Boosting HVAC Energy Efficiency ROI

2/13/2013 | Contributed by Joel Hill
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Building specs in the hotel/motel industry have changed considerably in the last few years. Namely, property owners and developers are making fewer decisions solely based on the initial cost of construction. Now, they also demand economic value of a green development, looking for meaningful return on investment from their environmentally conscious new-build and retrofit projects.

In part, this new view is a result of rapidly changing municipal and county building code requirements for all industries, which demand increased energy efficiency, but leave ROI issues solely the concern of the regulated. Soon, the minimum energy efficiency standards of the past will disappear; authorities will soon require “premium efficiency” equipment as the minimum standard in order to save energy, regardless of a property’s economics.

It will be incumbent on the project developers and facility managers to comply with these stricter, higher standards without compromising their companies’ demands for solid financial performance or the ability to compete with the newer properties and brands popping up all around them.

Additionally, once travelers’ time and distance considerations are met in their selection process, eco-conscious travelers increasingly demonstrate preference for hotel and motel brands that mirror their personal green standards, driving market share to competitors that have solved the green building dilemma on their profit and loss statements.

Design and construction decisions
With these requirements and attitudes in the forefront, property owners and developers face new design and construction decisions that require they educate themselves about their options. They must be prepared to ask tough questions of their architectural and engineering firm consultants so early design decisions that produce cost-effective construction budgets don’t unwittingly leave the property owner with expensive, long-term maintenance and energy costs that adversely affect total cost of ownership and erode the guest experience.

Given the HVAC system accounts for more than 50 percent of a lodging property’s energy costs, facility planners must know their options for systems that support both their construction budget goals, as well as their ongoing operational metrics.

First, energy efficiency—and the expected reduction in operating cost—in a hospitality property, unlike in some other commercial buildings, must be achieved with a high priority on quiet operation and good air quality to complete the guest experience. Fortunately, traditional commercial air conditioning systems are giving way to better technology with proven performance in both the U.S. and abroad. For example, previously, low-rise and mid-rise hotel/motel designs often included a packaged terminal air conditioner (PTAC) unit in each guest room. While PTACs are economical at a few hundred dollars per unit, they are inconsistent with energy-efficiency goals. PTAC systems consume as much as 60 percent more energy than other HVAC systems.

From a guest point of view, PTAC units, which are visible in the guestroom, are fairly noisy and consume precious square footage. And, a PTAC can immediately degrade the guest’s perception of the property.

If an alternative to PTAC is sought, owners and developers have three primary cooling options: a chilled water system, a water-source heat pump, or variable refrigerant volume (VRV).

While economical in some cases, the chilled water system is the least energy-efficient option and may present future issues if rampant commodity cost escalation occurs as many forecasters predict. Additionally, maintenance cost can be high, especially if there’s a failure in a major system, such as the chiller. Moreover, if a chiller failure occurs, there can be an unplanned substantial revenue loss and service disruption with already-booked guestrooms unusable until the repair is completed. Also, concerns about air conditioning redundancy often result in adding more chiller capacity than what is needed to condition the building, which increases the developer’s capital expense.

The water-source heat pump is a more energy-efficient option, but it may introduce a concern due to compressor noise in the guestrooms. Property size and guest and meeting room design and proximity to the system should be considered by highly experienced commercial HVAC engineers who advise the property’s architect and engineering team.

Long after the design team has moved on to future projects, the property’s general manager may live with high maintenance costs associated with the water treatment in the water-source heat pump system’s evaporative fluid cooler. Additionally, since all refrigeration system components are located in the guestrooms, significant allowance for service/maintenance access is required.

Variable refrigerant volume (VRV) systems offer the newest—yet proven worldwide—cooling technology and the highest energy efficiency, though at a higher price tag at the time of purchase than chilled water or water-source heat pump systems. However, property owners are achieving outstanding VRV system performance in terms of energy efficiency and operational cost, as well as guest experience factors. A low operating load ensures lower annual energy consumption. Property owners expect up to a 70 percent increase in energy efficiency with their VRV systems.

Also, these systems’ estimated 20-year life is an added benefit to the lower maintenance costs, reduced noise and enhanced convenience in the guestroom. Each guest can control his or her room temperature with a thermostat for easy, quiet, precision heating and cooling.

There are also facility presets for maximum and minimum temperature allowances for each room. The front desk controls the system’s activation and deactivation based on check-ins and check-outs.

Unlike traditional systems, VRV systems also give hoteliers the ability to isolate and control pre-determined zones in the facility, such as corridors and dining areas. Also, during slow seasons when meeting room functions are not booked, or periods when functions are most often booked later in the day, facilities crews may schedule cooled air only as needed to support the food and beverage guest experience rather than simply run the entire system because guest sleeping rooms in other parts of the building require it.

The VRV system uses a variable-capacity condensing uni,t which pipes refrigerant to multiple indoor guestrooms. The technology combines heat pump heating and the inverter (modulating) compressor to provide a simple, reliable and energy-efficient solution. While multiple rooms share a piping system, branch selector modules enable the system to simultaneously provide cooling to some areas and heat to others.

Third-party, energy-efficiency certification
Because VRV technology can offer a substantial energy enhancement, property developers in nearly all industry segments are choosing this HVAC solution when they are interested in a green project certification.

In 2000, the U.S. Green Building Council established an environmental certification known as LEED or Leadership in Energy and Environmental Design. There are nine criteria, including water efficiency, energy and atmosphere, indoor environmental quality, and innovation in design. Lower operating costs with increased asset value—in addition to decreased energy and water usage and reduced greenhouse gas emissions—are important value drivers for LEED-certified buildings.

Since the LEED rating criteria is weighted heavily toward energy efficiency, a high-efficiency HVAC system is a must for any property looking to have a green rating.

The maturing market for variable refrigerant volume
Although VRV technology was developed more than 30 years ago, the U.S. HVAC market was not a major target for global manufacturers until 2005. In the last several years the market has seen tremendous growth. The industry segment is growing by 30 percent or more each year. As the market continues to mature, the cost for high efficiency HVAC will continue to come down. Building developers are now seeing prices that are nearly 20 percent lower than what they were five years ago. Now that the U.S. market is quickly becoming one of the fastest growing markets in the world for VRV technology, significant investments are being made to design and manufacturer systems that are more and more optimized for the changing “green” building climate.

Joel Hill, LEED AP, is the branch manager for Direct Expansion Solutions (DXS) in Houston. DXS is a sister company of HTS Texas, the largest independent, commercial HVAC manufacturers’ representatives in North America. For more information about HTS and DXS, visit texas.htseng.com and www.VRVexpert.com.

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