LIMA Foundation

Prototype: Zero Emissions Building

The LIMA prototype has been developed by a research team lead by SaAS – Sabaté associates Architecture and Sustainability – with the participation of 40 companies from the sustainable construction and energy efficiency sector. It is based on a series of previous studies focused on drastically reducing the global environmental impact of buildings in warm climates and to provide a reference for future building in the Mediterranean area.

The reference building for the study of the prototype is a three storey apartment building with 12 flats with the same constructive characteristics as the 45m2 prototype. Both building´s environmental impact due to construction materials, water consumption, health and comfort aspects and especially energy demand and consumption were analysed in such a way that the results of exhaustive monitoring of the prototype could be extrapolated to the 12 flats.

The prototype was presented at the Construmat fair 2009, and is currently being monitored in standardised conditions at the Engineering and Architecture Campus of La Salle, Barcelona. A second phase will monitor the prototype in real use conditions.

Awards

One of the main features of the prototype is that it drastically reduces the environmental impact associated with the extraction of raw materials, the energy required to produce building materials, the energy required for the use phase of the building as well as water consumption:

• MATERIALS: 83.7% are renewable or recycled materials, reducing the impact associated with the processes of extraction and manufacture of building materials (damage to the environment by extraction of raw materials, local pollution caused by manufacturing processes, acid rain, etc.). 63% of materials come from renewable sources, mostly of plant origin (wood or bamboo), while 20.7% are from recycled materials (compost, gravel, etc.). Another aim is to reduce the toxic load of construction, limiting chemical inputs by finding natural alternatives for insulation, paints and oils.

• ENERGY: 97.4% reduction in CO2eq emissions over the 60 year life cycle. The reduction in energy use and emissions associated with construction materials is achieved by substituting concrete, steel and aluminium and other materials that require high energy inputs with materials of plant origin (wood or bamboo). To minimise energy consumption during the use phase of the building, LIMA offers increased insulation and solar protection, the use of heat recovery and ventilation regulated according to occupancy, centralised high efficiency heating and cooling with solar thermal collectors for hot water and heating, the incorporation of control systems and management, the use of low energy and LED lighting, class A + and A + + appliances and photovoltaic electricity generation.

• WATER: 52.9% reduction in water consumption by using water efficient appliances and fixtures, rainwater harvesting for plant watering and the washing machine, and the use of gray water from the shower for the toilet flush. It also incorporates biological sewage treatment.

Construction section

Roof ( U=0,25 W/m2·K)
– Soil for extensive green roof, 70mm
– Geotextile felt, polyester and PP
– Drainage and water retention, EP
– Filtering blanket, PP fibres
– Impermeable sheet, EPDM
– Geotextile felt, polyester and PP
– Wood fibre insulation, 120mm
– Vapour barrier of PP
– Cross laminated timber structural panel, 125mm
– Plasterboard, timber substructure (50×50), 15mm

Windows U = 1.1 W/m2 • K; solar factor g = 0.48). (U = 1.4 W/m2• K overall)
– Window frames of larch
– Laminated glass with air chamber and +3 = 6/15/3
– Exterior aluminium blinds, adjustable slats

Facade (U = 0.26 W/m2 • K)
– Horizontal timber cladding on timber substructure (30×50), 19mm
– Ventilated cavity, 30mm
– Semi-permeable sheet, veil PP
– Wood fibre insulation, 120mm
– Structural cross laminated timber panel, 108mm
– Ventilated cavity, 30mm
– Plasterboard, on timber substructure (30×50), 15mm

Slab
– Floating bamboo flooring, 15mm
– Wood fibre insulation, 30mm
– Geotextile-felt, polyester and PP
– Ballast, 60mm
– Geotextile-felt, polyester and PP
– Structural cross laminated timber panel, 125mm
– Cellulose insulation, 40mm
– ventilated cavity, 10mm

Ground slab (U = 0,36 W/m2 • K)
– Floating bamboo flooring, 15mm
– Wood-fibre insulation, 100mm
– Structural cross laminated timber panel, 125mm

Monitoring and results

The purpose of collecting energy and water use data is the empirical verification of the results obtained in the research phase. This is done in two different situations between 2011 – 2014:

a. monitoring of the prototype in standardised conditions, obtained by incorporating energy loads equivalent to the use of the building on the provisional site at the School of Architecture and Engineering La Salle, Ramon Llull University , Barcelona.

b. monitoring of the prototype in real conditions of use, in its final location in Sant Cugat del Vallès (Barcelona).

Example graph of data obtained from the prototype in 2011