Party Walls

The International Energy Conservation Code (IECC) has a number of requirements involving energy recovery on ventilation systems. Requirements vary based on climate zone, building type and size, equipment capacity, and equipment operating hours. As a result, many new construction projects must now incorporate energy recovery considerations into their design.

An energy recovery unit (ERU) equipped with a heat wheel can be a great way to satisfy these energy recovery requirements. The ERU can be a roof-mounted air handling unit, or can be an air handling unit located inside a mechanical room with outdoor air and exhaust streams ducted in. The heat wheel is positioned so that half of the wheel sits in the exhaust air duct and the other half sits in the outdoor air intake duct. During cold weather, the wheel spins, transferring heat from the exhaust stream to the outdoor air intake stream. During hot weather, the wheel transfers heat from the outdoor air intake stream to the exhaust stream. In both cases the heat exchange enables the building to take advantage of the more comfortable conditions of the exhaust air, while still allowing fresh air to enter the building. During extreme weather conditions, heat wheels can save energy on space conditioning while still allowing for healthy indoor air quality.
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As the Passive House standard continues to make waves across New York City and the U.S., an entirely new design process has evolved to respond to the challenges of higher insulation levels, balanced mechanical ventilation, and perhaps the most difficult hurdle – an air tightness level that most would think is impossible. For the recently certified Cornell Tech building on Roosevelt Island, the tallest Passive House in the world, a several year-long coordinated effort was required to achieve such a feat. So what is the requirement, how is it measured, and what are the strategies and considerations required to achieve it?

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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.

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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Boston has been making national headlines a lot this winter, mainly due to the #snowpocalypse that they’ve been enduring.

Never fear, the first sign of spring is about to appear in Beantown! NESEA’s Building Energy Conference is just around the corner on March 3-5, bringing experts from around the country to share their knowledge about new trends and innovative solutions within the realm of building science and renewable energy.

We’re sure it will rejuvenate and reinvigorate Bostonians and all Northeasterners alike. Note: Northeasterners like the people, not northeasters like the storm, just to be clear.

As with most of the Building Energy Conferences, there will be many speakers from SWA there to lead workshops and sessions about improving the efficiency of buildings and their systems (You can read more about that here). Today though, we want to talk about the other presenters and topics that we’re excited to see!

Here are a few of our recommendations that we can’t wait to check out:

• We have been preaching about addressing building resiliency and energy efficiency, want to hear it from another trusted voice? Attend Alex Wilson’s session Putting Attention Where it is Needed Most – Building Resiliency In Multifamily Affordable Housing.  March 4, 11am – 12:30 pm
• Codes are raising the bar, owners are seeing the benefits of building more efficient housing and more owners are addressing energy use at the time of capital upgrades and refi, all great news. The next wave we will see is the increase in multifamily Passive House construction and renovation using techniques where possible. Want to know how to incorporate passive house to your next project, you can talk to SWA’s Lois Arena, and you can also hear it from Katrin Klingenberg at her session The Building Science of multifamily Passive House. March 4, 4pm – 5:30 pm
• Water makes up a sizable portion of utility bills, we recommend attending Reinventing the Water Grid Part 1: Science, Behavior and Dollars. Water reduction strategies and monitoring can save money and reduce operations and maintenance costs through leak detection. We will be attending this session to reinforce what we are recommending and to see if there are new applicable techniques or recommendations we can incorporate into our projects. March 5, 10:30am – 12pm

To attend Building Energy 2015 in Boston, register here. We look forward to seeing everyone there!