HVAC Improvements For Existing Buildings – HVAC Retrofits

One way to identify tenant needs in existing buildings is to note what architects and designers are trying to create for clients in new buildings. The objective for a new building is to provide the ideal office space. Tenants are often looking for space that can address such issues as flexibility, modular space planning, environmental considerations and individual temperature comfort. A particular hot spot for many national tenants is to gain the highest level of productivity from their employees. This usually means the building will need plenty of HVAC zones, flexible office hours and point-of-use supplemental systems. These factors point to a flexible and often programmable HVAC system that can meet tenants' needs.

Architectural trends can also create new loads and requirements for an HVAC system in an existing facility. More natural light can increase heat loads; atrium designs can obstruct air distribution; additional zones can increase the overall volume of ventilated air needed, the quantity of heat to be rejected and the amount of outdoor air required. If a building doesn't have a flexible HVAC plant, then modifications or upgrades to the HVAC system will be necessary to compete with new building design and technology.

One factor that must be considered in any analysis of a possible retrofit is that an HVAC upgrade usually means that the building has to be brought into compliance with current codes. Some codes are based on prescriptive regulations; however, the trend to create a safer and healthier indoor environment can also bring new performance requirements. For example, over time, the percentage of outdoor air has gradually been increased, and current requirements may call for more outdoor air than many buildings have the capacity to condition. Bringing the building up to code may require a significant investment in upgrades beyond those originally planned.

Making Retrofit Decisions

HVAC systems are major energy users, and new HVAC technology is far more efficient than 15 to 20-year-old systems in place in buildings. In some cases, the energy savings alone are so substantial that they justify the upgrade investment. But in many commercial office buildings it can be difficult to justify an HVAC upgrade. Perhaps some upgrades have been performed over the years, reducing the energy savings now available. Or perhaps the owner has a too short a payback-period requirement for energy upgrades.

When energy savings alone do not clearly justify an upgrade, how does the facility executive responsible for a commercial office building determine whether and how to upgrade the HVAC system? It is best to start with the building profile. A relatively small or mid-sized building (less than 200,000 square feet) may present marketing opportunities not available to larger facilities. For instance, instead of converting a constant-volume system to variable-air-volume (VAV), it might be possible to make each floor a separate zone. The marketing plan could then be changed to focus on larger, whole-floor users with large bullpen work areas that do not require multi-zone improvements.

In a medium or large-sized building, upgrade options will depend more on the type of system already in place. If the base building system is a constant volume system, with the main fans delivering varied air temperatures to large sectors of the building, there isn't much choice. To serve the varied needs of today's tenants, the facility executive will need, at a minimum, to increase the zoning abilities. How this is accomplished depends on the building's design and business plan.

For example, new speculative office buildings sometimes install heat pumps, which can deliver heating or cooling to small or large zones, are easily programmable, and operate at about 50 cents a ton per hour. But is the first cost for installing heat pumps a good value for retrofits? Probably not if the building was configured as a constant-volume or multi-zone system. Using heat pumps would require running condenser piping throughout the building and changing the fresh air distribution; what's more, the actual conversion could not run parallel to the old system if this retrofit was attempted in the summer because the cooling tower would be reused.

In this case, options for conversion should be limited to a VAV conversion or to individual zone diffusing that does not reduce energy costs but does create comfort zones similar to VAV systems. VAV systems provide a constant temperature to the space, but the air volume varies with the comfort setting. If the building was constructed after 1975, it probably has some type of VAV system installed. The earlier systems did provide easy zone creation; however, after-hour and flexible operation were usually not part of the operating system.

The most difficult VAV retrofit decisions are the ones where the payback related to energy reduction has already been captured by vortex dampers or by the later addition of variable frequency drives. If the facility will not receive an initial influx of energy savings, HVAC retrofits will have to be justified based on increased flexibility, after-hour operation and supplemental cooling. The facility executive must spend the time necessary to understand the overall value to the asset from a marketing standpoint.

It is important that all values are considered when making the decision. More is involved than just the cost of energy. There will be other gains that are not so obvious. A new cooling tower or new chiller not only operates with less kilowatts per ton, it also has new heat transfer surfaces, better part-load abilities and generally reduces maintenance requirements. The amount of labor and maintenance required to service a temperamental HVAC system can be quite a surprise once it is segregated from general operating costs.

The facility executive must also look at the useful life of the existing system. Will there be parts available next year? Is there a service company that will be willing to support the system? If a decision is made to sell the building will the system be flagged as unserviceable? Can the system still be used when a big block of space comes up in two years? These are all questions to ask when a system is facing obsolescence and when reliability of building systems becomes a factor in the marketplace.

There are other building details that sophisticated tenants are aware of or will become aware of if they enlist a good tenant representative or broker. Consider a broker with a client that is considering an existing building over the brand-new building across the street. The potential tenant is concerned with the condition of the HVAC system and requests the following information:

• Is the ductwork and distribution system clean? Please offer some verification.


• How is the insulation attached? Is it interior or exterior fiberglass?

• Is sound batting provided?

• What is the zoning per terminal?

• What are the temperature setpoints of the zones? How many zones are in my space?

• What is the noise level of the terminals?

• Can we control the perimeter zones of the offices separately?

• Is there any asbestos on the HVAC system, piping or ceiling?

• How can I operate after hours and what is the cost per hour?

• If I want to add some additional servers, is there a tenant tower for condenser water?


• What are the watts per square foot and the cubic feet per minute of ventilation air?

• What am I guaranteed in the future?

• How will I be billed for use of my after-hour heating and cooling?

In the last few years, tenants have been even more concerned with the office IAQ (Indoor air quality) environment. The more important the staff is to the operation, the more concern for the users' welfare. Tenants are asking more questions like these:

• What is the outside air ratio?

• Where does the outside air for my area originate and can you achieve 100 percent economizing?

• Do you have a proactive plan for indoor air quality complaints?

• Do you allow smoking?

• Do you have pressurization, smoke tower, stairway pressurization or smoke exhaust system?


• Are there any negative air situations in this building and does any of the air come from infiltration?

• Is there any redundancy to the heating and cooling systems?

• What is the origin, quality and reliability of the electrical service supplying the building HVAC system?

Competing for Tenants

Potential tenants may also want to see the property's preventive/predictive maintenance program, or to review the energy or computerized maintenance program to determine what occurs when the building operates outside its design parameters. This is when a facility executive must know the market. Can the property afford not to retrofit? Very often an energy payback exercise will show the project being way off the owner's target. But the analysis must also take into account lease-up value, tenant retention, cash flow and ultimately overall asset value. If a property is competing with a state-of-the-art VAV building with lower operating costs and greater flexibility, where are the tenants most likely to go?

In a landlord's market, a building with an outdated HVAC system may do all right. In a tight market, with a lot of available space, that property may either have to reduce rent, offer concessions or decide to give tenants what they really want: An HVAC system that is flexible, usable, efficient and able to provide comfort and good indoor air quality for employees.

Julian Arhire is a Manager with DtiCorp.com - DtiCorp.com carries more than 35,000 HVAC products, including industrial, commercial and residential parts and equipment from Honeywell, Johnson Contols, Robertshaw, Jandy, Grundfos, Armstrong and more.

Healthcare And Facility Infrastructure

New diagnostic and treatment equipment occupies dedicated spaces. At the same time, there is increased emphasis on ambulatory care for many procedures and illnesses, with more selective inpatient admissions and decreased length of stays. There also is a trend toward networking remote primary care and diagnostic centers to other types of care facilities.

With these changes comes the need to provide more sophisticated HVAC, power, telecommunications/data and life safety systems. Owners, architects and engineers alike face the challenge of allocating space and developing a facility infrastructure that not only accommodates these systems but also allows optimal integration and flexibility today and in the future.

To meet the demands placed on system infrastructure and to provide future flexibility, space must be allocated for much larger mechanical, electrical and telecommunications distribution hubs and risers. One of the biggest problems in existing facilities, which may be 30, 40 or 50 years old, is finding and reprogramming enough space to revamp the entire core infrastructure and controls. In new facilities, owners may be understandably reluctant to add to the amount of space required for the engineering systems.

Indeed, the proportion of the cost of the building systems to the total cost of a new facility is now approaching 50 percent. Whether planning an upgrade or new construction, finding cost-effective solutions requires cooperation among owners, architects and engineers.

Optimizing the HVAC System

Energy efficiency, indoor air quality, comfort and flexibility for future changes are the key criteria to keep in mind when engineering the HVAC system, which must provide the optimal environment for a range of treatment and support spaces.

HVAC systems today comprise more individual units dedicated to meeting the different temperature and air-quality needs of spaces such as telecommunications/data equipment rooms, diagnostic equipment rooms, operating rooms, emergency rooms and in-patient rooms. Zoning also allows the mechanical engineer to employ specific tools, such as high-efficiency air filters, where they are needed.

To assure indoor air quality, the HVAC system must be able to provide proper filtration and ventilation, and minimize cross-contamination of building spaces. Airflow must be directed from clean areas to less clean spaces and then exhausted outside. Controls must use a reliable monitoring and alarm system to ensure maintenance of proper indoor air quality and pressurization standards.

"All-air" HVAC systems, which allow use of primarily outside air to, whenever possible, heat and cool a facility, enhance indoor air quality and the energy efficiency of the HVAC system. Efficient motors, variable speed drives and economizer cycles all can be used to minimize energy consumption.

In any case, HVAC systems are heavy energy consumers. But deregulation has provided the opportunity to use systems that can use multiple energy sources to run boilers and produce chilled water. At any given time, the facility can choose which energy source to use (electricity, natural gas or steam) depending on demand, cost and availability.

The nature of today's hospital demands selection of state-of-the-art direct-digital-controlled HVAC systems, which are accurate and flexible, allowing control from central and remote locations.

Power: Quantity and Quality

Flexibility of power system infrastructure and power quality are key criteria for the electrical power system design. Spare capacity has to be built into every major normal and emergency power riser. In most cases, minimum code-suggested values for feeder and equipment sizing may not be adequate for modern hospital design because of universal usage of computer equipment for a wide variety of functions.

The nature and sheer volume of hospital systems and equipment also create challenges. For example, more and more equipment today is electronic, which contributes distortion to the electrical system. Current causes this distortion and voltage harmonics that affect both normal and emergency power supply and distribution systems, and sensitive medical electronic equipment fed from it.

To minimize harmonic effects on the power system, 200 percent neutral should be the standard on all three-phase, four-wire systems and equipment. Rectifiers and trap filters are strongly recommended on all variable frequency drives. Emergency generator specifications have to include provisions for 100 percent non-linear loads. Usually, generators will have to be one size larger than the engine size to compensate for non-linear loads.

The high volume of electrical equipment also creates electromagnetic interference. This is not the place to try to economize on construction costs. Electrical engineers often recommend rigid steel conduits for major feeders - especially those passing through critical areas - rather than the thinner, less expensive electrometallic tubing, which does not block magnetic interference.

The ratio of emergency to normal power is increasing. The trend is to place more systems on the emergency generator than dictated by minimum code requirements. For example, cooling is not required to be on generators, but more hospitals are electing to do so. Indeed, owners of facilities designed to meet code and budget requirements just a few years ago now may want to add systems to the emergency generator, only to find that their generators do not have adequate capacity.

Internet, Telemedicine Make the Call

The design of the telecommunications infrastructure in hospitals today is driven by the expanding need for high-speed, high-quality computing and networking both within the hospital facility and between the hospital and the outside world.

Hospitals already have in place or are adding new local area networks (LANs), often Ethernet systems, to network all types of data, from patient records to radiology data, throughout the facility. Now networks are expanding, with installation of data ports at each bed, allowing access to view and update patient records as well as diagnostic images. (The future is in wireless, portable access via hand-held computers, already being seen in some applications.)

Expanding the network to each bed necessitates upgrading the infrastructure to comply with the latest standards. This, in turn, requires telecommunications closets to be dispersed throughout the building, with certain distance limitations between the closets and each data outlet and certain closet size requirements based on the size of the area and the number of outlets.

Meeting these standards and future needs requires a lot of space and, when upgrading an existing facility or planning a new facility, owners and planners must be prepared to allocate it. Usually this space is in the core of the building, not in an underutilized corner, to meet distance requirements.

The good news is that current standards in the design of the telecommunications infrastructure should serve health care facilities well for 10 to 15 years.

This means that - even if new cable itself may be required in the next decade - the number and spacing of telecommunications closets should remain consistent - the crucial issue in space planning. Indeed, many believe that the next generation of cable will be "all we will ever need" in copper cable. Additional speed will have to be accommodated using fiber-optic cable.

The logical extension of the LAN is a wide-area network (WAN) that enables telemedicine: remote access to patient records, diagnostic images and other data by computer, with the capability of simultaneous videoconferencing. A lot of institutions are talking about telemedicine, and some are forming pilot projects. Some are making the connections between the hospital and physicians' offices and outpatient clinics over the Internet. Others are using dedicated T1 or ISDN phone lines, which offer higher-bandwidth (i.e., high quality) communication as well as quick speeds.

In fact, much of the capability for the WAN depends on the main telecommunications equipment in the building and the cabling that goes out to the world. Many hospitals have multiple T1 copper phone lines coming in and some fiber-optic cable. The trend is to bring in more fiber, which is what is really needed to drive video imaging. Either way, space is needed in the main telecommunications room for the large amount of equipment to communicate with remote sites.

Life Safety, Security

As it is in emergency power, so it is in life safety: The trend is to exceed code in both existing and new facilities. Many existing hospitals have outdated fire alarm systems and inadequate sprinkler systems by today's standards. Owners are retrofitting with modern, computer-controlled fire alarm systems - centrally monitored and controlled from a fire command station, usually in the main lobby.

The new systems require new water service, fire pump and vertical distribution system and additional sprinklers. This complicates the cost and space issues. A sophisticated mechanical system can also provide smoke control, either automatically or manually from the fire control station. This is a highly reliable early warning system.

Security systems are vendor-driven, changing rapidly, and are generally planned and implemented after a building is completed. Much of a security installation is low voltage. Thus, engineers should assure that enough space and power are allocated in the backbone for security hub equipment. Needs differ, but most security systems today use some combination of card access and biometrics readers, motion detection, closed-circuit television and metal detectors, as well as personnel.

Higher Demands

It's also worth mentioning that stand-alone ambulatory care facilities may place even higher demands on infrastructure because there is more sophisticated equipment packed into them than in some hospitals, which contain patient rooms and more support spaces.

Now, what about controls? Given the size and complexity of the hospital setting, integrated controls would seem to offer distinct benefits. Yet it is not only expensive but often difficult to build a system that integrates control of all mechanical and electrical systems because many control manufacturers' systems are proprietary.

There has been an effort in the market to develop "open protocol systems" - creating an integrated control system - but applications have involved links between components or subsystems rather than completely integrated automation systems. Today, it is more common to selectively marry major control components to the building management system regardless of whether the controls use open protocols. Continued introduction of products that use open protocols promises to expand the use of integrated control systems.

In the final analysis, designing a health care facility infrastructure for the 21st century is all about optimizing system integration and flexibility to ensure that the facility will remain a fully functioning organism in the future. Perhaps nowhere else is the metaphor of infrastructure as "backbone" more apt than in health care.