Heating, ventilation, and air conditioning (HVAC) systems are a critical component of any building’s infrastructure. They are responsible for maintaining indoor air quality and ensuring a comfortable environment for building occupants. However, HVAC systems can also be a significant source of energy consumption and cost for building owners and managers. Therefore, it is essential for FMs to improve the efficiency of their HVAC systems to reduce energy costs and improve the overall building performance. Here are some ways you can improve the efficiency of your building’s HVAC system.
Conduct Regular Maintenance
Regular maintenance is essential to keeping HVAC systems functioning at their best. Facilities managers should schedule regular inspections, cleanings, and repairs to ensure that HVAC systems are running efficiently. Neglected HVAC systems can lead to dirty filters, clogged coils, and leaky ducts, which can reduce performance and increase energy consumption. Regular maintenance can help prevent these issues, extend the lifespan of the system, and save energy and money in the long run.
Use High-Efficiency HVAC Equipment
Upgrading to high-efficiency HVAC equipment can significantly improve the efficiency of the system. Facilities managers should consider using equipment that meets or exceeds industry standards, such as those certified by ENERGY STAR. High-efficiency HVAC equipment uses less energy than traditional equipment, which can lead to significant energy savings over time. Moreover, high-efficiency equipment is often designed to operate at part-load conditions, which can result in additional energy savings during periods of low demand.
Install Programmable Thermostats
Programmable thermostats are a valuable tool for improving HVAC system efficiency. They allow facilities managers to set temperature schedules that align with the building’s occupancy schedule. For example, the thermostat can be set to lower the temperature during non-business hours or weekends when the building is unoccupied and raise it before employees arrive. This simple step can reduce energy consumption and lower energy costs significantly. Also, consider automating your after-hours HVAC program or going HVAC on-demand for the weekends. These programs cut energy waste while giving your tenants more flexible work hours.
Optimize Airflow
Optimizing airflow is another essential factor in improving HVAC system efficiency. Facilities managers should ensure that HVAC systems are designed to deliver the right amount of air to each area of the building. The air ducts should be sized correctly to match the load requirements of the building, and they should be sealed to prevent air leakage. Additionally, filters should be checked regularly and replaced as necessary to ensure that the system is not overworking to compensate for restricted airflow.
Consider Renewable Energy
Facilities managers should also consider integrating renewable energy sources into their HVAC systems. Renewable energy sources such as solar and geothermal can provide an energy efficient and sustainable source of energy for HVAC systems. Solar panels can generate electricity to power the HVAC system, while geothermal systems can use the ground’s stable temperature to heat or cool the building. Although these options may require significant upfront investment, they can provide long-term cost savings and reduce the building’s carbon footprint.
Improve Building Envelope
Improving the building envelope is another way that facilities managers can improve HVAC system efficiency. The building envelope includes the walls, roof, windows, and doors that separate the indoor and outdoor environments. Improving insulation, weather stripping, and window and door seals can reduce heat transfer and prevent air leaks, resulting in less heating and cooling energy needed. The HVAC system will have less load to handle and thus function more efficiently.
In conclusion, improving the efficiency of HVAC systems can significantly reduce energy consumption and lower costs for building owners and managers. Facilities managers can achieve this by conducting regular maintenance, using high-efficiency equipment, installing programmable thermostats, optimizing airflow, considering renewable energy, and improving the building envelope. With these steps in place, facilities managers can ensure that their HVAC systems are functioning optimally, providing comfortable environments for building occupants while saving energy and money in the long run.
Fault detection and diagnostics (FDD) is the process of identifying and analyzing malfunctions or failures within a building’s systems to detect and diagnose faults as early as possible. Early detection minimizes the impacts of downtimes, prevents future failures, and improves overall system performance. FDD is crucial for maintaining the reliability and efficiency of a building’s HVAC system.
How Do FDD Systems Work?
FDD is typically achieved using sensors, monitoring systems, and diagnostic algorithms. These tools work together to continuously monitor the performance of the system and detect any abnormal patterns that may indicate a fault. The diagnostic algorithms then analyze the collected to identify the specific fault and provide recommendations for how to address it.
One of the key benefits of FDD is that organizations can proactively identify and address potential issues before they lead to costly downtime or equipment damage. Too often, building owners, maintenance staff, and systems integrators work within a reactionary model, which often follows these steps:
BMS alarm sounds for a VAV
VAV unit inspected
Maintenance request created
Repair or replacement made
This reactionary model works but is inefficient. How long was the VAV malfunctioning before the alarm? How much energy was lost before? How long as it been affecting occupant comfort levels? How much time is required for all steps? How much energy, money, and comfort are sacrificed during downtime? These questions represent the issues inherent in the reactionary model.
FDD sees the problem before the inefficiencies start by using analyzing data from fault trends to predict failures before the actual alarm sounds. If a VAV is consistently running below specification, FDD can flag the activity as consistent with a failing terminal unit. That gives maintenance longer lead times and shortens downtimes.
Diagnostic algorithms like this basic one, move through a series of steps to detect and identify solutions to equipment failures.
FDD Systems Lower Energy Costs
With the growing emphasis on energy efficiency, FDD is becoming increasingly important as a tool for improving overall system performance and reducing energy consumption. Recent studies show that between 5% – 30% of commercial building energy is wasted due to problems associated with controls (Deshmukh 2018). So, FDD offers a massive opportunity to increase energy savings by finding faults faster.
One of the most common types of FDD systems used in buildings is Building Energy Management Systems or BEMS. These computer-based systems monitor and control the HVAC, lighting, and other building systems to optimize energy efficiency. BEMS often use temperature sensors to monitor the performance of an HVAC system and detect when the system is not working as efficiently as it should. The diagnostic algorithms then analyze this data and identify the specific problem, such as a clogged filter or malfunctioning compressor.
Predictive Analytics
Another important aspect of FDD is the use of predictive analytics. Predictive analytics uses historical data and statistical models to predict when a system is likely to fail. This enables building operators and maintenance staff to take proactive measures to address potential issues before they lead to costly downtime or equipment damage. Predictive analytics can be used in a wide range of systems, including industrial equipment, vehicles, and even wind turbines.
Furthermore, the use of predictive analytics can enable organizations to take proactive measures to address potential issues before they lead to a complete system failure.
Improving System Performance
While FDD is typically associated with detecting and diagnosing equipment failures, building operators can use it to improve system performance. By identifying and addressing inefficiencies in a system, organizations can improve overall system performance and reduce energy consumption. For example, an FDD system in an HVAC system might identify that the system is running at a higher temperature than necessary, resulting in increased energy consumption. By addressing this issue, the organization can reduce energy consumption and improve overall system performance.
In conclusion, FDD is an important tool for maintaining the reliability and efficiency of various systems. By detecting and diagnosing faults early on, organizations can take steps to address the problem before it leads to costly downtime or equipment damage.
If COVID-19 taught facilities managers and building engineers anything, it’s the importance of proper design and maintenance of air and water systems for stopping the spread of pathogens. But aside from Coronavirus, there are other deadly bugs we need to control if we are to create healthy environments for building occupants. Legionnaires’ disease is one of them.
What is Legionnaires’ disease?
Legionnaires’ disease is a serious respiratory illness caused by the bacterium Legionella pneumophila. It is typically contracted by inhaling small droplets of water that contain the bacteria and can occur when water vapor or mist from a contaminated source is inhaled into the lungs. Facility water and cooling systems can become a source of Legionella bacteria if they are not properly designed, installed, and maintained.
Outbreaks are common with facilities like hotels, vacation rentals, medical facilities and cruise ships. Public hot tubs, for example, present ideal conditions for Legionella pneumophila and are common sources for outbreaks. About 1 in 10 people who contract Legionnaires’ disease will die due to complications from the illness. In health care facilities, the mortality rate jumps to 1 in 4, according to the CDC.
Controlling the Spread
To minimize the risk of Legionnaires’ disease growing within water or cooling systems, it is important to follow best practices for the design, installation, and maintenance of these systems.
Water Cooler System Design. Design water and cooling systems to minimize the risk of Legionella growth and proliferation. This includes using materials that are resistant to corrosion and scale formation, as well as designing the system to allow for proper water flow and circulation.
Regular Maintenance. Regularly clean and maintain water and cooling systems to prevent the buildup of Legionella bacteria. This includes flushing the system to remove any sediment or debris and using water treatment chemicals to kill bacteria and prevent the growth of biofilm.
Temperature Control. Maintain your water and cooling systems at a temperature too high for Legionella bacteria to grow. This typically means keeping the water temperature preferably above 124°F (51°C), and below 68°F (20°C). (Source: CDC)
Control Your pH Levels. Legionella bacteria thrive in water with a pH between 6.0 and 8.5. To prevent the growth of these bacteria, it is important to maintain the pH of the water in the system outside this range. Studies show that a pH of 9.6 prevents the bacteria’s growth in cooling towers. (Source: Water Research).
Disinfection. Regularly disinfect water and cooling systems to kill any Legionella bacteria that may be present. This can be done using chemicals such as chlorine or monochloramine or by using UV light to kill the bacteria.
Risk Assessment. It is important to regularly assess the risk of Legionella growth in water and cooling systems. Implement appropriate control measures as needed. This may include regularly testing the water for the presence of Legionella bacteria and implementing additional measures such as water treatment or increased cleaning.
In addition to these measures, it is important to educate employees and building occupants about the risks of Legionnaires’ disease and how to prevent it. This may include providing information about the signs and symptoms of the disease and reminding people to wash their hands frequently to reduce the risk of infection.
Overall, the key to preventing Legionnaires’ disease from water and cooling systems is to properly design, install, and maintain these systems. By following these best practices, you can significantly reduce the risk of this serious and potentially life-threatening illness.
Buildings are responsible for a significant chunk of emitted green house gases (GHGs) into the atmosphere. Therefore, they’re a leading contributor to global warming. In the U.S., buildings account for 40% of all U. S. primary energy and its associated GHG emissions. While these stats appear bleak, they actually represent a positive when it comes to FMs and owners. Because property owners and managers helm the ship of the Built Environment, they have the power to steer decarbonization efforts in the right direction. By adopting smart technology and building automation, property owners can significantly contribute to GHG reduction while saving money and futureproofing their investments.
With building decarbonization, small changes can make a big difference. Automating your after-hours HVAC program is an easy first step to reducing your property’s carbon footprint. You don’t need to take out a loan to invest in automation tech either. Online tools like cloud-based after-hours HVAC apps are inexpensive and simple to integrate with your existing BMS.
Cut Mistakes, Cut Waste
While after-hours request programs vary, the standard process works like this: the tenant fills out a work request for after-hours air conditioning or heating. Staff members record the request. The building engineer programs the HVAC to fulfill the request. The air con/heating is delivered at the require day and time. The property manager invoices the tenant at the end of the month.
Every step in this manual request process is an opportunity for errors to crop up. Forgotten emails, data entry mistakes and missed change requests are all more likely with a manual process. Mistakes cost time and energy, whether its extra lighting, access gates, lift rides or added HVAC service itself.
After-hours HVAC booking apps replace these manual step with wireless technology and network connections. Tenants create requests via a mobile or desktop app. The system then interfaces with the building’s BMS to schedule the request. The tenant, time and date are automatically logged, and the BMS delivers heating and air con on the requested days. By automating these steps, you cut out the wasted energy and help lower your carbon footprint.
Push Buttons vs. Cloud-Based Apps
Push button systems for activating HVAC service eliminate some, but not all, of the manual steps. They’re designed to deliver service as requested, giving tenants easy access to and control over HVAC operation. However, their openness can be a liability. Since anyone within the building can request service, savings from push button controls are often undermined by their public access.
There are no guards against everyone (ex. maintenance or cleaning staff) from accessing controls. So, unauthorized access can lead to unaccounted and wasted energy use. It’s also easy for occupants to “hit the button” minutes before leaving the room or floor, resulting in wasted energy from heating and cooling unoccupied spaces.
After-hours HVAC apps reduce energy waste by limiting access to the platform. In a cloud-based system, only authorized users can create HVAC requests. And the system records both the request and the requester. So owners always know who requests services. Plus, tenants can re-schedule and cancel bookings from anywhere there’s an internet connection. This helps save energy by eliminating empty room heating and cooling.
Data Equals Decarbonization
Automation goes hand-in-hand with data. Today’s smart sensors, IoT devices, machine learning, AI, digital twins, and BMS integration all point to the eventual integration of every building systems. In the near future, fire systems will “talk” with access systems to track occupants during an emergency. Access systems will work in tandem with HVAC systems to adjust heating and cooling demands based on occupancy levels. Building management systems will connect to utility providers to shift energy usage during peak demand. Such interoperability is already evolving, but it requires data to work properly.
By automating your HVAC requests, you can collect data on how and when your tenants are requesting HVAC services and use it to conserve energy. For example, you can identify seasonal trends and make targeted improvements and retrofits for specific zones of your property. Automation puts you in a better position to transition your property into a smart building and futureproof your assets.
Fire protection systems are one of the most complex and ubiquitous structures within facilities today. They contain many parts intertwined with other building components. For example, emergency lighting and smoke detectors wire into your electrical system. Fire pumps and hydrants hook up to your water mains. Fire alarms connect to your building’s access system to automatically unlock exterior doors.
Your HVAC system is also closely coupled to your fire protection equipment, and its maintenance and condition can directly impact the safety of your inhabitants and the extent of damage to your property.
1. Ductwork
Your system’s ductwork distributes conditioned air throughout the building. But during a fire, such distribution is unwanted. As temps rise and smoke builds, your HVAC’s return ductwork can carry smoke, toxic gases, and superheated air throughout other areas. This spreads the fire and puts occupants in danger. Even worse, supply side ductwork can actually “feed” a localised fire with fresh oxygen, increasing the temperature and property damage.
During a fire, smoke is the number one killer. In fact, most fire deaths are not caused by burns, but by smoke inhalation. Therefore, controlling its spread is safety 101. Plus, smoke can often emit from sources besides an open flame. Burnt toast or microwave popcorn could result in smoke rolling through an entire office floor. This could cause a panic and dangerous stampede to exits. So, any fire safety plan should also include the perception of fire itself as a real threat to life and property.
Duct smoke detectors can help. These devices reside within your ductwork where they detect smoke moving throughout your HVAC system and initiate pre-programmed actions. For example, one of your HVAC fan motors overheats and produces smoke. Once activated, the duct detector could turn on an exhaust fan, close a damper, shut down automation systems, signal an alarm and/or cut power to the fan motor itself.
2. Fire and Smoke Dampers
Fire dampers are another critical way your HVAC systems aid your facility’s fire protection system. Dampers are essentially air valves that shut off airflow in the event of a fire. They’re normally installed at any point where your system’s ductwork passes through a wall, floor or other fire-rated partition. The idea is to close off HVAC ventilation for any area where a fire exists. So, locating them within a fire-rated wall, for example, retains the integrity of the wall even if the ductwork falls away or is damaged by fire.
There are two basic types of dampers: fire and smoke. Fire dampers are usually triggered by a physical device such as a fusible link. Once the temperature rises above a specific point, the fusible link will melt and trigger the closing of the fire damper. As its name suggests, the damper’s main function is to stop fire from spreading through the ductwork.
Smoke dampers are part of the smoke suppression system. They typically connect to fire alarm systems, which trigger the dampers to close and prevent smoke transference. There are smoke/fire combination dampers as well.
Most fire codes require fire and smoke dampers to be actuated and tested every few years, depending on the facility type. Make sure you know your fire code and test that your dampers are physically working, installations are compliant and any replacements are compatible with your system.
3. AHU Support and Location
In the event of a fire, your alarm system should shut down any air handling units (AHUs) within the affected area or site wide. Again, the purpose is to contain the movement of smoke and air, and your AHU is the central place where this happens. However, operation isn’t the only consideration.
AHUs are large, heavy pieces of equipment weighing several tons depending on the size of the system. They’re also loud; that’s why they’re usually located within mechanical rooms and building rooftops. In multi-storey properties, these behemoths can become a danger to building inhabitants. During a fire, walls and floors weaken under intense heat, and those supporting heavy AHUs can give way quickly. While there’s little you can do to predict heat intensity during a fire, you can ensure your AHUs are appropriately located and that building floors are rated for their weight and size.
Conclusion
To function correctly, building systems must work together. It’s not enough just to tackle preventative maintenance for one system and ignore another. Their intertwining requires awareness of how changing one system affects another. Your HVAC system is no different. Upkeep and maintenance of it directly affects the effectiveness and efficiency of your fire protection system.
The COVID pandemic increased awareness and use of relatively new decontamination methods for medical facilities. In addition to standard surface cleaning and disinfection, hospital managers employ vaporized hydrogen peroxide (VHP) systems within negative pressure rooms to eliminate SARS-CoV-2. Sometimes referred to as “Deprox,” these systems distribute a mixture of hydrogen peroxide and water within a room. The mixture is small enough to decontaminate areas that are too difficult or impossible to clean by hand.
However, VHPs must work in conjunction with HVAC systems to be safe and effective, and most functional descriptions put strict limits on an HVAC’s operation during decontamination. Use the following information to guide your design when connecting to VHPs.
HP Vapor vs Aerosol Systems
There are two methods for dispersing hydrogen peroxide (H2O2) for airborne disinfection. One is vapor phase hydrogen peroxide (VPHP) and the other is aerosolised hydrogen peroxide (aHP). The main difference being the size and concentration of the hydrogen peroxide as it leaves the system. VPHP systems produce much smaller particles and at higher concentration than aHPs. They are much closer to a gas than aHPs, which are more of a “fog” ranging from 5 and 20 μm in size.
Exposure Limits
Both VPHPs or aHPs require some downtime for operation and room exposure levels to return to normal. Decontamination cycles may take up to three hours to complete. Exposure to hydrogen peroxide vapor can be harmful, resulting in irritation to the eyes, nose and throat. The OSHA standard for permissible exposure limits to H2O2 is 1 part per million parts of air (ppm) averaged over an eight-hour work shift.
Functional Descriptions
Include these sections when writing a FD that includes VPHP or aHP for negative/positive pressure rooms.
Room Modes—Room modes include isolation, deprox and standby. During the deprox process, the HVAC system should be turned off and dampers closed to ensure the VHP system works effectively.
Closing Dampers—When switching from standby or isolation to deprox mode, factor in a lag time to allow dampers to fully close. For example:
If the room is switched to deprox mode, the deprox LED will flash on and off for 75 seconds whilst the room dampers are driving closed. Once the 75 seconds have passed, the LED will be enabled.
Velocity Pressure Setpoint—Include a deprox pressure setpoint when setting duct velocity pressure points.
If the room is put into deprox mode, the velocity pressure setpoint is reduced to the deprox velocity pressure setpoint (To be determined at time of commissioning).
Smoke and Fire Detectors
Particles from VPHP or aHP can set off fire and smoke detectors. Consider the implications for your HVAC system. Since HVAC systems are normally integrated into fire systems to ensure proper exhaust of smoke, a false alarm may affect your system.
