Hot Water Technology Advancements: A Facility Manager's Guide
10/3/2023
Institutional and commercial facilities have witnessed significant advancements in hot water system technology over the past decade. While some are tried and true, maintenance and engineering managers need to be aware of innovations across various water heater types, from electric and gas to hybrid, heat pump and tankless heaters, as well as the use of lesser known but increasingly important heat recovery water heaters and heat exchangers typically heated by a boiler.
By understanding applications issues such as in building codes, installation, maintenance mistakes, and the challenges of various fuel types, managers can ensure that selected water heaters will deliver the intended benefits to their facilities and organizations.
New-generation water heaters
Electric water heaters. These units have adapted to the changing demands of institutional and commercial buildings. Recent technology enhances have led to improved energy efficiency, thanks to innovations in heating and insulation materials.
These systems now feature digital controls and smart technology, allowing precise temperature control and remote monitoring. Electric water heaters are relatively easy to install compared to their gas counterparts, since they do not require gas lines or venting. Routine maintenance primarily involves periodic element checks and tank flushing.
Gas and propane water heaters. Gas and propane water heaters remain popular in institutional and commercial facilities due to their rapid heating capabilities and cost-effectiveness. Advances in technology have introduced condensing models that extract additional heat from exhaust gases, leading to higher efficiency levels and lower operating costs.
Still, proper venting is crucial for gas and propane water heaters to guarantee the safe removal of combustion byproducts. Venting requirements vary, with some models requiring stainless steel venting due to the acidic nature of condensate. Gas and propane heaters also need an adequate supply of combustion air to support the burning process. This air comes from the surrounding environment or is provided through dedicated vents.
Hybrid and heat pump water heaters. Hybrid water heaters that merge electric and heat pump technologies have gained popularity in facilities due to their appealing energy efficiency. The technology within these hybrid units, including the heat pump technology, has improved significantly, making them suitable even for cold climates. They can extract heat from surrounding air or water, resulting in exceptional efficiency.
But the installation can be more complex due to the heat pump component, requiring proper ventilation and space considerations. Maintenance typically includes regular cleaning of coils and filters. Many regions offer incentives or rebates to encourage the installation of hybrid water heaters because of their energy-saving potential.
Heat-recovery water heaters and heat exchangers. Heat-recovery water heaters represent an emerging technology that is gaining recognition for institutional and commercial applications. These systems capture waste heat from processes, such as HVAC systems or refrigeration, and use it to preheat incoming cold water. This ingenious approach eases the load on the primary water heater and enhances overall efficiency. Installation usually involves integrating the heat-recovery unit with existing systems, often requiring professional expertise.
Maintenance typically includes periodic checks to ensure optimal heat exchange. Applications often use heat exchangers typically heated by a boiler or gas-fired heater to efficiently heat water for various applications. These systems are characterized by their reliability and versatility in providing a consistent supply of hot water.
Solar water heaters. These water heaters have gained prominence in institutional and commercial applications in recent years, since they align with sustainability goals and reduce the reliance on traditional energy sources. These systems use solar panels or collectors to harness the sun's energy and use it to heat water. Advances in solar technology have led to increased efficiency and reliability, making solar water heaters a viable option even in regions with less sunshine. The initial investment of solar water heaters can be higher than other systems, and proper placement of solar collectors is critical for optimal performance.
Tankless water heaters. Tankless water heaters, also known as on-demand water heaters, have experienced a surge in adoption in institutional and commercial facilities. These systems have become more compact and efficient, with modern models featuring advanced controls for precise temperature adjustments. Professional installation is crucial for tankless heaters and involves the sizing of gas, propane and water lines.
Maintenance primarily entails periodic descaling to prevent mineral buildup. While tankless heaters offer endless hot water and high efficiency, they tend to have higher upfront costs compared to traditional tank-type heaters. Nonetheless, their long-term energy savings often justify the initial investment.
Application considerations
Tank or tankless? Selecting between tank-type and tankless water heaters hinges on specific facility needs and budget considerations. Tank-type heaters are characterized by a lower upfront cost but are less efficient and have limited hot water capacity, making them more suitable for smaller applications. In contrast, tankless heaters have higher initial costs but provide continuous hot water, making them more ideal for larger settings with high hot water demands.
Fuel challenges. Each fuel type presents unique challenges. Electric heaters might have limitations in terms of peak demand and higher operating costs in some regions with expensive electricity. Gas and propane heaters require proper venting, which can be challenging within certain building layouts. Heat pump water heaters depend on ambient air or water temperatures, which can affect performance in extreme climates. Proper sizing and location considerations are essential for mitigating these challenges and optimizing the performance of each fuel type.
Smart controls and remote monitoring. Across all types of water heaters, the integration of smart controls and remote monitoring has become a game changer. These technologies allow for precise temperature adjustments, energy use tracking and proactive maintenance alerts. Managers can remotely monitor their water-heating systems, ensuring efficient operation and minimizing downtime. Smart controls of the water heaters also can be integrated into building management systems, enabling better overall energy management and greater cost savings.
Sizing and efficiency ratings. Proper sizing remains a critical factor in the performance of water heaters. With advancements in technology, it is essential to consider the specific needs of institutional and commercial buildings when selecting the appropriate size and capacity. Additionally, efficiency ratings, such as the Energy Factor (EF) for electric and gas water heaters, can guide decision-making. Understanding these ratings and their implications on energy consumption can lead to more informed choices, ensuring energy-efficient operation and cost savings over time.
Codes, mandates and rebates. As environmental concerns have grown, building codes and mandates have evolved to promote energy-efficient water heater technologies in institutional and commercial applications. Many regions have introduced stricter energy efficiency standards, necessitating the use of more efficient water heaters. Some jurisdictions have even mandated specific water heater technologies, especially those with high energy efficiency ratings, in particular building types. To offset initial costs, governments and utility companies often offer rebates or incentives to encourage the adoption of advanced water heater systems.
Institutional and commercial buildings have witnessed significant advancements in water heater technology to meet ever-changing hot water requirements. From electric and gas to hybrid, heat pump and tankless water heaters, managers have a range of solutions at their disposal. The use of heat-recovery water heaters and heat exchangers adds further versatility and efficiency to institutional and commercial hot water systems.
Updates in building codes, mandates and rebates emphasize energy efficiency and sustainability. Proper installation and maintenance, as well as the need to address common misconceptions, are crucial for reaping the full benefits of these innovations. By understanding the advantages and challenges of different fuel types and comparing tank-type vs. tankless heaters, managers can make smarter decisions when selecting the most suitable water heater for their applications.
Ken Wissner, QCXP, LEED AP, is sales manager with FST Technical – www.fsttechnical.com -- which provides testing, inspection, certification, and engineering services to institutional and commercial facilities.