Japan Sustainable Building Database

Air-conditioning system based on radiation cooling-heating panels and FCU

Radiation panel in a research lab

By adopting an air-conditioning system that combines long-life, ductless and fanless radiation cooling and heating panels with FCU (Fan Coil Unit), we have created a new indoor environment. The radiation cooling and heating panels installed upright by the windows liberally regulate indoor temperatures. Moreover, installing them near the external air inlets makes it possible to cool and dehumidify outside air at the same time, thus creating hybrid air-conditioning by combining with natural ventilation. For the external air inlets, we have adopted constant wind volume ventilation slits that allow ventilation to be fixed at a constant level. We have confirmed the energy saving effects and improvement of the windowside environment by actual measurement.

Natural ventilation system and natural light intake using solar chimneys

Rationale on natural ventilation for the complex as a whole

With a total of 15 solar chimneys distributed at regular intervals along the central axis of the complex, the upward flow of air is promoted by the chimney effect. This makes it possible for most areas of the complex to receive ventilation even when there is no wind. Besides natural ventilation, the solar chimneys also create a natural light intake into the inner corridors, which tend to be rather dim. The solar chimneys combine both architectural plans and environmental plans; they can also be used as spaces for pipework and ducts, and are designed to accept additional installations of experimental research lab air exhaust ducts in future. Finally, they are also designed to function as natural smoke discharge outlets from the corridors in the event of an emergency.

Sunlight blocking and rooftop greenery using green eaves and concrete overhang wall

Exterior view of green eaves

Green eaves and rooftop greenery are used to protect the environment of the surrounding goshawk habitats, and to reduce solar heat load and thermal load coming into the buildings. The structure of the green eaves is that ivy planted in planter boxes is trained along a metal mesh. Since rainwater from the terrace can be led directly into the planter boxes in this way, this will be a maintenance-free system that requires no irrigation equipment.
After painstaking studies, the plan is that the concrete planter boxes will block direct sunlight in summer, while in other seasons the light filtering in through the green eaves will create a soft indoor environment.
As a result, green eaves and overhang walls have been actively incorporated into the façade design of the overall complex. Not only does this produce an excellent performance with a PAL (Perimeter Annual Load) value of 207.4 MJ/m², but also creates buildings that are splendidly harmonized with the surrounding environment.

Wooden lattice ceiling system – resource-saving and easy to alter or renovate

Perspective view of research lab interior

The wooden lattice ceilings of the offices (research labs) are designed for long life and conservation of resources. To make alterations and renovation inside the rooms easier, the ceilings are fitted with wiring ducts to which power sources and task lights can be fitted, as well as lighting appliances and wiring routes for IT systems. Similarly, as the air-conditioning system does not need air outlets on the ceilings, walls or floors, but uses radiation cooling and heating panels, a ductless and fanless method is realized that is long-living and easy to maintain. Moreover, considering differences in the respective lifespans of buildings and equipment and the need to conserve resources, the ceiling is very similar to an unsuspended ceiling in format. This makes it possible to repair or upgrade equipment without removing the lattice ceiling.