Hideto Horike's concept proposes a keel structure like a ship, a monocoque structure like a space ship resulting in a steel architecture that realizes a new environment. In this design, the architects hoped to achieve a symbiosis with light and air in which dwellers float and play in wind like a sail boat cruising in the ocean, relying only on the power of nature.

In a space without columns, in a space without distinction of structural skeleton and interior wall with finishing, dwellers can flexibly construct their space, adapting it to their own lifestyle policy and family type. With this concept, a new lifestyle of geo-environmental living for the 21^st century would be produced.

The monocoque structure made of only thin steel panel performs to bear gravity and wind loads without columns. The concept adopts a flexible chemical joint system which makes it unnecessary to use on-site welding, high skilled and advanced technologies. Therefore, it is easy to maintain accuracy for realization of further beautiful details. Moreover, each joint space provides space for utility equipment. As well, the transportable-sized unit provides energy saving in building erection and a shortened construction period.

The entire keel structure is completed with the component system of the monocoque. A space unit in the module is sized at 3m x 6m x 3.3m to be transportable by truck. This unit is composed of thin steel panels to be double skinned, with an inner thin wall panel and floor panel. All units are mutually jointed using a steel and epoxy resin joint.

Hideto Horike believes it is of utmost important to reduce the energy consumption in providing comfortable thermal environments for the occupants. In this project, the service systems with maximum utilization of natural energies, such as solar energy, rainwater, wind, air, geothermal energy, underground water and the like, are proposed.

Wind Power Generation

On the ground within the site, dedicated windmills are installed for each dwelling unit. In general, approximately 20 percent of electric power required will be covered by this wind power generation system.

Rainwater Utilization

Rainwater on the roof is collected and stored in the basement and is used for toilet, maintenance water and plant irrigation to reduce the demand on the potable water supply.

Natural Ventilation

Natural ventilation (uplift) will take place within the cavity between the external skin and inner sandwich panel, due to the altitude difference. The air comes into the cavity through the bottom grills and leaves from the top grills of the wall cavity.

When the external skin receives solar heat, uplift force is accelerated to increase ventilation rate. The surface of inner panels is cooled by this natural ventilation to reduce the heat gain of the rooms in summer. Further this uplift will provide free ventilation, that is without mechanical or electrical power, for toilets.

Air-to-Air Heat Exchanger System

A waste heat recovery system is proposed. With an air-to-air heat exchanger, heat recovery out of the exhaust air is made to preheat or pre-cool outside air to be introduced by code. The outside air is introduced from the light well and exhaust air, after the heat is reclaimed, is supplied to the toilet as a makeup air. Then exhaust air from the toilet is connected to the wall cavity with duct system and discharged at the top of the wall cavity without any exhaust fan.

Geothermal Heat Pump System

The system utilizes geothermal energy as a heat source in winter and heat sink in summer. The system is composed of heat exchange tubes (9mm diameter link-polyethylene tubes) installed in the steel piles and a water source heat pump.

In winter, water is circulated between the heat exchange tubes in the piles to absorb geothermal energy through the pile surface. Then warm water is introduced into the water source heat pump to generate hot water for space heating. In summer the medium water is directly circulated between the heat exchange tubes and heat discharge/absorb tubes embedded within the wall and floors to make the occupied space cooler.

Air Source/Sink Heat Pump Air Conditioning System

As an optional system, an air source/sink air conditioning system is proposed.

One outdoor unit having an electric driven compressor is installed on the roof for each dwelling unit. The room unit(s), single or multiple, is installed within the occupied space and pre-insulated refrigerant tubes run between the outdoor and room unit(s). The average efficiency, COP, of this system is more than 4.5, that is the output energy is more than 4.5 times of the input energy. The wall cavity is used for refrigerant tube runs.

Evaporative Cooling System

As an optional system, an evaporative cooling is proposed. The rainwater, which is stored in the basement, is sprayed with atomizing nozzles over the surface of the inner panel to make it slightly wet. When the air travels upward within the wall cavity along the walls, evaporation takes place on the wet surface. Then the surface temperature becomes lower to reduce heat penetration into the occupied space in summer.