Building Energy Resilience

Basics of steam coil and face and bypass operation

Many air handling units in colder climates are equipped with steam heating coils. These coils use control valves to modulate the flow of steam to the coil. Due to the low mass of water in a steam coil, it has a higher propensity to freezing when conditions are right. One of the neat ways we’ve design around this is to use a Face and Bypass (F&B) damper arrangement to allow the coil to have maximum steam flow to prevent freezing. The F&B dampers direct a portion of the airflow through the steam coil and another portion bypasses the coil in order to achieve the necessary discharge air temperature and prevent a freezing airstream from damaging the steam coil. Pretty neat, huh?

In my previous post How to do BAS Graphics Right: Part I, I wrote about the 5 basic rules to BAS graphics I learned during my years as a controls system master integrator. If you’ve not read that post yet, I’d encourage you to go back and give a glance as it’ll put the rules below into perspective, and feel free to ask a question if you got one using the comment section at the bottom of the post. Here’s a quick recap of the rules:

In my first blog on Common VRF (Variable Refrigerant Flow) Installation Issues I focused on issues during mechanical and hardware installation that typically lead problems during startup and pre-functional checkout commissioning. This blog will focus on controls issues identified during commissioning design review which usually lead to issues during start up if not addressed up front during design. As mentioned in the previous article, VRF systems can allow for better comfort and overall satisfaction, but if not properly programmed for the owner’s specific application, can lead to numerous complaints during the first year of occupancy.

COVID-19 has turned our world upside down. From what we’ve learned about the transmission of COVID, spending time in an enclosed space with others is ill advised, and social distancing means working from home and homeschooling. I’ve been doing the former since March, even though Cx Associates’ offices reopened in June. Reopening the office was not an easy choice to make, as was my decision to remain at home, and I thought I’d write a bit about it.

I started this post before the COVID-19 pandemic. While a lot of our attention has shifted to slowing and fighting the pandemic, I hope you find some refreshment in a lighthearted but still important sustainability story.

The prospect of reopening schools under the new CDC guidelines in response to COVID-19 can be overwhelming for facilities and administrative personnel. In addition to increased surface cleaning, hand washing, maintaining six feet between classroom desks, and wearing face masks, the schools are faced with making decisions on how to best operate their HVAC equipment. As much as the world is trying to help them with these decisions, the HVAC guidelines from the CDC and ASHRAE are all encompassing; it is difficult to identify which measures are applicable and even more difficult to prioritize the measures under a school’s constrained budget. This may overburden an already burdened school facilitator. 

As we are all learning to adjust to life with COVID-19, many areas are considering re-opening schools for the coming school year. Although many teachers are finally starting to unwind into a stranger-than-usual summer break, now is the ideal time to get a jump on adjustments to school operations to make in-person education as safe as possible for students, faculty and staff alike.  

Last year, Cx Associates committed to offsetting the environmental impact of our business operations. After thorough research, we selected Carbonfund.org’s Carbonfree® Small Business Partnership Program. Through this initiative, we’ve neutralized nearly 80,000 pounds of carbon emissions from our estimated annual business operations for 2019 and will continue to do so on an annual basis.

Photo by Adam Rouse

On March 10, I returned to a very different world here in Vermont after having spent the prior two weeks visiting New Zealand. While at the Auckland airport on my trip home, I accepted a position at Cx Associates, not knowing how the coming weeks would unfold as the virus was beginning to explode in the states. Upon my return, I self-quarantined for the recommended 14 days, and then the stay-at-home orders and various recommendations kept me here. Ten weeks in, I’ve had to adjust to a new life and start a new job that was never meant to be remote, remotely. I’ve learned a thing or two about working from home amidst a pandemic and would like to offer you some of the ways I’ve found rhythm and comfort among the challenges, and resources to get you started should you feel a certain strategy might be beneficial.