DRDR – Demand Response Done Right

Building owners and managers are faced with a dilemma, the desire to participate in DR programs and the reality of defending the mission of the buildings they manage. Let me start by defining a few truisms:

Anyone that tells you they can participate in DR without loss of amenity is a bad manager. If you can dim lights and turn up or down HVAC systems without anyone noticing, then you should do it every day! DR should be slightly painful.

If one third of the workforce leaves every time you have a DR event, can you really afford to participate? Loss of productivity is very expensive and not acceptable.

Socializing why you are participating in a DR program is not only necessary; it will get employees and or tenants to actually help out by turning off un-necessary manual loads during an event.

Generally buildings respond to DR requests in a global, all or nothing fashion. Typical responses might be to turn up the chilled water temperature on the primary chiller or raise the control setpoints on the primary HVAC equipment. What if there was a way to respond in a more granular fashion? What if the owners or tenants could mark certain areas within the building “important” and have them adhere to a more stringent HVAC profile? What if you could use information from the lighting system or security system to understand where people are? With an open IT based integration platform you can. The concept of DRDR is simple yet can be complicated when put into practice. There is no shortcut to the upfront engineering and planning that must be done in order to understand each buildings mission. You will also need to investigate the existing building equipment and it’s granularity of control in order to apply the correct DR strategies.

Being able to leverage existing building systems through the use of a modular integration framework is the key to cost effectively deploying DR / PDP programs. Keeping the installed cost down while still providing the owner with the necessary tools to manage DR events for their portfolio is the only way to achieve reasonable ROI periods. Owners that have more than one facility with multiple building technologies are going to find it difficult to manage DR events at each building individually. But, by providing a single portal that unifies and normalizes data across their portfolio, they can manage all of their facilities from one place. The rules for participation are defined and executed from one interface. We enable a unified DR response across multiple small facilities in order to look like one large aggregate load. Buildings that were too small to participate on their own, now can. There are more small buildings than big ones in the United States (Table 1), being able to cost effectively control and aggregate them is crucial given the ever growing demand for energy.

Granularity of control between the various building subsystems rarely if ever align, because of this we create energy zones. Energy zones are made up of several key data components, Spaces, People, Lighting, HVAC, Security and others systems. We align all of these systems to work in an efficient manner by first integrating and collecting their data. Next, we use a Logical Building Model or LBM to associate the data to the corporate structure and the building infrastructure. Through the creation of these energy zones we abstract the data necessary to virtually link all of the elements to a common building, floor, tenant, area, space, etc. Once this is done we can now understand how they interact and define new business rules to increase energy efficiency of those systems.

An example might be where the lighting system allows for offices to be controlled individually but the HVAC system spans several offices. (see figure #1) Using the lighting occupancy sensors we can tell the HVAC system when the 1st office is occupied and or when none are. This allows the HVAC system to control its zone based on data abstracted from the LBM.

Figure #1

Integrated control of buildings isn’t just about energy savings, it’s about having the right data in the right format at the right time in order to make better decisions about how to run a facility. Building multi-variable reverse linear regression baselines of past building performance is one of the most important KPI’s for facility owners. Mixing these models with future forecast data allows us to tell a building owner what his building is going to do days before it actually happens.

It requires a holistic set of data in order understand how a building is performing. Two identical buildings could have very different energy profiles depending on hours of operation, occupancy and weather. Also, buildings have different purposes, it’s important to understand the work product of the buildings when making comparisons. Key performance indicators like energy intensity per square foot are meaningless unless you understand the other related datasets. It is more valuable to have KPI’s that are tied to the buildings purpose, for example hospitals use bed census as a KPI for operations. Why wouldn’t you tie your energy profile to the bed census data? An office buildings KPI is to provide a safe comfortable work environment, again tie the energy use to the business purpose. Linking data from the lighting system, elevators, BAS and others allow you to make an informed analysis about a buildings performance.

Owners of small building