Heating, ventilating, and air conditioning (HVAC) is required in most buildings to provide occupant comfort or enable the necessary environmental conditions for specific processes.
The HVAC industry is one of the most important and prominent industries as people will always need air conditioning for their space, whether it be for existing building or new construction. There are many different types of HVAC systems that can be used. These may be classified as industrial, commercial, or residential HVAC systems, although some equipment and systems fall into multiple categories. Commercial HVAC units differ from residential units in that they are typically reserved for buildings focused on meeting occupant needs and providing occupant satisfaction in large spaces as opposed to housing. Some examples of commercial buildings industries include offices, retail, hotels, education, healthcare, museums and event centers. Among the different commercial HVAC equipment, packaged rooftop units are the most popular for commercial air conditioners.. These units contain all four components of the refrigeration cycle within one housing.
There are many different commercial applications that require specific commercial HVAC equipment to deliver the best system performance and comfort for the building space. Maximizing energy efficiency can depend on how the HVAC equipment is selected and what the design requirements are. Even in circumstances where the parameters are the same, the priority of different characteristics may change altering which system is the most appropriate for an application. Some examples that can alter the outcome is the size of the heat exchanger, the amount of ductwork needed for the unit, and even ensuring the unit complies with local regulations and codes. If selecting a unit correctly, the business owner or facility manager could have lower operating costs and reduce preventative commercial HVAC maintenance costs.
Although packaged rooftop units tend to be the most popular units for commercial buildings, there are some other cooling systems that can be selected. Split systems are a type of system in which there is a condensing unit on the roof or side of the building piped to an indoor air handler unit, which can be in a closet or lofted in a ceiling. Water cooled systems, such as water source heat pumps, can be used as indoor or outdoor units and use water as the heat exchange medium for the refrigerant. Chillers are large commercial systems that supply the chilled water to the building and any HVAC systems in the building that utilize water as the heat transfer medium. An HVAC contractor can be used to help select the best system needed for the the building based on the needs of the building owner.
Below is a list of items influencing the HVAC system selection. Many of these will be much different for a commercial application when compared to one that is residential or industrial.
System Capacity
- Size: Physical area to be conditioned
- Construction Materials: The heat transfer characteristics of the building envelope
- Location and Orientation: Outdoor climatic conditions and solar contributions
- Use: The function taking place within the building controls the number of people, the desired temperature and humidity setpoints, quantity of ventilation, and other internal loads
Building Characteristics
- Space: Physical area to locate and service the system equipment and components. Commercial HVAC installation considerations should be taken into account
- Utility Availability and Cost: Electric, natural gas, and hot water/chilled water/steam may or may not be accessible with each having a different pricing rate and structure
- Integration: Aesthetic synergy with the architecture or connection to existing systems
- Local Ordinances and Codes: Adopted laws that apply to different building classifications
- Life: The duration of the analysis when selecting the system and the expected equipment longevity
Owner Directed
- Budget: First cost for equipment and installation as well as annual operation and maintenance cost
- Level of Control: The desire to have multiple thermostats or to maintain space conditions within a precise range
- Acoustics: Sensitivity to sound
- Indoor Air Quality: Targeting the minimum air quality thresholds or opting to exceed these values to improve occupant satisfaction
- Environmental Impact: Owner defined requirements regarding decarbonization and sustainability or to qualify for specific certification programs
- Owner and Facility Management Preferences and Capability: Preferences for systems based on prior experience and/or the technical capacity of the team responsible for maintaining the system
- Risk Tolerance: Redundancy and reliability contribute to the potential of failure and the impact to building operation
- Financing: Offset first cost with rebates and/or incentives or qualify for financing options by selecting eligible HVAC systems
The selection of the correct commercial HVAC system to optimize function and energy savings for an application is not trivial due to the multitude of interlaced variables that must be considered. This process is often left to experienced designers that are knowledgeable of the attributes of the many different HVAC systems available. In many cases, a designer narrows the options and then conducts a life cycle cost analysis (LCCA) to quantify the fiscal impacts between the options over the life of the building. This financial data is then balanced with the many non-quantifiable variables to identify the best HVAC system for an application. With regular maintenance, a commercial HVAC system can last for many years.