Automating building energy efficiency
05Nov
posted by: Jonathan Grech, JMartans Automation
Whether it’s motivated by financial or environmental concerns, energy efficiency is now a top concern. Although energy management is becoming easier with the development of smart buildings, many existing, ageing premises are in need of transformation.
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There is no shortage of statistics underlining the necessity for better energy efficiency in buildings. According to the European Commission, buildings are responsible for approximately 40 per cent of energy consumption and 36 per cent of carbon dioxide emissions across EU member states. Outside Europe, the US Department of Energy notes that an estimated 30 per cent of energy used in commercial buildings is wasted.
Unsurprisingly, this intense energy usage and high wastage leads to high energy costs. In a recent study of UK businesses, The Daily Telegraph and YouGov found that one-fifth of non-industrial businesses annually spend more than £250,000 on energy. These costs are only set to rise, as energy providers increase their rates and governments around the world introduce increasingly stringent regulations on energy waste and carbon emissions.
For example, the EU’s 2030 climate and energy framework has set a target of reducing greenhouse emissions by 40 per cent compared to 1990 levels. The same framework also sets a target for a 27 per cent increase in energy efficiency. It’s likely that member states that don’t achieve these targets could face fines, as we’ve seen with the EU’s 2020 renewable energy targets.
The case for greater energy efficiency in commercial buildings and facilities is clear. However, the challenge is to achieve these efficiency gains with minimal disruption and without high capital expense. This is what deters many from investing in smart buildings that, while highly energy efficient, come with a high cost that can take many years to recover.
For most, the solution is to modernise the building’s systems. As the EU commission notes, approximately 35 per cent of the buildings in European countries are over 50 years old, which makes the process of modernising for energy efficiency much easier for managers.
From JMartans’ experience of integrating building automation systems across Europe, there are several key areas where energy management can be improved. In older buildings, the effectiveness of these improvements is magnified.
Lighting control systems
Lighting is one of the biggest sources of energy usage in buildings, accounting for up to 40 per cent of a building’s electricity according to the Carbon Trust. Businesses have been integrating mechanical light control systems and energy efficient bulbs for many years to reduce lighting costs, but modern technology offers greater savings and more flexibility.
Building managers looking to reduce energy usage should consider their lighting controls. As a minimum, a lighting control system should include daylight harvesting and occupancy control to minimise unnecessary energy usage by allowing the building to respond to natural light and the movement of people throughout the day. Although these systems have traditionally been isolated, they are much more efficient and effective when integrated with building automation systems (BASs).
Integrating lighting controls with a BAS allows building engineers and technicians to view and manage system data from across the premises from one programme, in one location, rather than jumping between several.
The main thing to consider when integrating a lighting control system with a BAS is the compatibility of the systems. The two systems must communicate using a standard protocol, which in most cases will be BACnet. However, it’s important that the systems share information in the same way. It’s far more difficult and costly to integrate systems when the BAS uses BACnet IP and the lighting controls use BACnet MSTP.
Intelligent HVAC systems
Just like lighting systems, HVAC systems are one of the most energy intensive and costly aspects of building management. In fact, a whitepaper from Siemens stated that lighting and HVAC together account for more than three quarters of a retail building’s energy usage. To ensure a HVAC system is as energy efficient as possible, the type of system currently being used must first be determined.
There are two categories of HVAC system: constant air volume (CAV) and variable air volume (VAV). CAV systems are common in older buildings and require high amounts of airflow and energy to operate, as these units run fans and compressors at full capacity until a temperature point is met. VAV units, as the name implies, run a variable speed fan that can adjust to maintain a consistent temperature in a room or zone.
VAV systems are designed to be much more energy efficient than CAVs, not only because they don’t always run at full capacity, but also because they are better suited to meet the varying temperature requirements of different building zones. As such, they allow for greater control over environmental conditions and are best suited for integration with a BAS.
When integrating a VAV box into a building, it’s important that a controller is used that fits the technical capabilities of the facility’s staff. To get the most out of a smart HVAC system, the controller will need to be programmed and set to an energy efficient sequence.
Certain VAV box controllers, such as the ECB-VAV series from Distech Controls, offer preloaded applications that can easily be deployed without the need for programming, allowing for quick operation with minimal technical requirements from staff. Using the ECB-VAV series as an example, the preloaded program can be selected using Distech Controls’ Allure EC-Smart-Vue communicating sensor.
Again, the most efficient way to use HVAC systems is to integrate them into a BAS for comprehensive, centralised control. It also means that the HVAC system can use the sensors of other connected systems as an input. For example, if a lighting control system connected to a BAS uses sensors in a room to detect occupants, a smart VAV unit can also be activated by this same input to provide a suitable level of airflow to the occupied room.
Management systems
Finally, the best way to manage a building’s efficiency is by using a BAS that, in addition to being connected to the core functions in a building, is coupled with a building energy management system (BEMS). These systems provide better insight into energy usage from all connected applications, as well as offering benchmarking data from similar premises nearby.
It's important to note the distinction between a BAS and a BEMS. Put simply, the BAS allows for control over building processes, whereas a BEMS allows managers and engineers to monitor and assess energy data and actively rectify any issues.
For EU businesses, an effective BEMS like Siemens’ Desigo helps buildings to meet the requirements of efficiency class A of the EN 15232 European Standard for energy efficiency. Siemens notes that this can save up to 30 per cent thermal and 13 per cent electrical energy compared to class C.
As the push for sustainable business continues, ageing premises do not need to fall behind. By assessing the main areas in a building where inefficiencies arise and addressing them effectively, costs can be minimised and emissions reduced at minimal expense.
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