New Year, New Refrigerants: Updates on the Refrigerant Phase-out
The new year has come and passed and 2025 is in full swing! This also means the next stage of the HFC refrigerant phase-out is here, so let’s review what that means for us architects, engineers, and contractors. The American Innovation and Manufacturing (AIM) Act, passed in 2020, gives the Environmental Protection Agency (EPA) the authority to regulate and phase down the production and use of hydrofluorocarbon (HFC) refrigerants. HFCs are known greenhouse gases, most of which are rated with a global warming potential (GWP) several thousand times that of carbon dioxide (which is the baseline of the scale, with a GWP of 1). The EPA has thus banned HFCs by setting limits to the allowable GWP of refrigerants manufactured or imported for use in the U.S. To Implement this ban, the EPA has implemented phase-out dates for the manufacturing and installation of different types of HVAC equipment, see below: This means that the DX and Heat Pump equipment that we select and specify on our projects (other than VRF) can no longer be manufactured or imported with R-410A refrigerant. Going forward we must design and specify DX and Heat Pump equipment with refrigerants that meet the GWP limitations set by the EPA, which will mostly be R-454B and R-32 in our industry. With the shift to the newest refrigerants, one of our biggest restrictions as the selecting and specifying engineers over the past several months has been the ability to actually select the equipment with the new refrigerants and attain the refrigerant charges, equipment capacities, and efficiency ratings. Over the last month, a majority of manufacturers have confirmed the availability to select equipment with the new refrigerants, which allows us to finalize equipment selections and calculations. While there are still some minor restrictions in the availability of equipment specifics as the manufacturers continue to get the new equipment tested, the major equipment information is mostly available to move forward with selections. In summary, the new refrigerant changes are upon us and will require additional calculations and coordination for DX systems that should be considered for projects in various stages of design and construction. The equipment manufacturers have made big strides to provide us, as the engineers, the information we need to get equipment selections, but there may be some minor lagging information we may need to wait for confirmation on. Overall, 360 Engineering is excited to move away from the limbo between two refrigerant types and start moving toward a more sustainable future.
NPS Ozark Big Spring – Mechanical Coordination in Tight Spaces
The National Park Service was looking to renovate its existing Lodge building and cabins at the Ozark National Scenic Riverway Big Spring site in Missouri. The site includes thirteen (13) rentable cabin buildings, a concessioner’s house, a laundry building, a museum building, and the riverfront lodge. The area had experienced historical flooding in 2015 where the lodge itself was in 10’ of water on the main level photographed above. This flooding closed the park site, and all the buildings sat dormant until this project was initiated. The lodge experienced the worst damage, and all systems required full replacement. The other buildings onsite were lucky to be higher on the hillside and were not flooded. The lodge building provides spaces for park users and guests to congregate and eat meals and serves as a launch point on the river, where there is newly built dock access. This lodge is also outfitted with a commercial kitchen for the concessioner to provide meals for the guests. Close Coordination & Minimizing Mechanical Space Needs Missouri experiences high humidity, so the mechanical systems were designed with full dehumidification in mind. The existing systems serving the lodge were non-existent; there was no heating or cooling serving the building previously. This required new mechanical space to be created outside to account for these cooling and heating needs. These new outdoor systems serving the lodge are two heat pump condensing units and a makeup air unit for the kitchen. Makeup Air Unit at the Kitchen The makeup air unit was a tight fit, but we were able to work with the existing area on the side of the lodge. The two new heat pump condensing units, however, were going to require a new mechanical yard to be formed. This lodge is a historical structure, so everything needs to be done to maintain the current aesthetics. We took extensive care to minimize the mechanical yard footprint and position it to hide mechanical equipment from the general public’s view. Mechanical Yard Behind the Lodge Ultimately, the mechanical space created was the ideal size and location to leave the least impact on the site while still providing complete heating, cooling, and dehumidification to what was formerly a hot, cold, and stuffy building. Air Handling Units Above the Ceiling We had new heat pump air handling units installed above the ceiling inside the building. These units were about as large as you could fit within these existing ceiling cavities, but through close coordination with our structural engineer and architect, we developed solutions to make these units semi-removable for ease of replacement at the end of their life and provide ideal access for ease of serviceability during their operational lifespan.
Maximizing Energy Efficiency with Air and Water-Side Economizers This Fall
It’s that time of year again – the season of pumpkin spice everything, football games filling our weekends, and a prime opportunity to save on energy costs using air and water-side economizers. As temperatures drop during cool fall mornings (typically between 45-55°F), facilities have an excellent chance to leverage natural cooling to reduce mechanical refrigeration needs. Implementing and maintaining these economizer systems can result in substantial energy savings while also extending the life of HVAC equipment. Let’s dive into how economizers work and explore additional tips to optimize them this season. Understanding Air-Side Economizers Air-side economizers take advantage of the cool outside air to provide free cooling for buildings, significantly cutting down on the use of traditional air conditioning. When outside air temperatures are lower than the desired indoor temperature, air-side economizers allow fresh air to be brought in, mixed with the return air, and circulated throughout the building, reducing the need for mechanical cooling. Here are a few maintenance tasks and checks to ensure your air-side economizer operates at peak performance: Leveraging Water-Side Economizers Water-side economizers provide another energy-saving opportunity, especially for facilities equipped with cooling towers. As outside temperatures drop, cooling towers can cool water to lower temperatures without the need to operate chillers. Water-side economizers typically work by using the cooling tower water to precool the chilled water supply or to bypass the chiller altogether under the right conditions. To maximize the benefits of water-side economizers, keep these tips in mind: Additional Tips for Optimizing Economizer Performance Fall is an ideal time to optimize your economizer systems, taking advantage of cooler temperatures to reduce reliance on mechanical cooling and save energy. Whether you are using air-side or water-side economizers, regular maintenance, proper control setup, and monitoring can make a substantial difference in energy efficiency. By following these tips, you can ensure your economizers are operating at peak performance.
Understanding the Differences Between VRF and Split Systems
When it comes to heating, ventilation, and air conditioning (HVAC), two popular options are Variable Refrigerant Flow (VRF) systems and traditional split systems. While both effectively control indoor climates, they differ significantly in design, functionality, and applications. What is a Split System? A split system consists of two main components: an indoor unit and an outdoor unit. The outdoor unit houses the compressor and condenser, while the indoor unit contains the evaporator coil. These units are connected by refrigerant lines, allowing for heat exchange. Key Features of Split Systems: Simplicity: Split systems are relatively straightforward in design, making installation easier and generally less expensive. Zoning Limitations: Each indoor unit operates independently, but typically, you can only cool or heat one area at a time per system, limiting zoning capabilities. Cost-Effectiveness: They are generally more affordable upfront compared to VRF systems, making them a popular choice for smaller homes or individual spaces. Maintenance: Maintenance is usually more straightforward, with fewer complex components and simpler servicing. What is a VRF System? Variable Refrigerant Flow (VRF) systems are a more advanced HVAC technology designed to provide precise temperature control and energy efficiency. VRF systems utilize a single outdoor unit connected to multiple indoor units, allowing for individualized climate control in different areas. Key Features of VRF Systems: Quiet Operation: These systems tend to operate more quietly than traditional systems, enhancing indoor comfort. Energy Efficiency: VRF systems adjust the flow of refrigerant based on each space’s heating and cooling needs, resulting in significant energy savings. Zoning Flexibility: With the ability to connect multiple indoor units, VRF systems can effectively provide heating and cooling in different zones simultaneously, offering tailored comfort. Advanced Controls: VRF systems often have sophisticated control options, allowing for remote management and monitoring of each indoor unit. They Sound Pretty Similar, so What Are the Differences? 1. Design and Configuration 2. Energy Efficiency 3. Cost 4. Installation and Maintenance 5. Application Suitability Conclusion Choosing between a VRF system and a split system ultimately depends on your specific needs, budget, and the scale of your HVAC requirements. Split systems are excellent for smaller spaces where simplicity and cost-effectiveness are priorities. In contrast, VRF systems shine in larger, more complex environments that demand energy efficiency and precise control. Whether you opt for a split system or a VRF system, both can contribute significantly to your indoor comfort when appropriately selected and installed.
Sustainability Meets a New Era of Learning: Welcome to DPS RASA
New School Year, New School Denver Public Schools (DPS) pushed the design envelope with this over 60,000-square-foot ground-up new school. The current design houses grades ECE through 5th grade with a future Phase 2 expansion to bring it up through 8th grade and just shy of 80,000 square feet. Phase 1 was designed with Phase 2 in mind, from mechanical loads and water heater capacity down to sanitary sewer piping depth. As the architect, DLR Group led the design team in which 360 Engineering provided mechanical and plumbing engineering and consulting. Responsive Arts & STEAM Academy FNE (RASA) hosted its ribbon-cutting ceremony on Friday, August 2, 2024, just in time for the new school year! The RASA approach is built on a culturally sustaining, community-responsive foundation that respects all learners. It aims to foster a lifelong love of learning through creative and critical thinking, project-based learning, and the discovery of students’ talents. The model emphasizes the Arts as essential to learning, integrating them across subjects to promote higher-order thinking. Historically, students in Far Northeast Denver have lacked access to robust arts education, but RASA seeks to change this by valuing emotional education alongside logic and reasoning, creating a more holistic human experience. Energy Modeling and Mechanical Systems The design team was tasked with designing a highly energy-efficient building. Energy modeling was used to compare three mechanical systems: Each system has pros and cons, which were discussed in detail with 360’s input and guidance. The biggest decision points were identified as installation cost, energy efficiency (measured in Energy Use Intensity or EUI, given as a measure of energy use per square foot per year), maintenance requirements, and operational costs. The VAV RTU system was chosen as it provided the best efficiency with the lowest installation cost and a familiar system for the District’s facilities maintenance team to work with. This system also included air-side economizers and energy recovery wheels to further increase efficiency and make use of the dry Colorado air. Additionally, the controls systems monitor CO2 levels in the various spaces and modulate the outdoor air intakes to provide the right amount of ventilation (known as Demand Control Ventilation), providing the right balance between energy savings—less outdoor air to heat or cool—and indoor air quality, keeping CO2 levels down and enough fresh air coming in to keep learning minds active and alert! All Electric With RASA’s successful grand opening, the design team immediately began designing the Phase 2 expansion. We are excited to see the school we have designed realize its potential as a safe, energy-efficient facility that will foster growth in the next generation. With a mindset for the future, the school was designed to be all-electric: the mechanical system is powered using heat pump technology, domestic water heating is electric, and all kitchen appliances are electric—even the ranges and ovens are induction-type! This is the District’s first all-electric school.
Commissioning in the Hottest Place on Earth!
Our projects with the National Park Service take us to some pretty cool places…this is not one of them. Death Valley National Park (DEVA) holds the record for the highest recorded temperature on the face of our planet, at over 130°F! As you might imagine, it takes a lot to keep buildings comfortable in a climate like that. 360 is currently wrapping up a project in DEVA, specifically at Scotty’s Castle, where the design team replaced an outdated water source heat pump system with a full water-cooled chiller plant and hydronic boiler system. The team utilized a former stable building as a mechanical room to house boilers and chillers and routed buried piping hundreds of yards to the castle itself in tunnels built by Scotty nearly 100 years ago. The system utilizes a closed-loop cooling tower to minimize water loss while still taking advantage of the dry air’s low wet bulb temperature to reject heat from inside the castle to the ambient air far away from the building. All in all, a well-thought-out and resilient system that will provide effective and reliable cooling and heating (it does get cold in Death Valley sometimes!) for years to come, making the visitor (and Park staff) experience more enjoyable and sustainable. But the best system design can be crippled if the systems are not properly started up, tested, and deficiencies corrected before the building occupants move in—in other words, commissioning! The certified Commissioning Authorities (CxAs) at both 3601 and AE Design teamed up to visit the site, observe the system installations, and put the equipment through its paces to make sure everything is installed and operating as intended by the design team. The commissioning process began with a review of the construction documents as well as equipment submittals in order to familiarize ourselves with the systems being installed and the design intent for their function and operation. From there, we developed both pre-functional checklists (PFCs) and functional performance test protocols (FPTs). The PFCs are filled out by the installing contractor and serve as a quality control and assurance check to ensure systems have been provided and built with all necessary components for operation and are ready to be tested against the design intent and sequences of operation. Once the contractor confirms systems are ready for functional testing via the PFCs, the commissioning (Cx) team books a flight and heads to the site for testing. We check every system visually to confirm that systems and equipment match what was submitted and approved by the design team and that installed layouts match the design intent in the construction documents. We then work with the mechanical and controls contractors to test the systems using the FPT protocols previously developed. These tests include various modes of operation, such as typical occupied/unoccupied operations, generating false heating/cooling loads to make sure the boilers, chillers, various pumps, and valves all react as intended, and even simulating failure modes to make sure that redundant systems come online when needed and equipment is properly protected in the event of a real equipment or system failure in the future. The Cx team documents the installed conditions and the results of the various tests and provides a log of deficiencies to be addressed before final handover of the project to the owner. As needed, the Cx team makes additional site visits to follow up on deficiencies and make sure all systems have been observed as fully operational before issuing the final Commissioning Report. Commissioning is a vital process, particularly for complex projects and systems. The fact that our team made several trips to the site in order to complete all the testing and re-testing of systems to ensure everything is operating per the design intent and owner’s project requirements illustrates two key concepts. First, that commissioning is critical for the success of a project, as the list of deficiencies and the need for multiple trips to close out those issues clearly shows—rarely is everything installed and operating 100% correctly the first time it’s put to the test! Second, 360 and AE Design are committed to ensuring that the systems turned over to the owner are fully functional and will serve the building occupants well for years to come. It helps that we get to visit some pretty cool places—even if they’re actually rather hot! Interested in learning more about Scotty’s Castle? You should be! Check out the links below.2,3 1Wondering how 360 can be the designer and the CxA at the same time? We maintain objectivity by keeping the CxA completely uninvolved with the design team throughout the design process. Our CxAs work for the owner, either contracted directly or under the general contractor and are accountable to only them. While we obviously work together with the design team through the commissioning process, our CxAs always pursue the goal of helping the whole team achieve the owner’s project requirements and are not afraid to challenge the contractor or the design team when needed to attain that goal. 2https://www.nps.gov/deva/learn/historyculture/building-scottys-castle.htm 3https://www.dvconservancy.org/scottys-castle/
The Do’s and Don’ts of Architectural Design: By a Mechanical Engineer
At 360, we love to be team players and share our ideas and insights with our fellow consultants. And boy, do we have ideas! This month, we wanted to help out our architect friends with some brilliant tips and tricks for working with mechanical engineers and making buildings awesome. Disclaimer: This blog post was released on April 1st, and while 360 Engineering is not a licensed architecture firm, we do have some really great ideas for the advancement of architecture! Call us about your next project; we’ve got quadruple-paned windows ready for you!
COPs Higher than 3’s: The Efficiency of Heat Pumps!
If you’ve been thinking about your mechanical system lately, you’ve probably come across the magical buzzwords “Heat Pumps.” But why does everyone love them so much, and are they really that much better than gas-fired heating equipment? At its very core, heat pumps just move heat from one space to another, hence the name! At the technical level, they use refrigerant circuits, similar to what’s found in your air conditioner or refrigerator, to extract heat from one space and move it into another. In the ancient, inefficient past, you needed one piece of equipment to heat the space (furnaces, electric heaters, boilers, etc.) and another to cool the space (air conditioners, chillers, etc.) The beauty of a heat pump is that it comes with a small reversing valve within the outdoor unit that can flip the rotation of refrigerant and provide heating instead of cooling to a targeted space. That’s why they’re effective at heating AND cooling the space as a single system. If all of that has your head spinning, focus on the key terms: Heat Source: Where is the heat coming from? It could be inside the building, and you want to remove it, or outside it, and you want to bring heat inside. Heat Sink: Where are you dumping the heat? You can reject heat outside the building to cool the inside spaces down or reject heat inside the building if you want to heat it up. Coefficient of Performance (COP): This is a ratio of the amount of energy (heat) that comes out of the mechanical system compared to the amount of energy (electricity or fuel) put into the system. Higher is better! Heat pumps grab heat from the heat source and move it to the heat sink. That’s it! Nothing more complicated about it. Gas-fired appliances must burn fuel (heat source) to generate heat into the air/water (heat sink), and high-efficiency units have a COP of only ~0.97. Even electric resistance heaters must produce electrical heat to heat the air/water but have an almost equal input-to-output COP of ~1.0. “You get out what you put in.” However, heat pumps don’t rely on heat generation; most of the heat is just transferring already generated heat from one source to another space. And that requires significantly less energy input than generating that heat-so much less energy that the ratio of heat output from a heat pump when compared to the energy it takes to run a heat pump can be upwards of 300% or a COP OF HIGHER THAN 3! Whether it’s freezing outside or you’re sweating inside your building, heat pumps are an efficient way to relocate that heat to an appropriate heat sink. Gone are the days of accepting a 97% efficient furnace. Now, heat pumps are pushing the limits of energy efficiency, and who can say no to something 3-5 times more efficient than your current boiler? Here are a few of our current and recent projects where we’ve used heat pumps in the mechanical system design:
Lovers of Louvers: Mechanical Engineering Romance this Valentine’s Day!
It’s hard to imagine an inanimate object capable of being loved, but let me share my viewpoint. They matter! Louvers are used in both intake and exhaust applications for HVAC systems. Without louvers, we would have large openings on the side of the building with screens, allowing all the snow and rain to enter. So, how does a louver keep all the driving rain and snow out of the building? Louvers have varying blade shapes that provide different performances. All louvers are tested via a standard test to determine the point at which water will pass through. The air velocity in which water passes through a louver varies anywhere from 300 feet per minute (fpm) to over 1,000 fpm. When an engineer sizes a louver, they size one such that the velocity of airflow will remain below the tested penetration threshold. The louver plays an important role in keeping water out of the building. Louver sizing is also impacted by the amount of free area they provide. Louvers are rated with pressure drops, which need to be calculated in the sizing of fans within the mechanical system. A louver that has a high-pressure drop increases the need for a larger fan and more energy usage. A louver with a low-pressure drop allows for less fan energy. Who doesn’t love something that takes less energy? Louvers come in all shapes, sizes, and colors. They want to be sized to reduce the water penetration and pressure drop, but you can integrate them into the context of the building. There are rectangular ones, square ones, round ones, triangular ones, and, in the spirit of love, diamond-shaped ones. When I was a young engineer, spell check was a new tool. And on one project, all of the keynotes referencing louvers were autocorrected to “lovers.” The contractor had some fun with this, and I am now on the lookout for “lovers” on projects. -Denise M. Dihle, PE, 360 Engineering Founder, President, Principal
Cold Climates and Heat Pumps: How It Started, How It’s Going
Electrification and Sustainability Goals: Unveiling the Role of Heat Pumps As we’ve all continually heard in recent years, electrification is a major sustainability goal for many municipalities, states, and even countries around the world1. Along with electrification comes a plethora of buzzwords and phrases, one of the most familiar being heat pumps. Air-source heat pumps—the most common application due to the relatively low cost of such systems—can absorb heat from the ambient air and transfer that heat into an occupied building space. But how does that work when the outside ambient air is cold? Air-Source Heat Pumps Demystified: Operation in Cold Climates Heat pumps manipulate the chemical properties of refrigerants at different pressures to absorb and release heat energy, moving it from outside to inside to heat a building. At the right pressure, the boiling point of the refrigerant will actually be lower than the cold outside air temperature—and since heat energy always moves from the higher temperature substance (in this case, the outside air) to the lower temperature substance (the refrigerant), heat is absorbed from the “cold” outside air and then cycled to the occupied space. The Chilling Challenge: How Cold Can Air-Source Heat Pumps Go? So, heat pumps can pull heat from relatively cold outside air—but how cold can that outside air be? The short answer is that it depends on the type of heat pump you are working with. Most one-to-one split heat pump systems (i.e., a single outdoor unit connected to a single indoor unit) and packaged heat pump systems (e.g., packaged rooftop units) begin to significantly reduce their heating capacity around 40-45°F ambient temperature—which is when you really start needing the heat! However, these systems are typically designed to accommodate this derated capacity as the temperature continues to drop. Regardless, one-to-one and packaged heat pump systems are limited in how much heat they can provide at very cold temperatures. Below the “balance point” of derated heat pump capacity and building heating load, supplemental heat becomes necessary, typically in the form of some electric resistance heaters. Beyond Limits: Variable Refrigerant Flow (VRF) Systems Revolutionizing Cold Climate Heating The most advanced heat pump technology available today takes the form of Variable Refrigerant Flow (VRF) systems. VRF systems have been around in East Asia and Europe for decades and have gained a foothold in the U.S. in the last 15-20 years. This technology has seen an explosion of progress in that time. A few decades ago, VRF systems were only rated for heating in the range of -5°F to -10°F, below which the systems were configured to shut down to protect their internal components from the “extreme” cold! However, VRF systems today have heating performance data for operation down to -22°F or less! Granted, at a significantly derated heating capacity, but pause and grasp that this technology can pull heat out of -22°F air and move that heat inside your building! The upshot is that the balance point of VRF systems is much lower than the one-to-one or packaged heat pump systems described above. 360 Engineering has designed systems for large buildings in Denver and other cold climates capable of meeting the full heating load at -5°F without any supplemental heat systems required. Breaking the Cold Barrier: Technological Advances in VRF Systems Multiple technological advances have allowed VRF to progress to such a viable heating system, even in cold climates. Physical accessories on the outside casing of the heat pump units, such as wind baffles and snow hoods, mitigate the effects of weather on the operation and efficiency of the VRF heat pumps. Inside the heat pumps, flash-injection technology—where the system introduces a modest quantity of mixed-phase refrigerant (i.e., a mixture of gas and liquid) to cool the compressor—allows the compressor to operate at higher speeds by mitigating friction and accumulation of internal heat2. Higher compressor speed results in greater heating capacity for the system at lower ambient temperatures. On top of these technologies in the outdoor unit, VRF systems take advantage of heat recovery internally as well, moving energy from interior zones that have excess heat available to exterior zones that need that heat energy—bypassing the outdoor unit entirely through the use of an intermediate “mode control unit.” Future Trends: The Journey of Heat Pump Technology in a World Moving Towards Electrification Heat pump technologies have come a long way since they were first introduced in the HVAC industry. While limitations still exist for certain systems and applications, air-source heat pumps have become a viable and highly efficient option to provide the heat needed for buildings in cold climates. As the world continues toward electrification and the market demands better, higher-performing heat pumps, this technology will continue to progress toward greater heating capacities at colder ambient temperatures. References 1https://www.forbes.com/sites/energyinnovation/2022/11/15/the-worlds-three-largest-economies-go-all-in-on-heat-pumps-how-policy-can-cut-gas-use-and-energy-bills/?sh=532dbd9c564d 2https://www.achrnews.com/articles/145397-five-things-hvac-contractors-should-know-about-cold-climate-vrf