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Looking for a Fast Payback by Installing a Dedicated Domestic Hot Water System? You May Want to Look Elsewhere

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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Over Pressure (Part Two)

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.

Radiator steam “trap” failed open

Radiator steam “trap” failed open

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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Just Your Typical Blower Door Test… in Sri Lanka – Star Garment Innovation Center

As the number of projects pursuing Passive House certification increases, so does the demand for whole building blower door tests. And so, performance of recent blower door tests took us to uncharted territory, not only for SWA, but for the Passive House Standard.

Rendering of Star Garment Facility

 

Working remotely with a project team across the globe, the Passive House team at SWA was tasked with retrofitting an outdated factory in Katunayake, Sri Lanka, into a Passive House certified garment manufacturing facility. Jordan Parnass Digital Architecture (JPDA) recruited SWA to provide technical assistance to the project team. Responsibilities for this project included Passive House design analysis and recommendations, mechanical design review, energy and thermal bridging modeling, and the testing and verification necessary to achieve certification from the Passive House Institute (PHI).

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Foundation Waterproofing – Proper Installation and What NOT to do!

As mentioned in Foundation Waterproofing 101, water damage to a foundation can be very costly and difficult to repair. By paying close attention to how and where water might enter the foundation during the early stages of construction, typical failures can be avoided by following these simple guidelines…

For the Designer: Keys to proper installation

Design and Quality Assurance

  • Don’t wait to design the foundation waterproofing system after you’re already in the ground!
  • Specify and detail the appropriate system for each project. Meet with manufacturer reps early!
  • Require shop drawings and kickoff meetings to ensure the entire team understands the importance of the design! Review examples of common failures.
  • Get your consultants on board early: Geotechnical engineer, Structural engineer, Waterproofing/enclosure consultant.
  • Review warranties, require third party inspections, installer certification, and contractor training.

For the Installer: Keys to proper installation

Substrate preparation

  • Provide smooth continuous surfaces to install waterproofing – minimize jogs, protrusions, and sharp edges.
  • At slabs: compacted fill/rigid insulation board/rat slabs
  • At walls: fill bugholes, remove/grind concrete fins, mortar snots, fill form tie holes, verify form release agents and compatibility.

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Trying to Be Rational in an Irrational World

Think about the last time you went looking for a new car. What did you look for? I am guessing you started with your needs for a vehicle. Are you looking for a large car/SUV to move a lot of people or equipment, a car for commuting to work, or something to enjoy on the weekends? Next you probably were interested in the looks of the vehicle because it is a large investment and you should like what you drive. I am guessing you glanced at the miles per gallon (mpg) of the car. You even likely went online to see reviews from others on the comfort, crash test rating, and typical maintenance issues of the car. Of course, you will need to look at the sticker price. I am even assuming you asked to test drive the vehicle to make sure that the information that you obtained aligns with how you perceive the vehicle.

Image of animated home Now, what if I told you that you must make that vehicle purchase decision only based on the dimensions of the car, the features (radio, A/C, seat controls, etc.) of the car, some pictures of the interior, and the price. Do you think you could decide on which car you would want? My guess is that you would say I am crazy and that you wouldn’t make the decision on such a pricey purchase with so little information. But, that is exactly what millions of people do when making a significantly more expensive purchase… a home.

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