ASHRAE Journal -November 2012 - 69

of their space or hours of operation, as well as Floor Space Description/Building Location Savings (ft2) comparative visibility of the energy use of other 30% energy savings Residential, 5 tenants within the same building. 30,000 $15,000/yr Richardson, Texas9 In terms of integration of diverse data sets from multiple sources, almost all BEMS have some kind 164,189 –20.3% electricity usage, 66,000 Office, Dallas10 (17 stories) kWh/month, $69,600/yr of interface to the Internet or support a communications standard that allows data to be transferred and 1946 Industrial Facility shared among systems and a variety of information 9,000 16.5% energy savings ~$4410/yr Updated to LEED-NC Platinum11 sources. For example, some BEMS can get an upto-date weather feed, as well as interface with the Table 1: Example savings from using BEMS. local utility’s metering infrastructure. One particular building energy management system allows shifts can save between 5% and 20% of energy consumed, temfor remote commercial air-conditioning load curtailment. Its perature setpoint reductions can save 10% of energy consumed interface has up-to-the-minute energy data and a dashboard per degree reduction for heating, and load cycling can save 5% displaying power usage and cost over time, as well as a set of to 25% based on the configuration of the system.12 control options. The control options include visual cues to tweak Building energy management systems can mitigate building the thermostat to limit energy consumption during times of peak energy consumption by stabilizing the indoor environment in demand. Other, more sophisticated, cues include handing control real-time relative to occupancy, use, and weather conditions. over to the utility. It has a more holistic view of energy usage Furthermore, BEMS are also able to keep a building’s HVAC over a wide area and can remotely manipulate large energy- and lighting systems well tuned and performing at their best. consuming loads, to save the grid from peak-driven blackouts.5 Over the course of a year, building system performance can degrade up to 5%, which increases energy consumption and Energy Savings expenditures. By using a BEMS, continuous system commisSimilar to locally installed building energy management sioning and system adjustments help maintain system perforsystems, cloud-based BEMS have the potential to save an mance and ensure energy savings benefits.6 appreciable amount of energy consumption in buildings. For example, a building in Manhattan reduced its annual electricity Market Factors consumption by 7%.6 One group of buildings in North Carolina, Although migration of BEMS to the cloud has increased in all between 10,000 and 60,000 ft2 (929 and 5574 m2) , was able recent years, there are still barriers to adoption. The majority of to reduce energy expenses 3% to 5% and energy consumption, these barriers are characteristic of cloud computing in general. at most, 30% and, on average, 15%. In 2009 this group of buildSecurity is typically the highest ranked concern because of ings spent $630 million on energy. The expected payback for the multitenancy nature of cloud-based services where many the BEMS installed is between one and two years.7 different companies share the same service provider’s physical A different group of buildings in Orlando, Fla., using the resources such as the application hosting servers. The customsame BEMS reduced its energy costs 10% to 15%: monthly er’s need for visibility and transparency of operation are often electricity bills dropped to $4,500 from $5,000. Additionally, at odds with the service provider’s need to efficiently manage the buildings saw other benefits from using a BEMS such as and securely maintain entire data centers. less food spoiled; since the system monitored the refrigerators This leads to the next area of concern, which is reduced level and freezers it quickly alerted the manager of faulty operation.8 of control over an organization’s data and IT infrastructure Further examples of energy savings due to the use of a BEMS that is ultimately passed to a third-party service provider. As can be found in Table 1. a result, there is a level of risk and challenges associated with The potential for savings, both on energy consumption and migrating data, as well as switching cloud service providers. expenditures, from using a BEMS is clear. These energy sav- This places customers at significant risk if the need arises for ings come from the following select techniques implemented systems to retrieve data or if a cloud service provider exits by the BEMS: the market.13,14 • Temperature setpoint adjustments including: reappraisal Another barrier to market includes legal risk. Storing personal and relaxation; automated shifting based on indoor and outdoor data, such as residential load usage patterns, requires service conditions; companies to comply with jurisdictional laws and regulations • Load cycling (switching off components such as fans and with regards to data privacy. Depending on the nature of the pumps for a set period of time); and data and jurisdiction, regulations may apply to where data is • Overall stabilization of system control and indoor stored, how it is handled, and the procedures under which it may environment. be accessed. With the typical default contract from most cloud The lack of a stable indoor environment and building HVAC service providers putting the responsibility for compliance and and lighting system can result in an increase of 3% to 5% in privacy fully on the customer, the cost and logistics associated energy consumption. BEMS implemented temperature setpoint with these potential legal liabilities are often high.13
November 2012 ASHRAE Journal 69
ASHRAE Journal -November 2012

Table of Contents for the Digital Edition of ASHRAE Journal -November 2012
