Building owners no longer upgrade HVAC systems since they want the latest HEATING AND COOLING technologies; rather, they are planning to correct perceived flaws with existing systems. That means the jumping off point can be a comprehensive analysis of the current system. A detailed survey and inspection of all major products should determine age, condition, efficiency and expected left over useful life. This should incorporate a review of original construction drawings and maintenance and repair records. Overall performance testing or non-destructive tests may be warranted for major equipment components or systems, including piping and ductwork.
It is vital to assess the existing system to ascertain whether the system is triggering comfort problems. Many HVAC systems installed in the 1950s and 1960s were only designed to supply a moderate level of cooling. No-one expected a system to provide a frequent temperature year-round inspite of outside conditions.
Since cardio costs often justify HEATING AND COOLING upgrades, historical energy intake should be compared against industry benchmarks of us dollars or BTUs per rectangular foot for similar types of facilities. This evaluation will show how useful a building is and will identify possible concentrate on values for improvement. This may also indicate that, although an HVAC method is 25 or more years old, overall operating costs may be comparable to newer buildings, so that a complete system substitute may well not be warranted depending on energy savings. In this case, replacing selected components might be the best approach.
For a few equipment, such as centrifugal chillers, current equipment is much more efficient than products installed 20 or more years ago, using 40 to 40 percent less energy than older models. However, depending after the hours of procedure of the equipment, these personal savings alone might not exactly justify replacement unit due to high capital costs of new equipment.
One more consideration in evaluating a current system is whether it uses an obsolete technology. Building automation systems have evolved considerably during the last 10 to 12-15 years. Even with systems that are functioning moderately well, it can be difficult to get parts or to find service personnel familiar with older technologies. Also, new systems may have functions that the old systems lack but that would enhance mechanical system procedure and improve resident comfort.
Compliance with requirements and regulations is another key issue. Buildings built from the late ’70s to the mid ’80s were often designed to provide lower outside air quantities than required by current codes. Replacement of an individual HVAC system component may well not necessitate complying with the new limitations; however, this may be desirable to alleviate concerns that lower outside air quantities can result in indoor air quality problems.
An extensive HEATING AND COOLING system analysis is essential to evaluate the impact of increasing the exterior air rate. It is usually less simple as rebalancing the environment handling systems to provide additional outside air. Elevating the outside air will increase cooling and heat loads, which the existing cooling and heating vegetable and related distribution systems might not exactly have enough capacity to serve.
In the event an extensive system alternative is to be performed, compliance with the current codes will likely be required. HVAC upgrades must be carefully evaluated to determine the full magnitude of code-required upgrades; this work could make the project much more expensive than formerly expected.
Consider one owner who had recently been contemplating a major building renovation, including mechanical system upgrades. The existing water-cooled air-conditioning units on each floor were not measured to handle the amounts of outdoor air at present required. Even though the equipment was in good condition and could likely have continued to operate for several years, the owner elected to replace the units hence the building would meet the new ventilation standard, as well as to avoid future disruption if replacement was required after the building was fully occupied. Therefore, other system components, such as cooling towers and pumps, also had to be replaced.
Environmental rules may influence HVAC improvements. In 1996, the Tidy Air Act mandated evaluation on the manufacture of CFC (chlorofluorocarbon) refrigerants, which are used in almost all large chillers produced up until early ’90s. A few CFC refrigerants are still relatively widely available on the recycled basis; others are scarce or are incredibly expensive. An owner with a CFC chiller should consider refrigerant issues in deciding whether to replace the equipment.