HVAC Improvements For Existing Buildings- HVAC RetrofitsWhen is the right time to perform an HVAC retrofit to a commercial...
HVAC systems are major energy users, and new HVAC technology is far more efficient than 15to 20-year-old systems in place ...
It is important that all values are considered when making the decision. More is involved thanjust the cost of energy. The...
• Is there any redundancy to the heating and cooling systems?• What is the origin, quality and reliability of the electric...
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Hvac improvements for existing buildings

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HVAC Improvements For Existing Buildings - HVAC Retrofits
When is the right time to perform an HVAC retrofit to a commercial office property? The real estate market may provide the answer. In the commercial office sector, tenant expectations determine the appropriate level of building technology. These expectations vary as tenants seek space based on the category of business they fall into.
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

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Hvac improvements for existing buildings

  1. 1. HVAC Improvements For Existing Buildings- HVAC RetrofitsWhen is the right time to perform an HVAC retrofit to a commercial office property? The real estatemarket may provide the answer. In the commercial office sector, tenant expectations determine theappropriate level of building technology. These expectations vary as tenants seek space based on thecategory of business they fall into.One way to identify tenant needs in existing buildings is to note what architects and designers aretrying to create for clients in new buildings. The objective for a new building is to provide theideal office space. Tenants are often looking for space that can address such issues as flexibility,modular space planning, environmental considerations and individual temperature comfort. Aparticular hot spot for many national tenants is to gain the highest level of productivity from theiremployees. This usually means the building will need plenty of HVAC zones, flexible officehours and point-of-use supplemental systems. These factors point to a flexible and oftenprogrammable HVAC system that can meet tenants needs.Architectural trends can also create new loads and requirements for an HVAC system in anexisting facility. More natural light can increase heat loads; atrium designs can obstruct airdistribution; additional zones can increase the overall volume of ventilated air needed, thequantity of heat to be rejected and the amount of outdoor air required. If a building doesnt have aflexible HVAC plant, then modifications or upgrades to the HVAC system will be necessary tocompete with new building design and technology.One factor that must be considered in any analysis of a possible retrofit is that an HVAC upgradeusually means that the building has to be brought into compliance with current codes. Somecodes are based on prescriptive regulations; however, the trend to create a safer and healthierindoor environment can also bring new performance requirements. For example, over time, thepercentage of outdoor air has gradually been increased, and current requirements may call formore outdoor air than many buildings have the capacity to condition. Bringing the building up tocode may require a significant investment in upgrades beyond those originally planned.Making Retrofit Decisions
  2. 2. HVAC systems are major energy users, and new HVAC technology is far more efficient than 15to 20-year-old systems in place in buildings. In some cases, the energy savings alone are sosubstantial that they justify the upgrade investment. But in many commercial office buildings itcan be difficult to justify an HVAC upgrade. Perhaps some upgrades have been performed overthe years, reducing the energy savings now available. Or perhaps the owner has a too short apayback-period requirement for energy upgrades.When energy savings alone do not clearly justify an upgrade, how does the facility executiveresponsible for a commercial office building determine whether and how to upgrade the HVACsystem? It is best to start with the building profile. A relatively small or mid-sized building (lessthan 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), itmight be possible to make each floor a separate zone. The marketing plan could then be changedto focus on larger, whole-floor users with large bullpen work areas that do not require multi-zoneimprovements.In a medium or large-sized building, upgrade options will depend more on the type of systemalready in place. If the base building system is a constant volume system, with the main fansdelivering varied air temperatures to large sectors of the building, there isnt much choice. Toserve the varied needs of todays tenants, the facility executive will need, at a minimum, toincrease the zoning abilities. How this is accomplished depends on the buildings design andbusiness plan.For example, new speculative office buildings sometimes install heat pumps, which can deliverheating or cooling to small or large zones, are easily programmable, and operate at about 50cents 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. Usingheat pumps would require running condenser piping throughout the building and changing thefresh air distribution; whats more, the actual conversion could not run parallel to the old systemif 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 zonediffusing that does not reduce energy costs but does create comfort zones similar to VAVsystems. VAV systems provide a constant temperature to the space, but the air volume varieswith the comfort setting. If the building was constructed after 1975, it probably has some type ofVAV system installed. The earlier systems did provide easy zone creation; however, after-hourand flexible operation were usually not part of the operating system.The most difficult VAV retrofit decisions are the ones where the payback related to energyreduction has already been captured by vortex dampers or by the later addition of variablefrequency drives. If the facility will not receive an initial influx of energy savings, HVACretrofits will have to be justified based on increased flexibility, after-hour operation andsupplemental cooling. The facility executive must spend the time necessary to understand theoverall value to the asset from a marketing standpoint.
  3. 3. It is important that all values are considered when making the decision. More is involved thanjust the cost of energy. There will be other gains that are not so obvious. A new cooling tower ornew 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 laborand maintenance required to service a temperamental HVAC system can be quite a surprise onceit is segregated from general operating costs.The facility executive must also look at the useful life of the existing system. Will there be partsavailable next year? Is there a service company that will be willing to support the system? If adecision is made to sell the building will the system be flagged as unserviceable? Can the systemstill be used when a big block of space comes up in two years? These are all questions to askwhen a system is facing obsolescence and when reliability of building systems becomes a factorin the marketplace.There are other building details that sophisticated tenants are aware of or will become aware of ifthey enlist a good tenant representative or broker. Consider a broker with a client that isconsidering an existing building over the brand-new building across the street. The potentialtenant is concerned with the condition of the HVAC system and requests the followinginformation:• 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 airquality) environment. The more important the staff is to the operation, the more concern for theusers 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 percenteconomizing?• 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 frominfiltration?
  4. 4. • Is there any redundancy to the heating and cooling systems?• What is the origin, quality and reliability of the electrical service supplying the building HVACsystem?Competing for TenantsPotential tenants may also want to see the propertys preventive/predictive maintenance program,or to review the energy or computerized maintenance program to determine what occurs whenthe building operates outside its design parameters. This is when a facility executive must knowthe market. Can the property afford not to retrofit? Very often an energy payback exercise willshow the project being way off the owners target. But the analysis must also take into accountlease-up value, tenant retention, cash flow and ultimately overall asset value. If a property iscompeting with a state-of-the-art VAV building with lower operating costs and greaterflexibility, where are the tenants most likely to go?In a landlords market, a building with an outdated HVAC system may do all right. In a tightmarket, with a lot of available space, that property may either have to reduce rent, offerconcessions 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 35,000HVAC products, including industrial, commercial and residential parts and equipmentfrom Honeywell, Johnson Contols, Robertshaw, Jandy, Grundfos, Armstrong and more.

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