Hotels seeking to improve their energy profiles seem to fall into several broad categories:
Low- to mid-rise facilities, often one-design hotels, with limited, if any, banquet and function space.
Mid- to high-rise facilities with moderate- to full-service food and function space.
High-rise facilities or facilities in older buildings with extensive food and function facilities.
Each presents unique challenges to energy conservation and requires slightly different skills when it comes to energy auditing. This article will convey some of the author's experiences in energy conservation and auditing in these various types of facilities.
Occasionally, “value engineering” or 11th-hour equipment substitution at these (or any) facilities brings with it unanticipated operational or energy consequences. These facilities also can be plagued by equipment “glitches” that originated during design. More often than one might expect, installation or punch-list issues remain unresolved from early in a facility's history, contributing to excessive energy use. One indicator is premature equipment failure. Although this often is considered an equipment-reliability or quality issue, it also can stem from inadequate commissioning, an ineffective punch list, or a design that requires equipment to work outside of its performance envelope.
The previously mentioned anomalies often go unnoticed because there is no abrupt increase in energy use to provide a signal to the energy manager. In these cases, the U.S. Environmental Protection Agency's and U.S. Department of Energy's (DOE's) Energy Star program can benchmark a facility against other similar facilities to give an idea of how it “stacks up.” A computer building simulation also may offer guidance as to what the facility's expected energy use should be.
A lean, overworked staff, while seemingly good for the bottom line, often does not allow facility personnel sufficient time to perform equipment checks or routine inspections. They do not even have enough time in front of a building-management-system (BMS) screen to look for leaking valves or out-of-calibration sensors or actuators before they are off to solve the next crisis. Extended operations in this mode often lead to a feeling of burnout or helplessness among operators, which can lead to a just-keep-it-running mentality.
These facilities sometimes also are plagued by a dearth of adequate, up-to-date building plans. Complicating factors, such as mechanical or control systems that have been modified over the years in an effort to conserve energy, sometimes are found. Because these systems or modifications are not described adequately to building operating personnel, they are abandoned over time or function at a much reduced level of performance. Some of these facilities also feature equipment at or beyond the end of its economic life. Occasionally, the equipment is replaced with least-cost alternatives that prevent the building systems from functioning to their design intent. In a large facility, the major mechanical equipment may be so widely distributed that staff members do not pass each piece of equipment on a daily basis and, therefore, do not see the equipment unless they receive a temperature complaint or a component fails.
Older upscale hotels face all of the previously mentioned problems with the addition of complications caused by space redesign or ad-hoc renovations of function spaces and restaurants with little regard for how those zones operate within the context of the whole facility. Many of these types of facilities also are equipped with operable windows. Wall panels may have access holes cut in them or access doors that were not installed/secured correctly. These act in concert with elevator shafts and machine rooms to allow significant losses because of wind, piston, or stack effect.
Often, as a control system is upgraded to accommodate newer equipment and renovated areas, the graphic user interface is not upgraded or is neglected. This robs operating personnel of the ability to use the control system as a troubleshooting tool. Greater utilization of BMS control screens would allow facility maintenance personnel to more quickly diagnose temperature, noise, or equipment-operation complaints. Additionally, most of the previously mentioned facilities have a lack of communication that exists among engineering personnel, banquet staff, and housekeeping staff that prevents unity in efforts to reduce energy use.
FINDING A SOLUTION
The facility manager must be aware of the facility's energy use. It is not uncommon to work with clients who have not seen their energy bill or are not aware of their monthly demand (kilowatts) or use (kilowatt-hours). Often, the bills are paid in a central office located elsewhere in the country. The first step is for the facility manager to at least see the bills to understand usage patterns and the rate structure.
The personnel in charge should be able to commit several hours per week to improving energy conservation for a typical building/facility.
Step 1: Gather energy-conservation information. Sites on the Internet that will prove of great value include those for the Energy Star program (www.energystar.gov), Lawrence Berkeley National Laboratory (www.lbl.gov), and the DOE's Office of Energy Efficiency and Renewable Energy (www1.eere.energy.gov), which have material such as benchmarks and descriptions of how to perform analyses. Also, there are links to many valuable sites at www.amicusenergy.com.
Step 2: Identify a champion. Champion, cheerleader, spark plug: Call him or her what you want, but there should be someone within the management structure who is aware of and receptive to energy conservation. Having a receptive ear when you come to the capital-appropriation or approval stages for promotional-item budgets is a great benefit.
Step 3: Enter one or, preferably, two years of facility energy data into a spreadsheet. The spreadsheet will need billing periods (start and finish dates), demand (kilowatts), usage (kilowatt-hours), and total dollars. These can be entered directly from bills. The final column often is useful for calculating the “blended electrical rate” by dividing the total dollars by the usage for the month. Remember, if you purchase energy from a third-party supplier, the cost should be added to the utility bill for that energy source. From these charts, you can compare energy use year over year (Figure 1).
Typically, there will be a peak in the summer and/or winter with minimums in the shoulder season. These minimums typically reflect lighting, plug loads, and other non-weather-dependent usage. If your graph does not have a distinct minimum, it could mean there are problems, such as economizers not working or simultaneous heating and cooling. The difference in energy use between the spring and fall minimums and the summer maximum typically constitutes the energy used by the facility's air-conditioning system. If there are differences or abrupt changes in year-to-year usage charts, you should be able to identify a cause, such as facility expansion, contraction, new equipment, etc.
If the facility appears to have a high minimum load in shoulder season or no shoulder dip at all, begin to look at around-the-clock loads, such as lighting, plug and occupant loads, or possibly electric reheat. If the facility has a high summer peak, begin looking at air-conditioning systems, chiller systems, or building HVAC controls. Armed with this data, you are ready to walk the facility and look for energy wasters. These graphs can be taken further by comparing degree-days and normalizing for differences in billing periods or occupancy.
For a cursory review, the previously mentioned steps should give you some direction in pursuing energy conservation at your facility. Note that the utility often collects “interval data,” or 15-min records of a facility's electrical use. This data can be secured by contacting the local utility. While much more cumbersome to analyze, this data yields much greater insight into a facility's energy consumption.
Step 4: Study the facility's energy use. Once you have completed the previous steps, you can divide by the square footage of the facility and compare this number with “benchmarks” widely available on the Internet. This would give you an indication of how your facility's energy use compares with that of similar facilities in the nation. The Energy Star program is one such benchmarking tool.
Another technique many entities find beneficial is to begin an energy-awareness plan to remind employees of the value of energy conservation and encourage them to keep a sharp eye out for energy wasters around the facility. Utilizing employees to become active in the program by designing the program itself or sending in suggestions can prove valuable. Energy education helps make employees into “energy-smarter” people, allowing them to spot energy inefficiency on a daily basis. Pretty soon, you will have dozens of sets of eyes looking for energy waste and helping you toward your goal.
As you identify these energy wasters, you should document what energy waste is occurring, the repair costs, and the energy costs saved by the repair. With this data, a payback can be calculated, and budget allocations for the repair can be made.
Step 5: Chart the results as each new monthly bill comes in. By charting these results and tracking them to the previous year's usage in the same month, early results of energy-conservation efforts can be seen. Additional benefits can be gained by displaying the charts in a prominent location. It often is necessary to “normalize” the data for billing-period length to enable these year-to-year changes to be seen clearly from the energy bills. Information on some of these more advanced topics can be obtained from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) (www.ashrae.org) or the Association of Energy Engineers (www.aeecenter.org).
Numerous resources exist on the Internet, such as the sites mentioned previously. ANSI/ASHRAE/IESNA Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, is thought of as the “standard practice” in energy-efficient building design and also serves as a baseline for many state incentive programs. ASHRAE is developing various energy-efficiency guides to help designers plan facilities that can achieve 30- to 50-percent better energy efficiency than required by Standard 90.1. While several already have been published, “ASHRAE 30% Advanced Energy Design Guide for Highway Lodging,” as well as “ASHRAE 30% Advanced Energy Guide for Existing Buildings,” are scheduled for publication by the end of the year.
Most states have agencies or utilities operating within their borders that offer programs to help pay for energy-conserving equipment. Many times, these programs will co-fund energy audits or energy-related engineering studies.
There are several things to consider before entering into a performance contract with an energy-service company or equipment provider. While some performance contracts work to customers' benefit, others get mired in measurement-and-verification (M&V) energy savings within a cost-sharing agreement and may have long-term service contracts written into them. Making use of local energy-incentive programs usually will result in a comprehensive M&V plan developed in accordance with typical protocols. Another benefit is the additional revenue that the project will enjoy. A close examination of the maintenance scope and intervals or a check on another vendor's pricing may prove helpful in determining the cost-effectiveness of the included maintenance program.
Performance contractors sometimes are driven to take a lowest-first-cost approach to reduce their risk and ensure their project payback. Even when equipment operates as promised, these projects may not deliver as-built diagrams or installation, operation, and maintenance (IOM) manuals and may not be punch-listed or commissioned completely.
In all fairness, a typical hotel usually is not staffed sufficiently, and the operating personnel do not have an adequate construction and installation background to guarantee that a project is adequately supervised, punch-listed, and commissioned. In many cases, mechanical-systems renovations do not adequately consider the original design intent or how a facility's mechanical systems function as a whole. It often is in the mechanical systems that a project's inefficient operations are “built in.” Clients should specify the detail and delivery of items such as IOM manuals and as-built diagrams in contracts and enforce these items during a project's construction. It is imperative to have the project punch-listed and commissioned as if the construction were being performed in-house.
Outside assistance often proves helpful in developing or running an energy-conservation program to assist with the week-to-week administration of programs, assist with savings or payback analysis of energy-conservation measures, or even review a performance contract before it is executed. Outside consultants have the benefit of seeing a wide variety of facilities (often including competitors' operations). You may be able to benefit from their knowledge.
Although energy reduction at a facility seems like an insurmountable task, a consistent and modest effort at conserving energy while enlisting the aid of employees at the facility will produce an observable drop in energy use. Ask equipment operators where energy waste is. They know.
Louis Rugulo, PE, CEM, has more than 18 years of experience as a project manager and energy engineer specializing in the development and implementation of demand-side management for major clients. He is principal of Amicus Energy Solutions, an independent energy-engineering consulting firm specializing in retrocommissioning and energy-conservation services for a variety of commercial, industrial, and hospitality clients. He is an adjunct professor of engineering at Stevens Institute of Technology and a teaching associate at City University of New York. He can be contacted at [email protected].