Ancillary Service to the Grid Through Control of Fans in Commercial Building HVAC Systems

Abstract

The thermal storage potential in commercial buildings is an enormous resource for providing various ancillary services to the grid. In this paper, we show how fans in Heating, Ventilation, and Air Conditioning (HVAC) systems of commercial buildings alone can provide substantial frequency regulation service, with little change in their indoor environments. A feedforward architecture is proposed to control the fan power consumption to track a regulation signal. The proposed control scheme is then tested through simulations based on a calibrated high fidelity non-linear model of a building. Model parameters are identified from data collected in Pugh Hall, a commercial building located on the University of Florida campus. For the HVAC system under consideration, numerical experiments demonstrate how up to 15% of the rated fan power can be deployed for regulation purpose while having little effect on the building indoor temperature. The regulation signal that can be successfully tracked is constrained in the frequency band , where minutes and seconds. Our results indicate that fans in existing commercial buildings in the U.S. can provide about 70% of the current national regulation reserve requirements in the aforementioned frequency band. A unique advantage of the proposed control scheme is that assessing the value of the ancillary service provided is trivial, which is in stark contrast to many demand-response programs.

Distributed flexibility characterization and resource allocation for multi-zone commercial buildings in the smart grid

“…The thermal dynamic model of a n-zone building can be constructed by interconnection of a network of ResistanceCapacitance (RC) models of individual zones [6], [15], [16]. The thermal dynamics of the i th zone (i ∈ N ) are described by the following RC model:…”

“…It has been shown in [6], [9] that commercial building HVAC supply fan (which is controlled by a variable frequency drive) is a great flexible resource for providing ancillary services due to its fast and accurate responding characteristics. In [6], it has been estimated that 15% of the rated fan power can be used to follow a high-frequency regulation signal.…”

“…In [6], it has been estimated that 15% of the rated fan power can be used to follow a high-frequency regulation signal. However, this flexibility is estimated by only considering the proposed controller while requiring little change on the indoor temperature.…”

“…Moreover, the computational burden becomes overwhelming for buildings with a large number of zones. On the other hand, in order to track a dispatch signal, different control strategies have been proposed for commercial buildings [6], [12], [13]. However, these approaches could not take into account the different preferences of individual thermal zones.…”

“…However, these approaches could not take into account the different preferences of individual thermal zones. For example, in [6], the total airflow is proportionally distributed to each zone. If the supply fan is aggressively providing ancillary service, which means the airflow change from baseline is relatively large, the proportional allocation strategy might not be fair, and respect each zone's preference and flexibility.…”