Rehabilitating efficiently a building involves carrying out certain actions that allow to improve its energy efficiency, that is, substantially reducing its energy consumption and CO2 emissions. The actions to be undertaken to achieve this goal vary depending on the characteristics of the building: its age, type, the type of enclosure used on the facade, or its thermal installations; this also depends on the presence detector.Elements to achieve an efficient rehabilitation and operation of the presence detector:
- ACS and air conditioning equipment: the improvement in efficiency of the building's installations leads to the greatest savings in the overall computation of the building's energy consumption. This can be achieved by covering energy demand with the provision of renewable energies, as detailed in the following measures:
- Joint use of solar thermal installation with condensing boilers for the production of sanitary hot water.
- Installation of a natural gas heat pump to meet the ACS demand, using underfloor heating as a heating and cooling system, and incorporating a supply of solar thermal energy.
- Installation of biomass boilers, provided that the orientation conditions of the building's facades advise it and there is sufficient space for fuel storage.
- Implementation of other types of renewable energies such as geothermal energy, cogeneration systems, or hybrid systems.
- Thermal envelope: this is the membrane or exterior enclosure of the building that allows controlling the climatic conditions of its location, improving and adapting them to the comfort needs of its inhabitants. The efficient rehabilitation of a thermal envelope can be carried out in the following way:
- Insulate the exterior of the building’s enclosure with a ventilated facade formed by: an auxiliary structure anchored to the existing enclosure; a layer of thermal insulation fixed with adhesive mortar; and finally an exterior finish layer. The sub-structure leaves a few centimeters of air chamber between the layer of insulation and the outer layer. The joints connecting these plates are open, allowing a constant flow of air that ventilates the final facade.
- Improve the thermal insulation conditions of the glazing of openings and windows in the facade walls, by placing double glazing with an air chamber.
- Energy savings: presence detectors: the degree of energy efficiency of a ventilation installation is significantly increased by placing electronic elements such as CO2 or humidity sensors. These systems are increasingly used as experience shows that most office spaces, meeting rooms, stores, etc., have a maximum occupancy of 60% during the day. These elements are connected to the ventilation system to adjust it according to the pollution level affecting each space. The sensors are integrated into the ventilation system which can be single zone (the space to be ventilated consists of a single open area without divisions) or multi-zone (the area to be ventilated consists of several compartmentalized areas requiring homogeneous ventilation treatment). In both cases, ventilation initially operates with a minimum ventilation regime. The CO2 sensor will detect the increase in pollution based on the occupancy of the room and send this data to a regulating element that orders to increase or reduce the speed of the fan proportionally to match the flow to the needs of each moment. In this way, significant energy savings are achieved in relation to total ventilation systems. In systems that incorporate hygrometric sensors, the process is repeated once changes in humidity values in the environment are detected. The use of control systems with triple signal (CO2, relative humidity, and temperature) that incorporate sensors with the three environmental parameters, capable of discriminating which of the three is the most unfavorable when ordering the system to increase the fan speeds, leading to an increase in the volume of renewed air, is also common. There are also presence detectors equipped with sensors sensitive to movement that help conserve energy by activating the lighting only in those areas of the building where any type of activity is taking place, turning it off elsewhere.
