Intelligent building management systems help monitor and control energy-intensive equipment, reducing costs for c-store operators.
This blog is the first in a three-part series exploring building management systems and energy-efficiency strategies. This post focuses on reducing refrigeration, lighting and HVAC costs; future posts will tackle store- and enterprise-level strategies.
By Paul Carlson
Faced with thinning margins and rising operating costs, convenience store chains have explored a variety of ways to reduce energy use, save costs and boost profitability.
More convenience store operators are looking to intelligent building management systems — which eliminate manual controls and thermostats in favor of digital “smart” controls that interface with third-party devices — to more efficiently operate refrigeration, lighting and HVAC systems across their stores.
These systems monitor and control energy-intensive equipment based on a variety of conditions, enabling convenience store operators to potentially avoid excessive energy use during peak-cost time periods while also effectively managing store environments.
To see how building management systems can help reduce energy costs at the equipment level, let’s look at three main energy hogs — refrigeration, lighting and HVAC — which collectively account for about 80% of a convenience store’s energy use.
Keeping Products Cool and Costs Low
More refrigerated goods are making their way onto convenience store shelves. Even though these products still account for a moderate portion of a store’s overall shelf space, they require a disproportionately large amount of energy to maintain. One walk-in cooler and three walk-in freezers can consume up to one-third of a convenience store’s total energy use.
Uncontrolled refrigerated systems can waste energy by inefficiently maintaining case temperatures and ineffectively operating refrigeration cycles. Building management systems with digital refrigeration controls help overcome these issues by monitoring refrigeration cases and product temperatures to cycle compressors accurately within a tighter control range. Case controllers help prevent excessive compressor cycling and can automatically adjust case temperatures overnight to save energy while still preventing spoilage. Typically, digital controls result in as much as a 7–10% reduction in compressor runtime, which reduces operational expenses.
Store operators using condensing units that combine efficient scroll compressor technologies and variable-speed motor controls with high-efficiency fan blades and large condenser coils can see up to 40% higher energy efficiency than if they had used traditional condensing units.
Managing Interior and Exterior Lighting
When it comes to lighting, which accounts for between approximately 25-40% of a store’s energy use, lowering use and costs is as simple as turning off or dimming the lights when they’re not in use. That’s easy in theory, but more difficult in practice — especially when left to store personnel or mechanical time clocks.
Advanced lighting controls remove the human and mechanical elements and instead help manage interior store lighting using a variety of dependable inputs, including: ambient lighting levels; light sensors; motion detection; occupancy schedules; and occupancy triggers such as security systems. Using this data, convenience store operators can regulate interior lighting to meet their individual needs.
Many building management system platform schedules can receive site-specific sunrise and sunset data to efficiently control outside lighting. Different lighting zones such as wall packs and canopy lights can be controlled on a schedule, a light-level sensor or both.
Maintaining Comfort and Efficiency
Similar to lighting, efficient HVAC strategies hinge on accurately controlling temperatures and establishing schedules that reduce unnecessary use. Contrary to refrigeration and lighting, HVAC use varies by season and regional weather patterns, but they still can account for up to 20% of a convenience store’s energy use.
HVAC controllers can cycle rooftop fans according to discharge and return air temperatures, reducing compressor runtime and striking a balance between customer comfort and energy efficiency.
Further, operators can program these systems based on factors such as store occupancy and ambient humidity. For example, when store occupancy and humidity are low, the controllers can scale back the HVAC a few degrees to save energy without sacrificing comfort inside the store. Similarly, store operators can dial back the HVAC system overnight when the store is empty, further reducing energy use and costs.
Significant Savings Potential
By using advanced building management systems that control refrigeration, lighting and HVAC equipment, convenience store chains can potentially reduce their energy costs by tens of thousands of dollars every year. And while cutting these costs might be the initial goal, these systems also collect valuable operational data, which store operators can use to analyze store performance and help improve maintenance efficiency, leading to even more savings.
Paul Carlson, Emerson’s vice president/general manager — foodservice, is an accomplished executive with engineering, operations and leadership experience in positions at Earth Energy Systems, Trane, Coca-Cola, Cornelius, Control Products and Emerson. Over his 30-year career in the alternative energy, food & beverage and electronics industries, Paul has worked with both public and privately held organizations in many functional capacities, including product development and engineering, sales, operations and general management.