Historically, initial cost was the dominant factor in selecting a mechanical, electrical and plumbing (MEP) system in Kentucky since the state enjoyed very low utility costs. However, utility costs are escalating everywhere, and system efficiency can no longer be ignored.
Typically, about 40 percent of business electrical budgets go to HVAC and 30 percent to lighting, totaling more than $80 billion annually. Designs have been changing the past 10 years.
Selecting a building MEP system today is a complex decision that should be based on an owner’s energy and maintenance goals – and level of expertise. Generally, as system efficiency increases, so does its complexity. A high-efficiency MEP system can be compared to a European sports car, with peak performance realized only with proper maintenance and owner attention.
Good MEP selection decisions require weighing all the variables, and many owners lack the expertise to fully understand the pros and cons of specific HVAC and lighting choices. Parameters such as initial cost, annual energy savings, annual maintenance and system complexity should be considered. It’s usually advisable to consult an unbiased professional engineer to determine the optimum system to meet performance and maintenance goals of a project.
Many owners have fixed budgets and minimal staff to devote to the maintenance of complex MEP systems; these requirements are often overlooked during project planning because of the allure of the newest technology.
High-efficient systems do not just “run themselves” and often have computer-based controls that are too complicated for some owners. An owner tends to abandon project energy goals when it turns out they cannot devote adequate resources to the task. Any mechanical or electrical system that isn’t properly maintained or operated is likely to result in unanticipated costs and unrealized energy savings.
Three high-efficiency “green” HVAC systems today are chilled-beam, geothermal heat pump, and variable refrigerant volume (VRV). All can be similar in cost, exceed modern energy codes and allow for individual occupant control. All also vary in complexity, service requirements, operational characteristics and mechanisms.
Air-cooled VRV systems transfer heat from a refrigerant circulated by inverter-driven compressors. Many owners and staff prefer VRV systems because they are familiar with refrigerant requirements and low maintenance needs. These air-cooled systems, however, are less energy efficient than geothermal heat pumps.
Geothermal pumps exchange heat between refrigerant and water that is circulated through an underground well field ranging from 200 to 450 feet deep. These systems are well established in Kentucky, familiar to many owners and maintenance staffs, have a proven efficiency record, and are many engineers’ standard choice for a high-performance “green” building.
Chilled-beam systems are new to this region but are gaining momentum. While the visible “beams” portion of the system is relatively simple, the mechanical room backbone can be complex. It is important owners and staff fully understand a chilled-beam HVAC system prior to selecting one for their facility. While efficiency projections are promising, it will be several years before data is available to fully evaluate costs.
Energy-efficient lighting offers a considerable opportunity for energy savings. Fluorescents are three to five times more efficient than incandescent lamps and last 10 to 20 times longer, but there are many fluorescent technology options.
Fluorescent systems present complex decisions related to lamp type (T8, T5 and compact fluorescent), ballast type (rapid start, instant start, and programmed rapid start); efficacy (lumens per watt), color temperature, color rendering index, life and lumen maintenance, availability, switching, dimming capability and cost.
Additionally, emerging lighting solutions include LED lighting and induction-lamp systems whose lamp life is five times that of fluorescents. Currently, their efficacies are the primary limitation to significant adoption by users.
Meanwhile, lighting-control components are now required in Kentucky under the International Energy Conservation Code. Two primary control options are timed low-voltage systems and those using infrared and ultrasonic occupancy sensors to turn lights on and off. These options present inherent differences in complexity.
Today’s energy systems can include emerging renewable technologies such as photovoltaic arrays. While the current investment required for a photovoltaic array may not provide a “payback” sufficient for most owners – unless government funding is obtained – the price for this technology is dropping and should be considered for future projects.
In this era of escalating utility costs, energy efficiency is arguably the most important factor when assessing MEP system options. However, it is critical also to consider system complexity and maintenance staff capabilities before making a decision whose impact will last 20 to 30 years.