Helsinki Central Library

The new Helsinki central library serves as an extension of the natural park surrounding it. The park filters itself into the library traveling from the West to the East of the city block becoming “trapped” into building structure. The park pushes the masses both horizontally, North and East, and vertical, ground to ski. The result is a U shape building elevated thought a ramp traveling from the ground level and culminating in a roof terrace. Furthermore, the horizontal force of the park divides the building into two wings, North and East and transforms itself into an interior reading garden. Horizontally, the building is connected by the café at the ground level and the restaurant and sauna at the top level liked by a direct elevator.  The trapped park forms two panoramic windows seeking to scape looking in the direction of the parliament building to the West and Alexandria to the South. All the knowledge brought into the library by the city through the park makes the new Helsinki central library the brain of the metropolis; a direct receiver and transmitter of information and excitement clearly reflected by its constant ever-changing program of events and its permanent collection of knowledge.  

DURA MATER

The BRAIN of the Metropolis

HELSINKI CENTRAL LIBRARY

“Dura Mater is a thick and dense, inelastic, fibrous membrane which lines the interior of the skull. Its outer surface is rough and fibrillated and adheres closely to the inner surface of the bones, forming their internal periosteum, this adhesion being most marked opposite the sutures and at the base of the skull. Its inner surface is smooth and lined by a layer of endothelium. it send four processes inwards, into the cavity of the skull, for the support and protection of the different parts of the brain.” [Gray’s Anatomy,  Henry Gray and H.V. Carter]

The concept for the New Central Library of Helsinki is based on the  Human Brain, metaphorically connecting the city  of Helsinki with its natural creative engine, the Library,. Alike the Human Brain, whose various areas meet different functions, the library is organized in very different zones and functions, some completely opposite in characther and nature.

These funtions are all “kept together” by the exterior building envelope which creates a sort of continuity and consistency throughout the building. Similar to the Dura Mater of the brain, the Library envelope carries information both to its users and as a response to the environment around it.

Spirit, Mind, Body

The Library is accessible on its roof via a ramp that begins at grade on the main piazza. The promenade ascension is both a physical experience of the changing city scape and the spiritual counterpart to the idea of “change” in mind. Similar to Dante’s journey, the sloping uphill can be experienced as a transformative moment, arriving at the top floor room which faces  south towards Alexandria and the Finnish Parliament.

IMPACT OUT

Alexandria and the Parliament

The Library ultimate view points are the two large window-rooms of the top floor restaurant, Jazz bar and Sauna. These spaces face west and south, aligning respectively with the Parliament and House of Music, and the trajectory of the Alexandria Library in Egypt. These views activate a connection to the past, present and future of the library and welcome visitors to re-experience it in a forward thinking dimension.

IMPACT IN

Full space and Lobby Garden

Inside the Library spaces are diverse, complex and exciting. Organized around the central garden lobby, which can be designed as an enclosable winter garden, the two main wings of the library and the east and west bridges act as extension branches from the central garden core, similarly to the beautiful and serene areas created around the trees.

URBAN LOCI

Reciprocal Feeding

The Library acts as a receiver and emitter of information creating a “8” figure loop with the city of Helsinki and the World at large. Different from an enclosed enclave which protects knowledge, the Dura Mater Central Library collects and spreads knowledge at the broadest possible scale.

MAIN STRUCTURAL SOLUTIONS AND HVAC TECHNICAL SOLUTIONS

(Operational principle and factors affecting the energy performance)

OVERALL TECHNICAL STRATEGY:  DURA MATER PERFORMANCE ENVELOPE

This building is designed to use the building envelope as the primary thermal and electrical generator and regulator and uses the district heating, cooling and grid electricity as efficient back-up. The technical systems of this building are primarily housed within the multi-layered assembly of the building envelope carrying an interior and exterior narrow planar cavity or plenum for the flow of energy and material (hydronic heat, ventilative air, DC electrical). A translucent insulative core of aerogel, luminous concrete or motorized shading is bounded on both interior and exterior by these cavities and the surface is enclosed with and interior and exterior dual pane insulated glazing units.  This sophisticated jacket allows overall capillary-scale distribution of heat, air and electricity to all areasof the building and assists the building to distribute, balance and exchange the heat produced and heat consumed; fresh air delivered and stale air exhausted, electrical energy generated and electrical energy consumed in a constant flow of self-regulation, assisted by a full network of skin-integrated sensors. 

The intelligent envelope plugs into the four vertical shafts at the north end, south end and center of the building plan to gather distribution vertically and connect to the building center mechanical area in order to plug into a central brain unit, heat exchange, electrical control, water to water heat pump, air supply and exhaust, as well as the connection to the district heating and cooling.

ENERGY SUPPLY SOLUTION

The building will utilize district heating and cooling along with grid electricity only when the collection, exchange and balancing capacity of the intelligent envelope requires additional energetic input.  Water-to-water heat pumps will be employed to provide cooling and/or heating required for the building as the inputs required to balance the whole of the integrated system flows.

The building envelope incorporates building integrated photovoltaic panels (BIVP) in the exterior insulated glazing unit on surfaces facing SE, S and SW to produce electrical power.

The building envelope operates as a neural network of production collection and distribution for heat, air and electricity, coordinated by a large network of sensors throughout the same surfaces.  These are connected together through a central responsive logic and uses the district heating and cooling connection and grid electricity as back-up when required or more efficient than the building scale.

HEATING

Heat is gathered through the hydronic medium such as glycol in the exterior capillary cavities from solar radiation and collected from the continuous full-envelope flows of the hydronic system and air system with a central heat exchanger. The building heat pump efficiently boosts the skin collection with much higher efficiencies and the intelligent HVAC controls use the district heating when more efficient than the building scale collection. The insulated translucent envelope assembly will carry the hydronic heat medium such as glycol on the interior cavity or narrow plenum, providing radiant surfaces throughout the building to heat the occupants and spaces. 

STRUCTURES

The U value of the continuous envelope is kept as a super insulated assembly of U=0.102 W/m2K.  This is typical for the dual pane IGU, hydronic or air plenum, aerogel core, plenum plus dual pane IGU. For the glazed areas that provide view, a quad-pane IGU becomes the core of the two plenum spaces and the interior and exterior additional dual IGUs.

Exterior capillary plenums between the translucent insulated core of the envelope assembly and the exterior IGU provide areas for collecting solar thermal heating of water on clear days and BIPV in the exterior IGU generate electrical energy when solar energy is available. Interior thermal mass in the floors and structural members will buffer the potential temperature swings and help to naturally regulate the temperature in the building.

WINDOWS

The entire envelope acts, in various degrees, as a light transmitter, but there are areas that become “windows” with clear glass for views in and out, especially to the plaza to the west, the large north view, the framed south views and the views to the courtyard.  These are composed of the typical multi-layer skin described above, with the core aerogel removed and the expanded plenum dedicated to shading provision. The spectrally selective exterior insulated unit allows through only about one quarter of the potential heat gain with a g value of 0.27 and the low-e coating reduces radiant transfer from inside the building to the exterior.   Conductive heat loss is limited by the dual-dual IGU assembly with a U value = 0.372 W/m2K. 

The glass is butt-glazed and adhered to a unitized structural phenolic frame system that is low-conductance, a low thermal-expansion coefficient and isolates the exterior glass thermally.

Solar shading is integral in the core area of the envelope plenum and is tuned to the orientation with horizontal and vertical louvers motorized and operated with the responsiveness of the neural network of sensors and central programmed controls to shield the direct sun when either visually uncomfortable or a thermal liability.

LIGHTING

Lighting for the main spaces is provided by both the translucent skin and window/skylight areas so that lighting is first and primarily through available daylight and moves seamlessly through controls to an efficient electrically lit building during the dark hours. Smaller spaces share the same strategy with fewer clear window areas to minimize heat loss.  Daylight and occupancy sensors in the building envelope will deliver information to the controls to maximize the use of daylight and to keep the interior from becoming darker than desired.  The lighting system will integrated into the inside surface of the skin and interior partition walls and ceilings as LED diffusing panels powered by the DC distribution system of the envelope.  This daylight and diffuse electrical light will be complimented with strategically placed arrays of small highly efficient LED sources to add sparkle and localized area lighting.  These are also managed by an intelligent control system, a smart node that will respond to the system of deployed sensors.  This is designed to ensure that the electric lighting is glare free and will supply only the light needed.

Installed lighting power will be an average of 5 watts per square meter, while the effective lighting power density due to day light and occupancy response will be 1.8 watts per meter square.

VENTILATION

Ventilation air is introduced to the building through the four vertical shafts and gathered into the central mechanical space to be thermally moderated by the exhaust air through heat exchange.  The fresh air is distributed via the interior plenum of the building envelope which contains small valves to release the pressurized air to the interior spaces, much like an under floor air plenum that is instead incorporated into the envelope itself.

Ventilation will be provided to provide the stated air change rates. This air will be minimally conditioned to be delivered at close to room temperature. Additional heating, cooling and dehumidification will be provided via heat pumps or district heating/cooling systems based on the seasonal carbon/energy profile of these resources.  A high-efficiency heat recovery wheel will be provided to capture free heating or cooling from the building relief or exhaust stair stream. Additional free heating will be provided by capturing” greenhouse effect” heat from the double-wall system.

Demand controlled ventilation will be provided via CO2 and VOC sensors strategically located within the building envelope.  The SFP values include 2.5 for the central mechanical ventilation including heating, cooling, heat recovery, 2.0 for the central mechanical ventilation including heating and cooling, and 0.5 for the envelope-local ventilation within the spaces.

COOLING

Cooling is a small load for the climate and since the building envelope is designed to be a continuously responsive envelope balancing out heat sinks and heat sources, additional cooling requirements will be much lower than additional heating requirements. Nevertheless, cooling may be needed for occupant comfort.  The courtyard places a primary role is providing access to natural ventilation through the courtyard skin, which is operable for air movement, unlike the exterior building skin. Intake through the courtyard skin and exhaust through the vertical stacks of the building allows natural air flow during months when the outside temperatures are comfortable. If the capacity of the thermal mass and natural ventilation to cool the building is exceeded, district cooling and/or the building heat pump will provide cooler fluid to circulate through the envelope interior plenum, providing radiant cooling for comfort.

District or heat pump cooling will be provided for network rooms and other spaces with high heat loads and/or controlled 24 hour cooling needs.

DOMESTIC HOT WATER

The integrated envelope carries fluid that can be exposed to the solar radiation and collected for domestic hot water.  This will need to be supplemented during the winter months with heat pump or district hot water that can be utilized for domestic hot water generation via heat exchanger for large restroom fixture groups. Single isolated restrooms will utilize instantaneous electric water heating.