  This paper is the first part of a two-part series in which we present results
from an experimental demonstration of frequency regulation in a commercial
building test facility.
  In Part I, we introduce the test facility and develop relevant building
models. Furthermore, we design a hierarchical controller that consists of three
levels: a reserve scheduler, a building climate controller, and a fan speed
controller for frequency regulation. We formulate the reserve scheduler as a
robust optimization problem and introduce several approximations to reduce its
complexity. The building climate controller is comprised of a robust model
predictive controller and a Kalman filter. The frequency regulation controller
consists of a feedback and a feedforward loop, provides fast responses, and is
stable.
  Part I presents building model identification and controller tuning results,
whereas Part II reports results from the operation of the hierarchical
controller under frequency regulation.
