Building Energy Resilience

Over the past several months, it has been proven that HVAC systems play a role in the mitigation of the spread of a virus like COVID-19. The first line of defense – personal masking and social distancing – is by far the most effective in mitigation, but we’ve learned a lot about HVAC’s contribution to keeping people safe indoors. My last blog covered the why & how of ventilation (fresh air). In this blog I want to focus on ventilation control strategies: why & how the industry evolved from pre-pandemic minimalization, to early-pandemic wind tunnel 24/7, to a common sense, balanced approach on ventilation control.    

We’ve learned a lot about COVID-19, the spread of a virus, and the mitigation of the spread over the past several months. The recommendation of the first line of defense - masking and social distancing – hasn’t changed since this pandemic started in January 2020, but it seems like every other recommendation has evolved throughout these long months. In our business of HVAC, we have kept up with the industry and CDC recommendations on ventilation and filtration and have been active in assessing commercial and institutional buildings. 

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?

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. 

With the current COVID-19 global crisis, organizations all over the country are actively seeking ways to continue to provide the same level of services to their customers while keeping their employees safe. Cx Associates is known for its rigorous standards in the commissioning process, but a large portion of our work is contingent on our ability to be on construction sites, working with contractors to verify the installation and functionality of equipment. With Vermont’s order that all non-essential employees work from home, and with Cx Associates’ commitment to both keep our employees safe and prevent us from potentially spreading the virus on construction sites, we needed to quickly find a way to provide our on-site services remotely for the essential construction work that continues to move forward in a way that still matches our high standards. This blog discusses our approach to remote site work and how we're continuing to serve our clients while safely social distancing from our home offices.

Hospitals are racing to create as many isolation rooms as possible to help effectively care for patients with COVID-19 while keeping healthcare providers and others in the hospital as safe from infection as possible.

After an early morning departure and a snowy drive, my colleague and I arrived onsite to test, among other equipment, a packaged rooftop air handling unit with factory controls. At first, the unit appeared to check all our boxes, but as we dug into the details, it became clear that this would be a very expensive heating system to operate. This blog entry is about factory controls and the importance of getting into the weeds to identify issues like the one we found with this rooftop air handling unit.

A large healthcare client of ours recently opened a brand new USP 800 compliant compounding pharmacy, which we commissioned. We collaborated with the engineering team and the hospital during the design phase to help ensure prior issues weren’t repeated, and the hospital’s concerns were thoroughly articulated and addressed. At the conclusion of the design phase, the team was confident that the design direction was solid and would give the hospital what they were looking for.

The ground source heat pump is a wonderful technology that will be vital in achieving energy efficiency goals this century. This technology isn’t new, but it is beginning to become more accepted as a viable solution for large scale, high efficiency HVAC performance. There are two main types of ground source heat pump systems: those that are “Ground Water” (also called Open Loop) and those that are “Ground-Coupled” (also called Closed Loop), see Figure 1 below. In either case, the water from the ground is pumped to a heat pump, where heat is either extracted out of or rejected into the ground and moved into or out of the conditioned space.

I recently attended the Performance Evaluation Methodology for Building Occupancy Sensing Systems for HVAC Controls workshop, which followed the annual ASHRAE conference that just wrapped up in Kansas City, MO. The workshop focused on one of ARPA-E’s[1] research programs called SENSOR (Saving Energy Nationwide in Structures with Occupancy Recognition)[2], and brought together a diverse group of individuals, including researchers from national labs and universities, industry representatives, design engineers, and other interested parties.