Sandbox
Objective
This section explores how the next generation of smart building operations, functionality and maintenance is utilizing the (IoT) internet of things to operate at full interconnectivity, functionality and efficiency. Smart building, operations, functionality and maintenance capabilities cut energy consumption and CO2 emissions, reduce maintenance costs and extend equipment lifetime. Various systems offer actionable insights, drive fewer complaints from occupants, decrease the need for unscheduled maintenance and reduce energy costs and carbon footprint. In time of pandemic or other extreme events, smart buildings may offer autonomous operation.
For many people, the idea of a SMART building creates and implies an image of a building with complex IoT applications that can only be understood, integrated and operated by a cadre of a highly trained facility, IT, and project management professionals. A similar apprehension existed with the first generation of buildings with BAS (Building Automation System)— i.e. an intelligent system of both hardware and software, connecting heating, venting and air conditioning system (HVAC), lighting, security, and other systems to communicate on a single platform. Most larger buildings today have a BAS system for significant energy saving and operational benefits it provides.
An introduction of AI systems now expands the operational capabilities and even suggests the possibility of fully autonomously operated buildings, connecting with and responding to the signals from the grid.
Smart Building Operations
The difference between BAS and the smart, connected building operations
The difference between BAS and smart building operations is the ability to gather data, analyze and diagnose problems from multiple data input sources. Building automation systems (BAS) help facility owners conserve energy and optimize performance with controls that allow for examples like scheduling, occupancy and maintaining set-points. Smart building operations are a step ahead from this, and represent a facility's ability to gather the data and change operational outcomes accordingly. The key is data acquisition, analytics, and diagnostics.
The transition to smart operations does not have to occur all at once but can be gradual and phased. For owners with a robust, and at some levels integrated BAS in their facilities today, transitioning to a smart building environment will be easier to accomplish.
The very first step is to install smart meters that can provide near-real-time energy usage data showing energy consumption, and in some cases, at what cost. This on its own has the advantage of improving a building operator's insights to save energy, reducing the carbon footprint, improving the longevity of equipment and reducing costs. Smart meters offer utility monitoring opportunities on a more granular basis toward the conservation of our natural resources. The systematic tracking and optimization of building energy consumption with visual dashboards can also help not only to change the behavior of building occupants but also connect and make the building responsive to the price and demand signals from the grid as connected buildings. Blueprint Chapter 6 – Interfacing with City Services and Utilities provides further explanation.
The building operation KPI’s
How do we evaluate the effectiveness of the building operations? The KPI’s for the building operation are:
- Lower energy performance gap: building operation presents several inefficiencies compared to project conditions that lead to an energy performance gap. This gap can be reduced by monitoring systems.
- Lower maintenance and replacement costs: smart-ready services reduce maintenance and replacement costs since they permit to prevent or detect faults and failures.
Using the holistic H-KPI framework1, provides a more comprehensive view, enables aggregation and normalization of smart building indicators, and allows better quantification and comparison of operations in different types of buildings, The H-KPI;s use three levels: Level 1- technology, Level 2- infrastructure and level 3 – benefits.
The interactions across the three levels of analysis is a central component of the H-KPI methodology. For example, sensors deployed at Level 1 inform the building management infrastructures at Level 2. The benefits of deploying the smart controls are then manifested at level 3.
Level 1-Technologies
The first step is to install sensors to monitor building performance in real-time. Sensors provide data to a one or more processing units that uses that information to drive heating and cooling equipment as well as actuators, dampers, fans and other components to control a building's operation. They are capable of collecting environmental and operational data of buildings and reacting to the collected information in real time. They are the front end of smart building systems.
From a data standpoint, a commercial building is a complex business with diverse needs. The right combination of sensors in an integrated network is worth much more than the sum of its parts, with significant value for predictive maintenance, operational efficiency, downtime reduction, environment stabilization, and occupant comfort1. The following are the type of sensors found in smart buildings:
AHUs, chillers, and boilers all need pressure sensors to monitor pressure in ducts, condensers, and evaporators, and water supplies. High or low pressure readings are an invaluable predictor of leaks, pump failures, locked rotors, clogs, and other mechanical failures. They’ll provide proof of flow and can be used as a control point for things like fan speeds or air flow through duct work. You’ll also be able to monitor building zone pressure to regulate the inflow of outside air.
Many facilities have precise environmental humidity requirements — laboratories, libraries, manufacturing plants, et cetera — due to the materials or processes housed within them. Even in office and residential buildings, however, humidity regulation is a critical component of occupant comfort. Humidity sensors within air handling units help you determine how much outside air you need to introduce into the building and keep you timely in your response when RH is exiting the desired range.
Few sensors see more widespread use in HVAC than temperature sensors, which play crucial roles in virtually all units. Your temperature sensors will monitor duct temperatures, chilled and heated water loops, inside and outside air temperatures, and more. They also provide input for functions such as fan or valve control and flow regulation.
These are essential for tracking the run status of all fan and pump motors. A current sensor provides proof of function and eliminates the need to manually check each unit to see if it’s running. If current is flowing, the unit is working.
The best way to reduce costs on constant conditioning of outside air is to track CO2 for Demand Control Ventilation (DCV) and either recirculate inside air or introduce fresh air, as needed.
A power meter in a chiller or boiler helps with the efficient management of load shedding agreements and detection of mechanical problems (when, for example, power usage is excessive).
Water flow (both return and supply lines) must be monitored in boilers, chillers, or cooling towers to provide proof of flow and measure usage. BTU meters are a version that combine the functions of flow meters and temperature sensors to trend energy usage and detect inefficiencies (which may result from clogs, excessive ice, humidity changes, and other malfunctions).
These devices track amperage (current) that passes through a conductor. The format of the switch will vary, depending on the application. They’re useful in monitoring the status and run times of circuits, motors, and equipment while also detecting mechanical failures.
A relay can provide a layer of protection for mechanical equipment that may overload under excessive currents. A load-switching relay can easily handle resistive currents for lighting fixtures (e.g. incandescent, LED, fluorescent), and capacitive currents (such as power supplies and loudspeakers). Inductive loads, as with fans, transformers, and electromotors, require careful attention to maximum loads to prevent damage to the relay.
A transducer modifies an electrical input to a different kind of signal either passively or actively. These are used for monitoring load trending data and the controls and status of the equipment (such as a fan or pump) receiving the altered signal.
IAQ compliance requires careful monitoring of the indoor climate with sensors that track RH, CO2, temperature, and VOC outputs. It’s also critical to track these things for the general comfort and safety of occupants and to protect sensitive materials or equipment. Such units can be wall or ceiling-mounted, and fitted to be controlled by hand or remotely via the BMS or even a wireless application. While it is possible to install individual sensor types for each aspect of IAQ, the best and most cost-effective approach would be to install a network of all-in-one style sensors with the capability to monitor every aspect (or as many as possible) from a single device in each location.
When it comes down to it, building management is about keeping a building functional and cost-efficient for the people and processes housed within. This is most achievable with an accurate data model on space usage — where, how long, and in what numbers people are residing in the building — to guide the setpoints and schedules in your system. Some systems can be turned down or off, even during times the building is in use, if certain areas are less active or perhaps not active at all. Data from occupancy sensors will guide planned maintenance outages, field service of equipment, energy management for peak hours or off hours, and more.
For example, temperature sensors allow you to measure and monitor ambient, or surface conditions in or around the building, in real-time. This allows you to maintain optimum conditions and improve efficiency. Desk occupancy sensors detect and monitor the presence of people, in real-time.
Where (and Why) Should Sensors be used?
Sensors and meters need to be integrated throughout the building, from individual flow meters within the valves of a boiler’s hot water loop to a simple wall thermostat in the lobby. Each sensor acts like a nerve that connects HVAC, power, lighting, and other systems to the BMS for a complete picture of unit health and performance. It’s critical that sensors are installed within the following units and systems for an optimal set of control points and insights.
The AHU will use an array of pressure, humidity, temperature, current, and CO2 sensors to keep operations efficient and help you optimize setpoint automations and strategic cycle scheduling. Pressure sensors keep track of filter status, whereas RH, CO2, and temperature sensors should be positioned periodically in all ducts. A current sensor monitors each fan motor.
Water Cooled Chillers: The chilled water loop and condenser water loop will need temperature sensors to help you better control the valve that determines circulation speeds. Return and supply lines use flow meters to provide proof of function and gauge pressure sensors to enable the BMS to calculate differential pressure between supply and return. A current sensor is needed for all pump motors to detect on/off status, locked rotors, and functionality.
Use a flow meter on both the supply and the sewer drain to reduce your costs. The meter helps you detect how much water went down the drain by showing the difference between the volume of water initially supplied and the water discharged into the sewer. As much as 50-60% could be lost to evaporation. Proving this will save on utility charges that assume all water supplied was also sent into the sewer system. Immersion temperature sensors are a useful control input for fan rotation, and as with other units, current sensors should track all pumps and fans to ensure they’re working.
Temperature sensors provide the needed input to control dampers, fan speeds, or power to suit the demands of the space. VAV boxes with heating and cooling coils will also use temperature sensors to control those points. A current sensor monitors the fan motor (and thus the fan status).
The boiler requires a complex network of sensors to track power, pressure, current, temperature, and flow. The power meter assists in regulating load shedding processes as well as detecting issues in the boiler pump motor. Current sensors also provide proof of function for the pump motor. Gauge pressure sensors monitor the supply and return lines for total pressure (and allow for calculation of differential pressure). Temperature sensors track the heated water loop to help you determine pump speed and control the valve for water recirculation with efficiency. BTU flow meters are a valuable input for trending boiler efficiency and measuring the total energy it consumes. Overconsumption can indicate compressor cycling issues, clogs, or malfunctioning pumps.
An optimal energy bill depends upon efficient management of your energy consumption. Modern power and current monitoring systems must provide more than a whole-building view. Individual breakouts of performance and trends at each circuit enable you to pinpoint energy consumption, detect inefficiencies or problems, and predict electrical or equipment-based maintenance needs. It’s best to meter as many lighting circuits, fans, motors, pumps, and equipment power supplies as is feasible. An ideal meter can accurately monitor 50, 100, or potentially even more circuits — you won’t need a matching number of meters to make individual monitoring possible.
Wall-mounted and ceiling-mounted IAQ and occupancy sensors can be easily fitted for every room or hall that will be occupied or contain climate-sensitive materials or equipment. Keep precise track of the humidity, temperature, and CO2/VOC levels in these areas to detect potential blockages or failures in the ventilation system and to respond quickly to increased needs in times of high occupancy. In many applications, these sensors will also be necessary to help you maintain compliance with codes for the space.
IoT connectivity
To support such a massive connectivity required for the deployment of sensors, demands many wireless technologies are investigated. The existing wireless IoT connectivity technologies include diverse types of connectivity technologies, such as LPWAN, 5G, WIFI, IP with different specifications and performance characteristics.