Airside energy efficiency is of increasing importance as building envelopes grow tighter, mechanical ventilation rates are better enforced, and heating and cooling loads grow due to increased amounts of outside air and high internal heat gain. This is especially true of large commercial and industrial (C&I) buildings that have high cooling loads (such as data centres, which have loads driven by internal heat gain). This article summarises the main conclusions of a market report recently published by Navigant Research.
The airside energy efficiency market is expanding globally as the need for higher ventilation competes with the need for lower energy costs. Airside energy efficiency fits into a wide array of efficiency-improving measures in HVAC. These include better controls, more efficient equipment, and the integration of environmental information into heating and cooling procedures. Airside efficiency is unique in that it eliminates the need to heat or cool air part of the time by utilising outside air conditions or by preconditioning air via exhaust.
The main technologies related to airside energy efficiency for HVAC are airside economisers and energy recovery ventilation systems (ERVs). Both technologies have existed for decades and their popularity continues to increase throughout the world. Both are climate-specific and perform most effectively in various climatic regions and as such, regulations surrounding their use are region specific. Economisers tend to perform best in buildings in mild climates and ERVs tend to save the most energy in cold and humid climates. Building use is also important for the expansion of the markets for these technologies, benefitting heat-intense buildings like data centres.
In certain climates where these technologies perform especially well, such as the temperate, dry northern USA, adding an airside component to the HVAC system can result in a greater ROI compared to increasing the mechanical efficiency of other components. However in some regions, economisers are required by the building code. A ROI should not be considered in these cases given that the building owner has no alternative.
In North America and Europe, regulations surrounding the installation of airside energy efficient HVAC systems are strong and gaining ground. ASHRAE, for example, establishes baseline ventilation rates and efficiencies that most building codes in North America adopt. ASHRAE 90.1 specifies that economisers and ERVs must be installed on individual fan cooling units that exceed a certain equipment capacity (4.5 tonnes). These regulations are gradually requiring an increasing number of commercial buildings to install these systems and maximise their airside efficiency. While the initial expense of these systems does present a higher initial capital and installation cost to building owners, they have a rapid payback in energy savings, especially in the climate zones for which they are best suited (zones 1-8 for ERVs and zones 2-8 for economisers).
Other global regions, such as Asia Pacific, will experience growth primarily as cities become denser and the building stock expands. Installing airside energy efficient systems is a relatively inexpensive way to ensure continued savings on energy costs, especially in highly conditioned buildings like data centres.
The airside energy efficient HVAC market is expected to be led by growth in the ERV segment, especially in Europe. According to Navigant Research, the global airside energy efficient HVAC market is expected to grow from US$2.7bn in 2016 to US$4.4bn in 2025. By 2025, Europe is expected to represent 54% of the ERV market, with North America and Asia Pacific each accounting for around 20%. Economisers are expected to grow at a similar rate, but are not suited for as many buildings or as many climates as ERVs.
Economiser installations (both an outside air damper and controls) are expected to lead in buildings like data centres in cool climates, where cooling load is high and there are many annual hours of free cooling. In addition, the lack of internal humidity generation in data centres makes them ideal for space cooling by outside air.