The First Low Energy House in Jordan

Aqaba House, Copyrights Joseph Zakarian, Jo Magazine

UPDATED – Jordan’s first low energy house in Aqaba is a residential project designed with the intention of creating a prototypical low-cost energy efficient building that achieves substantial energy use reductions without incurring additional construction costs.

After launching a design competition for a prototypical energy efficient house the house owner – a Jordanian environmental researcher- in collaboration with the Jordanian Center for the Study of the Built Environment, chose to proceed with a practical low energy design with an architecture that resonates with local aesthetics.

The competition’s winning scheme by the Dutch architect Florentine Visser, was based on a 3-floor design that included the many spaces required by the owner’s brief (including 6 bedrooms, 3 bathrooms, a car garage, and a basement) in a house with a total area of approximately 420 sqm.

In her approach to designing an energy efficient house, the  house’s architect used a combination of passive low energy design strategies and efficient active systems. Passive strategies are strategies that use design to reduce the need for heating and cooling. In the context of the Middle East passive design mostly refers to passive cooling strategies since the cooling requirements of middle eastern buildings far exceed their heating requirements.

Active systems, on the other hand, are mechanical systems such as heating, ventilation, and Air conditioning units (HVAC) efficient active systems use less energy to heat, ventilate, or cool buildings.

Most successful low energy buildings use a combination of passive strategies, active systems, and renewable energy generation to reduce their energy use ,with some buildings achieving the ultimate target of net zero energy, which essentially means that a building -or a  development- generates all the energy that it consumes.

Passive design strategies

The architect approach started with traditional environmentally-responsive design strategies such as careful planning and orientation. The house’s spaces were arranged so that functions with short term use, such as bathrooms and corridors, were located on the south west side -the hottest area in the house- thus providing a buffer zone to keep space with longer terms use, such as bedrooms at the north eastern side of the house, away from solar heat gain and therefore cooler.

House Plans. Copyrights Florentine Visser

The design also featured the use of architectural shading and landscaping to reduce solar heat gain. Shading elements were optimized to block insolation from the summer’s high sun, while allowing the winter’s low sun to enter the house to minimize the winter’s heating needs. In addition, shading was also provided to the outdoor spaces on each floor, creating a comfortable outdoor space with access to breezes.

To further reduce solar heat gain and the need for cooling, the design also employed modern passive methods such as the use of insulation in the building’s walls and roofs. The cavity walls were insulated by blocks with aggregate and insulation materials. In addition, the roof construction and the heat bridges’at the floor-to-wall connection were also insulated, both uncommon insulation practices in the Jordanian construction industry.

House Plans. Copyrights Florentine Visser

The use of modern insulation was coupled with the use of a traditional passive method known as thermal mass, which relies on using walls and roofs whose mass can absorb much of the solar heat and thus prevent it from making its way into the house interiors. This method was implemented through the use of stone cladding, which is common in Jordan. In addition, the thermal mass of the North facing walls which accommodate the bedrooms was also increased by filling their wall cavities with sand and by finishing them with plastering that included straw. The house’s roof garden also played a role in reducing cooling needs not only in providing planting shade but also as a thermal mass. The mass of the garden’s 40 cm thick soil helps absorb solar heat before it reaches the house interior below.

The design also featured an optimized natural ventilation strategy which was not limited to employing cross ventilation and the careful placement of windows and doors. The design also featured the use of the staircase tower as an outlet wind tower by placing a ventilation opening in it which helped create a pull of cooler air from the house’s windows. Natural ventilation was coupled with the use of evaporative cooling as a cooling method in some outdoor spaces. Evaporative cooling is a traditional environmentally-responsive cooling technique where a water feature is used to reduce air temperature indoors or outdoors.

Active design strategies

In addition to passive strategies, and to further increase the house’s energy saving and improve its interior environment and comfort levels, the design team recommended the use of active methods such as a solar cooling to complement passive strategies. Solar cooling is a solar powered active cooling system that uses hot water from solar panels as an energy source for an adsorption chiller, producing chilled water for space cooling. The advantage of using this system is that in the summer when the need for cooling is at its most , solar energy is usually available to produce hot water to run the cooling system. Furthermore,  In addition to solar cooling , the house also includes energy efficient appliances and lighting fixtures.

Water and Landscape

Outdoor space , Copyright Joseph Zakarian, Jo Magazine

While Jordan relies mostly on imported energy, it also struggles with major water scarcity issues. In fact Jordan is one of the world’s poorest countries in terms of water resources. As a result, water conservation was as important to this project as energy efficiency.The house design thus featured substantial water conservation measures. The house is equipped with a dual plumbing system, which separates grey and black water disposal. Grey water from showers and sinks is filtered by a bed of sand-gravel with bamboo, and is used to supply the garden with its required irrigation water.

In addition, the required irrigation water was also reduced by the Landscape architect’s choice of water efficient plants and trees that are suitable for the Aqaba climate. It is estimated that the house’s water saving would exceed 50% compared to an equal size house in the same ares, as a result of savings in irrigation water together with the savings achieved as a result of he use of water conserving fixtures in the house.

Cost analysis of low energy design

Perhaps the most noticeable feature of this project beside its combination of low-energy design with contemporary local aesthetics, is the low cost of implementing these low-energy strategies. To achieve a balance between initial costs and energy use savings, the design team proposed three cost scenarios for the project to identify their additional initial costs (compared to a standard construction in the same area) and their expected energy savings.

The first scenario only included the passive strategies and excluded  the solar powered cooling system. Its budget was estimated to be 18% more than a standard Jordanian construction. On the other hand the house is expected to achieve energy saving of 32% which suggests a short payback period of approximately 5 years depending on energy prices.

The second scenario includes the addition of active methods such as the solar cooling system and results in an increased initial investment of 45%  (compared to a standard construction in the same area) with a 72% energy savings, which suggests a 10-year pay back period.

A third scenario, which sought to take energy savings closer to a net-zero energy house by generating energy using photovoltaic cells showed a 67% increase in the initial capital investment with a 93% energy savings. This scenario, however had a very long pay back period, where the initial costs can only be reclaimed after 14-years of occupancy. Ultimately, the construction budget did not allow for this additional capital investment and the second scenario was implemented.

While the project is a private house, it is to remain open for the public for a year as an Energy Efficiency Demonstration House to inspire future designs of surrounding developments around Aqaba.

For more information on the project design, its cost, technical aspects, and lessons learned, a detailed report is available on the Jordanian Center for the Study of the Built Environment (CSBE).

Karim Elgendy is an architect and a sustainable design researcher based in San Francisco. He can be contacted at: Karim [at] Carboun [dot] com

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