Retro-commissioning—the process of identifying and quantifying opportunities to increase energy efficiency in older commercial buildings—can save energy, reduce operating costs, and improve occupant comfort. But hiring a team of experts to conduct the retro-commissioning process can be costly, and many experts don't have time to service smaller buildings less than 50,000 square feet, leaving out 44% of commercial buildings in the U.S.

The Retro-Commissioning Sensor Suitcase gives owners of small buildings affordable access to building retro-commissioning that decreases operating costs and increases building comfort and efficiency. The patented technology is estimated to save 10% on total energy costs per building per year. Wide use of the Sensor Suitcase system to retro-commission these smaller commercial buildings could help save 235 trillion Btu of site energy each year, worth about $5.1 billion (based on 2012 consumption and prices).

The system comprises five components:

• A compact case with 16 slots for sensors
• Sixteen sensors designed to gather and store data about how a building uses energy
• A data control module in the suitcase
• A handheld tablet
• Analysis software.

When a sensor is in a suitcase slot, it is connected electrically and can share data with the data control module. This data control module configures each sensor during installation. Software on the tablet guides the user through the configuration/installation process for each sensor. The sensors may be placed on lighting fixtures, near thermostats and on diffusers in rooms, and on rooftop HVAC units. The type of measurement taken may include the temperature of the air coming out of a diffuser into a room, the air temperature in a room with a thermostat, or when lights are turned on or off. For each location in which the user places a sensor, the data control module automatically configures each sensor to measure the desired data.

At the end of the 4- to 6-week data collection period, the user retrieves the installed sensors, reinserts them in the suitcase slots, and initiates download of all sensor data to the data control module in the suitcase. The user then connects the suitcase to a personal computer via an Ethernet cable to transfer the sensor data files from the suitcase for data analysis. The user runs the analytical software on the computer and enters the building’s utility bill information and occupancy schedule. Fault detection and diagnostic algorithms, developed and embedded in the analytical software, identify high-impact problems in lighting and HVAC system control and operation. The software then automatically generates building-specific low-cost recommendations that explain the problem and location, describe recommended actions to alleviate the problem, and estimate how much money will be saved.

The system combines user-friendly hardware, software, graphical user interfaces, and step-by-step instructions in a reusable, portable diagnostic toolkit, embedding the knowledge and skills of a highly experienced building commissioning practitioner into an integrated and scalable hardware and software package that can be easily deployed by building services personnel.

APPLICABILITY

The Retro-Commissioning Sensor Suitcase is ideal for a number of types of businesses:

• Companies that service small buildings
• Companies that own many small buildings that require retro-commissioning
• Companies that rent equipment (such as the suitcases) to individual small-building owners
• Utilities or other organizations that lend tools to building owners for use in improving the energy performance of their buildings.

Despite being intended for use in small buildings, the suitcase can be used to supplement data collection and analysis for retro-commissioning of larger buildings as well.