Thermal comfort, indoor air quality and daylight are key factors in the comfort of building occupants. Despite the interconnection of these aspects and the related requirements, the way to achieve indoor air quality and thermal comfort are not clear enough in some EU countries. This situation underlines the importance of addressing the topic of Building Operation, which is crucial for ensuring adequate comfort and quality levels and at the same time achieving effective energy efficiency.
The difference between the anticipated and actual performance of buildings is known as the performance gap, and it has been observed often that the actual energy performance of buildings after their completion, is not as good as the expected one during design. This performance gap –the difference between expected and actual energy performance- is often related to the user behavior of the building occupants. In addition, when performing deep renovation of buildings, the design and construction processes also face this challenge. For instance, the ALDREN project has found that out of the 34 different national and regional implementations of the Energy Performance of Building Directive (EPBD), the calculated primary energy indicator after renovation could vary from 73 kWh/m2 to 5 kWh/m2. This is of great concern, especially when deep renovation are aiming at least 60% energy demand reduction.
As a way of reducing the performance gap, close attention is being given to building automation in the operational phase of buildings. In broad terms, building automation typically involves a number of automatic controls for heating, ventilation and air conditioning (HVAC) systems, lighting, access control, energy management, fire alarms and other controls with the aim to better control the building’s systems. Building automation may involve the use of an electronic building management system (BMS), and buildings fitted with such systems are often called smart buildings. For HVAC systems, building automation systems can deliver critical information on the operational performance of a building as well as enhancing the safety and comfort of the occupants and contributing to energy efficiency.
When operation and monitoring systems are installed, whenever possible, their installation and use should be as simple as possible. Building automation systems are divided into three levels: the field, automation and management level.
- Field level: The field level is responsible for the operation of the different technical systems of a building, via sensors and actuators that convert the received data into switching signals, for lighting, heating, air conditioning and ventilation systems.
- Automation level: The automation level has the task of controlling and regulating the building systems. This is based on the data supplied by the field level and the specifications from the management level.
- Management level: At the management level, the higher-level operation and monitoring of the processes take place, as well as the signalling of an alarm in case of detection of faults, via notification systems.
In this context, a way to increase energy efficiency is by using energy on demand and when needed. For instance, one of the benefits of having an automated HVAC system is achieving appropriate temperatures in winter and summer by regulating the temperature before anyone arrives in the building and after everyone leaves. The main advantages of building automation systems are their contribution to the comfort of occupants, the ability to maximise the use of natural light, to regulate the amount of fresh air in the building and by doing so improving the indoor air quality. Building automation systems can be combined with energy management systems to monitor data on energy consumption at the management level. Providing detailed reports and recommendations helps inform the decision-making process of optimising energy consumption and minimising the relevant operational costs.
The user interface (management level) - whether for occupants or building maintenance - displays the status of the system, detects shortfalls and makes the necessary adjustments, for instance, to maintain comfort, room temperatures at certain times, lighting control, lowering the consumption of hydronic system through variable frequency drives and in case of malfunctioning, providing notifications to end users.
The 4RinEU project is currently testing a state-of-the-art building automation prototype to aid deep renovation via the development and testing of the Plug and Play Energy Hub. The Italian demo case uses a hydronic module that can be connected in series/parallel allowing control and monitoring of complex heating and cooling systems, integrating available renewable energy sources (solar thermal) to improve the match between thermal energy demand and production. The Plug and Play Energy Hub system is controlled by an integrated digital controller providing (a) the supply of space heating and instantaneous domestic hot water when connected to a hot water source; and (b) the provision of an account of thermal energy consumed by the final user, distinguishing between domestic hot water and space heating. In this case, building automation and passive measures for energy efficiency are expected to have a significant impact on the heating consumption.
The Plug-N-Harvest project is developing a new modular, plug and play concept product for Adaptable and Dynamic Building Envelopes, deployable to both residential and non-residential buildings, which is able to provide high energy use reductions and high levels of energy harvesting from renewable energy. The Plug-N-Harvest system aspires to transforming static building envelopes to active ones by deploying off-the-shelf energy harvesting, storage and thermal comfort elements, therefore being able to dynamically adapt to available exogenous energy assets. This combination is expected to maximise the free use of environmental energy in a user and micro-climate (indoor and outdoor) oriented manner.
The project BIM4EEB is developing a tool linking BIM (Building Information Modelling) models to Building Automation Control Systems. The aim is to develop a common BIM management system with linked data and a set of tools for increasing semantic interoperability between software and stakeholders involved along the overall renovation process.
The project Switch2save incorporates building automation to deal with the losses in non-residential buildings via the use of large windows or glass facades. Switch2save targets active management of radiation energy transfer through glass-based building envelopes by integrating transparent energy-smart materials with switchable total energy transmission values (g-value). Such materials are electro-chromic (EC) or thermo-chromic (TC) systems, and intelligent switching of these allows significant reduction of both heating energy demand in winter and cooling energy demand in summer. Switch2save’s unique and lightweight combined EC and TC smart insulating-glass unit will be a breakthrough in performance (+20%); low-cost potential (-33% manufacturing cost) and with increased design opportunities compared to state-of-the-art smart shading solutions.
Despite their novelty, building automation systems have shown their usability when used to link the operation of the building to other aspects of energy efficiency. Their importance in regard to BIM as well as other aspects of building monitoring, and the opportunity to gain understanding of the real vs predicted performance of new and renovated buildings is significant.