CompriVAP Heat Pump Solution: Turning Waste Heat into Value

In this blog post, we’ll explore how the CompriVAP system works, the advantages it offers, and why it stands out as a key technology for the future of sustainable industry.

Contents

1. What is CompriVAP?

2. CompriVAP vs. closed-loop heat pumps

3. CompriVAP: Enabling carbon-free process steam

4. Economic perspective: CAPEX vs. OPEX

5. Savings potential: Fresh steam vs. waste heat recovery

6. Requirements, performance, and system sizes

7. The three variants of the CompriVAP system

1. What is CompriVAP?

CompriVAP isn’t a conventional machine, rather it’s an innovative system that utilizes industrial waste heat sources to generate usable steam. The system operates as an open-loop heat pump. The real breakthrough lies in the smart combination of proven technologies, re-engineered for robust industrial use – a hallmark of GIG Karasek’s engineering expertise.

1. Technology and how it works

CompriVAP is based on the well-established Mechanical Vapor Recompression (MVR) technology:

• How it works: Steam is mechanically compressed to a higher energy level using one or more electrically driven compressors. Once compressed, it can be reused as a high-grade heat source. Depending on the type of waste heat available, the CompriVAP system may also incorporate a heat exchanger and a flash tank as pre-treatment stages. This setup ensures that the process steam and heat source can operate independently.

• Reliability: All core components and machines used in the system are well-established industrial technologies that have been field-proven over decades of operation.

GIG Karasek boasts extensive expertise in the development and application of industrial compression systems and backs every CompriVAP installation with contractually guaranteed performance levels.

2. Key benefits of CompriVAP

• Improved plant efficiency: By harnessing waste heat effectively, CompriVAP significantly reduces overall energy consumption, leading to substantially lower operating costs compared to traditional steam generation with fossil fuels.

• Flexible partial-load operation: The system dynamically adapts to fluctuations in both heat input and steam demand, maintaining peak efficiency across a control range of 60 to 100%.

• Seamless industrial integration: Thanks to its modular and sophisticated design, CompriVAP can be integrated into existing process environments even retroactively without disrupting ongoing operations.

• Operational reliability and low maintenance: Engineered for continuous 24/7 operation. Annual maintenance regarding the compressors typically requires only a few hours to a couple of days.

Figure 1: CompriVAP system with multi-stage compressor system. © GIG Karasek

2. CompriVAP vs. closed-loop heat pumps

When compared to conventional closed-loop heat pump systems, CompriVAP offers a range of advantages that go beyond energy efficiency with enhancing the economic viability and safety of industrial processes.

• Water as the working medium: Traditional closed-loop systems often rely on synthetic refrigerants such as ammonia or propane, which pose risks to operational safety and can negatively impact the ozone layer and greenhouse effect. CompriVAP, by contrast, uses plain water and in ideal setups even the waste heat source itself as the working medium. This results in improvements to safety and environmental performance, as well as minimizing maintenance requirements.

• Broader application range: CompriVAP enables the generation of steam across temperature and pressure levels that many closed systems simply cannot reach reliably.

• Cost efficiency: By using standard industrial components and offering easy integration into existing infrastructure, CompriVAP delivers significant cost savings both in terms of investment and operational expenses. 

Further Reading: Industrial Heat Pumps in Comparison: Technological Differences and Application Areas

3. CompriVAP: Enabling carbon-free process steam

One of the most critical levers for decarbonizing the industrial sector is the electrification of steam generation. According to the International Energy Agency (IEA), the world needs to install around 500 MW of industrial heat pump capacity every month over the next 30 years in order to achieve net-zero industrial production by 2050.

With CompriVAP, industrial operators already have access to a future-ready technology that transforms waste heat into carbon-free process steam – provided the system is powered by renewable electricity. Even on its own, the use of waste heat offers substantial CO₂ savings. When combined with green energy sources, the carbon footprint can be brought down to a minimum.

In the face of tightening climate regulations and rising CO₂ pricing, solutions like CompriVAP, which not only recover waste heat efficiently but also enable full integration of renewable power, will play a pivotal role in the industrial energy transition.

Case study: BASF Ludwigshafen – carbon-free steam from industrial waste heat

A prime example of this groundbreaking technology is the planned industrial heat pump system at BASF’s location in Ludwigshafen. BASF SE has selected GIG Karasek as its EPC partner (Engineering, Procurement, Construction) for what will become the world’s most powerful industrial heat pump system of its kind. The plant will recover waste heat from a steam cracker and convert it into carbon-free process steam using CompriVAP technology. Powered by renewable electricity, the system will deliver up to 50 MWth (megawatts thermal) and is expected to save up to 100,000 metric tons of CO₂ emissions annually. Start-up is scheduled for 2027.

Tilmann Hezel, Senior Vice President Infrastructure, BASF Ludwigshafen: “BASF is committed to achieving net-zero CO₂ emissions by 2050. To get there, we need to adopt new technologies that can be embedded in our chemical production sites and help us generate the energy we need in a sustainable way. Industrial heat pumps play a key role in electrifying steam generation and thereby decarbonizing it. We're proud to have found GIG Karasek as a technology partner for this project. Their decades of experience in this field make them an ideal fit to implement this project.”

Figure 2: Visualization of the large-scale CompriVAP heat pump system for the BASF location in Ludwigshafen. @ GIG Karasek

4. Economic perspective: CAPEX vs. OPEX

Harnessing industrial waste heat not only reduces CO₂ emissions, but also cuts down on primary energy demand, the use of fresh steam from gas boilers, and cooling water consumption. This concept is especially attractive for energy-intensive industries, where vast amounts of waste heat remain untapped.

CompriVAP unlocks this hidden potential and converts unused energy into valuable, usable steam:

• CAPEX (Capital Expenditure): Depending on specific application conditions, CompriVAP systems typically achieve payback periods of just 2 to 5 years. * 
• OPEX (Operating Expenditure): Thanks to the highly efficient use of waste heat, operational costs are significantly reduced. 

The combination of drastically lower operating expenses and fast return on investment delivers a clear competitive edge – particularly in sectors like chemicals, pulp and paper, or food processing, where energy costs make up a substantial portion of total production costs.

* For preliminary budgeting purposes, the global industry benchmark for investment in industrial heat pump systems can be estimated at approximately €1 million per 1 MW of thermal power. Actual costs may vary depending on site-specific factors and system design requirements.

5. Savings potential: Fresh steam vs. waste heat recovery

A benchmark cost comparison between conventional steam generation in a pulp mill and the electricity costs of a six-stage CompriVAP system delivering 15 MWth of thermal output reveals the substantial OPEX savings potential:

• High efficiency: With a COP of 3.72, the system ensures a rapid return on investment. 
• Significant savings: Compared to steam generation from fossil fuels, the CompriVAP solution offers 60–70% lower operating costs in this application scenario. 

Additional economic benefits arise from the reduced energy required to discharge excess heat, as well as potential future savings on CO₂ certificate costs, which are not yet factored into this comparison.

* The COP (Coefficient of Performance) measures how efficiently a heat pump converts electricity into usable thermal energy. A COP of 3.72 means the system generates 3.72 kWh of heat per 1 kWh of input power.

Figure 3: Cost comparison between steam generation and electricity needed for a CompriVAP system © GIG Karasek

6. Requirements, performance, and system sizes

CompriVAP systems offer flexible integration into existing industrial processes but require specific technical conditions to be met for optimal performance.

1. Requirements for heat sources

To ensure efficient and reliable operation, several key parameters of the heat source must be considered:

• Input medium availability: A sufficient volume of low-pressure input medium must be continuously available. 
• Suitable heat sources: Compatible heat sources include liquid waste streams, such as wastewater or process condensate, as well as gaseous streams, including flash steam, and exhaust air from drying processes or process gases. Even heat from potentially explosive media can be recovered under proper safety conditions. 
• Temperature: The incoming heat source should maintain a temperature above 70°C. 

• Energy content: The thermal power of the heat source must be at least 1.5 megawatts.

Additionally, the desired steam output parameters, such as temperature, pressure, and flow rate, must be clearly defined.

2. Performance ranges

CompriVAP systems feature a modular design and are available in a range of capacities, making them highly adaptable to different process requirements:

• Thermal power: 1.56 to 40 MW

• Steam production rate: 5 to 60 metric tons per hour

• Steam temperature: Up to 215°C

• Steam pressure: Up to 20 bar(g)

3. System footprint and size

System dimensions vary depending on configuration and capacity:

• Compact units: Starting at 6 × 6 meters
• Large-scale installations: Up to 30 × 38 meters 

• Multi-level designs enable optimized space usage

Regardless of system size, the core principle remains the same: CompriVAP utilizes Mechanical Vapor Recompression (MVR) to generate steam efficiently and can be seamlessly integrated into new or existing plant environments.

Figure 4: CompriVAP system with flash tank. © GIG Karasek

7. The three variants of the CompriVAP system

The configuration of a CompriVAP system depends on the specific application, the properties of the available heat source, and the required steam output parameters. The setup may consist of a single compressor or multiple compressors arranged in series and/or parallel, depending on performance needs.

Based on the condition and nature of the heat source, three system variants are employed:

1. Contaminated media or substances unsuitable for direct use - indirect heat transfer via a heat exchanger between heat source and boiler water, evaporation of the boiler water in a vacuum flash tank, increase of pressure via the compressor.

2. High-quality steam - direct compression of the available steam to the desired pressure. 
3. Hot water with boiler-grade quality - direct evaporation in a flash tank and subsequent increase of pressure via the compressor. 

Variant 1: Contaminated media (liquid/gaseous media that condenses during heat transfer)

When dealing with contaminated heat sources, the CompriVAP system employs a closed-loop boiler water circuit to generate fresh steam. The core components of this configuration include a heat exchanger, a flash tank and one or more mechanical compressors:

Figure 5: Layout of a CompriVAP solution including a heat exchanger, a flash tank and a compressor system © GIG Karasek

• Heat transfer: The thermal energy from the heat source is transferred to the boiler water via a heat exchanger without any mixing of the media.

• Heating: The boiler water is heated to the maximum available temperature before being directed into the vacuum flash tank.

• Flash evaporation: Inside the vacuum flash tank, a portion of the water instantly vaporizes due to the reduced pressure, which lowers the boiling point.

• Steam generation and pressure boosting: The generated steam is gradually compressed in a multistage compressor cascade until the desired operating pressure is reached (e.g., 6 bara).

• Water circulation: The remaining liquid (residual water) stays within the closed loop and is continuously recirculated using high-performance, energy-efficient pumps.

• Feedwater supply: Since steam is extracted from the system, the resulting water loss must be compensated with fresh feedwater.

• Blowdown: A controlled discharge of a portion of the boiler water is performed to limit the concentration of dissolved salts and other impurities.

• Injection water: Injection water is used to fine-tune steam moisture levels and enhance the efficiency of the compressor cascade.

Advantages:

• Clean steam generation even when using contaminated heat sources. 
• Ideal for industrial processes that utilize waste heat sources such as exhaust gases, process vapors, or wastewater.

Figure 6: CompriVAP system including a heat exchanger and a flash tank. © GIG Karasek

Variant 2: High-quality hot water feed

In certain scenarios, hot water can be fed directly into the flash tank without passing through a heat exchanger. This is possible, for example, when using condensate that already meets the required water quality standards. The resulting vacuum steam is then compressed to the desired pressure level and can be reintegrated into the production process.

Figure 7: Layout of a CompriVAP solution including a flash tank and a compressor system © GIG Karasek

Advantages:

• Easy integration: No additional heat exchanger required. 
• Efficient utilization: Direct evaporation of hot water inside the flash tank. 

Variant 3: High-quality steam input

In this configuration, the heat source is already available in the form of high-grade steam. Since the steam is free of impurities, it can be fed directly into the compression stage to be pressurized to the required level and utilized for heat recovery without requiring an additional heat exchanger and a flash tank.

Figure 8: Layout of a CompriVAP solution with a compressor system © GIG Karasek

Advantages:

• Exceptional energy efficiency with a COP (Coefficient of Performance) of up to 30. 
• Proven MVR concept that compresses steam which stems originating from a waste heat process and directs it back to be reused as a heating medium.

Case study: Sappi Saiccor 16 MW evaporation plant – 300 tons per hour

A tangible example is the evaporation plant installed by GIG Karasek at the Sappi Saiccor pulp mill in South Africa. With an impressive compressor power of 16 MW, the system evaporates 300 tons of water per hour, making it the largest operational installation of its kind in the global pulp industry.

Figure 9: Evaporation plant with compressor power of 16 MV for sulfite liquor at the Sappi Saiccor site. © GIG Karasek

Conclusion: Why choose CompriVAP?

CompriVAP is an innovative, reliable, and energy-efficient solution for steam generation that not only reduces operational costs but also significantly improves your company’s carbon footprint. By harnessing waste heat and integrating seamlessly into existing systems, CompriVAP represents a forward-looking technology for modern industry.

More than just a sustainable solution, CompriVAP offers substantial economic benefits. With a payback period of just 2 to 5 years, significant reductions in operating expenses, and a measurable boost in competitiveness, investing in CompriVAP delivers both ecological and financial value.

Want to learn more about the CompriVAP concept? Use our online OPEX calculator to evaluate the economic potential of a CompriVAP solution for your facility or get in touch with us directly for a personalized consultation.