Party Walls

To meet the goals of the Paris Climate Agreement, we must make decisions that will result in the greatest near-term carbon savings. This means taking into account both embodied carbon—those upfront emissions associated with the extraction, manufacture, transportation, and assembly of building materials—as well as the carbon that’s emitted over the course of the building’s operational phase.

We can build a high-performance building with very low operational emissions, but if its embodied emissions are so high that even if it’s a net-zero energy building (meaning it has net-zero operational energy consumption) it would take decades for the building to reach net-zero carbon (meaning it has net zero whole-building lifetime carbon emissions), we’re not actually helping to solve the critical issue of near-term carbon.

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One of the most important drivers in achieving Passive House certification (or achieving any goal!) is getting the project team involved from the start. Becker + Becker, the owner, architect and developer for the creative retrofit of the Pirelli Building, hired SWA’s Passive House, LEED, Enclosures, and Accessibility teams to coordinate during early design. Becker +Becker is invested in rebuilding for resilience, sustainability, and occupant health and comfort and appreciates the necessity of getting goals defined at the outset.

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Letter grades are coming!

NYC’s building owners and real estate management firms now have one more thing on their plate to consider: Local Law 33 of 2018. LL33 compliance will assign letter grades to buildings required to benchmark energy and water consumption. The energy efficiency score will relate to the Energy Star Rating earned using the U.S. EPA Energy Star Portfolio Manager (PM). The law will come into effect on January 1, 2020, and will utilize the previous year energy data to set the energy efficiency score and letter grade as follows:

A – score is equal to or greater than 85;
B – score is equal to or greater than 70 but less than 85;
C – score is equal to or greater than 55 but less than 70;
D – score is less than 55;
F – for buildings that fail to submit required benchmarking information;
N – for buildings exempted from benchmarking or not covered by the Energy Star program.

Why is my letter grade lower than expected?

Property owners should be made aware that if their property earned an energy efficiency score of 75 for the 2018 Benchmarking filing, the new score for the 2019 benchmarking filing may have fallen as much as 20 points. In LL33 terms, what could have been a letter grade “B” could now be “C” or “D” based on PM updates implemented in August 2018. Property owners will want to learn how the Energy Star PM update will affect their LL33 letter grade.

To understand the correlation and impact that the August 26, 2018 Energy Star PM update will have, it is important to look back at what took place as part of that update. (more…)

Following up on our blog post in August 2018 – Just Your Typical Blower Door Test… in Sri Lanka – Star Garment Innovation Center – we have exciting news coming out of Sri Lanka. The Star Garments Innovation Center is now officially certified as a Pilot EnerPHit building, the building retrofit standard under the Passive House Institute (PHI).

EnerPHit certification for this project is a milestone achievement on many levels. The Innovation Center is now the first certified Passive House in Southeast Asia and one of only a handful of certified PH projects in tropical climates. PHI deemed the project “a milestone in industrial energy efficient retrofitting in a tropical monsoon climate.” Many of the passive measures employed at the Innovation Center, including continuous exterior insulation, highly efficienct windows, variable refrigerant flow heat pumps for cooling with wrap around heat pipe for enhanced dehumidification capacity, and balanced ventilation with heat recovery can be utilized across all future construction projects in tropical climates. The Passive House team here at SWA is excited to see the potential growth in tropical-climate Passive House construction as a result of the Innovation Center’s success.

But what good is certification if the building doesn’t perform as well as the energy model predicts? Well, we have exciting news on this front too!

At the very start of SWA’s involvement in the project back in the summer of 2016, SWA conducted a utility analysis of the base building prior to any renovations to predict and later verify the energy savings of the Innovation Center by designing to the PH standard. Once the energy model was developed, SWA predicted approximately 50% in energy savings when compared to the previous building’s energy bills.

Fast forward to Fall of 2018 and the building has now been occupied for a full year. The two inevitable questions are:

1. How much energy is the Innovation Center saving as compared to the previous building?
2. How does the modeled energy use for the Innovation Center compare to what it is actually using after a full year of occupancy?

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Installing a dedicated domestic hot water (DHW) plant is a common energy conservation measure (ECM) in the New York City multifamily market. According to Local Law 87 data, approximately 80% of the audited multifamily floor area uses steam heating boilers to produce domestic hot water.[1] A recent SWA analysis of data from steam buildings with tankless coils that implemented this ECM suggests that auditors may want to think twice about recommending this measure widely.

Two unsupported arguments are typically made in favor of installing a dedicated DHW system.

1. A new condensing boiler or water heater (we will just say “water heater” here for simplicity and to distinguish the dedicated system from the heating boiler) will operate at a very high efficiency.
2. Scotch marine steam boilers are inherently inefficient and are plagued with high standby losses. Large Scotch marine boilers fire to meet small DHW loads, and correctly sizing a new dedicated water heater will eliminate short cycling.

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Going Beyond Carburetor Technology in the NYS Market

Fun Fact #1: Space heating and domestic hot water generation represent two of the greatest energy end uses in New York State.

Fun Fact #2: More than 70 percent of all New York City buildings utilize steam for space heating.

Background

The clear majority of the distribution systems in these NYC buildings are supplied by high mass steam boiler plants. Digging down a bit further, it is important to note that the most common air:fuel control for these boilers is a mechanical linkage that connects a single servo motor to both the combustion air damper and the fuel control valve(s). We know that adjusting one part of the linkage’s movement affects fuel and air rates elsewhere in the range, making accurate adjustment difficult. We also know that modern linkageless controls use separate servo motors to operate the fuel control valves, combustion air damper, and (in some cases) the flue damper, allowing for finer control.

In fact, SWA recently completed a demonstration study (partially funded through NYSERDA’s Advanced Building Program) to evaluate linkageless burner retrofits on two buildings with respect to energy savings and carbon reductions, as well as qualitative or non-energy benefits. The retrofit materials were funded by Preferred Utilities Manufacturing Corp. of Danbury, CT, who also provided manufacturer’s technical support. The study also focused on quantifying the seasonal efficiency of intermediate-sized, high mass steam boiler plants, which had not previously been studied. The demonstration addresses this gap in the industry’s knowledge.

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Welcome back! In Part One we talked about how steam pressure gets too much attention. Controlling pressure for its own sake should never be the end goal—steam pressure is just a means to an end. In this post we’ll discuss one way that controlling steam pressure can be useful—where it can help you balance the system, control the temperature, and yes, save energy.

Two-pipe Steam

The biggest issue plaguing two-pipe steam heating systems are steam traps. Steam traps are supposed to do just that—trap steam—keeping the pressurized steam on the supply side of the system and allowing air and water (i.e., condensate) to pass through into the returns. Keeping the supplies and returns separate is critical, but steam traps are too failure prone to accomplish this reliably.

At the start of any heating cycle, the system is full of air, which must be removed for steam to enter the heaters. In most two-pipe systems, the steam pushes the air out of the heaters, through the traps, and into the return piping where it eventually exits the system through a vent in a vacuum or condensate tank. That’s what happens when the traps are working. But a failed open trap is no trap at all. It lets the steam flow into the return piping and, with pressure on both the supply and return sides, air is trapped in the system. This affects those farthest from the boiler—the heaters near the ends of the mains and on the top floors—the most.  (And with air trapped inside keeping the metal cold, are they even heaters?)

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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.

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