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System Integration in Green Buildings
Another plus for system integration is integrating the functionality of two systems to gain functionality that neither system could do alone.
Sinopoli PE, LEED BD+C, RCCD
Smart Buildings LLC
seeking a green building certification or energy rating for a new
building or the renovation of an existing building generally push the
idea of system integration to the background. To some extent this is
understandable. They’re probably familiar with integration in the
typical fire alarm, smoke control, elevators, access control,
essentially life safety integration; but not aware of the functional
benefits of integrating other systems and the potential opportunities
to analyze an integrated database of system data points.
Usually the idea of system integration is not even discussed during project conception or schematic planning. For new construction the owner is dealing with the initial and more immediate issues such as the sustainability of the site, construction logistics, materials, etc. For existing buildings, system integration may get lost in initial issues related to building assessments and audits, cost estimates, scheduling, scope of renovation, etc.
However, long term operation of a green building is mainly based on energy conservation, water efficiency and indoor environmental quality, all of which are controlled, monitored and driven by building control systems. Integrating these and other building control systems has significant advantages and can provide some additional building operational support. One benefit is acquiring data from the building systems, normalizing it into a standard data format, creating a database, analyzing the information, identifying correlations and outliers, and creating optimal rules for real time system operations. Another plus for system integration is integrating the functionality of two systems to gain functionality that neither system could do alone. This is the maxim that “the whole of the sum is greater than the parts”.
What follows are some examples of system integration opportunities to support green buildings:
If a building has motorized exterior shading, typical lighting controls and a DDC system, there’s a need to integrate the systems and optimize several variables within them. It’s really about controlling the penetration of sunlight. We’re trying to use daylight to offset the lighting system, thus saving energy and at the same time maintain a minimum recommended light level for the space. Too much sunlight may result in heat gain and trigger cooling from the HVAC system which would require additional energy. Too little sunlight or daylight harvesting may result in greater use of the lighting system. We try to balance the optimal lighting need for the occupants with the energy consumption of the lighting or HVAC system. The position of the shades affect thermal loads in the space via the amount of sunlight the shades let in as well as potential heat from the lighting system. At the same time there’s a need to take advantage of daylight harvesting. An integrated system approach between the different systems can be used to control active and passive sources of heating, lighting, shading and ventilation via a preset sequence of operations.
While most of the focus and attention regarding green buildings is on energy, there are LEED credits related to water use which address landscaping, water use reduction and innovative wastewater techniques. Water is a uniquely critical resource and also has a direct connection to energy use. Every drop from the faucet requires some pumping or treatment which uses energy, therefore reducing potable water use reduces energy consumption. From a green building perspective, the interest is primarily in how we manage and monitor the water use in buildings. More specifically, the focus is on systems that will allow us to collect data on water use and provide actionable information to the facility or property manager. The water management system can identify water leaks and running fixtures, provide information as to when the fixtures are in use, flow rates, restroom traffic patterns and how water usage changes with the season.
By integrating data from a power management or energy management system with the water management system, an owner can measure energy consumption of the water distribution or irrigation systems but also use the power usage and gallons per minute (gpm) of the pumps to detect inefficient or failing pumps. For example, if you see the kw/gallon drift up from historical data for the same gpm (i.e. not just a performance curve variance), you know that the pump (while operational) is needing service because it is less efficient.
For building owners demand response is a real opportunity to generate small to modest revenue. It also forces building owners to think about how exactly they can reduce energy consumption which is beneficial even when there isn’t a demand response event. To take advantage of demand response building owners need to develop a detailed energy curtailment plan (or more likely an array of reduction plans based on different levels of energy usage)
Curtailment plans for building owners are more than just about energy; they must take into consideration business operations, priorities within the organization, critical systems and spaces, and occupant comfort and productivity. The ultimate goal is to maximize the attainment of the required energy reduction, while minimizing the effect on occupants and building performance.
The response to a curtailment event for sizable buildings is automated and requires the integration of the energy consuming systems. For example, a power monitoring and control system (PMCS) can provide data that would trigger demand or energy reduction sequences. The process could involve the building KW load data from the PMCS triggering a reduction of lighting levels via the lighting control system; commands to the DDC system to raise the space temperature setpoints for selected zones to reduce the cooling load, turning off selected pieces of equipment to represent KW load reduction or raising the chilled water discharge setpoint for simulated reduced cooling load as an energy reduction sequence.
Different building uses require different approaches to curtailment. For example, a hospital or other healthcare facility may have a curtailment plan that turns off all non-essential lighting, delays the use of dishwashing or laundry and reduces the number of usable elevators and escalators. The curtailment plan in an office building may involve resetting the temperature for air conditioning, slowing fan speeds, reducing overhead lighting, turning off all non-critical or unused equipment and doing so only in non-executive areas. Educational facilities may curtail the use of cafeteria and kitchen equipment, reset thermostats or delay the use of laboratories. The point is that each building owner or manager needs to develop varied detailed curtailments for different levels of reduction and automate the response using system integration.
The development of this automated logic is not easy; as buildings become increasingly complex the decisions regarding their performance become more intricate and there are many more variables in the decision making process. The demand response policies will need to touch on every significant building situation or scenario affecting energy, operational costs, life safety and tenant comfort.
Much of the data used as the basis for “policies” will rely on near real-time data from the building systems, however critical data and system-to-system communications are needed with the facility management systems, business systems, the utility grid and other external systems, such as weather or energy markets. An automated building will require numerous policies, control logic, system integration and sequences of operations taking into account a great number of variables to optimize or fulfill the demand response requirements.
A typical commercial building will have an energy management system. It will need to integrate power consumption data from the HVAC system, power management and control systems and the lighting system in order to provide the owner with information on the energy consumption of the building.
The more expansive use of integrated systems related to energy management is for enterprise applications. These include large campuses, retail, and enterprise commercial holdings, where there are multiple buildings in different locations or multiple buildings using different building management system. Integration will allow the acquisition of different remote building data from disparate building management systems to be integrated in to an enterprise database and allow the owner to view enterprise data, with the capability to drill down to particular buildings or control systems.
Other examples of system integration related to energy management and green buildings include:
Building systems integration continues to demonstrate a significant and
positive impact on building life cycle cost, primarily impacting
operations and energy consumption. As the process for implementing
integration projects continues to develop and improve and as buildings
become more complex, owners and facility managers will more readily
adopt the integrated approach.
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