ECOFEATURES
• Orientation and plan • Thermal mass • Winter solar heating • Summer cooling
• xeriscape
DESCRIPTION/BRIEF/CONCEPT
The Meir House is located in the first solar neighbourhood in Israel, Newe Zin, and
was designed as a prototype towards creating an energy-conserving urban buildingcode. It combines external insulation and internal thermal mass with open plan.
Through QUICK simulation prior to construction and monitoring post-construction,
the Meir House proves the success of an integrative approach to the design of a bioclimatic
desert house.
ECOFEATURES EXPLAINED
Orientation and plan
Considering the
site’s geometry and climatic constraints, among them solar angles, air
temperatures and wind directions, the log axis of the house is east–West, with four
bedrooms and the living room to the south. The ground floor is exposed in all fourdirections. The kitchen, baths and laundry room are located at the northern part of the
plan and the garage serves as a western buffer. All spaces, excluding the garage, are a
single thermal zone. The house also includes a number of verandas and balconies
facing in different directions. Main fenestration is placed to the south, with smaller
openings to the north for cross-ventilation. However, all rooms have openings in two
directions to ensure appropriate ventilation. There are only a few, small, recessed
openings in the west façade. The second floor is exposed in all four directions.
Winds are north and northwesterly in the early noon and evening hours, whereas
at night and early morning they may turn northeast by southeast. Average maximum
windspeeds range between 40kmh1 in winter and 30kmh1 in summer. The environmentally
responsive open plan layout proved to be successful as far as heat transfer
and circulation are concerned.
Another advantage that the Meir House integrates with its form is weatherprotected
adjacent open spaces. The south and north verandas and the southeastern
balcony are protected from wind by the mass of the building to the north and west
and by the garden wall to the west. These spaces are shaded partly by overhangs,
partly by deciduous plants (such as vines and Prosopis), and partly by pergolas with
agricultural shading fabric that has a 75 per cent shading coefficient.
Thermal mass
The wide diurnal temperature fluctuations characteristics of the Negev Desert climate
dictate the use of thermal mass, both for internal temperature damping and for
energy storage. Based on simulation results, the construction optimises thermal performance
by using medium-weight exterior walls and heavy-weight interior vertical
and horizontal partitions. The exterior walls are 250 mm cellular concrete (YTONG)
blocks, painted with a high reflectivity ochre-coloured paint. The low conductivity
(0.2Wm1 C) of the YTONG blocks eliminates the need for traditional sandwich wall
sections or external insulation that demands precise construction. Floors are reinforced
concrete poured in place. The roof is cast reinforced concrete, covered by extruded
polystyrene, aerated sloped cement and waterproofing.
Climatic conditions and termites exclude the option of
wooden frames for windows and doors. Aluminium
frames encase double glazing for acoustical considerations
and are fitted with mosquito screens. To further
reduce solar gains in the summer, external aluminium
rolling shutters filled with insulation (expanded
polyurethane) and interior venetian horizontal and vertical
blinds are fitted.
Winter solar heating and solar water heating
Approximately 24m2 (30 per cent of the south façade or
approximately 14.5 per cent of the total floor area) and
8m2 of the east façada is glass, achieving a passive
approach to heating the house. The addition of a collapsible
greenhouse (2.25m2) on the balcony, made of
polycarbonate 
sheeting recovered from a dismantled
agricultural greenhouse, yielded winter temperatures of
35–36°C during the afternoon (while the ambient temperature
was 14–15°C) increasing the room temperatures
by 1–2°C with the help of a small fan that pushes
the air into the living spaces. Through passive designs,
orientation, thermal mass and the collapsible greenhouse, savings of almost 90 per
cent on electric back-up bought from the utility company were realised, compared
with a typical electrically heated house in the Negev Desert climate. The Meir House
includes solar water heating using a high-efficiency solar collector (7000 kcal for a
1.5m2 collection area) and 150 litre water heater.
Type Heat only, excluding Unit cost (NIS) Cost of electric (NIS)
bathrooms (kWh m2 a1)
Meir House 5.5 0.25kWh 250.00
Typical house 72.2 0.25kWh 3250.00
Savings 66.7 3000.00
Savings are US$750.
Summer cooling and stack ventilation
Although the higher windows provide solar access to the
northern parts of the plan (necessary in the winter), the different
height of spaces and operability enhance stack ventilation
and exhaust hot air from the upper strata (during the summer).
North- and south-facing windows enable cross-ventilation during
summer nights, when outside temperatures are below
thermal comfort. Mesh screens play a definitive role by cutting
windspeed down to 20–25 per cent of external windspeeds,
but these screens are a necessity, keeping out pests and
insects.
Xeriscape
An intense post-occupancy project was carried out to reduce
by landscaping the amount of wind-driven dust. By laying
stone paving, pebble ground covering, and planting drought
and salinity-resistant plants, airborne dust is trapped and kept on the ground. Plants are drip-irrigated by a computer, providing a relative humidity
sensor by-pass to the automatic operation mode.
LESSONS LEARNED/PITFALLS
Initially a ceiling fan installed over the two-storey living area was thought adequate to
create air movement when windows remained sealed at times when ambient temperatures
were greater than interior temperatures. This proved insufficient owing to
the large volume and complex geometry of the space. To correct this, a smaller fan
was added on the ground floor to supplement circulation. The open plan has proved
very efficient as a strategy for the creation of a thermally uniform house, but has
drawbacks regarding acoustics, privacy and smells transferred from the kitchen.
Architect:
Isaac A. Meir, 1992–1994
Owners:
Orna and Isaac Meir with their three
children
Location:
Sede Boqer Campus, Negev Desert
Highlands, Israel; 30°N, 34°E; 470m
above sea level
Climate:
Arid, with hot and dry summers; cold
winters; 1017 degree days per year
Area:
208m2
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