A BIO-POOL HOME KEEPS COOL NATURALLY
Chemical-Free Pool is Key to Lower Energy Costs
Cooling by Wind and Water
Well
known for some of the best sunshine and year round warm weather on the
Big Island of Hawaii, Waikoloa Village is also affectionately called
“Waikobloa” - thanks to the strong easterly winds that
blow through this community. A major concern in designing a new home here, is how to create pleasant
indoor-outdoor spaces to the pool, garden and views, in the presence
of these often fierce, 20-30mph winds. While most residents here simply shut out the wind and turn on the A/C, an innovative design by Robert Mechielsen of Studio RMA, Los Angeles,
uses the wind to advantage for circulating cooling air throughout
all the rooms minimizing the need for fans and/or A/C and hence greatly reducing energy costs.
 In this design, a bio-pool serves as a cooling mechanism for the air
currents passing over it, cooling the breezes
into the indoors which are then sucked throughout the upper levels and out of roof vents.
The innovative roof design is therefore particularly crucial. Firstly, the placement of the roof vents ensures that the cool pool air is drawn in through the house and exited out the roof and secondly, Robert's slanted roof design takes the brunt of the
winds blowing from the back of the house, deflecting them away from main living areas and pool in the front. This work-horse of a roof also supports the solar energy systems to generate electricity and hot water for the house, and so accomplishes many functions.
The bio-pool not only makes a good size swimming pool but is a truly beautiful architectural feature, extending along the front living
areas right up to the house's patio edges. It can even serve
as a reservoir should there be water shortages since one carp, one aerator pump and a 20% shallow bed of
aquatic plants, maintain high water quality completely chemical free. Conventional pools treated with chlorine, could not be sited this close to the structure as chlorine is too corrosive.
Choosing the Construction
Material
The clients chose Structural Concrete Insulated Panels1 (SCIP) for their new home construction, for its resiliency against fires and earthquakes, termite retardance, low maintenance over the long term and it is much more energy efficient than the "stick built" (wood and stucco) homes in the area.
Sustainable architecture proponent Robert Mechielsen loves to design with this material. It allows large wall openings, with few supporting posts or columns, enabling living areas that literally open to the outdoors. In Hawaii, this is the ultimate design for enjoying the views and balmy climate. 
Together with the clients, Robert’s goal is to achieve Platinum level LEED2 credits for this new home project. As an “eco-think-tank” team,
Robert, his staff and the clients are hoping to set the example for
affordable “green building” of residential homes in West
Hawaii. Both Robert and his client Dr. Markus Lenger, received their formal education in Europe, and bring the best of green technologies to the US, incorporating as many as is practical in this project.
Affordability
The project’s goal is to stay within a fixed budget, which is
approximately 5% more than the same square footage cost of conventional
stick building. The energy efficiency savings over 5 to 10 years,
along with low maintenance and lower house insurance premiums, will
mean greater cost savings in the long term compared to a stick built
home.
Proposed Features
These “green building” features are proposed:
- Orientation of house on the site along with roof design, creates
“negative” wind-free living areas.
- Minimize footprint and grading requirements in the siting and design
of the house. A two-story home not only makes a smaller footprint,
but opens up more rooms to the ocean views.
- Passive solar design minimizing windows on the hottest side of
the house and using long roof overhangs and shading elements (trees,
shutters, etc).
- Wall, floor and roof insulation against heat is provided by SCIP,
which also makes extremely tight seals possible.
- Interior layout of the rooms, windows and doors, maximizes natural
light and natural ventilation so less electrical energy is needed
for lights, fans and/or a/c.
- The swimming pool is a bio-pool, acting as a cooling mechanism
for the air currents passing over it, and in addition to recreation,
it serves as a reservoir. When rainwater is not available, filtered
city water fills the pool.
- Energy star appliances to be used in kitchen, laundry, a/c, fans.
Water wise flushing toilets. Solar water heating.
- Recycled and natural materials for flooring, cabinetry, countertops.
- Solar and Wind energy system - solar energy from solar panels on
the roof, and a wind turbine at the back of the property.
- Landscaping is to be as low maintenance as possible using water-wise
plants and grasses. The sprinkler system uses water recycled from
the house’s bathing water runoff and roof rainwater runoff,
stored in underground tanks.
- The Hydrologix® Bio-Wastewater Treatment system will replace the septic tank, and the grey water by product will be used for landscape irrigation.
- Further energy efficiency will be achieved via a computer controlled lighting and window/door closure system which will also manage entertainment and appliances.
Elevation Drawings
Front of house from the street, west facing
Side view, north facing
Floor Plans
The V-shaped layout, maximizes exposure of the rooms to the cooling
air breezes passing over the bio-pool and into the house.
Ground floor (upper floor is not shown).
For more information contact:
Frederica Lenger, email "hawaiiecohome [@] mac.com"
Mo Whelan, Studio RMA, www.studiorma.com
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