of the city.
The operating costs of a district cooling
plant are mainly driven by the electricity
and water consumption of the plant
itself. The increased efficiency generates
profit. Additional savings result from
attractively low service costs for a large
10,000 RT chiller compared to smaller
equipment.
Both engineering and construction
companies benefit from the spacesaving effect of the Siemens Compressor
Refrigeration Packages and the reduced
engineering complexity as compared to
existing conventional design, thanks
to fewer auxiliary components such as
pumps and valves.
3-D schematic of the Siemens Refrigeration Compressor Package SRCP 10 for district cooling
2
Features of the solution
Capacity 10,000 tons of refrigeration
with one unit
Cooling liquid R134a
Two compressors on one single shaft
Each compressor has inlet guide vanes
Lowest friction losses
No gear required
One electrical motor as driver
Motor available for 50 Hz or 60 Hz
Dimensions 11.2x7.7x5.0 m (LxWxH)
Max. weight of single transport
unit 45 tons
Advantages of the solution
Excellent coefficient of
performance (COP)
Enhanced efficiency
High reliability as the compressor
design is based on oil and gas
requirements
Less space needed
Less engineering/piping
Overall attractive life cycle costs
Implementation
The cooling demand in cities is directly
correlated to the impact of the sun, in
other words the load profile of a district
cooling plant varies drastically from day
to night. To compensate the varying
refrigeration demand, a combination of
the Siemens refrigeration compressor
package with smaller chiller equipment
is feasible.
3
The future of energy supply:
Intelligent, efficient, sustainable and profitable
Renewable energy and distributed generation are gaining ground. And we need to mitigate climate change.
District cooling in combination with solar thermal power offers the opportunity to to do just that.
or two hours between the electrical power
generated and the cooling demand.
How does it work?
As a leading company in solar thermal
power plants, Siemens is in the position
to build such plants outside the city and
to feed the power produced into the
national grid, which supplies the district
cooling plants. This is a perfect match
as the impact of the sun provides the
electricity to drive the district-cooling
plants at the very time when cooling is
required since the sun has heated the
buildings.
There are alternative solutions to compensate for this, one being the possibility
to install thermal storage in the district
cooling plant, to extend its cooling
capacity in the evening hours. The other
is to install thermal heat storage at the
solar thermal power plant in order to
extend the operating hours of the turbogenerator set in the evening hours.
This technology is an excellent way of
using the power of the sun to remove
heat.
Taking into account that the buildings are
cool in the morning and still heated in the
evening, there is a slight difference of one
Concentrated solar power stations cover the electricity
demand of the district cooling plants.
Siemens
supply
Solar thermal power plant
4
District cooling plant
Siemens experience
Appropriate for solar
thermal power plants:
excellent
very good
good
not appropriate
Siemens turbines power solar plants all over the world
Siemens has secured orders for 45 steam turbines for solar thermal power plants:
More than 40 steam turbine generator sets in Spain, using parabolic trough technology
Units for central tower technologies with air, water/direct steam and molten salt rating from 1.5 MW to 123 MW
Units for ISCC applications in North Africa
Steam turbine for Fresnel application in Spain
Use the power of the sun to remove heat
by employing Siemens competence.
6 am
12 am
3 pm
Time
6 pm
9 pm
12 pm
Efficient District Cooling 142,867
MWh, equivalent to 71,433 tons of
CO2 emission from 30 thousand cars.
The use of solar thermal power
eliminates CO2 emission, i.e. emission
is zero.
33,000 cars
80,000
30,000 cars
40,000
0 cars
0
Ef
D C fic
i
P l ent
an
t
su S
pp ol
lie ar
d Th
DC er
Pl ma
an l
t
0%
to 165,317 tons of CO2 emission from
70 thousand cars.
120,000
nv
e
D C nt io
Pl na
an l
t
25 %
Window A/C 330,635 MWh, equivalent
70,000 cars *
Co
50 %
Power/Load
75 %
160,000
L
w oca
A/ l
C
Cooling Power
Demand
Over one year, the calculation for 5,000
apartments results in the following comparative figures.
100 %
Excellent coefficient of performance (COP)
emission reduction
do
Solar
Generation
Usually the electrical supply is provided
by power stations and the emission has
to be calculated as 0.5 kg CO2 per kWh.
As a comparison, a typical car emits 2.4
tons CO2 per year.
in
For regular Window A/C mounted at the
apartment, the electrical demand is
1.62 kWh per RThour, leading to 204,095
For a high-efficiency district-cooling
plant equipped with thermal energy storage, electrical demand is 0.70 kWh per
RThour, leading to 204,095 kiloRThour,
which results in an electrical power demand of 142,867 MWh per year.
In other words, a switch from Window
A/C to an efficient district cooling plant
with Siemens Refrigeration Compressor
Package (SRCP 10) is like reducing the
related emissions from 70 thousand cars
to 30 thousand cars. And, finally, using
the electrical power generated by a
Siemens solar thermal power station,
eliminates the emissions completely.
W
Let us assume 5,000 apartments, each
covering 120 square meters, in a tropical
(hot, humid, dusty) area, with a cooling
demand for 260 Wthermic chillers operating 4,600 hours annually.
kiloRThour, which results in an electrical
power demand of 330,635 MWh per year.
Tons CO2
Let us take a theoretical example to
illustrate the advantages of the Siemens
Refrigeration Compressor Package in
both economic and environmental terms.
* Emission equivalent to
5
Published by and copyright © 2010:
Siemens AG
Energy Sector
Freyeslebenstrasse 1
91058 Erlangen, Germany
Siemens AG
Energy Sector
Oil & Gas Division
Wolfgang-Reuter-Platz
47053 Duisburg, Germany
Siemens Energy Inc.
10730 Telge Road
Houston, Texas 77095, USA
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