- J. Patrick Banse, PE, LEED AP, Senior Mechanical Engineer, Smith Seckman Reid, Houston
- Daniel L. Doyle, PE, LEED AP O+M, Chairman, Grumman/Butkus Associates, Evanston, Ill.
- Robert Jones Jr., PE, LEED AP, Associate Director of Electrical, JBA Consulting Engineers, Las Vegas
- Craig Kos, PE, LEED AP, Vice President, ESD Inc., Chicago
- Essi Najafi, Senior Vice President/Principal, Global Engineering Solutions, Rockville, Md.
- Paul J. Orzewicz, PE, Mechanical Engineer, Project Manager, RMF Engineering Inc., Baltimore
- David A. Smith, PE, EDAC, Principal, National Director of Health Care, KJWW Engineering Consultants, Madison, Wis.
CSE: Many aspects of sustainability (power, HVAC, maintenance, etc.) require building personnel to follow certain practices in order to be effective. What, if anything, can you as an engineer do to help increase chances of success in this area?
Kos: One method to support the effectiveness of sustainable systems is to incorporate an energy management system (EMS) into the building design, in addition to the typical building control system. The EMS uses facility metering data on each system and subsystem for measurement and verification that the sustainable design features are being operated per the design intent. Trending of energy usage through an EMS and the analytical tools it can apply to the data also allows facility managers to determine if the sustainable design feature requires maintenance or optimization by monitoring the energy usage and comparing it to the facility’s historical data.
Daniel L. Doyle: It is not unusual for a design and construction team to spend months or even years planning, designing, and constructing a new building and then turn it over to a facility operations team that has had no involvement in the design process and little or no training on how to operate the new building systems and controls. Thus, it should not be surprising that today’s complex control systems are often overridden and the buildings don’t operate as efficiently as intended. The facility operations team should be involved in the project as early as possible; their years of hands-on experience can result in great input on making systems simpler and easier to maintain, helping to ensure ongoing success. Most projects could also benefit from significantly more staff training, including off-site training during the design phase followed by on-site training on the new systems as they are brought on-line, before the building is fully occupied and turned over. Minimum training activities should be incorporated into bidding documents. Large new buildings and major additions or renovations should be commissioned to help ensure that the systems are all working as intended when the project is turned over. Owners should also consider adding monitoring-based commissioning systems to help ensure that buildings will continue to operate efficiently, long term. When a new building is turned over after commissioning, the operations staff should receive extensive documentation, including commissioning reports and functional performance tests, equipment manuals, and an operations manual for the building systems (including operating setpoints, hours, sequence of operations, water and airflow values, and designed occupancy temperatures).
Najafi: A hospital’s BAS can help building personnel monitor and control the environment while improving energy efficiency. Direct digital control (DDC) and maintenance software has improved greatly over the past few years, providing alarms and warnings when there are failures, and advance notification for scheduled maintenance tasks. Even though much of these systems are automated, they still require user input/control, so we’ve implemented specific training for building personnel to be a part of the contract documents, requiring certain knowledge milestones to be achieved by the building personnel prior to full turnover.
Banse: Early in the project discuss sustainable features with the owner and other team members and identify their requirements or requests to be included. Define what is important and what the project can afford. Look for alternative ways of achieving the goals and saving energy with high-efficiency equipment. Declining hospital resources add to the challenge facing design engineers. Be creative.
Orzewicz: Most of the practices required of building personnel to maintain a sustainable building are not exclusive to sustainable buildings. Although systems and design parameters may vary slightly between the average building and a sustainable design, the steps to ensuring that both operate as efficiently as possible are the same. The most impact that you can have as a designer is to provide proper service clearances and access to the equipment to enable the building staff to perform their duties. Proper maintenance of the building systems leads to increased efficiency, increased performance, and most importantly, increased occupant comfort.
Smith: It is important that the facility staff understand and are comfortable with how the system should function. Every system will require maintenance and monitoring. We do retro-commissioning and one of the biggest issues is that staff have modified the systems to something other than the design intent due to a lack of knowledge of how it is supposed to work. Many of these systems in their current state actually are costing the facility over a conventional system rather than saving energy/money.
CSE: Please share a success story in which you were able to deliver a highly sustainable project to a hospital client. Statistics on energy savings and other supporting evidence would be helpful.
Smith: We were able to be a part of the first LEED Silver hospital in the state of Wisconsin. It was certified under the old 2.0 LEED NC system. We were able to meet energy requirements using mostly conventional high-efficiency systems with a heat recovery chiller to recapture heat from equipment. Energy use within that facility has been measured at 190 kBtu/sq ft/yr.
Doyle: Grumman/Butkus Associates recently worked with Advocate Illinois Medical Center in Chicago, a 1.14-million-sq-ft hospital complex, to revamp its chiller plant. Three main chillers were replaced, as well as pumps and cooling towers. An air-cooled chiller serving operating rooms was also replaced, as were three other air-cooled units. (During the same period, we helped the client retrofit boiler burners in a separate project, also contributing to energy efficiency.) The chillers installed exceed ASHRAE 90.1-2007 requirements by 32% to 46%. The project was partially funded by nearly $270,000 in rebates from the local utility, and resulted in estimated energy savings of more than $100,000/year attributable to the chiller work alone. The boiler project will also provide significant ongoing savings and resulted in a 10.4% improvement in therms per heating degree day, helping the client manage energy costs even during Chicago’s brutal “polar vortex” of 2013-14. As an additional benefit, the chiller project eliminated equipment that used ozone-depleting refrigerant. This project is a good illustration of how important engineering retrofits can be in improving health care facilities’ sustainability and lowering their operating costs. Making new construction “green” is obviously important, but the potential for greening existing buildings through intelligent analysis, retro-commissioning, redesign, and equipment replacement is vast and remains largely untapped.
CSE: Please share any experience you have using sustainable heating/cooling technology, such as geothermal systems or ground source heat pumps.
Najafi: We have designed a number of projects with geothermal capabilities, most recently this year for the historic renovation of Roosevelt High School and the Duke Ellington School of the Arts. Each had approximately 500 tons of capacity with a combination of water source variable refrigerant volume (VRV)/variable refrigerant flow (VRF) systems and geothermal heat pumps for an enhanced energy performance.
Smith: Engineers need to be extremely careful with geothermal (geo-exchange) in areas of the country where the cooling and heating loads are unbalanced. While the Earth can be considered an almost infinite heat sink, the local field cannot as soil, rock, and clay are not perfect conductors. The field must be sized for the larger of the heating/cooling load or augmented with boilers or chillers. Using a lake for the geo-exchange can be a more effective system as the lake expands the overall surface area for heat transfer.
Banse: Our firm has designed projects with ground source heat pumps; one has been in operation for about a year and another will complete design by the end of this year. Energy models were created to determine the best design approach, with anticipated energy use used in a lifecycle cost analysis (LCCA) for the systems. The approach that works best is to perform this work early, involve the owner and interested parties in developing the design criteria, and have an accurate cost estimate for use in the LCCA.
CSE: Please describe your experience with high-performance building projects.
To answer this question, we first need to define “high performance.” Many projects start out with a set of vague goals, such as obtain a certain level of LEED certification (for instance, Gold) or simply to be a “green” or “high-performance” design. We need to set more specific goals, such as having an energy usage at XX% below some standard metric, such as ASHRAE Standard 90, California Title 24
, or the IECC. I generally suggest that clients consider setting energy efficiency goals at least 30% below ASHRAE Standard 90.1-2010 for new construction, and 20% below for major renovations. These are reachable goals (though perhaps a stretch), generally obtainable without overburdening project budgets. To meet these goals, the energy efficiency features built into the design must then withstand “value engineering.” This is often a euphemism for stripping out quality and scope to meet a previously set budget. If an owner intends to design and construct a high-performance building, a realistic budget should be established. Unfortunately, owners sometimes ask a general contractor or construction manager (CM) to budget the project without setting clear expectations for sustainability. The general contractor (GC)/CM then uses square foot numbers for standard buildings based on jobs bid and built during the recession, when the contractors were slower and bid prices lower. Without clear expectations set by the owner, value engineering often derails sustainability intentions. After setting a realistic budget, the building owner should evaluate value engineering options based on lifecycle value. If this is done, most efficiency features will not be removed from the scope. Features that don’t make the cut based on lifecycle cost probably shouldn’t have been considered initially. When given proper data, most building owners, including those in finance and the C-suite, can understand the relative value of various energy efficiency design features and make good decisions. Finally, it is common for a new building to be built (or new systems installed) without incorporating sufficient—or any—metering to allow ongoing performance tracking. Metering is a favorite target of value engineering: “We’ll add it later.” How can a building be called high-performance without ongoing tracking and verification of performance? Sufficient metering is essential for any building targeting “high-performance” status. Once metering is installed, performance can be tracked against the modeled performance as well as the standards referred above (IECC, ASHRAE 90.1). The actual performance data will reveal whether the building is actually high-performing.