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.
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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.
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Over the course of my career I have evaluated BAS graphics packages as a function of my daily 9 – 5. I have been doing this since 2002 and in those days, most BAS manufacturers barely had functioning websites. However, the products they sold allowed their vendor networks to create Human Machine Interfaces (HMI) and Graphical User Interfaces (GUI), and these interfaces haven’t really functionally changed a whole lot since those days of pre-broadband internet and before the smartphone was commonplace. Given that we may be stuck with outdated user interfaces for some time to come, it makes it all the more important that proper care is given to how the information is displayed and to ensure users can easily absorb the information they need from the BAS.
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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.
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Thanks for following the second part of the ground coupled heat pump design. If you haven’t already, now’s a good time to go back and read Part 1. In the first part of this post, we discussed the importance of understanding thermal imbalance in a ground source heat pump system and the longevity impacts associated with an imbalanced system. Despite the issues associated with a thermally imbalanced system, there are ways to address building loads with additional technology that will further enhance the performance of the ground-coupled heat pump system, as well as provide long term performance.
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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.
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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.
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Sometimes certain parts of the commissioning and retrocommissioning process can seem trivial to both the contractor and the commissioning agent. Of course, the process involves some important and significant checks, such as ensuring the piping design detail matches the as-built piping, and that the specified ductwork sizes match the as-built ductwork size. But the commissioning process also deals with some of the finer details that may not seem as consequential or that have already been checked by multiple parties. So, why would the commissioning agent also need to check it again? In this post I am providing a couple examples of real-world commissioning issues that we’ve found. Each is an excellent reminder of why the seemingly minor commissioning verification steps are still required and important, even though they may seem inconsequential.
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I looked back through our blog history and realized I have never written about the importance of a lovely little document called the Owner’s Project Requirements, or OPR for short. An OPR is created through collaboration with many involved parties; it synergizes everyone’s ideas into one goal-focused document. At Cx Associates we are such believers in defining the goals and criteria for project success that we often develop OPRs even for internal business improvements to help focus and guide the process.