Which HVAC system is right for you?

NATIONAL REPORT—With estimates that hotel guestroom energy consumption accounts for approximately 40-80% of total building energy use, of which cooling and heating are the majority, it is vital that hotel management know the type of system that works best for their operations and the factors in choosing them.

There are plenty of options out there for hoteliers: PTAC (packaged terminal air conditioner), a single-unit combination air conditioner and heat pump placed below a window frame; VTAC (vertical terminal air conditioner), a compact, through-the-wall packaged system, capable of providing total heating and cooling functions for single zones or multiple rooms; VRF (variable refrigerant flow), a single outdoor condensing unit connected to many indoor units, like fan coil units at entry foyers or bathrooms. VRF units simultaneously heat and cool different zones thanks to individually controlled refrigerant flow to different evaporators; and VRP (variable refrigerant packaged heat pump), a VTAC that mirrors the performance of VRF but in a packaged system—it includes the ability to bring in conditioned outside air as well as actively dehumidify.

But which solution should a hotelier opt for? There are many variables to take into account when choosing the best HVAC unit for a property.

Many hotel franchises have specific preferences for HVAC, according to Blair Hildahl, founding partner, Base4, an architecture, engineering and interior design firm. “But for those that do not, there is a pattern in usage of certain HVAC systems. In general, PTACs are better suited for budget-friendly hotel projects. As you move up the guest-expectation scale, VTAC and VRF systems respectively make more sense.”

He sees the VRPs as a good fit for mid- to upper-scale hotel properties. “More specifically, I see these systems frequently in modular hotels,” he said. “VRP makes the entire guestroom HVAC system (including fresh air) independent within the guestroom module by eliminating the outside air ducting to each room. In simpler terms, using VRPs can limit the necessary on-site connections after modular boxes are set into the building, which is very beneficial in keeping schedules.”

Rob Lafleur, director, product management, Zoneline, GE Appliances, a Haier Company, also sees that the type of system is based on the level of property. “The focus is less around cost and more geared toward guest experience as the tiers increase,” he said. “For example, hotels with suites typically opt for a VTAC (also known by the industry as SPVAC—single package vertical AC) or a VRF system (or a premium-featured PTAC), which is more hidden and quieter than some of the open-to-room, through-the-wall applications. With VTAC, you can also use one unit to condition a multi-room suite versus the approach of using multiple PTACs. This gives the room HVAC more of a house-like ‘hidden AC’ feel. VRF gives high efficiency, hidden appearance and quiet operation.”

Noise levels of the units are definitely a consideration. “Going by the functionality, noise levels should be considered when making a choice, as PTACs and VTACs have exterior grilles, making it an easy surface for noise transmission,” said Hildahl. “VRFs are superior when it comes to noise insulation, as they do not allow any external noise in. Hotels in urban, highway and airport areas should prefer VRF, where noise might be a concern.”

With heating and cooling of guestrooms such a large contributor to energy usage in hotels, the efficiency of the units is a major factor to consider. “PTACs and VTACs might be enough for cooling and heating needs, but when it comes to guest satisfaction (noise problems) and energy efficiency, VRF delivers higher ROI,” he said. “It’s going to positively impact your bottom line in the long run.”

New systems across all types of HVAC are making advancements in energy efficiency, according to Bill Huber, national accounts manager, Friedrich. “New technology and engineering advancements continue to push the envelope of energy efficiency across all products,” he said. “PTACs are more efficient than ever and VTACs have new DOE [Department of Energy] efficiency minimums required by the end of this month. Adding ECM motors and invertor, variable speed compressors to the products really steps up the efficiency game to a whole new level.”

To help conserve energy, according to Hildahl, it is important to deploy a good energy management system (EMS). “EMS is a combination of hardware and software that works to lower hotel energy consumption and improve maintenance operations,” he said. “A preemptive measure would be choosing the right, region-specific thermal insulation, which is a complex math and should be addressed in the design stage.”

The biggest issue that Lafleur sees when it comes to HVACs is incorrectly sized systems. “Regardless of the type of system you choose, it’s key to do your homework up front and select the right BTU-size system for the heat load of the space you are conditioning,” he said. “Just as important is the sensible heat ratio, which will dictate how much dehumidification will be provided to the space. Too often, we see oversized units that don’t run long enough to keep the space at comfortable humidity levels, resulting in cold, clammy spaces or short cycling units. We also see systems that simply can’t provide enough dehumidification for the climates they are in.”

He continued, “PTACs like our GE Zoneline Dry Air 25 series have additional dehumidification capacities for applications like these. Ultimately, these issues lead to inefficient units that consume more energy, even if they are a very efficient unit to start with.”

Another issue for Lafleur is make up air, designed to “make up” the air in your interior space that has been removed due to process exhaust fans. “Make up air, required by many codes, is also important for room comfort and efficiency, and should not be overlooked when sizing the HVAC system,” he said. “The heat and humidity loads added by these systems should be accounted for in the overall sizing of the HVAC system for that space.”

For Douglas Mackemer, national director of parts, supplies and specialized equipment, Carrier Enterprise, the most important thing when it comes to choosing an HVAC system is to talk with all of the players involved. “The best choice of equipment for a hotelier is relative to the type of hotel, upfront build and construction costs,” he said. “Each of these…have advantages and disadvantages. Conversations need to be had with the hotelier, designer, engineer and architect as to which is the best option.” HB