The Visual and Verbal Arts building of a university in Florida was recently selected to serve as a test site for BuildingIQ’s Automated Demand Response (ADR) capabilities. The 30,476 sq.ft. building underwent a major renovation in 2015 that included reconfiguration of the interior space and the HVAC system.
As part of a collaboration with the local utility, BuildingIQ tested the potential for ADR to reduce peak electricity demand during the summer (air conditioning) season, as well as the winter (heating) season. The town where the university is located, like much of Florida, relies upon electric heating rather than gas. As a result, HVAC can account for as much as 50-70% of electricity consumption in many buildings in the state.
The ADR testing program was able to make excellent progress and showed impressive results, but not without facing interesting challenges.
The testing team faced three major challenges:
- Finding the right balance between demand reduction and client comfort.
- Establishing the practical upper limits of reducing winter heating demand
- Establishing systems, expertise, and teamwork needed for real-time monitoring of DR events, and providing rapid response to issues of client comfort.
The local utility was particularly interested in winter ADR capability. Initial test runs, which were scheduled to begin in January 2017, were delayed until late May due to renovation work on the aging 30,476 sq. ft. building. Early runs were thus confined to the summer months when there was no heating demand and student occupancy was low.
The upside of the summer schedule was that the BuildingIQ team was able to aggressively push the technical limits of the ADR system without intruding upon tenant comfort. Eventually, winter testing was possible in early 2018.
Results were encouraging. Eighteen summer ADR events were carried out in 2017 at different times of the day and for durations ranging from 30 minutes to four hours. Table A and graph below provide details.
Demand drop ranged from a low of 7% to a high of 49%, with the average drop for the 18 events at just over 27%. The longest event, running for four hours starting at 2:00pm on a hot July afternoon, also showed the largest drop in demand of 49%. There were no tenant complaints, even when the DR event was pushed aggressively.
The utility and the building operators appeared satisfied with the results of the summer DR testing. Such large drops in demand have been impressive, raising expectations of success with the winter testing program.
The goal for the winter DR tests was to minimize electricity demand by reducing electric heating at the VAV and RTU levels. Eight events were performed in January 2018, during the early morning. The average demand drop for the eight tests was 47.8%.
It is important to note that the large difference in demand reduction between seasons was mainly due to the power demand of the electric reheat coils. The use of multiple heating sources, instead of reliance on electric reheats, helped maximize the demand reduction without affecting occupant comfort.
Next steps are both short term and long term. In the next few months, the team will be:
- Refining the rapid response system to ensure continuous client comfort. Client complaints to the building engineer are immediately relayed to the BuildingIQ operator who can adjust airflow and temperature zone by zone.
“Client comfort is paramount,” says Estatio Gutierrez, Optimization Engineer for BuildingIQ.
“And for this to be effective we need to link our own teamwork with the client. Their feedback is critical. Tenants don’t communicate to the BuildingIQ team directly. They take their complaints to the local building operator, who in turn contacts us saying, for example, it is too hot in this specific area, please correct. In this case we would immediately send some colder air and continue monitoring the zone closely and refreshing the air. If a serious comfort issue arises we will manually stop the DR event for that specific zone and analyze the problem. In managing DR, as with all aspects of BuildingIQ’s 5i Platform, learning is continuous and service is interactive.”
Site Reference: https://buildingiq.com/resources/case-studies/