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

Tech Notes: Universal Design v. Accessible Design

“Isn’t Universal Design just a different term for Accessible Design?” We hear this from architects and designers a lot. While similarities exist, Accessible Design and Universal Design are actually quite different.

outlets, switches, env controls

This image depicts the prescriptive Accessible Design requirements for light switches and operable parts under the Fair Housing Act. Unlike Universal Design, Accessible Design is not intended to be flexible, with little or no room for tolerance.

The term “Accessible Design” typically refers to compliance with Federal accessibility laws and state and local building codes; including the Americans with Disabilities Act and the Fair Housing Act, among others. Accessible Design requirements are based on anthropometric research – or the study of the human body – and are intended to address people with disabilities. Laws and codes that require compliance with Accessible Design requirements include little or no room for tolerance.

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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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Tech Notes – Medical Diagnostic Equipment and Accessibility

By Victoria Lanteigne, Senior Accessibility Consultant

The United States Access Board recently issued new standards under Section 510 of the Rehabilitation Act of 1973 for Medical Diagnostic Equipment (MDE). The Proposed Standards provide design criteria for MDE such as examination tables and chairs, scales, radiology equipment, mammography equipment, among other medical equipment. The new accessibility requirements, “establish minimum technical criteria that will allow patients with disabilities independent entry to, use of, and exit from medical diagnostic equipment to the maximum extent possible.”

The Proposed Standards provide technical criteria that will facilitate the use of equipment for people with disabilities in the supine, prone, side-lying, and seated positions. A few key requirements from the Proposed Standard are following:

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Solar Photovoltaics and New York Energy Code

By Eric Wallace, Energy Engineer

Industry Trends

Over the past decade, the story of solar photovoltaic (PV) power has been one of both accelerating deployment and consistent, significant reductions in cost. This success has been driven by increasingly advantageous economies of scale, and supported by incentives and initiatives at all levels of government.

Figure 1. Solar PV systems have seen a dramatic reduction in cost

In late 2015, the federal Investment Tax Credit [3], a primary financial incentive for solar PV systems, was extended at its current rate of 30% through 2019, despite a contentious environment in Washington. It is scheduled to be stepped down through 2022, after which the commercial credit will expire and the residential credit [7] will remain at 10% indefinitely.

The National Renewable Energy Laboratory’s annual solar benchmarking report [4] shows that over the past seven years, PV system costs have dropped 58.5% in the residential sector, 59.3% in the commercial sector, and 68.2% in the utility-scale sector. As a clear sign of the times, utility-scale solar achieved the U.S. Department of Energy (DOE) SunShot Initiative’s goal of $1.00/W early this year, three years ahead of schedule [9]. According to the U.S. Energy Information Agency (EIA) [8], these trends should continue, leading to solar power’s increasing presence as a key component of the national electrical generation mix. The EIA projects solar to be the fastest growing form of renewable energy, increasing by 44% by the end of 2018 for a total deployed capacity of 31 GW and accounting for 1.4% of utility-scale electricity generation.

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