º£½ÇÊÓƵ

Royal Dutch Library Storage

Delft, Netherlands

By uniting conservation science with elegant, low‑energy engineering, º£½ÇÊÓƵ played a key role in helping the Royal Library of the Netherlands safeguard an enormous national collection of books while driving toward energy positivity.

Our integrated team has shaped the building services engineering (MEP), building physics and structural engineering strategies for the new automated repository near Delft, creating stable conditions for millions of books and archives, and doing so with an approach that is as resource‑light as it is resilient.

The project consolidates the collection in a purpose‑built facility designed by Office Winhov in the Harnaschpolder, on the edge of Delft and Midden‑Delfland, where a passively conditioned, oxygen‑reduced store is paired with a front‑of‑house building for specialist handling and logistics. The overall footprint is about 7,400m², with the repository conceived as a cultural asset that must protect its contents for generations while fitting sensitively within a changing urban landscape.

This is a project defined by magnitude and precision. Inside the repository, a robotic system manages hundreds of thousands of crates to serve requests from the library’s headquarters in The Hague. Every movement, every opening, every environmental shift is controlled to protect paper, inks and bindings from fire risk, moisture and temperature shock. It is the combination of scale and delicacy that sets this commission apart, and it is where our integrated engineering has brought particular value.

We delivered a passive, low‑energy environmental design that keeps millions of items stable without conventional cooling, ensuring long‑term conservation.

Our team engineered a highly precise structural system with exceptional flatness and stiffness to support 16m robotic cranes operating at tight tolerances.

Our experts relocated maintainable plant outside the oxygen‑reduced store, reducing operational risk and safeguarding the collection by minimising disturbances by people.

Extensive rooftop photovoltaics, placed without compromising fire safety or depot climate stability, made the building energy‑positive.

Challenge

The primary challenge was to maintain conservation‑grade conditions for a collection measured in the millions within an almost entirely unoccupied, oxygen‑reduced environment. The store operates at approximately 13% oxygen to prevent ignition, which imposes strict constraints on both maintenance access and equipment selection. Servicing activities that would normally take place in situ had to be reconsidered to keep people out of the oxygen‑reduced volume and eliminate any water‑bearing plant from sensitive zones. At the same time, the client sought a net‑zero operational profile and long‑term resilience against flood risk in a low‑lying Dutch landscape.

The second challenge was structural performance at height with near‑industrial tolerances. Robotic cranes pick and place crates up to around 16m, which made floor flatness and stiffness critical. Loading patterns vary significantly as aisles are filled and emptied, so the slab and supporting structure needed to limit differential deflection to maintain precise crane alignment across the full working height. All of this had to be achieved within a strict municipal height envelope and with efficient use of the plan, so that storage capacity is maximised without compromising the logistics system.

A third challenge lay at the interface between conservation and workflow. Items leave a cool, oxygen‑reduced store with year‑round 50% relative humidity and pass into a people‑occupied picking area where condensation risk must be eliminated. Conditioning therefore had to be carefully zoned and sequenced, allowing staff to work comfortably while preventing microclimatic shocks to cold, moisture‑sensitive objects. Finally, the client needed capacity and adaptability: space planning had to anticipate digital substitution over time, while still leaving a clear pathway for potential expansion without compromising the sealed integrity of the depot.

Solution

The client had a clear vision, backed with details studies, which we implemented in a design. We began with first principles of passive performance. The repository follows a ground‑coupled, low‑energy strategy akin to the Danish model, using the stable temperatures several metres below ground to moderate the fabric. The mass of the envelope and meticulous insulation detailing create a slow, seasonal temperature swing that keeps average internal conditions below about 16C, well within the band for long‑term paper conservation. There is no conventional cooling plant in the store. Instead, we employ gentle air recirculation to prevent vertical stratification and to fine‑tune air movement and mixing.

To address the constraints of the oxygen‑reduced space, we moved as much maintainable equipment as possible out of the depot and on to upper plant floor of the front‑of‑house section. Critical nitrogen generation and distribution equipment is located for safe access, with the depot volume reserved for only non‑critical fixtures. Where demonstration lighting is provided for visitor presentations, it is treated as expendable so that any failure does not interrupt repository operations. The building services concept is therefore defined by separation, robustness and simplicity, with the oxygen‑reduction system backed by appropriate redundancy while the recirculation system is designed to ride through outages without immediate risk to the collection.

Structurally, our engineers designed a heavily reinforced floor slab with exceptional flatness and stiffness to support crane rails and tall racking over the full operating height. We optimised column spacing and beam depths to balance capacity, headroom and storage density, iterating the grid so that the building fits the municipal height constraints yet preserves maximum crate positions. This structural tuning, coupled with the rational, column‑aware arrangement of aisles, allows precise automated movement with minimal energy and minimal maintenance intervention inside the depot.

We paid equal attention to resilience. The depot deck is raised approximately 1.8m above surrounding ground and service penetrations are lifted even 1 meter above that point, with enhanced sealing of joints and openings to reduce the probability of water ingress across design life, in line with long‑horizon flood scenarios evaluated by the client. In a country where much land sits near or below sea level, elevating the collection and simplifying the envelope buys critical time and safety in extreme events. Complementing this, all technical equipment susceptible to flooding risk is placed on upper levels, further isolating operations from ground‑water hazards.

On energy, we worked with the client to unlock the roof area for photovoltaics. The early preference was for a highly reflective white roof to limit solar gain, and this characteristic has been retained beneath the PV panels. However, advances in panel fire safety and a carefully designed roof build‑up allowed the installation of a larger PV array without compromising conservation risk. The result is a building designed to be energy‑positive in operation, with the passive depot and modest recirculation loads more than offset by clean, on‑site generation.

Finally, we future‑proofed the envelope for potential expansion. At selected wall zones, reinforcement is omitted and recessed steel cover plates are installed so that a future opening can be cut from the outside without water‑cooled sawing inside the oxygen‑reduced store. This small piece of foresight protects today’s integrity and tomorrow’s options.

Value

Our greatest contribution is the synthesis of conservation‑grade performance with an ultra‑low‑energy, low‑maintenance architecture that is realistic to operate at the scale of a national library. By prioritising passive strategies and minimising technical equipment within the oxygen‑reduced zone, we have reduced operational risk and simplified maintenance regimes, keeping people out of the store and safeguarding conditions for the long term. That integrated approach draws on our experience of large, automated repositories elsewhere and informs the careful zoning that prevents condensation when items transition from the cold store to the staffed picking area.

We have also unlocked capacity, precision and resilience. The tuned structure gives the robotics a stable platform at full height, preserving alignment despite changing loading patterns, while the elevated, sealed fabric and raised penetrations mitigate future flood risk in a low‑lying setting. The photovoltaic strategy turns a vast roof into an asset, supporting an energy‑positive operational model that aligns with national sustainability ambitions. Through these moves, we help the client protect a growing collection that numbers in the millions while reducing energy demand and carbon in use.

Lastly, we have respected the architectural intent and the site’s civic role. Office Winhov’s design gives the repository a recognisable civic character that alludes to the form of books while positioning the building within an emerging urban landscape between Delft and Midden‑Delfland. Our engineering supports that ambition by keeping the store quiet, robust and largely self‑regulating, so that the building can do its most important job for the next century without visual clutter or intrusive plant. Together with the client and design team, we have created a repository that protects the past, performs in the present and anticipates the future.