Tomorrow's Environment: Energy Auditing Looking Back To Look Ahead
This month, I presented a seminar at the ERAPPA 2009 annual conference in Portland, ME, on central plant master planning by applying the concept of looking back to look ahead.
The basis of the discussion was to assess existing conditions, compare them to today’s operation and facility management standards, and then establish a consistency in basis of design (BofD) for each building application. The most obvious differential in BofD is when an institution is considering a major building renovation, addition, or new building. Building programs today will most likely require the project to be energy efficient and possibly LEED® New Construction certified, or at least LEED-compliant but not certified.
Taking this BofD information and comparing it to existing buildings that will usually have significantly different BofD creates a double standard for central plant cooling capacity needs. Older buildings have less stringent design and operating criteria from the new, high-performance buildings. As a result, these older building will have a low square foot per ton requirement and a high Btuh/sq ft/yr consumption.
Auditing ComparisonsThe same comparison should be taken when implementing an energy audit. In the past few years, during the course of completing several audits, one observation that has jumped out at me, is that the institution (college campus, health care campus, or industrial firm campus) has double standards for operation and facility management of their multibuilding sites. Older building will have far less stringent space temperature and humidity requirements. In addition, some facilities may have changed their space usage (e.g., field house now an open office administration application) over the years, but the BofD was not adjusted and BofD documentation was not updated by the facility management group.
Another example of how subtle changes over time can occur without anyone noticing was a beautiful, gothic library with its granite stone structure and stained glass windows. When built over a hundred years ago, no one was thinking about where rare books, painting, and tapestries would be preserved in the building. No, this building was not seen by its owners and occupants in the same light as a new library would be programmed to operate today. This building had cold, stone interior-to-exterior blocks with no interior insulation or vapor barrier. The fragile single-pane glass had an operable sash to allow cool air in on those hot summer days and high, vaulted ceilings to allow the heat to rise on those hot summer days.
In the winter, this cavernous, multi-level library must have been a challenge to maintain space comfort with its original single-pipe steam system. Over time, the heating system was replaced with unit ventilators for heating and ventilation, followed by conversion of the two-pipe heating system to a two-pipe heating and A/C system. Then eventually, the unit ventilator outside air intakes were blocked, and ventilation was provided by multiple central HVAC systems with minimum outside air and humidification. This beautiful granite stone library had morphed over time to raise occupant expectations and the curator’s expectations that precious books, etc., could be preserved within this building.
Looking Back For the FutureAs we began our energy audit at this site, we first focused on the owner project requirements (OPR), which in this situation was to have the expectation that this facility could not accommodate the latest technology in library application. Other energy auditors may have jumped right into suggesting the HVAC controls were antiquated (e.g., pneumatic controls) and other energy management features could be applied, but we began by looking back by assessing the original BofD.
Next, we listened to the occupants and documented their HVAC expectations. For buildings built in the 1970s though 2000, the BofD and owner’s expectations were somewhat in line with each other. When we began our energy audit of a 2007 LEED-certified building, we were not surprised to learn occupant’s expectations were in sync with the more energy-efficient BofD for this building they were now working in when compared to the previous building(s) they had worked in the past.
For this 19th-century building, we found the occupants had come to accept marginal space comfort because of the perceived antiquated HVAC systems. The BofD expectation mirrors the first set of buildings (1970-2000) that were built, but these occupants accepted the space comfort deficiencies, assuming it was because the building was so old, even though there had been two HVAC renovations between 1980 and 1998.
Our energy audit report looked back to look ahead, summarizing that OPR and BofD findings were our number one recommendation. We did not believe an effective energy audit implementation could be successful without first establishing a consistent OPR and BofD. For more on energy auditing, look to next month’s “Tomorrow’s Environment” column. ES