New ČSOB Building in Prague

Excellent experiences from concentrating a significant part of the ČSOB headquarters into a single building in Radlice in 2007 led the bank to decide to move the remaining components of the group, especially its subsidiaries, to Radlice, resulting in the construction of a second building adjacent to the first one.

ČSOB has proven to be conservatively sound in the best sense of the word and accepted three decisive characteristics for the new investment project, practically identical to those from which the previous building stemmed. These were contextual architecture, a socially oriented and structured work environment, and an ecologically and technologically progressive construction concept.

The ten-year gap since the first bank building proved to be almost generational and illustrated the dynamics of development in various areas of construction and office work environment requirements. The illustration was initially unintended, as the user-appreciated existing building had far more examples to follow and develop than to revise or correct.

For the interpretation of the first task, which consisted of integrating the building into the environment of the Radlice valley, respecting the neighborhood and the required cultivated appearance without ostentation, it was necessary to use instruments corresponding to the selected plot on the hillside. The theme became the habitation of the slope while preserving its morphology and greenery, and the anticipated means were thus the pronounced horizontality of the proposed building and the connection of the desired green roofs with the greenery descending from the Dívčí hrad's hillside.

The architects responded to the brief with a design of low pavilions set into the slope, with proportions in both volume and subdivision that support a horizontal dimension. They allowed the mass of the hill to penetrate the building right to the facade, which creates a sort of sandwich layering the roughness of the chiseled reinforced concrete eaves (possibly reminiscent of the protruding limestone slabs on the opposite side of the hill, in the Prokop Valley) with the precision of inserted constructions and transparent interiors.

In preparation for the design phase, the investor defined in quite detail the expected social, psychological, and physical (and consequently physiological) aspects of the work, or better, living environment in the building. The fact that a single community will use the building led to the creation of a non-standard concept of hierarchical arrangement of the internal environment – with a lively, bustling social center and quiet, tranquil workspaces in the outer segments.

Given the increasing mobility of workers, the reduction of routine tasks, and the growing amount of communication forms, the physical workspace no longer equates to just a desk but instead encompasses the entire building – ranging from central social spaces with a café and shared services, lively and oriented towards mutual communication, to workplaces for concentrated and undisturbed individual work, even including rooftop gardens. It was possible to deduce that the areas of bustling segments could be designed to be markedly smaller than those of quiet segments, leading to a request for a concentric structure with an emphasis on addressing the sensitive issue of transitions between its various segments.

The architects essentially chose a star-shaped concept for this. The busier segments were shaped like a central atrium and its galleries – a sort of community center. In contrast, the calmer segments were placed in diverging pavilions with individual workspaces, which surround halls at their center on every floor. These halls serve as communication nodes, leading into the pavilion and to the workplaces of the most tranquil segment, and are spaces for activities needed just a few steps away from the desk (printers, tea kitchens, places for operational informal conversations and phone calls), which nevertheless disturb others working nearby.

The passages between segments – that is, between quiet workplaces by the facades and the halls, as well as between the halls and the galleries, form membranes. These are operationally and often visually completely permeable, but possess properties of noise, operational, and psychological filters. In the hierarchy from the noisiest to the quietest spaces, a distinctly graduated noise level can thus be perceived. At the same time, they socially structure the environment – from practically private zones, through semi-private – community, to entirely shared spaces (architecture and urbanism here are the only theme).

Extraordinary emphasis in the brief was placed on respecting the most natural and archetypal qualities of the environment – light, space, sound, air and its flow, heat and temperatures, color, materials and their surfaces, and last but not least, intuitive use of the building and its furnishings. The effort to create a physiologically as naturally healthy state as possible, as is feasible in a closed object and under reasonable technical and economic conditions, was a common intersection of the architectural and construction-technical concepts.

The architects' design incorporated transparency of the building with a variety of spatial layouts, practically continuous visual contact with the external space – landscape and sky, maximum daylight, acoustic diversity and individualization, but also as material stratification of spaces and significant amounts of sometimes very dense greenery.

The new ČSOB building in Prague – Radlice is conceived as extraordinarily progressive and considerate of the environment.

Right from the very start of conceiving the investment intention, orientation towards environmentally friendly approaches played a substantial role. This included choosing the location as a place with excellent public transport service (metro, tram), as well as the subsequent selection of the construction site – it is indeed a brownfield, a site that was previously used during the construction of the metro.

Environmental orientation is encoded in the very spatial concept of the object. One of the significant factors of comparable buildings is thermal gains, which are a negative consequence of large glazed areas, which are very much needed for maximizing daylight in workplaces and direct contact with the outside environment, both of which are biologically, physiologically, and psychologically very desirable factors. To significantly eliminate thermal gains, the orientation of the longitudinal pavilions is utilized, which uses the north and south facades as dominant, considering the fact that east and west facades bring almost three times higher thermal gains due to the angle of sunlight than the much more favorable south and north facades.

In the Radlice valley, westerly winds predominate, and to utilize this factor, the main atrium with its roofed space is oriented so that airflow, or pressure and suction of outdoor air, is used with the help of a damper system to ventilate warm and stale air.

Energy for heating and cooling the building is obtained through heat pumps from a ground well system. The extent of this field has no comparison in the Czech Republic, and thus the building belongs to a group of twenty European buildings of this category with this cutting-edge technology (where all of these objects come only from the last few years, when technological development allowed such extensive applications).

The designed borehole field is calculated in terms of capacity so that the planned technological concept would not need to account for a classic boiler room, and therefore burning gas for heating or water heating. The object includes a comprehensive recovery of heat generated during operation and besides calculating heat given by the presence of people, office equipment, and of course also alongside gains from solar radiation through the facade, thoroughly utilizes surplus energy from kitchens, server rooms, etc.

The amount of energy obtained from the ground mass is practically sufficient for summer cooling as well. Only during periods of tropical temperatures is there a consideration that cooling power will be supported by a small hybrid cooling unit.

Elements for the transfer of heat or cold to the office space, that is, the terminal units, are radiant heating and cooling systems built directly into the ceiling structure (BKT), supplemented in exposed areas of the building with surface radiant panels (oBKT). Heating and cooling also supply the exchangers of the ventilation equipment.

The borefield serves not only for extracting energy but also for long-term storage of it. In the summer, thermal energy is stored, and conversely, in the winter, cooling (more accurately – heat is extracted). The ground mass, which is heated using this system in the summer period, can be utilized more effectively for heating at the onset of winter, and conversely, the mass cooled in winter can be used more effectively for cooling in summer.

Simply put, the massive energy reservoir allows for the storage of energy gains from the summer period with minimal energy demands for winter and to make use of the underheated ground mass in the summer.

At the same time, it should be emphasized that, contrary to the use of classic cooling systems, which discharge excess heat into the air, storing it in the ground on hot summer days is far more considerate of the surrounding environment, as it does not cause an additional increase in air temperatures around the building and in the locality.

A similar, albeit considerably shorter cycle is the daily/night thermal cycle. The building is also capable of exploiting this via the accumulative capacity and thermal inertia of the internal constructions, particularly the reinforced concrete ceiling slabs, along with all the masses inside the object.

In the office building, due to the user load, cooling of the internal spaces to a favorable temperature during daytime working hours must be done practically for 8-9 months of the year. For most of this period, there is also a sufficient amount of outdoor cooling available at night, as only exceptionally do nighttime temperatures not drop below 20°C.

Capturing and redistributing nighttime cooling into daytime hours occurs through a combination of natural ventilation and free cooling. By controlled opening of the shell, mostly selected windows, it is possible to pre-cool the volume of internal air and all surfaces in the interior for free. In addition, the mass of massive ceiling slabs can also be actively cooled by using media, so that the following day they can maintain favorable lower ambient temperatures throughout the entire working time through radiation and convection.

Last but not least, the object also takes advantage of the irregularities of thermal gains and losses between opposing, opposite-facing facades and spaces. During transitional periods, it is necessary to cool spaces by southern facades on sunny days, while it is necessary to supplement heat in spaces by northern facades. Therefore, excess energy from the spaces adjacent to the southern facades will be distributed to the northern spaces using heat pumps.

Given the mentioned, practically year-round surpluses of heat (for practically three-quarters of the year from its own operation and in the remaining winter quarter from sufficiently capacious energy ground wells), we are preparing further, progressive expansion.

This will involve interconnecting energetically with the neighboring older ČSOB building, which will enable winter supplies of cheaper ground energy for heating the older building from the new building and thus reduce the consumption from the existing gas boiler room. This connection will allow for the application of a year-round cycle of energy storage and subsequent extraction for both buildings, which will offer optimization – especially allowing the use of heat from the older building for the autumn preheating of the ground mass, which will enhance its capacity for winter heating of both buildings.

This connection, while neither building will be dependent on it in any way, is also interesting for reducing operational risks, as it brings the desired backup for cooling and heating both buildings and simultaneously diversifies the energy sources. It is expected that, except for particularly cold or warm periods of the year, a potential heating or cooling outage in one of the buildings (whether planned or extraordinary) could be compensated by supplying from the other building.

The facade of the new building facilitates natural ventilation for each workspace as well as the ventilation of all spaces in the building. The system of automatically controlled and specifically placed windows and openings works with outside air year-round – during acceptable outdoor temperatures, the internal spaces are ventilated only through windows, and the air conditioning units are not activated at all. This not only fully utilizes the energy potential of the outer air mass for the current internal climate and pre-cooling the constructions but also maintains a high content of negative ions in the internal environment as a physiologically significant parameter.

Automatically controlled systems of movable external shading against undesirable thermal gains are already taken for granted, and to support internal thermal stability, creating a second envelope of the object that also preserves visual contact with the internal environment and contributes to the transparency and illumination of the building with daylight.

It is also worth mentioning the use of triple glazing, which, alongside thermal-insulating and soundproofing capabilities, was pre-designed to create thermal comfort by bringing the internal surface temperature of the glazed areas closer to the temperature of the internal space.

The facade of the building and both the main and small atria ensure maximum daylight at every workspace. When daylight is insufficient, workplaces and all other user spaces in the building are automatically and smoothly illuminated by LED lights with direct-indirect lighting. In workplace areas, this refers to a variable system of standing lamps communicating with each other to eliminate contrasts in the space. The lighting is efficiently controlled by presence sensors and hence only operates during the presence of a person, and in the case of office workspaces, is also individually locally adjusted according to need.

The building is "smartly" managed with the measurement of many comfort parameters of the internal environment: temperature, humidity, carbon dioxide, etc. Functional units are evaluated in detail both in terms of the quality of the working environment and energy consumption. The management of the high inertia of accumulation ceilings uses predictions of future states through an integrated system, including, among other things, weather forecasts and expected occupancy of workplaces in the forthcoming days, etc.

The object is equipped with technology for capturing, treating, and reusing rainwater for irrigation.

Last but not least, all roofs of the building are designed as gardens with plants and trees typical of the natural flora in the area. The gardens serve not only as a practically integral part of the workspace but especially for retaining rainwater on-site and eliminating the heat island effect in the locality, which will contribute to a favorable microclimate.

The underground parking lot is equipped with charging points for standard and fast charging of electric cars and e-bikes.

For managing passages and entrances, user-friendly biometric technology is installed for palm vein reading – the reading of the blood flow of the passing person's palm. Booking systems with local and remote use and presence control are used for the operation of meeting rooms and other spaces.

In summary, the building is conceived and subsequently designed with priorities that include care for the environment, optimal working environment (not only physiologically but also psychologically and socially), and economic efficiency.

At the same time, it also provides high flexibility and minimizes operational risks – for example, by eliminating gas, it reduces vital dependence on a single medium – electricity, which can still, for some time, be practically provided autonomously through diesel generators.

Thanks to all the aforementioned technologies and eco-friendly materials used, the SHQ building achieved the highest level of LEED Platinum certification in the comprehensive category of New Development. This guarantees efficiency both during construction and particularly in the utilization and operation of the object, and thus overall consideration for the environment.