Reduce energy-consumption, and improve comfort with active chilled beam system
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Significantly improve the energy-efficiency of the hospital HVAC system, reduce energy use and maintenance costs by upgrading or designing around a chilled beam system for cooling and heating. Energy reduction can be primarily derived from reduced reheat and fan energy required to operate the system. In addition to the energy- and cost-saving benefits of a chilled beam system, there are significant space savings with chilled beams with a space reduction of 50% or more in duct area and supply and return chases and a 30 to 40% air handling unit footprint reduction, potentially increasing the usable floor space in a building.
Project Talking Points
Chilled beams are ceiling mounted heat exchangers. Primary air is introduced into the active chilled beam through induction nozzles. This series of nozzles induces room air into the chilled beam and across its water coil where the room air is either cooled or heated. The now cooled or heated room air is mixed with the primary air and discharged back into the space to control the room temperature.
In 2011 ASHRAE and ASHE approved and published Addendum h to ANSI/ASHRAE Standard 170 – 2008 Ventilation of Healthcare Facilities. The standard stipulates ventilation and exhaust rates and strategies for the various areas within healthcare facilities. The addendum opened the door for the use of fan coil units and chilled beams in patient areas in order to reduce the amount of supply air reheat, saving energy and reducing cost.
Hospitals use more than double the energy per square foot than the average commercial building. Nearly 65% of all electricity produced in the U.S. is used to operate commercial buildings (Source: U.S. Green Building Council). When considering the amount of energy used to operate healthcare facilities, it is clear why there is a priority to focus on more energy-efficient, sustainable hospital design.
In the U.S., hospitals are seeking ways to reduce costs and improve sustainable design of its facilities. Pioneering hospital systems, including Moses H. Cone Memorial Hospital in Greenville, North Carolina and Huntsville Hospital in Huntsville, Alabama, are already reaping the benefits of energy-saving chilled beams in patient rooms. These hospitals have primarily used an overhead active chilled beam system, but this is not the only option for hospital owners. Active chilled beams can also be used at the floor as a displacement chilled beam system, with the added benefits of improved IAQ, which provides a more healthy room environment for patient healing and enhanced working environment for hospital staff.
One of the primary benefits of using a chilled beam system in a hospital is the significant energy savings possible when compared to traditional HVAC systems. A U.S Department of Energy study showed that 20% to 60% of HVAC electricity used in a typical commercial building is the energy used to power pumps and fans, which transfer heating and cooling from the central plan. With a chilled beam system, less air is required, therefore less fan energy is required, saving energy and reducing operating costs. In some cases, the potential fan energy reduction can be 30 to 40%, depending on climate and application.
Best design practice is to use active chilled beams with a 100% dedicated outside air system (DOAS) that eliminates the HVAC system from recirculation of air between rooms. A comfortable room climate promotes people’s health.
A feature article in the Summer 2013 issue of Inside ASHE Magazine, titled Chilled Beams: Can they work in U.S. hospital patient rooms?, examined a test installation of chilled beams in patient rooms at Holston Valley Medical Center in Kingsport, Tennessee. According to the articled, the initial results showed improved air circulation around the beam and patient bed compared to the previous system (an overhead diffuser and return located at the door). Additionally, not a single patient complaint was recorded or reported to the maintenance staff.Patients in other rooms continued to have thermal comfort issues with the previous system during that same period. Not only did the testing show overall improved comfort, it is also concluded that the temperature around the patient beds was more comfortable and consistent with the temperature at the room thermostat.
Architectural advantages include reduced ductwork and equipment space requirements; architectural flexibility with option to install in ceiling and under-sill/wall; modular configuration; increased floor to ceiling height, making it ideal for use in refurbishment or retrofit projects.
These benefits are well known and proven in Europe and North America. According to leading expert Stanley A. Mumma, Ph.D., P.E., Prof. Emeritus, Architectural Engineering at Penn State University, who has studied the rise and success of chilled beam technology, chilled beams are here to stay. He elaborates the importance of working with experienced engineers and manufacturers of the system to ensure the application is appropriate for chilled beams. He also notes, that a recent article promoting VAV Reheat over Active Chilled Beams with DOAS, is wrong. When the CORRECT design and applications are used, the benefits of the active chilled beam system are apparent. (Reference: 2014 NEBB Annual Conference Presentation titled “Delivering Building Performance and Energy Efficiency)
Triple Bottom Line Benefits
Cost benefits: Chilled beam systems require less supply air from the building air handling system and, therefore less fan energy is required, saving energy and reducing operating costs. Also, because most of this reduced preconditioned air volumes, room reheat energy is significantly reduced. In some cases, the potential energy reduction can be 30 to 40 percent, depending on climate and application.
Environmental benefits: Chilled beams provide a tremendous energy saving opportunity. ANSI/ASHRAE Standard 170-2013, titled Ventilation of Healthcare Facilities revised the ventilation requirements for spaces within healthcare facilities where recirculation of room air is allowed. This change opened the door for the use of chilled beams in patient rooms. Since that time, numerous leading healthcare providers have designed and are successfully using the system in their facilities today. Reduced energy consumption leads to reduced CO2 and other greenhouse gas emissions because less energy is required and produced.
Social and satisfaction benefits: Chilled beam systems are energy-efficient, provide good occupant comfort and are known for quiet operation. Additionally, chilled beams have no moving parts, making them very low maintenance when compared to fan coils for exampleActive chilled beams typically use 100% outside air and there is no recirculation of air between rooms, reducing the risk of any cross contamination.
Quality and Outcomes: When compared to all-air systems, overhead and displacement chilled beams typically operate quieter and are less susceptible to drafts that may provide a more relaxed healing environment for patients and medical staff.
Commissioning Connections: When installing a chilled beam system it is important that the units are installed in the locations shown on the design drawings in order to maintain comfort of the conditioned spaces as intended by the building’s engineers and design team. Once the beams are installed, lowered into the ceiling grid and sitting in their final position, the air and water connections are made according to manufacturer's guidelines. Properly trained and authorized personnel should perform the commissioning of the chilled beam system according to the system’s installation manual.
Purchasing Considerations: When determining the best heating, ventilation and air conditioning system for a building, there are a number of factors that must be considered: ventilation requirements, room purpose and usage, comfort, IAQ, energy-efficiency, maintenance and, of course, cost. Proper ventilation, particularly in critical room environments such as patient rooms, hospitals and laboratories, is vital to health and safety of space occupants and therefore must be the primary consideration. Secondary, but also a key purchasing consideration, is cost (both short and long-term savings) when selecting a system. Several factors contribute to the selection of a chilled beam system:
- Hospitals are considered to be among the most energy-intensive buildings. Therefore, as a best practice, designers should consider all means for reducing the consumption of primary energy while maintaining the safety and comfort of the occupants.
- Because each chilled beam system design is unique, it is important that design engineers work closely with the manufacturer’s engineers to ensure the system selection is done properly for the specific application and goals of the project. There are a number of considerations to take into account when selecting and designing a chilled beam system, including sensible cooling capacity, acoustics, the beams performance and reliability, space temperature and humidity, and most important, that there is adequate ventilation and effective room air distribution to maintain occupant health and comfort.
- The HVAC and lighting energy used in a hospital is more than 2.5 times greater than a commercial office building. Movement toward energy conservation and sustainability across all building sectors, driven by the Architecture 2030 challenge and supportive legislation (House of Representatives (HR.2454) and Senate Bills (S.1462 and S.3464), call for a 30% to 50% energy reduction target by 2030. Chilled beams can significantly reduce the amount of fan and reheat energy used by a hospital, helping building owners, engineers and architects reach these goals. Your supplier should be able to provide a comprehensive total cost of ownership analysis based on your specific project.
- Chilled beams provide an opportunity to use less building materials. Ask your potential suppliers if they can assist you in developing those numbers for your cost benefit analysis. Because chilled beam systems require less primary air, a building’s ductwork and equipment space requirements are significantly reduced. This saves on equipment and supply costs and adds more usable floor space. Additionally, chilled beams offer architectural flexibility with option to install in ceiling and under-sill/wall units. This modular configuration can be very cost effective for use in refurbishment or retrofit projects.
- Space savings with beams: With a chilled beam system, the duct area, as well as fire and smoke control dampers, can be reduced by 50% or more saving material first costs.
- Energy savings with beams: When compared with a traditional HVAC system, chilled beams provide superior energy savings by reducing the reheat by 50% and reducing annual fan energy 30 to 40%. Depending on the size and scope of a project, the design engineers may be able to provide energy modeling to customers to estimate specific savings.
- Suppliers with broad experience in the development and sale of chilled beam systems are best suited to provide solutions for the most difficult room air distribution challenges. The manufacturer should have research and development laboratories equipped with the latest data acquisition systems to provide a wide-range of testing options for customers, from simple airflow demonstrations to sophisticated mock-up tests for challenging applications, such as hospitals, labs and pharmaceutical projects.
How-To: Determining your stakeholder groups for building systems first requires thinking through design, planning and building phases and second through the user experiences during operations and maintenance. These are different stake holder groups but should be at the design table earlier on.
- Because chilled beams are part of a complete mechanical system, early design planning needs to take place between the architect and mechanical engineers. Input from the owner and occupants should be taken to establish project energy, comfort and safety goals. This input should be taken into consideration when selecting the best mechanical systems to meet these project goals.
- Key performance indicators:
- Reheat energy reduction in patient rooms
- Duct cost and area reduction
- Supply and return duct chase square footage reduction
- Once it is decided that a building’s HVAC systems will be designed around a chilled beam system, the mechanical engineer should work closely with the chilled beam supplier’s application engineers to ensure the system selection is done properly for the specific application and goals of the project. Experience is a key component in choosing the chilled beam supplier. (See purchasing considerations)
- While chilled beam systems are well tested and more widely used than ever in North America, they are relatively new as the system of choice in hospital in areas such as patient rooms, therefore long-term case studies are not readily available at the writing of this PIM. Several leading healthcare systems, such as Cone Health Systems and Huntsville Hospital, have implemented the system and early indicators show improved patient and staff comfort, no maintenance issues, and considerable energy savings.
North Tower at Moses H. Cone Memorial Hospital (Greensboro, North Carolina). Energy saving measures, such as the chilled beam system used in patient rooms, nursing stations and employee break areas in the new North Tower at Moses H. Cone Memorial Hospital were among the design strategies used in the building’s LEED® Silver design. The building is the most environmentally friendly project designed to date by Cone Health® system. The chilled beam system is expected to lower energy use by 20%. Maintenance on the chilled beam system has been minimal and has been easily worked into routine maintenance/cleaning schedule, according to first-year feedback. Temperatures around patient beds has been found to be more consistent with temperature at the thermostat than that of a traditional HVAC system, leading to improved thermal comfort and healing environment for patients and better working environment for medical staff and visitors.
A 2014 article in Healthcare Design Magazine stated the chilled beam system uses 51% less energy and a conventional constant volume reheat system and required 32% less ductwork above the ceiling. Additionally, the system helps limit the risk of cross-contamination of air.
While detailed case studies are yet to be available on chilled beams in patient rooms, specifically, their successful use in laboratories (a more challenging room air environment than most hospitals) has been studied for years.
Some articles and resources follow:
Tahoe Center for Environmental Sciences Laboratory Installation
R&D Magazine: A Complete Design Package
Cool Controls for the Energy Efficient Lab
Cutting Energy Use in Hospitals (looks at new statutes and guidelines that are now being implemented as shown in the Moses H. Cone project).
Laboratories for the 21st Century: Best Practices Guide
Chilled beams in laboratories: Key strategies to ensure effective design, construction and operation
MCD Magazine – Moses H. Cone Memorial Hospital
FOX8 News: House Call: North Tower – Hospitals Going Green
Can Chilled Beams Work in Patient Rooms
Regulations, Codes and Standards, Policies
FGI Requirements: ASHRAE Standard S170 2013 for hospitals
Cross References: LEED
Education and Training:
- PDH – Professional Development Hours are offered for those attending chilled beams in healthcare seminars by TROX USA, Inc.
- AIA – American Institute of Architects: TROX USA is an AIA/CES Provider and offers a certified course in Multi-service chilled beam design and application. Course #AIATROX101; Provider #: 40107288
- PIE – The Practicing Institute of Engineering, Inc.; Educational courses offered to New York Engineers only; Courses offered include: Chilled Beams; Displacement and UFAD.
- Operations and Maintenance
- Buildings and Grounds
- Engineering/Facilities Management
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