Climate change is an inevitable process and all mankind must prepare to confront it. The global survival strategy shall comprise of reducing man-made greenhouse gases and, at the same time, of adapting to global warming. Honeycomb housing could be an important urban and architectural element of this strategy.
When half a century ago, my grandfather was taking care of his bees in our “Garden of Eden” in Arad, Transylvania, I was often helping him with the hives. Although I’ve experienced the kamikaze stings many times, I feel fortunate to have discovered their marvelous world.
The beauty of the hexagonal grid lies in its simplicity and flexibility. No wonder it was adopted by Mother Nature when she created the honeycomb. The bee hive is one of the most efficient and functional natural structures and can provide much inspiration to architects. The honeycomb concept achieves the main objectives of sustainable design: reduced use of land and natural resources, environmental protection and self-sufficiency.
The concept is based on prefabricated hexagonal modules with a central dome and clerestory skylight. The modules are covered with soil, leaving only the domes exposed. They provide access, natural light and ventilation to the living space below. This configuration allows each unit to have two entrances, one at the lower street level and the second from the rooftop garden. The design incorporates an optional central lift, making each dwelling wheelchair accessible to all levels. This flexhousing™ feature is essential considering the growing elderly population and the large number of persons with reduced physical mobility. Sheltered vehicular access and parking are provided at the lower level.
In existing urban areas, the honeycomb concept could be used to reclaim lands with unattractive or hostile environments where traditional housing would not be appropriate. Such lands may include infill lots near highways and other pollution sources, and “brown” or contaminated fields, where artificial re-grading would in fact rehabilitate the land and create green space. Such re-development would contribute to urban intensification, which is an essential component of sustainable development.
In a honeycomb village, the spatial separation between buildings, which in conventional subdivisions results in much wasted land, is practically eliminated. Each hexagonal module has its own independent walls, achieving complete privacy and noise control. The structure is made of reinforced concrete, is noncombustible and can be designed to withstand earthquakes and other impacts. The honeycomb concept also offers great flexibility within the hexagonal grid, in terms of unit layout & size, and most importantly, in terms of site planning. Of course, the feasibility of this concept depends on the acceptance of communal land and building ownership, not different from a condominium development.
Honeycomb housing would also provide protection against severe weather events which are occurring more frequently because of climate change, such as extreme heat waves and storms. It could be most appropriate in geographic zones with inhospitable climate, such as deserts, hot (i.e. Sahara) or cold (i.e. the Arctic). In the more distant future, the honeycomb concept could be used to develop human settlements on Moon and Mars.
The following two figures illustrate a sample village of approx. 12 hectares (29.65 acres) with 260 dwellings, made up of two symmetrical communities located both sides of the transportation corridor. The residential area alone covers 8 ha (19.77 ac). The settlement can be easily expanded and/or planned in many other shapes.
Each dwelling is located within walking distance from public transportation. Figure1 illustrates a two-way railway track, developed in the median of the highway, which could be a streetcar or an elevated high-speed monorail. The train station is at the centre, with sheltered linkages to all major facilities required by the community. In extreme climates, these facilities can be developed inside large geodesic domes that would enclose the open spaces between buildings. Small scale live-work units including retail and personal service shops can be developed along the pedestrian pathways leading to the residential clusters, creating the Main Street.
Orientation, both above and below ground, and the identification of each individual dwelling, is an important issue. Extensive mapping and signage will be required, combined with a variety of treatments of the walls in terms of finishing materials and colours, for easy identification. Fortunately, we live in a communication age and an electronic guidance system could be easily developed.
Being exposed to the sun, without shadows from buildings, the rooftop gardens are ideal for leisure, play and gardening. The layer of soil prevents heat loss or gain, keeping the interior warm in the winter and cool in the summer. It works ideally as a heat sink in the desert climate with large day-night fluctuations of temperature.
A walk through the rooftop gardens along the trails connecting the entrance doors to the domes would reveal a rolling landscape, with drainage creeks and small ponds, vegetable gardens and orchards. Some domes could support windmills; others could have greenhouse extensions.
The clerestory domes can be expanded with greenhouses, which could also be used to grow fruits and vegetables in a protected and controlled environment. Poultry and small domestic animals could also be raised. The rooftops could also accommodate septic beds for sewage treatment, which would become an integral part of a natural recycling process where everything is reused.
The following figure is a sample of rooftop gardens above the school area
The central courtyards created by dwellings in alternative X can be enclosed with geodesic domes. In addition to playground and pool, these climatically controlled spaces can be used for year-round food production. The size of a courtyard and dome can be enlarged by increasing the perimeter with more dwelling units, thus providing the opportunity for creating mini ecosystems.
The concept is based on several types of prefabricated hexagonal modules with a footprint of 30m2 (or 323 sq.ft.) in both alternatives. The roofs of all modules are shaped as truncated hexagonal pyramids for optimum spatial, structural and water drainage performance. The optimum configuration is subject to detailed structural design and testing.
Two alternative designs are proposed: alternative X has one-storey units with glazing open onto an interior courtyard, while alternative Y has two-story units without windows (with the exception of entrance domes and skylights) and must rely on specially developed light wells in order to receive natural light. A specific site can use either alternative, or a combination.
Section and Plan of Alternative X
There are two types of modules: XA and XB for interior space, both on one level, and one module XC to cover outdoor dwelling space and vehicular area. Both modules XB1 and XB2 are provided with doors and windows that open onto the central courtyard (a geometric effect of the hexagonal pattern).
Module XA provides the main entrance from the street and the access to the rooftop garden, through a clerestory dome. The core of this module incorporates a stair revolving around an optional lift which would make all levels accessible to people in wheelchair and could also be used for moving heavy objects. This module also accommodates the hallway, the kitchen and a washroom.
The interior layout of module XB is developed for various residential functions: XB1 for living and dining, XB2 for bedrooms and XB3 for bathrooms, laundry and storage. An average two-bedroom dwelling unit of 120 m2 (1292 sq.ft.) gross floor area, requires 4 modules: XA + XB1 + XB2 + XB3.
Section and Plan of Alternative Y
There are two types of modules: YA and YB for interior space, both on two levels that can be adapted to various residential functions. A third module YC, with the same footprint and with optional skylight, can be used to cover outdoor space and the street.
Module YA provides the entrance from the street and the access to the rooftop garden through a clerestory dome. The core incorporates a stair revolving around the optional lift. This module also accommodates the entrance hall, the kitchen and a washroom on the lower level, and a bathroom, the laundry with storage and cupboards on the upper level.
Module YB has a clerestory dome with a sunwell that bring light to the lower level used for living and dining. The upper level accommodates two bedrooms and an ensuite. They are all lit from the clerestory dome. Module YC is supported by columns that follow the wall pattern of modules YA & YB and can be adapted for larger openings required by driveways and parking. An average two-bedroom dwelling unit of 120 m2 ( 1292 sq.ft.) gross floor area, requires 1 module YA + 1 module YB.
Elements for further Research & Development
The elements of the concept listed below, not necessarily in their order of importance or priority, need further design, research or testing. The ultimate goal in developing these elements is to enable the community to become self-sufficient in water, energy, and waste treatment. Ultimately, a life scale prototype of several modules shall be constructed to allow the research and development of the ensemble.
Structural Design and Testing
The superior structural performance is not only based on the vaulted shape of the individual modules, but also on their interlocking with each other in the hexagonal grid. Following the detailed structural design, a working model shall be built to experiment with various stress scenarios. The exact configuration dimensions, reinforcing and concrete composition of the prefabricated modules shall be established for optimum function and efficiency. Developing the best method of prefabrication, transportation and erection are also crucial for the economic viability of the concept.
Passive Solar System
The concept applies the principles of passive solar heating. The clerestory windows welcome the winter sun to penetrate in an optimal fashion. Then, the inside surfaces of the dome (painted white) reflect the sun’s rays toward the walls and floor. There is a great thermal benefit from having a large area of exposed concrete surface at floors, walls and ceilings. Concrete has a high thermal mass and will absorb the excess heat on sunny days, store it and release it when the indoor temperature drops. The only heat loss (or gain) will occur through the windows of the clerestory domes. To minimize this heat loss (or
gain), the walls and roof shall be insulated and the windows could get special treatment described below at Insulating Windows and Insulating Adjustable Louvers.
Photovoltaic Solar System
The above ground exposed surfaces, such as the roofs of the domes can be clad with photovoltaic panels. These could be developed as shingles or roofing membranes using Nanosolar technology. The utility switch, inverter and batteries can be located on the upper hall near the hydrogen generator.
The surplus electric energy collected from the photovoltaic panels and windmills can be used to produce Hydrogen and Oxygen from water, through hydrolysis. Hydrogen then can be used to produce energy as needed, with power cells or other types of generator. The Hydrogen tanks can be stored under the soil, protected from heat and vandalism. The Hydrogen, Oxygen and Nitrogen generating equipment is located on the upper hall near the door to the roof top garden.
Both alternatives have a larger clerestory dome with vertical windows and an entrance door. Module YB also has a smaller clerestory, shaped like a truncated hexagonal pyramid, with slanted windows that direct the solar rays into the Sunwell Distributor.
All windows will have the exterior panes made of one-way safety glass for privacy and security and will be provided with external adjustable louvers. The motorized louvers will be developed for sun and thermal control. The double glass panels will be designed as transparent air-tight containers, connected to reservoirs at top and bottom; thousands of tiny beads of insulating foam will be blown in and sucked out by an air pump, as required. The insulating beads would increase the thermal resistance value of the glazing to the level of the insulated walls.
Adjustable Insulating Louvers
The clerestory windows are provided with insulating louvers mounted on the outside. These are made adjustable to take into account orientation and time of the day and can be operated by electric motors, which can be controlled by a computer. The same computer can control the insulating windows.
Ventilation and Air System
The Oxygen obtained from water through hydrolysis will be used to improve and could even create the indoor air. Carbon Dioxide will be released, or consumed, by plants, through photosynthesis. Nitrogen will be produced by the waste treatment system. The quality of the interior air can be controlled and the intake of exterior air can be reduced or even shut off completely, depending on outdoor pollution level. This would become very important in case the outside air would become contaminated.
Rainwater is filtered through the various layers of soil, flows down the sloped roofs, and is collected by perforated pipes placed along the valleys of the hexagonal grid, flows down vertical pipes placed at the intersection of three modules into cisterns located below the floor slabs. A series of pipes placed under the floor slab along the perimeter of the hexagons connects the cisterns into a network. From here, the water is pumped up into storage and distribution tanks, located above the kitchens and bathrooms. These tanks will also be provided with exterior taps for filling up from water tankers or fire trucks as needed.
Hose bibs will be distributed over the entire area and a dripping pipe network for efficient use of water could be incorporated. All surplus water resulting from rain or watering the gardens is collected and recycled.
If necessary, the issue of high or fluctuating underground water table can be addressed as part of a storm management study required for each specific location. This would involve soil engineering and possibly incorporating a grid of drainage pipes (or weeping tiles) placed under the floor slabs. This grid could be connected to the water network. The storm water management may require the creation of collection pools and creeks which could be incorporated into the park’s landscaping (as illustrated in Figure 2). These pools and creeks would also contribute to irrigation and to creating a tempered microclimate for the rooftop gardens.
In colder areas, despite all heat loss preventive measures, the dwelling will need a back-up heating system. Radiant floor heating is probably the most efficient and comfortable way to supplement passive solar heating. In a desert climate, a similar system would cool the floor. It may make sense to incorporate a geothermal system as an underground heat exchanger to make use of the difference of temperature between the surface and the underground soil. It could be very cost effective, as it would not require additional excavation and it could use the underground piping network of the water system.
Waste Treatment and Recycling
The toilets will be flushed with “grey water”. The waste water from toilets will be collected in a septic tank. From here the sewage will go through a complex process involving filtering and aerobic bacterial treatment. The water can be used for gardening and the solid waste as organic fertilizer. The methane gas produced can be used as fuel for back up generators and to extract Nitrogen.
Plant Growth in Artificial Soil
The rooftop gardens are artificially created; therefore the composition of the soil layers used to cover the hexagonal modules must be researched. Subject to its properties, some of the original soil may be reused as base material for filtering. The use of organic fertilizers and the integration of waste treatment shall be studied for creating the top soil and its maintenance with minimum or no import required.
The transparency of the above ground domes and greenhouses, with no hidden corners, makes the rooftop gardens safer than in conventional housing green space. A network of surveillance cameras and motion detectors can be installed and monitored from a central station and from each unit as well, allowing close observation of children’s playing and other activities. The vehicular access would be controlled through gated checkpoints.
Without special measures, the uniformity of the underground streets and buildings could make it difficult to find an address. In addition to visible and well lit signs and house numbers, such measures can also include colour-coded walls and identifying features, sculptures, etc. An orientation and mapping system similar to GIS can be developed to enable the residents and visitors to easily locate their destination.
Geodesic Dome Ecosystem
The courtyard created between dwellings can be enclosed with a glazed geodetic dome to create a mini ecosystem. This could be the subject of a special research program.
Sunwell (for alternative Y)
In alternative Y, conventional livingroom windows are replaced by sunwells. A Sunwell consists of three main parts: the Receptor, the Conveyor and the Distributor. The Receptor, mounted on top of the clerestory dome of module B, has a rotating dish of mirrors, follows the sun and reflects solar radiation into the Sunwell Receptor tube. This has specially developed layers of glass which would reject harmful rays, but would allow light to penetrate into the Sunwell Conveyor. The Conveyor has specially coated and textured surfaces, acting as mirrors that convey the light waves down the well towards the Distributor. The Distributor is located in the centre of the raised ceiling of the living/dining area and will reflect the light onto the sloped ceiling. The entire cathedral ceiling becomes a giant naturally lit chandelier.
Simulated Sunny Environment
To counteract the main drawbacks of an underground living space, mainly loss of direct sun exposure and view of the exterior, a simulated sunny environment could be introduced.
The Honeycomb concept offers a housing solution that reconciles modern human needs with protecting the natural environment. It also provides a practical way to make use of lands which are not suitable for conventional housing. In this respect, Honeycomb Villages would be an integral part of sustainable development.
Another benefit of the Honeycomb is that it could provide housing in extreme climates, becoming an intrinsic part of our adaptation strategy; it could even be considered for future Lunar and Martian settlements.