Does fault detection really compete against building automation? Would mixing both be a better solution for the customer? PHILIP DESROCHERS from ADMS Technologies explores these questions.
Over the last five years, the demand for intelligent controls in building automation has been growing significantly with the arrival of governmental energy saving requirements. Software companies have developed new applications intended to help building operators find faulty equipment in their systems in order to cut on wasted energy and operation costs. This has lead to a new market opening in fault detection and diagnosis for building control systems, creating new competition for building automation companies.
The real question remaining is if fault detection really competes against building automation, or whether mixing both would be a better solution for the customer. This article explains the fundamentals of both services and demonstrates how, in fact, mixing alarm monitoring with fault detection can generate a very powerful solution to manage building automation systems.
WHAT IS A BAS?
First of all, let’s explain what a building automation system (BAS) is and what it does in a building. The BAS is a computerised network of electronic devices meant to control all building systems, such as HVAC, lighting, hot water, chilled water, pumps, boilers and all other necessary equipment to generate a perfect indoor environment. It follows programmed logic to create the environment the building operator wants, such as a specific air temperature or level of humidity.
Most of available BAS systems are available with alarm modules that raise a notification in the BAS software interface, an SMS or an email when a component of the system reaches a critical status. These alarms are binary, meaning they are active or not. They occur only when a unique variable changes or surpasses a specific threshold. For example, a boiler exceeding its maximum temperature meaning that something is not right. These alarms are a really good start at managing the BAS’s performance, but they limit the facilities manager to reactive actions on critical equipment, as they are not able to see issues arising within the system.
In a situation where a mechanical component fails, the BAS compensates, using the rest of the system to still generate the same conditions. This kind of situation does not trigger an alarm in the BAS, letting the system run inefficiently and increasing operation costs. A good example is overheating the building supply air because of a faulty cooling coil or a leaky cooling valve. In this situation, the BAS does exactly what it is intended to do by changing the system to reach the temperature set point. No alarm is triggered because the temperature still reaches the set point, but the system runs at a much higher energy cost.
FAULT DETECTION AND DIAGNOSIS
Fault detection and diagnosis software are intended to prevent these exact situations. The way it works is simple. It connects to the BAS sensors and data points to identify faulty equipment, inefficient control sequences and other mechanical failures. It enables the manager to be proactive before an alarm is triggered. Moreover, it allows important energy savings and simplifies investigation processes to save time. Broken dampers, leaky cooling valves, wrong sensor calibration and oversized components are all issues that are hard to find in these complex systems. Using fault detection technology gives access to the right information to measure performance, quickly find discrepancies and make informed decision on how to operate the BAS.
BENEFITING FROM JOINED TECHNOLOGY
Using both fault detection and alarm monitoring is the optimum solution to overall building operation management. It is important to break the paradigm that fault detection is a rival to BASs. Good fault detection software does not search for errors made by the control system or points where the design is wrong. It analyses the global system integrity, thereby helping the automation system to do a better job. It oversees all the sensors to understand how the environment can impact the BAS and points out what could be done to be more efficient. It is obviously more a complementary tool than a rival. Adopting fault detection in building management is a key strategy for cutting cost, saving energy and better using assets. It brings buildings to today’s technology level.
Philip Desrochers is a building operations specialist at ADMS Technologies.