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Heat Transfer Technology


An efficiency boost


Steam is an essential element in the energy supply system. As a primary energy source, it fulfills many important functions, whether it’s used to operate a turbine, as process steam for use in industry, or for district heating.


Therefore, heat recovery steam generators (HRSG) are important components of many power plants: They substantially increase a plant’s overall efficiency, and help to minimize the costs of fuel. You also benefit from greater flexibility when operating at part load or during load changes.


Talk to us about your particular need

Heat Recovery Steam Generators (HRSGs)

Natural Circulation HRSGs

Robust drum technology also makes it possible to use steam for basic applications, such as electricity generation or supplying heat. An innovative drum design improves flexibility and efficiency in power plant operation.


Our HRSGs from 10 MW to the largest gas turbines offer lower installation costs, less site risks, and, potentially, and earlier commercial operation for the entire plant. How do we accomplish this? Through a higher degree of standardization of pressure part modules.


The benefit of design: Cold-casing and counter flow evaporator

Horizontal natural circulation: Cold-casing design

Designed for natural circulation of the water/steam mixture in the evaporator tubes, our horizontal HRSG uses a cold-casing design. Completely insulated and lined with sheeting, cold-casing design allows you to quickly start-up your gas turbine. Additionally, it enables you to use higher gas temperatures associated with modern gas turbines.

Vertical natural circulation: ‘Counter flow’ evaporator design
Our HRSG’s unrivaled, state-of-the-art patented 'counter flow' evaporator design offers:
- Free expansion of headers and tubes
- Readily accessible headers and bends for inspection
- Stress-free repair and maintenance
- Easy on-site construction


Waste Heat Recovery Units (WHRU)

Harnessing energy to the maximum

The WHRU offers an efficient method of recovering thermal energy from the waste heat of gas turbine exhaust gases. This method allows a significant increase in the efficiency of the turbine train, and a decrease in both fuel demand and pollution. We are able to supply the entire scope for your gas turbine train, bringing the total number of parties required for project realization back to only one.
The standardized design fits every type of gas turbine, ranging from 10 to 70 MW. It is therefore in perfect harmony with, but not limited to, the existing Siemens gas turbine portfolio.

Exhaust stacks and diverter systems

Broad product spectrum for every need

Siemens is recognized globally for quality and innovation in the area of exhaust stacks and diverter systems. Where a tight shut-off or good control is required, we’re there with a variety of dampers for the power and environmental industry. Exhaust stacks and bypass systems, incorporating diverters and silencing equipment for gas turbine plants are included in our extensive product portfolio. Choose from a variety of high quality products that best meet your individual needs.

Bringing you customizable technology

Exhaust gas bypass systems add operational flexibility, efficiency, and safety to a combined cycle power island. The heart of any bypass system is the diverter damper. Siemens’ diverter dampers combine state-of-the-art design principles and technology with empirical field data. While based on a high level of standardization, our diverters are also custom engineered to meet your specific required combustion turbine characteristics, as well as your individual requirements. Stacks, especially, are designed to your precise project specifications.

Saving you time and money

Simple cycle power plants consist of a combustion turbine and an integrated chimney or exhaust stack. Many power island projects start with a simple cycle design to minimize initial capital costs, reduce equipment installation time, and enable power generation as quickly as possible. Our design portfolio offers base mounted and elbow duct versions.

Putting your safety first

Siemens’ guillotine-type blanking plates are extensively used in exhaust gas bypass systems as a secondary shut-off device in conjunction with a diverter damper. When your combustion turbine is in operation, the damper creates a “man-safe” environment within the downstream-located HRSG. As a stand-alone solution, the guillotine damper typically utilizes a temperature-proof design with rack-and-pinion drive system and a gas-tight, fully enclosed bonnet. Almost the full cross-section of the duct is available once the guillotine blade fully retracts, resulting in a very low pressure drop.

Keeping your HRSG warm

The primary function of an HRSG stack damper is to slow down the cooling rate of your HRSG between individual gas turbine starts. During sustained shutdowns, stack dampers prevent rain from entering the HRSG. Available in standardized, parametric two-blade, or individual four-blade designs, our stack dampers can be readily retrofitted to existing HRSG stacks.

Withstanding your toughest conditions

Siemens’ louver dampers are robust flow control and/or shut-off devices specifically designed for the demanding environment in combustion turbine exhaust installations. Our engineers design and build louver dampers in accordance with your plant-specific parameters and individual specifications. To ensure you have the right damper for your individual needs, we offer various designs, dimensions, and shapes—with or without duct section. Additionally, we use different construction materials based on your plant’s operating temperature and pressure, abrasive or corrosive environment, as well as other process operating conditions.

Maintaining high-operational ability

We provide a full range of spare and wear parts for your complete exhaust gas systems and damper portfolio—available for start-up and commissioning, operational and strategic purposes, as well as fulfilling long-term availability requirements. We have direct counterparts with expert knowledge and lean processes, so that we can offer both quick response times and cost-efficient solutions.

Standing by your side

Installation: Technical advisory services support your local contractors or assembly groups. How? With our OEM expertise, we can ensure a smooth and efficient installation. Our specialists are available everywhere you are.

Commissioning: Proper installation and start-up are essential for a reliable and fault-free, long-term operation of mechanically moving equipment in severe flue gas environment conditions. Put your trust in our service expertise ensuring optimal performance during your warranty period, as well as throughout the whole service life of your installed system.

Maintenance: When considering an upgrade—whether it be a simple check or a continuous maintenance program—we offer a comprehensive selection of on-site inspection, survey, and testing services.

Service and warranty

The Siemens’ guarantee

Our high-standard of engineering and maintenance services; our in-depth know-how about the power generation process and its components: This is what operators of power plants around the globe benefit from. With more than eighty years of experience, Siemens is an OEM with the reputation for solving steam generator challenges. With us at your side, you can maximize your performance, while simultaneously lowering both costs and risks. Our engineering staff, tools, and work processes are second to none giving you the competitive edge.

Downloads, support, and services

Your source of information

This is where you can find material to download, contact details, and links to the services we offer.

Energy Customer Support Center

Siemens AG
Freyeslebenstrasse 1
91058 Erlangen

(Charges depending on provider) (From the German fixed network € 0.14/min. and from the German mobile phone networks max. € 0.42/min.)


Plant service

Maintenance, repair, modernization – our Power Generation Services ensure that your facility maintains its value. Enjoy long-term confidence.

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From consulting to financing – Siemens offers financial solutions for business-to-business customers worldwide. Talk to the experts.

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Online Customer Portal

The latest information, news, product details – in our exclusive Customer Portal you are directly informed. Keep your finger on the pulse.

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A selection of our projects around the world


Give your power plant a boost

Does your power plant need to provide flexible dispatch? Or do you want to be able to extract heat? In both these cases, a steam generator is essential: and we’ll find the right technology for your needs.

Talk to us about your particular challenge