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
Gunnison County Library – The Road to Net Zero
Gunnison County Libraries was looking to replace its existing library in Gunnison, Colorado, with a new sustainable building providing flexible and functional community space. The 15,000-square-foot public facility also needed to stand up to the harsh and variable weather conditions experienced in Gunnison. The high-elevation mountain sun is intense all year round, while winter ambient temperatures in the Gunnison Valley can drop below negative 30 degrees. In addition to cold temps, deep and heavy snow is common, so careful design of the roof systems by the Anderson Hallas Architects team was critical to handling snow and ice. Energy Modeling and Assistance in Achieving Sustainability Goals 360 Engineering provided mechanical and plumbing engineering services, including energy modeling and assistance in achieving sustainability goals for the project. The design team was tasked with providing a building with an EUI (Energy Use Intensity) under 30. As a reference, the median EUI for a library in the US is 71.6 (Energy Star Benchmarking). The energy-efficient mechanical system combined geothermal ground source heat pumps and a variable air volume dedicated outside air system (VAV DOAS) with new DDC controls. The energy model completed at the end of the design predicted an EUI of 27. Building EUI (Energy Use Intensity) goals for Net Zero What does a low EUI have to do with Net Zero? A chart was developed by Building Green (BuildingGreen.com) to provide EUI goals for buildings that, combined with a solar PV array, provide a pathway to a Net Zero building. The Gunnison Library, a single-story, 15,000-square-foot building, has a targeted EUI of over 50. However, the chart developed by Building Green is based on a building using 70% electric and 30% natural gas. Having a goal of reducing fossil fuels and a fully electrified building shifts this chart, and the design goal of under 30 EUI puts us on the right track to achieve Net Zero. Utilizing Solar The Gunnison Library utilizes an 18kW solar array with the intent that solar PV could be expanded as the allowable kW per array increases. The 18kW array provides 1.2 watts per square foot and is a minimal array, considering the average size of residential arrays are 7.1 kW (NREL). So, how is the building doing? Over the last five months, the building has been operating with an EUI of 15.5! As mechanical engineers, this isn’t just a triumph; it’s a testament to our role in shaping a future where Net Zero isn’t a lofty ideal but a measurable reality. It’s a call to action for mechanical engineers everywhere—to engineer not just systems but sustainable solutions that propel us toward a future where our buildings don’t just weather the storm but become beacons of environmental responsibility.
Exploring Complete Electrification in Denver
At 360, we are constantly looking for ways to comply with the ever-changing permitting requirements and climate change mitigation efforts that the city of Denver implements. Our world is constantly evolving, and we need to find solutions to new climate challenges each day. In this blog post, we will discuss the opportunities for Complete Electrification in Denver. Our team is critically looking at options to ensure each project we work on not only meets the required regulations but is cost-effective too. Read along to see the importance of electrification and its impact. What We Look At In 2019, buildings and homes accounted for 64% of all community-generated greenhouse gas emissions in the city of Denver1. In 2020 Denver had the worst air pollution in 10 years2. Natural ventilation isn’t as effective when the air quality continues to decline, and moving to an all-electric system could mitigate safety issues associated with poor air quality while also reducing greenhouse gas emissions. Limitations of Electrification Let’s Wrap it Up With the new regulations coming, Life Cycle Cost Analysis (LCCA) will become even more important to show the offset of maintenance, utility, and upfront costs between mechanical systems. It is important to know the regulations to ensure the safety and longevity of your product. Energy modeling is already required in some cities like Boulder and will become required in Denver to demonstrate energy compliance. For any questions or inquiries or to get started on your next project, Contact Us. References 1 https://denvergov.org/files/assets/public/climate-action/documents/denver-nze-implementation-plan_final_v1.pdf 2 https://www.colorado.gov/airquality/tech_doc_repository.aspx?action=open&file=2020AnnualDataReport.pdf Vocabulary Direct Expansion (DX): the most common type of air conditioning in the US where the indoor air is cooled with a refrigerant liquid. Electrification: the conversion of a machine or system to the use of electrical power. Energy Use Intensity (EUI): refers to the amount of energy used per square foot annually. Life Cycle Cost Analysis (LCCA): it is an economic evaluation technique that determines the total cost of owning and operating a facility over a period of time.
Optimized Cooling Tower Design for Increased Performance and Efficiency
At 360 Engineering, we consistently optimize projects by creating custom designs and recommendations. This project we started in 2018 for the National Renewable Energy Laboratory (NREL) was no exception. Once COVID-19 hit, we learned how the economy could quickly derail a project, but we steered it on the right track by helping NREL find a viable path forward and breaking the project into two phases. NREL realized one of its cooling towers at the Solar Energy Research Facility (SERF) was using a significant amount of water, and they brought our team in to find a solution. During a gas line replacement project, water was encountered immediately below the access road, and it was determined to be a leak of the condenser water lines from the cooling towers to the chilled water plant. “360 Engineering reconfigured the operation of the cooling tower condenser water plant to optimize both the performance of the plant as well as increase the system redundancy moving forward.” This project included our long-time electrical engineering partner, AE Design, and structural and civil engineers from Martin/Martin. We have an amazing team of expert consultants who have worked with us on NREL projects since the beginning. For any questions, inquiries, or to get started on your next project, Contact Us.