When it comes to domestic hot water systems, nothing is more frustrating than trying to diagnose delivery temperature problems. Hot water systems are notorious for long wait times, temperatures that are too hot, temperatures that are too cold, or demanding large amounts of energy that result in high operating costs. A poor performing domestic hot water system has a big impact on operations.
RESIDUAL AFFECTS OF UNCONTROLLED TEMPERATURES
1. Occupant Comfort - Hot water is seldom thought about until you experience long wait times or inconsistent temperatures. Delivering hot water quickly helps keep patients safe and comfortable throughout their stay while providing healthcare professionals and staff with the water they need.
2. Patient Safety – Utilizing hot water temperatures to manage risks of Legionella is a fundamental control measure. The risk of healthcare associated infections increases when a system is unable to maintain temperatures outside of the bacteria's growth range. Conversely, when water temperatures are too high the risk of scalding increases. Hospitals often treat those who are most vulnerable to waterborne pathogens and those that are at risk of scalding. Patient safety is dependent on the hot water system's ability to maintain minimum safe temperatures while reducing the risks of bacteria growth and scalding.
3. Operating costs - The estimated annual energy cost of hot water systems in the U.S. is $2.5 trillion. It is safe to assume that increased water and energy use due to poor performing domestic hot water systems will significantly affect a facility's operating costs. Industry estimates suggest that implementing water-efficient practices, which would include optimizing hot water systems, can decrease operating costs by approximately 11 percent and energy and water use by 10 to 15 percent.
4. Sustainability – Five-hundred million gallons of water is wasted each day in the U.S. due to inefficient hot water systems. Hospitals and healthcare facilities comprise 7 percent of the total water use in commercial and institutional facilities. Hospitals can significantly reduce water waste in the U.S. by simply improving the performance of the domestic hot water system.
IDENTIFY THE SOURCE OF HOT WATER ISSUES
When experiencing hot water delivery problems, the first step is to identify the source. This can be done by starting at the hot water generator (i.e. water heater) and systematically working your way through the supply and return piping system. Hospital water systems can be complex, so this article will focus on common components, while assuming the distribution piping is sized and insulated properly.
1. Hot water generation and storage – It is relatively easy to identify issues with hot water generation or storage. Are you generating hot water at the desired temperature? Are you able to provide enough hot water during times of peak demand? If so, the issue is not at the hot water source, but elsewhere in the distribution system. Generating higher water temperatures at the source to compensate for low water temperatures farther out in the system will not provide the result you want and will consume much more energy – simply increasing the water heater's operating temperature 5°F will increase energy use as much as 12 percent.
2. Master mixing valve – Master mixing valves are often found in hospitals when elevated water temperatures (140°F and above) are produced and distributed for laundry, dishwashing, or as a control measure for waterborne pathogens. Located near the hot water source, these valves safely provide "mixed water" to patient rooms and other areas that do not require elevated temperatures. Below are common indicators that the master mixing valve may be the source of your hot water delivery issues:
- Mixed water outlet temperature is constantly too high or too low.
- Mixed water outlet temperature is too high or too low after extended periods of no demand.
- Mixed water outlet temperatures fluctuate.
- Mixed water outlet temperature cannot be set to the desired temperature.
3. System balancing – Long wait times for hot water in select areas of the building is a key indicator that the domestic hot water system is not properly balanced.
In an unbalanced system, the hot water circuits farther away from the heat source (i.e. water heater) will struggle to meet or maintain desired temperature while the hot water circuits closest to the heat source may consistently maintain desired temperature. The reason is due to water taking the path of least resistance.
In order to balance a system, valves are installed on each hot water return circuit to create resistance. This resistance encourages water to choose an alternate path while still allowing enough flow through the circuit to overcome heat loss. A properly balanced system will maintain and deliver hot water quickly and consistently throughout the building.
Multiple issues can affect the proper balancing of a system – system design, valve selection, commissioning, scale, renovations, repairs, or neglected maintenance. The bottom line is most recirculation systems do not work properly. As such, we have multiple balancing valve technologies on the market designed to improve system balancing. Automated balancing valves, such as the Hycleen Automation System, are the best option to ensure a building consistently maintains hot water temperatures throughout the system. Hycleen provides a perfectly balanced system based on custom parameters, automates weekly maintenance to prevent scale build-up, monitors temperature in real-time at each return circuit, and continuously logs data for verification, risk assessment, and reporting.
4. Recirculation pump – Once hot water generation and storage are eliminated as the source of the problem, it is common for the recirculation pump to immediately become the focus. However, the pump is seldom the source of the problem when diagnosing hot water temperature issues. Before assuming the pump is undersized, it is vital to ensure the master mixing valve is operating correctly and that the system is properly balanced. Increasing the pump size in an existing system may have unintended consequences such as accelerated erosion, degradation, or pitting of piping material due to increased water velocity.
Over the years the Erlabrunn clinical center, consisting of nine specialist clinics, a medical supply center, and an in-patient hospice, experienced numerous renovations to the facility. This lead to a maze of domestic hot water piping winding through the complex resulting in chronic issues delivering hot water. After many unsuccessful attempts to correct the poor delivery temperatures in remote parts of the system, Erlabrunn chose to install the Hycleen Automation System by GF Piping Systems.
"Our previous drinking water supply circulated at high temperatures and high pressure," explained Mr. Gunther, technical director at the Erlabrunn clinical center. "Therefore, we were looking for a circulation system with automatic balancing capabilities to guarantee the best hygienic conditions and inhibit bacteria growth over the long term."
In addition to correcting hot water delivery issues, Erlabrunn also chose Hycleen to simplify compliance with the public health authorities' inspection and documentation requirements. Mr. Gunther can now easily access critical information when monitoring the performance and safety of their potable water system.
The installed Hycleen system consisted of 72 automated balancing valves and 2 control panels. Within 60 minutes of start-up, the system functioned flawlessly achieving desired temperatures throughout the complex. Any irregularities that occur, such as low temperatures or defective valves and sensors are reported directly to the facility engineer via the building management system.
Thanks to a perfectly balanced system, Erlabrunn clinical center reduced energy use by lowering the set temperature on their water heater while delivering the required hot water temperatures throughout the complex.
IMPROVE PERFORMANCE WITH AUTOMATED SYSTEMS
Hospitals must consider implementing smarter, more intelligent systems that take advantage of market innovations to improve domestic hot water delivery and simplify water management. These automated systems, such as Hycleen, deliver hot water consistently, reduce operating costs, automate fundamental control measures, allow operators to quickly respond to potentially hazardous system changes, and simplify compliance with an established water management program.
GF Piping Systems
GF Piping Systems is committed to providing reliable, innovative, and sustainable solutions to meet the rigorous demands of healthcare water systems.
Visit us at www.gfps.com/us/healthcare to learn more.