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Shutting Down Chillers to Create a Fast Building Demand Response Method 

Shutting Down Chillers to Create a Fast Building Demand Response Method 

From eSociety, January 2020

As the primary electricity consumers with great flexibility in changing their power demands, buildings play an important role in power demand responses on the grid. Fast and effective building demand response methods are needed. These methods can improve grid reliability and quality during emergency situations to avoid blackouts and grid collapses.

In a recent article from Science and Technology for the Built Environment, Chengchu Yan, Ph.D., with Nanjing Tech University, presents a fast building demand response method for urgent responses to smart grids. The article describes the principle, implementation actions and results of the proposed demand response in a virtual building.

1. What is the significance of this research?

Although many existing demand response (DR) measures are available for building air-conditioning systems, they cannot economically or effectively meet the urgent DR requests from grids in emergency situations due to their limitations of response speed and/or thermal comfort control. 

The proposed method can provide an immediate power reduction for urgent responses to smart grids by shutting down some operating chillers while it can also achieve a uniform indoor temperature by adjusting the indoor air temperature set-points stepwise according to an “incremental schedule.’’

2. Why is it important to explore this topic now?

Sufficient and stable power supply is of great importance for smooth operation of a power grid. The integration of increasing shares of renewable energies, particularly intermittent wind and solar energy generations, has brought great challenges on grid power balance and reliability. 

Buildings have a great potential for relieving the power imbalance and peak load of the grid. However, most building owners/operators do not value such potential appropriately, leading to billions of dollars in efficiency, energy and infrastructure savings left untapped. This article, aiming to unlock the true potential of buildings through demand response (DR), provides a promising solution to alleviate the peak demand and imbalance problem.

3. What lessons, facts and/or guidance can an engineer working in the field take away from this research?

An ideal building DR measure for urgent responses to grids should be able to achieve power reduction quickly and reduce the notices and complaints of building occupants as much as possible. It is difficult to achieve such desired effect when existing DR measures are separately used in centralized air-conditioning systems. 

This paper provides building operators/engineers a simple and effective method to approach an ideal DR by combining the demand-side-based and supply-side-based control measures simultaneously.

4. How can this research further the industry’s knowledge on this topic?

A coordinated control of the supply and demand side is important for avoiding control disorders of centralized air-conditioning systems when implementing direct load control DR measures in an existing feedback control system.

5. Were there any surprises or unforeseen challenges for you when preparing this research?

How to determine the amount of power reduction is critically important for any DR methods, which is a complicated task involving the accurate prediction of power consumption of the buildings under different circumstances and control strategies. In our research, how to maximize the number of running chillers to be shut down while minimizing the sacrifice level of thermal comfort is challenging.