Energy strategies for HVAC systems
By Manny Rosendo
According to the Environmental Protection Agency, healthcare organizations spend nearly $8.8 billion annually on energy to meet patient needs. In a typical hospital, the biggest consumer of electrical power is the HVAC system, accounting for as much as 42 percent of total usage. The HVAC system and chiller plant alone can push a hospital’s electric bills to more than a million dollars a year.
With the right peak performance strategy and technologies, it is possible to cut HVAC and central plant energy use by as much as 40 percent and reduce a facility’s carbon footprint. One of the nation’s largest public healthcare systems, Broward Health Medical Center (BHMC), registered savings of $311,000 in just one year, including more than $30,000 in a single month. This was possible after implementing advanced analytics and optimization, providing visibility and transparency into the performance and service of its HVAC system and 6,000-ton chiller plant.
For a hospital, or any commercial building, the chiller plant is of critical importance. It is the circulatory system of the HVAC, responsible for the continuous flow of air. Yet the Department of Energy states that 95 percent of all chiller plants are inefficient. Does this mean that all of these plants are broken? No, however it does indicate that the plants at your facility are almost certain to be wasting energy and money, and you may not even know how much.
Because every hospital is unique, understanding your HVAC as an integrated eco-system is important for achieving maximum efficiencies. Based on experiences with major medical facilities, here are steps a hospital can take now to generate immediate and long-term significant energy cost savings.
Evaluate your system’s current state
Everything begins with the documentation of the equipment and correlating specs. As you know, the efficiency of the chiller depends on the amount of energy or electrical current consumed for cooling, measured in kilowatt per ton (kW/ton). The lower the kW/ton rating, the more efficient the system. While not everyone is using this criteria, it has proven to be the cleanest metric for measuring optimization, regardless of the type of equipment or power source.
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Many management teams look at British Thermal Units (BTUs)/sf, or the amount of BTUs required to heat a space per square foot, as a key metric. However, if the system is not operating at peak efficiency, this metric fails to provide enough detail to help determine the problems. When documenting any current issues or pain points with your system, take time to extend your thinking beyond the symptoms to what is causing them.
Know what you’re trying to achieve
Once you have a clear picture of your system’s current performance, it’s time to align common objectives with those of other stakeholders to target realistic goals. You’ll want to ensure that everyone involved in decision-making, including operations, finance and the executive suite, is in agreement. You are looking for immediate and appropriate feedback to help you gain control of your building and ensure higher comfort levels. The focus is on controlling and lowering expenses.
It’s easier to prioritize work orders and fixes if you use a software solution that provides a concise roadmap for ECM (Energy Conservation Measures). There are some advanced solutions available, and the right technology tools can enable better articulation of opportunities with payback analysis, along with clear tracking and measurement of results.
Solutions that provide around-the-clock monitoring and interactive dashboards provide building engineers and facilities managers with greater control and visibility over their sites. This helps improve troubleshooting, and leads to better dialogue with your vendors and sub-contractors.
Lowering costs must also be balanced, or coupled, with maintaining comfort consistently throughout the building. Reducing energy consumption should be considered across a timeframe, not just one point in time. An investment that keeps your hand on the heartbeat of the plant and the hospital’s energy usage, letting you know instantly how the system is running, is well worth the expense as it can result in up to 40 percent energy cost savings.
BHMC was able to identify and correct HVAC performance gaps almost immediately. With 85 percent of their building under automation, they have attained superior energy efficiency with a 26-percent reduction in energy use and an enhanced kW/ton ratio of .85.
Understand the data and feedback loop
Your facility probably already has a Building Automation System (BAS) or Building Management System (BMS) running your HVAC. While these systems have been around for years, they may not be able to give you the advanced analytics needed to holistically optimize your HVAC plant.
A BAS isn’t built for analytics – it’s for sequences, and sequences are static and theoretical. For example, because of how you think your building is going to operate, you create a sequence, and then it turns out this isn’t how it actually operates. That's why you need advanced analytics to show how the system is really operating, and then you can tweak your building automation sequences to better optimize, thus establishing a smart feedback loop.
For a more precise understanding of your data and feedback, ask a few key questions:
•What is the most appropriate data for our goals, and why it is important?
•To capture the feedback we want, how often should the data be collected?
•Are all sensors and meters calibrated and working properly?
Present data as an action plan
Sure, information can be great to have, but it is only valuable if it can be acted on for results. Because it’s tempting and easy to overload on information, we advise following a sequential approach: Plan – Do – Check – Act.
Having too much data is as good as having no data. While a traditional BMS presents data, many times it can be too much and overwhelming. With all of this data you have two options: 1) ignore it (which happens all too frequently due to an overload of alerts, alarms, notifications, etc.), or 2) implement building analytics that enable you to digest the data, analyze it and take intelligent and actionable steps that lead to optimization. This second option is the next evolution of building management systems.
If you’ve taken care to identify the most appropriate data for your goals, the information captured will help build the business case; supporting all decisions regarding changes to your HVAC system and chiller plant. So, first verify the data. Next, define and prioritize the required action items. Then, don’t wait – take action.
Stabilize current operations
Many hospitals use re-commissioning or retro-commissioning to ensure their plants are operating correctly. Although this improves performance, it is a static exercise that corrects issues only at one point in time.
A better approach is to use constant commissioning. This will provide complete transparency and ensure your systems are running properly, 24/7. Constant commissioning immediately notifies operations when something is wrong, rather than waiting until the next commissioning, which could be a year or longer.
Let’s face it, over the course of 12 months, equipment ages and degrades and other variables can impact your systems. Maybe there are closures or additions to the facility. Unusual weather conditions can occur along with a multitude of other factors that can strain or change the operational integrity of your plant.
The most important benefit of constant commissioning is the visibility of efficiency, or inefficiency, on specific pieces of equipment. Continuous monitoring ensures that a plant’s true performance is in line with its original design standards. This type of tracking allows you to conduct cost-saving analysis and to adjust components as needed in order to maintain optimal energy efficiency.
Because the plant is a dynamic environment, issues are constantly occurring. In today’s lean economy, few hospitals have extra facility workers, so they must focus on the most important faults. Your system should be able to prioritize those faults for you.
At Broward Health, 70 percent of all calls to their help desk center are from individuals complaining that they are too hot or too cold. A proper feedback loop could identify root causes quickly and allow employees to focus on proactive, preventive work rather than on reactive control issues.
Once you have a constant commissioning program in place, you can also ensure that all repair work both achieves and maintains/improves your efficiency. For example, by leveraging constant commissioning, Miami Children’s Hospital was able to uncover serious inefficiencies in their plant that they then brought to their vendors to address. The objective is to develop a “fix forever” mentality.
By stabilizing first, you can often avoid spending money unnecessarily and you can expect to yield long-term savings. Efficiencies and savings are already “latent” with your current HVAC system, waiting to be discovered.
Find the ‘Peak’
Your system is stabilized, now you’re ready to find its “peak performance” capabilities. It’s easier to accomplish this if you view achieving peak not as an expense, but as an investment that delivers true ROI via energy savings. Your organization has made a substantial investment in the chiller plant and other HVAC components. Perfecting and protecting that equipment requires an “investment” mind-set as well.
No matter the age of your system, you can start conserving energy right away by maximizing what you already have in place. Identify the key equipment, implementing set point adherence and then commit to preventive maintenance. By closely watching usage trends in this key equipment, you will be able to determine problems before they happen.
This is called predictive maintenance. This methodology will enable you to analyze data in order to better model improvements and track actual cost savings, supporting your investment.
Now, you are ready to drive your system to further peak performance by applying optimization science for around-the-clock predictive maintenance. New technologies can automatically direct your HVAC system to efficiency levels not otherwise possible with conventional sequencing.
Achieving HVAC and central plant peak performance will generate significant cost savings, protect your current plant investments and give a boost to your green initiatives. Next generation, cloud-based technologies, such as those developed by Entic, apply mathematical models and analytics to automatically manage your HVAC system, thus creating unprecedented performance.
Manny Rosendo writes this month on the peak performance strategy and technologies that companies can use to cut HVAC and central plant usage and save energy and costs. He is co-founder and CEO of Entic, a specialist in HVAC and central plant peak performance, providing commercial and industrial facilities with up to 40 percent energy savings through its proprietary, cloud-based technology.