Siemens Refrigeration Compressor Package The environmentally compatible chiller

Answers for energy.

How to keep the district cool?

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 dominantdemographic 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.

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.

Modern architectural design generates a rapidly growing cooling demand.

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-gene-rating equipment such as computers.

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

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 CO

2 emissions.

1

Billion inhabitants

Rural

Urban

2005

6.5

51 %

49 %

2025

43 %

57 %

= 100 %8.0

Source: UN Source: Siemens Megacity Report (2007)

Undecided17 %

Agree58 %

Disagree25 %

Global population Constantly growing floor space Commitment to investment for environment

Siemens Refrigeration Compressor Package (SRCP) Optimized for 10,000 tons of refrigeration (RT)

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.

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 equip-ment. This is thanks to the implementati-on 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.

Both engineering and construction companies benefit from the space- saving 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.

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.

Taking into account that the buildings are cool in the morning and still heated in the evening, there is a slight difference of one

or two hours between the electrical power generated and the cooling demand.

There are alternative solutions to com-pensate 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 turbo-generator set in the evening hours.

This technology is an excellent way of using the power of the sun to remove heat.

Solar thermal power plant District cooling plant

4

Siemens supply

Concentrated solar power stations cover the electricity demand of the district cooling plants.

Let us take a theoretical example to illustrate the advantages of the Siemens Refrigeration Compressor Package in both economic and environmental terms.

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 opera-ting 4,600 hours annually.

For regular Window A/C mounted at the apartment, the electrical demand is 1.62 kWh per RThour, leading to 204,095

kiloRThour, which results in an electrical power demand of 330,635 MWh per year.

For a high-efficiency district-cooling plant equipped with thermal energy sto-rage, electrical demand is 0.70 kWh per RThour, leading to 204,095 kiloRThour, which results in an electrical power de-mand of 142,867 MWh per year.

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 CO

2 per year.

Over one year, the calculation for 5,000 apartments results in the following com-parative figures.

Window A/C 330,635 MWh, equivalent to 165,317 tons of CO

2 emission from

70 thousand cars.

Efficient District Cooling 142,867 MWh, equivalent to 71,433 tons of CO

2 emission from 30 thousand cars.

The use of solar thermal power eliminates CO

2 emission, i.e. emission

is zero.

Siemens experience

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

Appropriate for solar thermal power plants:

excellent very good good not appropriate

Use the power of the sun to remove heat by employing Siemens competence.

6 am 12 am 3 pm 6 pm 9 pm 12 pm0 %

25 %

50 %

100 %

75 %

Time

Po

we

r/Lo

ad

Cooling PowerDemand

SolarGeneration

5

Excellent coefficient of performance (COP) emission reduction

* Emission equivalent to

Loca

l

Win

dow A/C

0

40,000

80,000

160,000

120,000

Ton

s C

O2

Conventio

nal

DC Pla

nt

Efficie

nt

DC Pla

nt

Sola

r Therm

al

supplie

d DC P

lant

70,000 cars*

33,000 cars

30,000 cars

0 cars

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.

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Subject to change without prior notice.The information in this document containsgeneral descriptions of the technical optionsavailable, which may not apply in all cases.The required technical options should thereforebe specified in the contact.