Although the actions covered in this section require more time and investment, they can dramatically increase the efficiency of your facility without compromising patient care or comfort.
There are usually four steps to implement longer-term solutions. Before looking into these solutions, the hospital should analyze energy use so it is understood where energy is being used and where the hospital can save the most energy. Then, before any solutions are implemented, it should be understood exactly how they will benefit the hospital. The next step is the installation of the equipment. Finally, it is essential to continue maintenance of the equipment and ensure it continues to function as efficiently as possible.
Additionally, whenever faced with major equipment replacement, consider the full life-cycle costs, including maintenance and energy. Because hospitals tend to occupy the same facility for decades, considering life-cycle costs can help you to save money in the long run.
Commissioning is a technical procedure that encompasses building inspection and systems testing to ensure facility performance according to equipment specifications and the owner’s expectations. Commissioning can increase a hospital’s efficiency, which decreases operational costs and increases equipment lifetime. Additionally, not only can commissioning uncover problems currently occurring, it can also help the hospital take preventative measures to avoid future problems. When commissioning is applied to an existing building that hasn’t been commissioned before, it’s called retrocommissioning. Hospitals can be excellent candidates for retrocommissioning because they tend to be energy-intensive, have long operating hours, require large amounts of outside air, and may use old equipment. Moreover, many hospitals have acquired new wings over the years without the benefit of a commissioning study or even recalibration of their building automation systems (BASs).
The majority of problems identified by commissioning tend to concern HVAC systems—in particular, air-distribution systems. Hospitals can benefit substantially from commissioning and retrocommissioning. A 2009 study by Lawrence Berkeley National Laboratory found that 75 percent of retrocommissioning projects had a payback period of 2.4 years or less. If your building was previously commissioned, consider investing in recommissioning every three to five years.
Hospitals can also perform ongoing monitoring-based commissioning, which uses sensors and software in addition to standard commissioning practices to provide a real-time account of systems within a building. This way, when large problems occur or things break, they can be fixed immediately rather than having the problem go undetected until recommissioning takes place. It also provides more persistent energy savings than conventional commissioning. Spaces should always be recommissioned when their use changes. As part of your contract, require your commissioning agent to provide instructions and documentation that can be used for future staff training and maintenance checklists.
Building Automation Systems
Approximately 73 percent of healthcare sector floor space is controlled with a BAS, also known as an energy management system. This system can control the HVAC, lighting, security, and other systems from one central location. This can increase efficiency and allow for easier monitoring of these various systems. By monitoring things like occupancy, temperature, lighting, and pressure, the BAS can run the different systems only when they’re needed and with minimal energy when they are running. Hospitals often have older, pneumatic-control systems that can be recalibrated or replaced with electronic systems. These newer systems are able to save much more energy than the older systems in place in many hospitals. BASs can also be useful for continuous monitoring and commissioning. In that case, data analysis software or a third-party diagnostic service can help identify operational anomalies. A BAS saves energy by:
- Only running systems when they’re required, by deciding which equipment needs to be running where and when based on a schedule of when and where the building is generally occupied and the weather
- Ensuring that the different systems within the building are running at minimum capacity
- Decreasing peak demand by reducing power to certain systems, like lighting, when the power draw of a building reaches a set number (with minimal impact on occupant comfort)
BASs are very effective in hospitals due to the large amount of energy hospitals consume and the specific needs of different rooms. BASs must be commissioned and operated properly for full energy-saving benefits to be realized.
Installing energy-efficient lighting has the potential to cut energy costs while improving satisfaction and performance among patients and staff. Hospital lighting retrofit projects can have an average payback of less than 1.9 years, according to a study of 10 hospitals in New York.
LEDs. LEDs are well on their way toward becoming an effective option for a growing variety of uses, including replacing incandescent lamps, parking lot lighting, recessed downlighting, ambient lighting in offices, and many high-bay applications. Despite technological advances, successful application of LEDs still requires care in selecting products that will meet specific illumination needs, match manufacturer claims, and be compatible with any controls that are employed. In a 2014 case study, a hospital replaced 1,262 CFLs with LEDs that were compatible with the existing sockets and ballasts. According to Next Generation Luminaire (NGL) Downlight Demonstration Project: St. Anthony Hospital (PDF), this decreased total annual energy use by 59 percent. The estimated energy savings were 131,279 kWh per year, translating to annual savings of $15,193 at $0.12/kWh.
LEDs require less maintenance than most other light sources as they boast a life ranging from 25,000 hours to more than 100,000 hours, depending on the application. The competition ranges from 1,000 hours for incandescent lamps to as much as 70,000 hours for induction lighting. For conventional lamps, such as incandescent, fluorescent, or high-intensity discharge (HID) lamps, life is defined as the hours of operation after which half of a representative sample of lamps can be expected to fail. In contrast, LEDs don’t generally fail outright, rather, their output declines over time—so the industry generally defines LED life as the point at which the light output has declined to 70 percent of its original value.
Fluorescent lamps. If your facility uses T12 fluorescent lamps or commodity-grade T8 lamps, relamping with high-performance T8 lamps and electronic ballasts can reduce lighting energy consumption by 35 percent or more. Adding specular reflectors, new lenses, and occupancy sensors or timers can double the savings. Paybacks of 1 to 3 years are common. LEDs, in the form of replacement tubes, retrofit kits, or new fixtures, have also become a viable option, offering considerable savings even compared to the best fluorescent options.
Smart lighting design in parking lots. Parking lots are often overlit; an average of 1 foot-candle of light or less is usually sufficient. The most common lamps used for outdoor lighting are HID sources—including metal halide and high-pressure sodium lamps. In recent years, fluorescent lamps, CFLs, and induction lamps have also become viable sources for outdoor lighting, offering good color quality and better control options than HIDs. But the best choice in most outdoor applications is LEDs—they can reduce light pollution and light trespass while offering high efficiency and long life. LED fixtures can be expensive, but costs are decreasing and performance continues to improve. LEDs also work better than other light sources with dimming and occupancy-sensing controls, which can lead to increased energy savings in parking lots.
Security lighting. Using occupancy sensors with outdoor security lighting can save energy and improve security.
Daylighting. A design strategy that uses a mix of both natural and electric light sources increases comfort and reduces energy costs. Appropriate window shading and separate shades on high windows are relatively low-cost retrofit options to increase daylighting. Light pipes and skylights can bring sunlight into interior spaces on top floors. Dimming ballasts and daylighting controls can be used to reduce the amount of electric light used when daylight is present. Natural light also provides other benefits besides energy savings. Patients in rooms with more natural light recover faster, and staff in hospitals with more daylight have higher productivity and job satisfaction. Additionally, with more daylighting, the hospital will rely less on electric lighting and can divert more energy to critical equipment during a power outage.
LED signage. Installing LEDs in exit signs can decrease energy and maintenance costs as well as increase safety, as LED exit signs are brighter than conventional signs.
Autoclaves are used to sterilize equipment (usually surgical instruments) with hot steam at high pressure. Due to the high pressure, they require steam to be at higher temperatures than do most other steam appliances found in hospitals. By installing steam temperature boosters for autoclaves or spot steam generators that serve only autoclaves, the facility can reduce the temperature of the steam generated at the central plant and thus reduce energy costs. Autoclaves are also good candidates for heat recovery. The heat from the waste water or steam used in autoclaves can, using heat exchangers, be used to preheat water for autoclaves or boilers.
Cogeneration and Other Sources of Heat Recovery
Cogeneration systems provide both heat (for space or water heating) and power. Known as combined heat and power (CHP) systems, they have more applications and offer more savings potential for hospitals than for any other class of commercial building. CHP systems are particularly useful to hospitals because they can provide critical power when the grid is down. Though CHP systems cannot replace the need for backup generators (they’re required by law), CHP can still provide a reliable source of power and heat. Backup generators are more likely to have problems when they’re needed because they’re not used often and not always as well maintained. CHP systems are much better maintained because they’re in daily use. Additionally, backup generators take a few seconds to start up after a grid failure, whereas CHP systems will already have been running.
Some hospitals are installing advanced incineration systems to destroy medical waste. Capturing and using the waste heat from incinerators can be cost-effective in some cases. The University of Michigan saved $400,000 in annual steam bills by coupling medical waste incinerators with cogeneration.
Laundry and kitchen equipment as well as showers, boilers, and autoclaves can benefit from heat-recovery systems, which can be added as a retrofit. Waste heat from boiler exhaust stacks can also be effectively recovered and used to preheat boiler makeup water.
HVAC systems account for a large fraction of hospital electricity and natural gas consumption. Opportunities for savings exist in a wide range of heating, ventilation, and cooling equipment.
Use efficient boilers. Condensing boilers achieve high efficiency by capturing additional heat released from condensing flue gas. Although more expensive, a condensing boiler has an average simple payback period of 5 years, with a 20 percent return on investment. The energy performance of existing boilers can be enhanced with stack gas heat recovery (also known as condensing heat exchangers), air preheaters, water recovery equipment, outdoor temperature controls, and pipe insulation. When replacing boilers, ensure they’re the proper size for the load required by the hospital—which could have changed significantly since the last boiler was installed. It can be beneficial to install multiple smaller units. Since boilers are more efficient when operating at a higher capacity, this approach allows more, smaller boilers to be operating more efficiently instead of one large boiler operating inefficiently.
Install adjustable-speed drives (ASDs). ASDs can be added to pumps and fans in HVAC systems, saving energy by allowing motors to adjust their output to fluctuating heating, cooling, and ventilation needs. Installing ASDs saves the most energy in spaces with lower ventilation requirements and can decrease power used by fans by up to 50 percent. Further savings are possible by using energy-recovery equipment, demand-controlled ventilation, and efficient fan motors.
Use demand-controlled ventilation. Equipment can adjust the outside air ventilation depending on the occupancy and ventilation needs of the space. Occupancy can be determined a few different ways, with carbon dioxide (CO2) sensors being the most common. Areas with dense and sporadic occupancy patterns, such as lobbies or cafeterias, may be appropriate for demand-controlled ventilation using CO2 sensors. Occupant counting, such as ticket sales or video recognition, can also be used to estimate occupancy levels and determine ventilation needs. Occupancy sensors is another method, but it cannot differentiate between one person and full occupancy. Because of this, areas with fairly consistent and less dense occupancy levels, like offices, are good candidates for controlled ventilation using occupancy sensors. Finally, if fluctuation in occupancy can be predicted, such as in classrooms, ventilation can be scheduled with the BAS. All of these methods attempt to eliminate unnecessary ventilation and thus save energy without decreasing comfort.
Choose appropriate size fan. Install fans that are the right size for the application so they’ll operate most efficiently. A whole-building analysis helps to ensure that fans are properly sized. Though this analysis may add to the cost of a project, the cost of a smaller fan will be lower, and the cost of operation will be decreased.
Install displacement ventilation systems. Displacement ventilation can decrease energy use and reduce the likelihood that germs will spread. Cool air is supplied near the floor, and when it comes into contact with occupants, it absorbs the heat. This warm, contaminated air rises to the ceiling and is taken out of the room at the ceiling exhaust. Displacement ventilation only works for cooling, so a separate heating system is required. Ceiling heights should be at least 9 feet for this measure to be effective.
Install a coil bypass. Adding a coil bypass to the heating and cooling coils can be useful. When the heating and cooling coils do not need to be in use, the bypass damper can open, allowing air to pass through the bypass with a much lower pressure drop. This saves fan energy. Since the installation of the coil bypass and controls can be expensive, this measure only makes sense for hospitals in climates where heating and cooling are often unnecessary.
Replace old chillers and boilers with efficient models. When heating and cooling equipment is nearing the end of its life, there is an opportunity to install efficient and variable-capacity chillers and boilers. These replacements can offer considerable savings.
Use efficient auxiliary equipment. Chilled-water systems are custom designed for each application, and employing efficient auxiliary equipment, like efficient pumps, valves, controls, and operating strategies, can often have a bigger impact than selecting an efficient chiller. Annual energy costs of a chiller can amount to one-third of its purchase price. In descending order, the most efficient chiller compressors are generally centrifugal, screw, scroll, and reciprocating.
Install water-side economizers. A water-side economizer evaporatively cools water in a cooling tower and delivers it to a building’s chilled water coils via a flat-plate heat exchanger. In northern climates, the opportunity for free cooling with a water-side economizer typically exceeds 75 percent of the total annual operating hours, whereas in southern climates, such free cooling may only be available during 20 percent of operating hours. Typical simple payback periods from energy savings range from 2 to 5 years.
Install Energy Star equipment. Look for Energy Star–qualified commercial food service equipment when making new purchases. Dishwashers, fryers, griddles, hot food holding cabinets, ice machines, ovens, refrigerators, freezers, and steam cookers are now available in energy-efficient models which are often 15 to 30 percent more energy efficient than standard equipment.
Install new prewash sprayers in kitchens. Prewash sprayers are used to remove food from dishes, utensils, pots, and pans before they are placed in a dishwasher. Although all new low-flow sprayers are currently required to limit flow rate to 1.6 gallons per minute (gpm), many existing sprayers use up to 5.0 gpm. Given the small initial cost of low-flow prerinse spray valves, the payback for this measure is typically less than two months.
For more information on increasing energy efficiency in the kitchen, see Cooking.
Install more efficient washers. Use Energy Star washers to decrease energy and water used by washers. Energy Star washers are 37 percent more efficient than other washers and also generally have larger capacities so that fewer loads of laundry have to be done. Additionally, front-load washers are more efficient than top-load washers because they can vary the amount of water used with the size of the load. Choose washers with higher spin speeds to decrease the energy needed for drying. Install dryers with sensors that turn the dryer off when clothes are dry. Finally, train staff how to best use the washers and dryers to maximize efficiency.
Reduce laundering temperatures. Hospital laundry is typically done in water at 160°F, but according to the Centers for Disease Control and Prevention (see Laundry: Washing Infected Material), hospital laundry can be safely washed at temperatures below 160°F. This is assuming the cleaning agents work in colder water and are used in the proper amounts.
Use ozone laundering. Hospitals are one of the best candidates for ozone laundering because there’s a large quantity of laundry that is not too soiled, and disinfection is particularly important. Ozone is a cleaning and disinfecting agent. It is injected into the water entering the washing machine where it breaks down soil molecules and destroys bacteria. Ozone breaks down soil molecules better than traditional cleaning agents, like chlorine. Ozone laundering uses cold water rather than hot water because ozone lasts longer in cold water. Using ozone laundering also decreases washing and drying times, so the motors in the appliances have to run for less time. According to PG&E’s Energy Solutions for Ozonated Laundry Systems in Hospitality Facilities (PDF), on average, ozone laundry systems (including washing and drying) save 8,651 kWh annually, or 3.5 percent. Additionally, ozone laundering decreases water and detergent use because detergent and rinsing are generally not necessary unless the laundry is particularly soiled.
Use CO2 laundering. CO2 laundering uses CO2 instead of water. CO2 is used in the machine at high pressure when it’s a viscous liquid to clean the dirty laundry. Then, the pressure is reduced and the CO2 turns back into a gas, so there’s no drying necessary. The CO2 is removed from the machine and then filtered and distilled after each load to be used again. CO2 washers save water and energy in addition to having shorter washing cycles and increasing garment life, since there’s less heat and agitation. CO2 laundering is appropriate for hospitals because it provides absolute disinfection.
Hospital Plug Loads and Efficient Medical Equipment
Nonmedical equipment. There are ways to reduce nonmedical plug loads in different parts of hospitals (office, kitchen, and laundry), as described here.
Medical equipment. Although there is not a lot of medical equipment available with an emphasis on energy efficiency, there are a number of developments in progress, including rating systems for the efficiency of medical equipment. Medical imaging equipment represents a good source of increased efficiency because it draws a lot of power when not in use and is in use only in short bursts. The Magnetom Amira from Siemens is an energy-saving magnetic resonance imaging scanner that is currently available. This machine saves energy by switching into standby mode when not in use. Energy Star is also coming out with ratings for medical imaging machines with different modes that will decrease power draw when the machines are not actively being used. The Appliance Standards Awareness Project is also a good way to stay up to date with standards and developments with medical equipment.
Solar. Since hospitals are typically large facilities, they may be good candidates for solar photovoltaic (PV) power. There are many things to consider when installing PV, including mounting, positioning, tracking, shading, and weather. If roof space is limited, parking lot canopy PV systems can be a good choice. PV systems in parking lots also have other benefits, such as providing a very visible commitment to the environment; and they provide shade and shelter for parked cars. If the hospital owns empty or unused land, that can be another good option for installing PV, as it makes good use of otherwise unused land and often has a larger capacity than rooftops. The PV system can be owned either by a third party or directly by the hospital. For more information on PV and financing options, see On-Site Commercial Solar PV Decision Guide—For the Healthcare Sector (PDF) from the DOE.
Windows. Windows provide daylight and views, but they also affect heating and cooling loads. Your particular climate will have a large effect on what’s best for your hospital. If cooling loads are dominant, glazing that transmits adequate light for daylight activity while minimizing solar heat transmission is best. In buildings where heating is the major HVAC load, glazing should be carefully chosen to minimize heat loss and, in some cases, configured to increase passive solar heat gain while maximizing daylighting. For more information on windows, see Building Envelope.
Cool roofs. Eliminating heat gain through the exterior roof and walls can be a cost-effective and low-risk way to reduce cooling loads and peak demand. One of the most effective measures is using light-colored roofs. See Cool Roofs to determine if they may make sense for your hospital.
Improved insulation. Insulating exterior walls and roofs can have a big influence on room comfort and energy costs in older facilities. Nearly 40 percent of hospitals are improving the insulation in their buildings. Also, check insulation on ducts and pipes as well as hot water tanks. Replace or repair damaged insulation.
Elevators. Energy use can be reduced by installing more efficient elevators, though this usually results in long payback periods if installed for the energy savings alone. There are other benefits to efficient elevators, though, such as high performance and improved reliability.
Vending machine controls. Consider upgrading to Energy Star–qualified vending machines. This can reduce energy use by up to 50 percent (depending on the age of the machine), producing annual savings of around $150. Energy Star vending machines also come with software that can put the vending machine into low-energy lighting and refrigeration modes when the area is unoccupied, which can cut energy use by up to another 20 percent.
Office equipment. Use Energy Star office equipment such as monitors, printers, scanners, copiers, fax machines, and power adaptors. Replace cathode-ray tube monitors with liquid crystal display monitors.