Within a commercial building, all of the heating, ventilation, and air conditioning (HVAC) systems are governed by thermodynamics, a branch of science that deals with the relationship between temperature and energy. The first law of thermodynamics is a generalization of the law of conservation of energy, which states that energy can neither be created nor destroyed. Given that heat is a form of energy, it has to be removed to cool a space. This requires using energy to move air molecules through a building to achieve the correct temperature in different areas. Therefore, cooling a building efficiently requires numerous rules, tactics, and tradeoffs that can be incredibly complex.
Being exclusively focused on helping commercial and industrial customers dramatically improve the efficiency of their HVAC systems, Encycle is reducing many of the typical complexities associated with building cooling through artificial intelligence-based technology. Here we examine these challenges and explain how our Energy-as-a-Service (EaaS) approach simplifies HVAC energy management across building portfolios, delivering reductions of up to 20% in HVAC energy use and carbon emissions while maintaining comfort.
COMMON BUILDING COOLING CHALLENGES
1. HVAC equipment is usually oversized to accommodate worst-case scenarios.
The demands placed on commercial HVAC systems can be brutal. Large structures like retail buildings and distribution centers require a lot of power to cool the space they serve. Not surprisingly, this power demand requires extensive integrated systems that must provide comfort during the hottest and most humid conditions.
To ensure comfort levels are met even during historical conditions that only occur 1% of the time, these systems are intentionally oversized. Unfortunately, this excess cooling capacity of an HVAC system can result in negative consequences that include:
- Short cycling – This situation occurs when an HVAC unit turns on and off too frequently, causing the compressor, blower fan motor, and other components to work harder. The added wear and tear on these parts can shorten the lifespan of the system.
- Less gradual cooling – Intense cooling bursts make it harder to control temperatures in different areas.
- Inadequate humidity control – Oversized systems have powerful compressors that, due to their size, may not run long enough to properly dehumidify the air and causing “clammy” spaces that affect comfort. High humidity levels also significantly impact a variety of indoor air quality (IAQ) issues, increasing the concentration of some pollutants.1
- Higher energy costs – HVAC systems consume the most energy when they turn on, and larger systems require the most energy. Even systems with high energy efficiency ratings won’t achieve their advertised efficiency levels if they are oversized for their application or not responding appropriately to real-time conditions.
2. HVAC units vary in efficiency and maintenance conditions.
Like any other expensive equipment, HVAC systems need to be serviced regularly to maintain proper operation. Even with regular inspections, the condition of an HVAC system will vary with age and attention. Component wear, leaks, or failure in just one HVAC rooftop unit (RTU) can negatively affect operational costs. Since all RTUs are needed to provide optimum temperature and air exchange at the desired efficiency level, identifying faulty or underperforming units is essential.
Problems can also arise from the design of the HVAC system or because equipment and controls are improperly connected or installed. Today’s sophisticated equipment choices require knowledgeable programming that every installer or systems operator may not have. Often, the settings for setpoint thresholds or operating hours and schedules are improperly programmed.
3. Thermal loading fluctuates by zone throughout the day and year.
In air conditioning, the thermal cooling load is the amount of energy that must be removed from a space to keep temperature and humidity constant. This cooling load will vary throughout the day based on several factors that can make it challenging to maintain required indoor conditions:
The amount of cooling is maintained at a constant comfort level for many buildings, usually to match building occupancy. Building occupancy (the number of people who occupy a building) and occupant actions (how people behave in a building) result in heat gains and losses.
- Radical “swings” in occupancy and occupant actions – As an example, a restaurant will experience more significant heat gains during busy lunch or dinner hours when more guests occupy dining areas. Similarly, a gym will have a higher cooling load when it’s full of people exercising.
- Employees’ thermostat adjustments – While attempting to manage comfort, thermostat tampering results in energy waste and cooling problems when left unchecked.
- Unexpected shifts in building usage – We saw this during the early stages of the Covid-19 pandemic when commercial buildings suddenly experienced a shutdown or substantial reduction in building usage. Building owners and facility managers found themselves adjusting their HVAC setpoints and schedules from standard energy-saving modes to unoccupied or other flexible schedules to minimize energy use and costs in response to the “new normal” for facility occupancy. Traditional HVAC control approaches like these can fall short in optimizing RTU operations, requiring significant manual effort to reconfigure equipment and compromising occupant comfort. The pandemic taught us that adaptability is key during a continually changing business landscape.
Thermal load over a 12-hour period.
Effective loads can be more easily maintained when probable patterns are determined and maintained. Occupancy fluctuations require a real-time automated response; otherwise, you’re likely overspending on staffing and electricity.
Outdoor temperatures and trends in climate
Outdoor temperatures strongly affect a building’s latent cooling load and energy requirements. In the summer months, the peak cooling load occurs in the afternoon when temperatures are at their highest points. During this time, utility companies charge the highest rates because electricity is at its peak demand. To avoid these charges, an HVAC system must be run strategically. Cooling down a building early in the day or staggering RTU operation can help.
In May of 2021, the National Oceanic and Atmospheric Administration (NOAA) released an updated set of climate averages for the contiguous United States based on a 30-year averages of key climate observations made between 1991 and 2020. The data shows a continued national warming trend where the 30-year average temperature for the 48 states climbed to a record high of 53 degrees Fahrenheit.2 Since 1901, when climate normals were first recorded, the U.S. has warmed 1.7 degrees Fahrenheit, which is very close to the global warming rate for that same period.
With varying degrees of latitudes and geographic features, states within the contiguous U.S. experience a wide range of climates. NOAA Climate.gov has an interactive map that shows how average state temperatures are projected to change in coming decades if global emissions continue along their current path.4
Urban heat islands represent another temperature challenge for building owners and facility managers. The Environmental Protection Agency (EPA) acknowledges the heat island effect, where closely built structures, roads, and other infrastructures in metropolitan areas absorb the sun’s heat more than natural landscapes. Urban heat islands typically lack greenery, shade, and ventilation and create pockets of heat with daytime temperatures averaging 1 to 7°F higher than outlying areas.5
4. Buildings are divided into different zones that are built and used differently.
When you hear the word zoning, you probably think of how property is divided based on the way it will be used. A building is not much different in that it is divided into separate zones, each built or used differently with its own cooling requirements. HVAC systems must compensate for a range of cooling loads serving zones within a building. The following are some examples of variable zoning needs in commercial facilities:
- Cafeteria or kitchen areas with heat-producing equipment
- Store entrances and docks where doors are frequently opened and closed
- Micro-climates like reception areas, server rooms, and pharmaceutical storage spaces that need to stay cool
- West-facing exterior rooms that are subject to daily fluctuating heat gain due to sunlight
5. Buildings have their own unique characteristics and designs.
Buildings have unique sets of variables and requirements that make static HVAC control practices less than ideal. Considerations must be made for a building’s architectural profile where features like high ceilings can strain the best HVAC system and present a challenge to maintain a comfortable environment.
A building’s thermal envelope, or separation between the conditioned interior and unconditioned exterior spaces, will impact cooling efficiency. High-performing building envelopes reduce heat gain, lowering electric bills by minimizing the load on air conditioners. Installing energy-efficient windows and doors, window shading and glazing, proper insulation, and roof coatings are effective ways to tighten and improve a building’s envelope.
ENCYCLE’S HVAC ENERGY MANAGEMENT SOLUTION
Encycle’s Swarm Logic® energy-saving technology favorably addresses these complexities – dynamically and autonomously.
Encycle’s unique, data-driven Swarm Logic technology helps simplify building cooling while reducing typical customers’ HVAC-related energy spending, consumption, and carbon emissions by 10%-20%. The EaaS solution uses a subscription-based fee model that requires little to no capital investment, making it an attractive option for multi-site companies looking to improve their bottom line and reach sustainability goals.
How it works
Swarm Logic dynamically synchronizes HVAC RTU control decisions, enabling RTUs to operate most efficiently by responding in real time to changing conditions such as building occupancy levels and outdoor temperature. The multi-patented technology creates dynamic models for each building’s thermal load profile and RTU performance. With Swarm Logic, RTUs become part of an IoT-based closed-loop system that coordinates their activity and distributes energy consumption more logically among the individual RTUs. The enterprise-wide solution requires no human interaction to maintain or monitor its actions.
- Swarm Logic reduces energy costs while maintaining consistent customer-prescribed comfort, including critical micro-zones in a building
- Delivers 2X to 5X return on program fees almost immediately after deployment
- Swarm Portal™, Encycle’s web-based reporting and analytics platform, provides intuitive insights into Swarm Logic performance and energy savings
- HVAC unit health and operational reporting and analytics shift maintenance activities from reactive to proactive
- Data gathering and AI capabilities respond efficiently, dynamically, and remotely to shifts in energy usage and demand patterns, including peak demand spikes
- Supports sustainability goals by reducing greenhouse gas (GHG) emissions through improved energy efficiency
- Autonomous operation frees facility management teams to focus on higher value-add activities
- Minimizes risk of technology obsolescence
- Swift and easy
Two building control system approaches
The beauty of Swarm Logic is that it can be integrated with existing building automation systems (BAS) or compatible smart thermostats, delivering a valuable solution for everyone. Swarm Logic complements existing building control technologies to achieve even greater savings. You can choose the approach that works best for your needs and your budget.
1) Integrate with a BAS using Swarm Service™.
Swarm Service allows customers to integrate Swarm Logic software with their existing building controls, unlocking new levels of HVAC energy savings.
2) Integrate with smart thermostats using SwarmStat™.
Swarm Stat allows customers to integrate Swarm Logic software with compatible smart thermostats, creating a Virtual BAS™ for a fraction of the cost of a traditional BAS. This BYOT solution utilizes IoT-based technology to enable HVAC control strategies that were previously executed only by larger, more expensive BAS .
Whether you’re interested in controlling thermal loads, identifying underperforming HVAC units, saving money, or increasing your sustainability, Encycle can help. Our IoT-based technology and advanced analytics will simplify your buildings’ cooling operations while delivering dramatic reductions in HVAC energy spend and consumption. Swarm Logic has been deployed at over 1,000 sites with more than 10,000 RTUs and is optimizing over 125 MW of customer electric load across North America.
Tell us about your building cooling and energy management goals, and we’ll help you gain the insights you need to reach them. Call us at 1-855-857-4031.
Contributing author: Keith Hudson, VP, Product Management, Encycle Corporation
1 “The Inside Story: A Guide to Indoor Air Quality.” CPSC.gov, U.S. Consumer Product Safety Commission, 6 Sept. 2016, www.cpsc.gov/Safety-Education/Safety-Guides/Home/The-Inside-Story-A-Guide-to-Indoor-Air-Quality.
2 Bob Henson, Jason Samenow. “NOAA Unveils New U.S. Climate ‘Normals’ that are Warmer than Ever.” The Washington Post, WP Company, 5 May 2021, www.washingtonpost.com/weather/2021/05/04/noaa-new-climate-normals/.
3 “Climate Change and the 1991-2020 U.S. Climate Normals.” NOAA Climate.gov, 19 Apr. 2021, www.climate.gov/news-features/understanding-climate/climate-change-and-1991-2020-us-climate-normals.
4 “What Will Average U.S. Temperatures Look like in Future Octobers?.” NOAA Climate.gov, 31 Oct. 2018, www.climate.gov/news-features/featured-images/what-will-average-us-temperatures-look-future-octobers.
5 “Heat Island Effect.” Environmental Protection Agency, www.epa.gov/heatislands.