Compactness:
The building has a 0.37m-1 form factor for its 5,920m2 of usable space, giving a ratio which is hard to improve. Compactness means the relation between surface and envelope and the climate controlled area can be optimised, thereby reducing the former. This principle has been merged with important strategies aimed at simultaneously securing good natural lighting for work areas, as will be explained later on.
The characteristics of the site requires long walls facing south-west and north-east. This meant that a careful re-orientation study was performed when designing the spaces combined with the eaves in the parts facing the sun. (Figure 1) Using this system, 89% of the surface openings face south and east, achieving thermal gains in winter, and a self-shadowing effect in summer, thereby reducing the cooling load, whilst at the same time ensuring natural light. On its longest sides, the resulting surface resembles a “saw-tooth”, one drawback being the increased surface envelope. This disadvantage is offset by the design, which leads to a 24% reduction in the building’s cooling loads, according to the simulations carried out.
Increased insulation in the thermal envelope:
Table I shows the thermal transfer coefficients used in the building envelope compared to those stipulated by Spanish Building Regulations (CTE) and ASHRAE (ASHRAE 2007). The insulation coefficients used, a key factor (U=0.17 W/m2K on facades, and U= 0.15 W/m2K on the vegetation canopy) will restrict loss through transfer and therefore lead to a reduction in demand. One drawback is the increased energy in the materials that can be reduced or even removed through the use of natural insulation (100% natural black agglomerated cork), and an extra financial cost which is offset by the reduction in energy consumption. One further aspect to be taken into account in this section is the effect of thermal inertia achieved in the structure of the building itself (reinforced concrete), particularly with the green roof, which covers 73.5% of its surface.
Table I. Thermal transfer coefficients used in the LUCIA building compared to Spanish Building Regulations (CTE) and ASHRAE
Natural Lighting:
Table II. Comparison of the lighting systems in a normal building and in the LUCIA building. Illumination systems
*Data obtained from the energy simulation report using the DOE-2 system for energy calculation and cost analysis, and the EQUEST 3.64 programme
Open-plan car park design:
The decision to construct a compact building has been merged with an increase in natural lighting of indoor areas through the widespread use of tubular daylighting devices (27 in all) and skylights above the staircases. In addition to offering beneficial effects for health and wellbeing, natural light reduces the electricity requirement for artificial light (See Figure 2). The system affords a number of excellent benefits: these are static elements which simply reflect incident sunlight, as a result of which they require no power to work. According to the simulation carried out, the annual 146,190 kWh lighting that would be needed by the reference building (ASHRAE standards) would be cut to 74,790 kWh in the LUCIA building (approximately half) thanks to these devices. The cost of these 27 devices was calculated in the project estimate to be around 13,483 €.
Table II. Comparison of the lighting systems in a normal building and in the LUCIA building. Illumination systems
Open-plan car park design:
Figure 2. (Axonometric section. Tubular
daylighting devices, open car park, and biomass trigeneration place).
