Traditional control sequences for HVAC systems in large commercial buildings have
historically led to poor energy efficiency. To overcome this issue, ASHRAE has recently
published Guideline 36 (G36), a collection of high-performance control sequences aimed at
reducing energy consumption and cost for building owners. While these sequences are effective
in increasing energy efficiency, their influence on a building's capacity to deliver demand
flexibility remains uncertain. Prior research suggests a potential trade-off between energy
efficiency and demand flexibility because permanently reducing energy use negatively impacts
the available amount of load that can be reduced when responding to grid signals. To investigate
this hypothesis, we created Modelica simulation models for an air handling unit with a G36
trim-and-respond sequence, calibrated these models to a fully instrumented experimental
building testbed X1A in FLEXLAB, and simulated different demand flexibility scenarios.
Counter to expectations, results show that, during a “shed event” with prior pre-cooling, G36
reduces demand by around 3.1 W/m2 more than the traditional control sequences, at the cost of a
reduction in comfort (1.5 °C-hour/day) across five different cities across the United States. Our
results provide encouraging evidence that, under the tested conditions, G36 does not decrease
demand flexibility. This study should increase the confidence of building owners, designers, and
operators who are looking to take advantage of demand flexibility programs while complying
with increasingly stringent building energy efficiency standards.