CWS Chilled Water System Vessels
The Adveco CWS range is built for commercial projects with larger cooling demands. It’s a specialised range of premium carbon steel primary system vessels designed to serve a diverse range of cooling applications, typically incorporating heat pumps, chillers or fan coils that need chilled water storage.
The CWS range offers 10 models from 300 litres to 5,000 litres. That extra capacity lets a chiller system considerably improve performance: better temperature control, longer chiller life, less condenser cycling and faster system start-up.
Every CWS tank has multiple large bore flanges as standard, at high and low level, giving greater versatility for a wide range of system applications with moderate to high flow rates. These tappings mean the tanks work with multiple cooling sources, including heat pumps.
Each CWS tank comes with dual-layer insulation: an inner lining that acts as an anti-condensation underlay, plus a further 100mm of outer insulation.
Chilled Water System Vessel Design: Features & Key Technologies
- 300 – 5,000 litre capacity
- Rated for 6 bar working pressure at standard
- High, mid, and low-level connections
- Large connections for a wide range of commercial applications
- Dual insulation featuring inner anti-condensation lining
- Ideal for use with heat pump based cooling
What is a commercial chilled water buffer vessel?
A chilled water buffer vessel is a storage tank that sits between a chiller or heat pump and the building’s cooling circuit. It stores chilled water so the cooling source doesn’t have to respond to every fluctuation in demand directly, charging up when demand is low and releasing stored capacity when cooling load spikes. CWS is Adveco’s chilled water system range built for this role at larger commercial scale, from 300 to 5,000 litres.
The problem CWS solves
Cooling demand in commercial buildings tends to grow faster than plant rooms do. A data hall gets busier, a comfort cooling refit adds load, a retail unit converts to something with a bigger cooling need, and suddenly the chiller that was sized correctly five years ago is cycling constantly to keep up. Short-cycling wears the chiller out faster, costs more to run, and still leaves temperature control worse than it should be.
The usual fix, a bigger chiller, is expensive and often physically doesn’t fit. CWS solves the same problem a different way: add buffer capacity instead of buffer chiller capacity. The chiller runs longer, steadier cycles instead of chasing every demand spike, and because CWS is built with a low profile specifically for tight plant rooms, you get that extra buffer without needing more floor space or headroom than you already have.
Designed to work with compact spaces
With a low maximum height, from 1.87m to 2.265m with insulation, CWS is easier to install in plant rooms despite its larger volume, especially where clearance is tight. Because the vessel is shorter, CWS uses three internal partitions to help with stratification and stop preferential flows. The outer insulation can also be temporarily removed to help with siting during installation.
The vessels lend themselves to packaged plant rooms too, so you get the benefits of offsite construction: better production oversight and faster delivery to install times.
CWS is rated for standard working pressures of up to 6 bar. For projects that need more, such as multi-storey buildings with basement plant rooms, 10 bar versions are available on request in all sizes.
Why buffer capacity matters for cooling
Chiller systems, much like heat pumps, work better when they’re not constantly switching on and off to meet short bursts of demand. Adding chilled water storage between the chiller and the load cuts condenser cycling, improves temperature stability, extends chiller life, and speeds up system start-up, all without needing a bigger or more expensive chiller. CWS is built specifically for this role: 10 models from 300L to 5,000L with multiple large bore connections at high and low level to handle moderate to high flow rates.
One of CWS’s main advantages is its low profile, from 1.87m to 2.265m including insulation depending on model, which means larger storage volumes still fit into plant rooms with restricted headroom, a common constraint in retrofit projects and multi-storey buildings. Internal partitions help maintain stratification despite the reduced height, and the dual-layer insulation, including an anti-condensation inner lining, protects against moisture build-up common in chilled water applications.
CWS suits standard 6 bar systems, with 10 bar versions available for higher pressure installations such as basement plant rooms in tall buildings, and works well as part of offsite-constructed packaged plant rooms where production oversight and faster install times matter.
CWS or CWT: which chilled water tank do you need?
Adveco offers two ranges of chilled water vessel, and the right one depends on how large and how complex your cooling installation is.
CWT is the straightforward option: a carbon steel chilled water buffer built for a single cooling loop, working from -10°C to +95°C at a standard 3 bar (6 bar on request), in the same 300L to 5,000L capacity range. It’s the vessel to specify when a chiller or heat pump is feeding one cooling circuit and all you need is buffer capacity to stop it short-cycling.
CWS is the larger-scale option for cooling installations with more going on. Where CWT covers the basic buffering job, CWS adds the low profile design for restricted plant rooms, dual-layer anti-condensation insulation, and the multiple large bore high and low-level connections needed when a system draws from more than one cooling source, such as a heat pump working alongside a conventional chiller.
If you’re not sure which fits your project, tell us the cooling sources involved and the plant room constraints and we’ll point you to the right vessel.
Technical Specifications & Downloads
Literature
CWS 300 – 5000 L Data Sheet
Specifications
Connection sizes given in inches. Dimensions given in millimetres.
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Frequently Asked Questions
A storage tank that sits between a chiller or heat pump and the cooling circuit, absorbing fluctuations in cooling demand so the chiller isn’t constantly cycling on and off.
Yes. CWS has a low maximum height, from 1.87m to 2.265m including insulation depending on model, so it fits in plant rooms with restricted clearance despite offering larger storage volumes than a standard-profile tank.
Yes. CWS works with heat pumps, chillers, or fan coils that need chilled water storage, and the high and low-level connections support multiple cooling sources including heat pumps.
Standard CWS is rated to 6 bar. For higher-pressure applications such as multi-storey buildings with basement plant rooms, 10 bar versions are available on request in all sizes.
Adding chilled water storage reduces how often the chiller cycles on and off to meet short bursts of demand, which improves temperature control, extends chiller life, and improves system start-up times compared with a chiller running without a buffer.
Yes. CWS vessels work well in packaged plant room construction, benefiting from the production oversight and faster delivery to install times that offsite manufacturing offers.
CWT is a straightforward single-loop chilled water buffer. CWS is built for larger, more complex cooling installations, adding a low profile design for restricted plant rooms, dual-layer anti-condensation insulation, and multiple large bore connections for systems drawing on more than one cooling source.
Every CWS tank has an inspection and clean-out flange for straightforward servicing, and multiple sensor pockets for controls or BMS integration. Beyond that, a chilled water buffer needs little ongoing attention, most of the maintenance load sits with the chiller or heat pump it’s buffering.
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50 Years
Adveco Ltd. is the independent hot water specialist for the commercial built environment and has historically traded as A.O. Smith Water Heaters in the UK.
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