Wet surface air coolers
Alfa Laval Wet Surface Air Coolers (WSAC®) are custom built, closed-loop cooling and condensing systems that combine high performance, low operating costs, compact size and reliable operation. Renowned for their robust design and high efficiency, Alfa Laval WSACs are used in a large number of demanding industries. Their low water consumption and high cooling capacity have made them a popular choice in applications where low temperatures are required for process improvements.
- Lowest possible process fluid outlet temperature thanks to evaporative cooling
- Minimal water consumption – cooling water can be re-circulated and the makeup water can be of low quality
- Low energy consumption
- Compact size and lowest lifecycle cost
- Well-proven technology and long service life
Alfa Laval WSAC systems are engineered-to-order, closed-loop cooling and condensing systems. Thanks to Alfa Laval’s WetSurface technology, these units provide maximum cooling in a compact unit and use a minimum of water and electric power. The robust and simple design brings stable thermal performance and low maintenance requirements. An Alfa Laval WSAC is a closed loop system, meaning there is no risk of contaminants entering the process stream. Our WSAC systems can be fully customized to your requirements, for example they can be designed to withstand corrosive media, cool several process streams in parallel or with the ability to run in both dry-cooling and wet-cooling mode.
We will be happy to discuss the benefits an Alfa Laval Wet Surface Air Cooler can bring you and show you how we can help improve your operation.
Meet our experts
Full cooling capacity cooling systems all year round
The sustainable alternative to cooling tower systems & air coolers
Effective and efficient cooling
Minimize life cycle cost & maximize cooling performance
Highly durable equipment
Alfa Laval WSACs are engineered to meet heavy-duty industrial requirements and standards. They can sustain pressures up to 2500 psi and be designed to meet ASME, TEMA, PED and API specifications. All materials in contact with the process stream can have full ASME material certification if required. The units are fireproof and can be constructed for use in Ex environments.
The tubes can be either straight or serpentine shaped. Straight tubes are the preferred choice for fouling process media and when a low pressure drop is required. The piping can be arranged and valved so that any tube bundle can be taken out of service for maintenance while the unit is in operation.
As standard, all components are made of hot-dip galvanized steel with excellent resistance to corrosion. For applications with corrosive media, the tube bundles can be delivered in a variety of materials, for example different grades of stainless steel, super duplex and titanium.
All Alfa Laval WSAC systems are unique and custom designed to fit the exact requirements of their intended duties. This includes inlet and outlet temperatures, ambient conditions, flow rate, presence of corrosive media, required pressure drop, etc.
Redundancy can be built into the units in order to minimize or eliminate downtime for maintenance. This can include components such as spare fans, spray pumps and even tube bundles. The units can also be designed to cool several separate process streams independently.
From small to large
WSAC systems come in all sizes from small, packaged units to large field-erected systems:
The packaged systems are skidded, pre-piped and pre-wired units, complete with control cabinets. These factory-tested, plug-and-play units ensure a fast and easy installation, and keep the associated installation costs low.
Our modular systems are ideal where cooling capacity needs to be expanded simply and efficiently. These medium sized WSACs have casings made of heavy-gauge steel and are delivered in pre-fabricated modules that are easily assembled on site.
Field-erected WSAC systems
Our largest systems are field erected. The basin is made of concrete and the overlying structure can be made of either fibre reinforced plastics (FRP) or concrete. A field-erected system is comprised of custom-designed tube bundles, which provide optimum maintainability over the lifetime of the system. A field-erected WSAC system offers the lowest total cost of ownership for duties where high-capacity cooling/condensing is required.
Comparison with other technologies
WSAC systems produce the coldest possible process outlet temperature compared to other technologies.
Other WSAC advantages are shown in the following table.
In this example the air temperatures are:
Dry bulb T = 37.7°C (100°F)
Wet bulb T = 26.1°C (79°F)
|Wet Surface Air Cooler (WSAC)||Cooling tower plus heat exchanger||Traditional air-cooled heat exchanger (dry)|
|Practical approach temperature||5.6°C (10°F)||8.3°C (15°F) in total, 5.6°C (10°F) for CT and 2.7°C (5°F) for heat exchanger||8.3°C (15°F)|
|Coldest practical process temperature||31.7°C (89°F)||34.4°C (94°F)||46.1°C (115°F)|
|Water consumption||Low-medium||High||Not applicable|
|Total system cost||Low-medium||Medium||Medium-high|
Optimizing your cooling processes is a straightforward way to improve sustainability – both in business and environmental terms. With the right equipment you maximize cooling performance and energy efficiency, while keeping water consumption and service costs low. Check out our brochure to find out how we can help you improve your cooling operations.
How it works
An Alfa Laval WSAC can be used for liquid and gas cooling, as well as condensing duties.
The WetSurface technology used in a WSAC system is based on evaporative cooling. The hot process medium flows through prime surface tube bundles that are sprayed with water. The heat causes the water to evaporate and the vapour is removed by fans that draw cool air over the tubes.
The water that does not evaporate is collected in a basin and is reused as spray water. The same cooling water can be reused 6-10 times, depending on water quality.
Next, the air/water vapour stream is forced to make a 180° turn, which effectively removes free water droplets and minimizes drift.
An Alfa Laval WSAC is a closed loop system, meaning there is no risk of contaminants entering the process stream.
For liquid cooling the maximum inlet temperature is 82°C (180°F).
For single phase gas cooling the maximum inlet temperature is 232°C (450°F).
For vapour condensing the maximum inlet temperature is 82°C (180°F).
Limited water resources made a Middle East refinery use Red Sea water for its cooling needs. The large salt content of sea water causes high fouling and corrosion, generally making it extremely difficult for cooling.
A gas processor in Texas, U.S. wanted to improve efficiency of the NGL fractionator process while reducing operating costs and increasing NGL production. Learn how the Wet Surface Air Cooler offered the perfect solution.
Less water consumption
The Chuck Lenzie Generating Station, a combined cycle power plant in Nevada, was challenged to cool the closed loop auxiliary water while conserving make-up water based on allowed annual limitations of water availability.
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Accelerating sustainable solutions
Imagine a more sustainable world. A world in which less is needed to produce even more. A world in which we efficiently meet our growing energy needs and at the same time reduce CO2 emissions. Imagine a world where we can harness the power of natural resources while preserving them. At Alfa Laval, we don't just imagine this world. We build it together with our customers and our partners.
Rethink your refinery
When partnering with Alfa Laval, you get access to a range of process optimization services. They cover all stages of your project from initial idea generation, through the feasibility-and basic design study, to installation and commissioning of our equipment. Working closely with licensors, engineering companies and end-users, Alfa Laval’s refinery team brings world-leading expertise in process optimization to all types of refinery projects, maximizing the probability of project success and ROI.