Check into hotel, motel, resort high-tech designs: HVAC and sustainable buildings/energy efficiency
- John Barrot, PE, LEED AP, Associate Principal, Arup, New York City
- Kevin Christensen, PE, LEED AP, Vice President/Director of MEP Engineering, Epstein, Chicago
- Wesley S. Lawson, PE, Senior Associate, Bala Consulting Engineers, King of Prussia, Pa.
- Steven Mulcahy, Principal Engineer, Southland Engineering, Las Vegas
- Christine Sauer, PE, Senior Fire Protection Engineer, JENSEN HUGHES, Baltimore
CSE: What unique HVAC requirements do hotel, motel, and resort projects have that you wouldn’t encounter in other buildings?
Christensen: Besides the compliance with energy codes, the greatest challenge can be the physical space available to run ductwork and piping. For the hospitality market, the feeling of the space is a critical component to the architectural design. Open and airy spaces are generally the design norm. This usually translates to higher ceiling heights, which very often can create almost unworkable plenum space.
Lawson: Hotels normally have a different level of acoustical requirements than multifamily buildings. Many times, this will drive the HVAC system selection. The entire design team must be careful not to select a lower-end HVAC system that requires more attenuation, as it may drive the cost to equal that of a higher-level HVAC system with less attenuation. An example of this would be having a heat pump system with attenuation as opposed to a fan coil system.
Mulcahy: The interesting thing about Las Vegas is the perpetual change. Rarely does a week go by that I am not hit with a unique design challenge. The desire by properties to outdo each other leads to each project being unique in some way.
CSE: Have you specified variable refrigerant flow (VRF) systems, chilled beams, or other types of HVAC systems into a hotel, motel, or resort? If so, describe its challenges and solutions.
Lawson: Bala has seen VRF as a very good system to use in hotel applications. VRF allows for minimal acoustical concerns, the localization of maintenance (no compressors in the room), and the flexibility of using a small unit in each room. Owners have largely been happy with this system when used. Chilled beams are not a great application for a hotel, especially if the owner wants operable windows. It is very important to control the façade, therefore the humidity, in any chilled-beam application.
Mulcahy: We incorporate chilled beams and/or chilled floors in our projects where appropriate. Dew point and chilled-water-supply temperatures are always a consideration for those types of systems.
Christensen: I have been involved with teams that have proposed these types of systems, but they usually are not approved by the owner for three main reasons: (1) They do not want to deviate from their established standards/guidelines; (2) it sets up a completely new O&M protocol that is different than all the other facilities; and (3) the individual managing the project on the owner side does not want to risk their facility being the first one to deviate from the standards. This is generally true for larger established hotel/motel operators. I would think there would be a greater possibility to convince upstart or one-off operators to install these systems.
CSE: What types of dedicated outside-air systems (DOAS) are owners and facility managers requesting to keep their facility air fresh?
Lawson: Bala has had good success using constant-volume DOAS systems in hotels. The constant-volume system allows for constant air exchange to keep the air fresh within the building. The constant exhaust in the bathrooms also helps mitigate the buildup of humidity in the rooms from long showers. The energy code often drives these types of systems to have energy-recovery capabilities as well.
CSE: What types of air balancing or environmental balancing do you include in your design? Describe the project.
Mulcahy: Air balancing is required by our local energy code. All projects require it.
CSE: When designing a hotel, motel, or resort with a pool or spa facilities, what unique HVAC, humidity, and air-balancing issues must you address?
Lawson: The biggest concern of any pool or spa space is humidity control. Not only how to control the humidity within the space, but how to keep the humidity from transferring to adjacent spaces. The HVAC system equipment always requires local control within the pool and spa spaces. There also is a large set of obstacles when these pool and spa spaces are located along an exterior wall. Great care needs to be taken to treat the façade to mitigate condensation, especially during the colder months.
Sustainable buildings/energy efficiency
CSE: What unusual systems are hotel owners requesting that help save energy and/or electricity when a room is unoccupied?
Mulcahy: Recently, occupancy and vacancy sensors have been required by the energy codes. In addition, now plug-load control is becoming a requirement within guest rooms of resorts.
CSE: Energy efficiency and sustainability are frequent requests from building owners. What net zero energy and/or high-performance systems have you recently specified on hotels, motels, and resorts (either an existing building or new construction)?
Mulcahy: Typically, PV power sources are used when they make sense for the project. In addition, fuel cells and cogeneration opportunities are explored on many projects to see if they make sense based on the project location and local utility costs.
CSE: What types of sustainable features or concerns might you encounter on a hotel, motel, or resort that you wouldn’t on other projects?
Christensen: Because these facilities generally are 24/7 operations, they are different than a lot of other building types except maybe hospitals. The concern for operators is twofold: (1) If a system is not required to be running, how do we make sure it is turned off or placed into a minimal energy-usage state? (2) For the systems that are running 24/7, are the most efficient equipment and products being used? Operators have to extend their operating costs onto the customer, and if these costs can be reduced, then the cost to stay at the hotel can effectively be reduced.
Mulcahy: Because of our unique climate, it is not uncommon to use very large plate-and-frame heat exchangers to maximize free cooling. We have done several 5,000-ton retrofits this year.
Lawson: A combined heat and power (CHP) microturbine system makes a lot of sense for hotels. The biggest driver for a CHP system is how to use the heat, and a hotel provides a natural heat sink with the domestic hot-water system. The engineer must be able to project the hot-water usage and storage properly, as to not undersize or oversize the CHP system. Having a locally controlled heat sink allows for lower construction costs and makes the application more feasible.
CSE: What types of renewable or alternative energy systems have you recently specified to provide power for such projects? This may include photovoltaics, wind turbines, etc. Describe the challenges and solutions.
Mulcahy: PV systems have been specified on a lot of recent projects where the payback on the equipment costs make sense. The challenges with PV systems is typically the payback period without utility rebates is essentially at the life of the equipment. The other challenge is finding enough space to place panels on large projects where land is a premium.
CSE: What are some of the challenges or issues when designing for energy efficiency for such facilities?
Mulcahy: A lot of times, the energy use and size of large resort facilities make it difficult to have renewable energy systems large enough to make a noticeable impact on the overall project. While every amount helps, other projects are better candidates for net zero.