Linkageless Burner Retrofits for Steam Boilers

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.


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.

mechanical linkage system and linkageless system

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.

Read more

Electrify Everything? (part 1/?)

So in utility and policy circles, electrification is all the rage. Grid electricity is getting cleaner (i.e. resulting in lower CO2 emissions), on-site renewables are taking off (sometimes even with storage), and heat pump technologies are getting better. More regional and utility initiatives are encouraging building owners/designers/developers to forego onsite fossil fuels entirely (or at least mostly) to help meet CO2 emission reduction goals. But is electricity really more sustainable than natural gas? Is it cheaper? Which is better, really?

Read more

Low-Carbon Concrete: Reducing the Embodied Energy of a Notorious Emitter

It is safe to say we are in a climate crisis. Of the last 17 years, 16 have been the hottest on record.[1] Sea level is expected to rise by as much as eight feet by the end of the century.[2] And by 2050, as many as 140 million people will have been displaced by climate change.[3] The time to act is now, and a major area of impact is buildings, which account for 40% of carbon emissions in the United States. Better envelopes, lighting, and mechanical systems are helping buildings become more efficient, which means an increasing proportion of carbon—up to 68% of a building’s lifetime emissions—is locked up in materials.[4] This “embodied” carbon gets released during a material’s extraction, manufacture, transport, maintenance, and, eventually, disposal.

If our industry is to meet the 2030 Challenge of carbon neutrality by the close of the decade, we will need to reevaluate building materials and select low-carbon alternatives.

Embodied carbon life-cycle

Figure 1: Courtesy of Faithful+Gould

Read more

Five Year Solar Performance on Connecticut Home

Written by Gayathri Vijayakumar, VP – Senior Building Systems Engineer

Over the last 10 years, we’ve seen great strides in the solar PV market in the United States. Between the federal tax credit and utility-sponsored incentives, the price to install PV systems came within reach of many homeowners. For others, eager to make a positive impact on the environment, power purchase agreements with solar companies and no up-front costs made it possible to utilize their roofs to generate electricity.

While the calculated cost-effectiveness of solar panels relies on the future price of electricity (which we can’t predict), we can confirm that they do deliver energy. In a very scientific study of exactly one home, owned by a SWA engineer, five years of generation data is available. Sure, it’s not the pretty Tesla roof, but these panels were installed back in November 2011. At 4.14 kW, with no shading and great Southern exposure, the panels were estimated to generate 5,400 kWh/year of electricity in New Haven, Connecticut (Climate Zone 5). The panels have exceeded expectations, generating on average, 6,200 kWh/year, which is roughly 70-80% of the electricity required by the 2,500 ft2 gas-heated home and its 4 occupants.

Read more