Transformers: Problems in Disguise

Sometimes a significant source of energy inefficiency in a building can be hiding in a place difficult to detect. In some buildings, a single transformer can have a substantial impact on electrical consumption.

Image of currents flowing through a transformer

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Some Background

Transformers are responsible for stepping the incoming voltage to a building up or down depending on the design, intended use, or connected equipment.  A standard electrical socket in a US home or office will deliver 110-120 volts AC. Some appliances require 240 V instead. Large mechanical equipment, such as the air handling units, distribution pumps and chillers found in commercial or multifamily buildings may require 460 V. In buildings where the incoming voltage from the utility does not match the voltage required by connected equipment, a transformer is used to deliver the necessary voltage.  The voltage entering the transformer is called the primary voltage and the voltage delivered by the transformer to the facility’s equipment is called the secondary voltage.

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Harvey and Irma: Hurricanes, Floods, and the Days After

They call it hurricane season. That time of year when tropical depressions form off the west coast of Africa somewhere north of the equator. The rotation of the earth and the prevailing winds cause these low-pressure pockets to migrate slowly westward, and if conditions are apt, pick up strength along the way.

As deadly and destructive as hurricane winds are, it is typically the associated water that causes the most physical damage: horizontal rain at 100 mph overwhelming already stressed buildings, prolonged periods of heavy rain inundating drainage infrastructure, and coastal storm surges pushing tidal waters many feet above normal.

Hurricane Irma

Hurricane Irma, a record Category 5 storm, is seen in this NOAA National Weather Service National Hurricane Center image from GOES-16 satellite taken on September 5, 2017. Courtesy NOAA National Weather Service National Hurricane Center/Handout via REUTERS

As of this writing Hurricane Irma is just north of Puerto Rico with Category 5, 185 mph winds. And Harvey, a rain event lasting days and dumping up to 50 inches of rain ravaged Texas and Louisiana one week ago. Because of where and how we chose to build our communities, these disaster events will remain inevitable. There are concrete steps we can and should take to improve the resiliency and disaster resistance of the buildings we build, but in reality, much of what we built in the past is disaster prone and not resilient. Read more

VRF Systems vs. Electrical Resistance Heaters – A Case Study

Variable refrigerant flow (VRF), also known as variable refrigerant volume, was a concept developed by Daikin Industries in the 1980s. The technology is based on transferring heat through refrigerant lines from an outdoor compressor to multiple indoor fan coil units. VRF systems vary the amount of refrigerant delivered to each indoor unit based on demand, typically through variable speed drives (VFDs) and electronic expansion valves (EEVs). This technology differs from conventional HVAC systems in which airflow is varied based on changes in the thermal load of the space.

The two main VRF systems are heat pump systems that deliver either heating or cooling, or heat recovery systems that can provide simultaneous heating and cooling. These two applications, plus the inverter-driven technology of the outdoor compressors, allow for greater design flexibility and energy savings. In applications where heating and cooling are simultaneously called for in different zones, VRF heat recovery systems allow heat rejected from spaces that are being cooled to be used in spaces where heating is desired. Read more

Which LEED Rating System Do I Use? Part 1: NC versus Midrise

Here’s a question our clients often ask: “I’m building a new residential building, should I use LEED for New Construction (NC) or LEED for Multifamily Midrise?” The answer isn’t exactly simple, especially with the introduction of new credit requirements in LEED v4 and the fact that USGBC allows project teams to choose between the two rating systems. Ultimately, it’s often a difficult decision based on the goals and final design of the project. So, in an effort to help clear up the confusion and possibly make the decision a little easier for you, we decided to break down a few scenarios that highlight key differences between the rating systems that may not be apparent upon first glance. In this first installment, we’ll start with a smaller multifamily building to get a sense of the essential differences between the rating systems and begin to understand the critical decision-making points.

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Moderate Rehabs in Pre-War Buildings: Practical Limits to Hydronic Building Energy Savings

Written by Bryan Simpson, Mechanical Engineer

New York City has established high goals for CO2 reductions as part of the 80 x 50 plan enacted under Mayor de Blasio’s administration. In short, NYC aims to reduce its CO2 production by at least 80% by 2050 (from a 2005 baseline). This requires vast energy conservation and renewable energy production proliferation across the city’s energy, transportation, waste management, and building sectors. Buildings themselves account for 68% of current CO2 production in the City, and as such have the largest reduction targets1. Goals can only be met by implementing repeatable and scalable scopes of work in coordination with policy updates and improvements in other energy sectors. To better understand the efficacy of these moderate improvements on overall energy consumption, we’ve analyzed the results from a recent portfolio rehabilitation. These findings help us to create a map of where we need to go in order to approach 80 X 50.

Figure 1: 80 x 50 NYC Buildings CO2 Reduction Goals, NYC Mayors Office of Sustainability, Roadmap to 80 x 50 Report

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