We received the following announcement from Taco Comfort Solutions about their commercial pumps and wanted to pass it along.

New and Improved Commercial Pump Nameplates Are On Their Way!

We are excited to introduce you to our newly designed nameplates. We’ve tried to incorporate as much of the relevant data you need in the field into our new design including a location for the PEI value of each pump. The new design also provides a more accessible location for our Taco Tag, giving you all of the digital support you may need.

You can see the difference in layout between the old and new design below. Fields to note are the DOE Basic Model No., PEIcl, and Taco Tag placement.

The DOE Basic Model No. is provided for easy cross reference of your qualifying Taco pump with the DOE energy rating data base at er.pumps.org.

As PEI values are uploaded into the Hydraulic Institute database, we’ll begin to include the HI Energy Rating Label in the document package shipped with each pump.

Pumps have already started shipping with the new nameplate!

If you have any questions about the new nameplates or how it might impact you, please reach out to us at sales@buymeinc.com or call us at 800-355-7061.

One of our most trusted brands, Patterson-Kelley, provided us with this great explanation breaking down turndown in commercial boilers.

Boilers are rated on thermal efficiency, which is simply the chemical energy added to the boiler, divided by the energy added to the boiler water. As more energy is transferred from the hot gas into the boiler water, the thermal efficiency increases and the temperature of the hot gas decreases. Turndown ratio plays a key role in this energy transfer. Many engineers and owners have been intentionally mislead regarding turn-down ratio’s and this article will dispense with the misleading information and down right nonsense about turn-down ratios and efficiencies!

Almost all boilers are tuned to add excess air, which ensures ideal combustion of the fuel for proper air-fuel mixing. The excess air can also prevent the burner from overheating by “pushing” the combustion flames off the burner.

When energy from the hot gasses is transferred to the boiler water, the gas temperature dips below the dew point, which causes vapor to become liquid. The energy released from the conversion is picked up by the boiler water and results in a significant boost in efficiency.  Every pound of condensate from flue gases condensing adds approximately 1000 btu’s to the boiler water. However, dry flue losses and loss of vapor can result in energy loss.

Energy loss can be readily calculated if the amount of CO2 and O2 in the flue gas and the stack temperature is known.

 With the evolution of boiler technology, manufacturers have found a way to offer units with multiple firing rates, and units that can modulate seamlessly between fixed low fire rates and fixed high fire rates. The fixed fire rates are defined as the boiler turndown capacities, and modulation is accomplished by reducing the air and gas flow into the boiler.

The benefit of this modulation is threefold; it reduces cycle losses, it reduces the wear on the components, and it can potentially lead to higher thermal efficiencies.

Impact of Turndown

This begs the fundamental question – wouldn’t a boiler with extreme turndowns be much more efficient than one with 5:1 turndown?  The answer to that is ‘NO’! And the proof of that is a simple engineering calculation that anyone can verify for themselves (shown below).

To achieve high turndowns the boilers are tuned to deliver greater amounts of excess air at low firing rates to keep the burner from overheating. The additional excess air will significantly reduce the dew point of the water in the flue gas and alter the losses in the dry gas.  To illustrate this effect, the example used in Figure A is updated to reflect a 20:1 turn down where the O2 is set to 11% (corresponding to a CO2 of 5.6% and 97% excess air).  The results are highlighted in Figure B below.

Note that the dew point has been lowered from 130.6° F to 117° F  and the boiler is no longer in the condensing range.  This represents a 3.7% DECREASE in overall efficiency and this is just the beginning of the bad news! 

When excess air well above 50% is used in the boiler, it impacts the stability of the combustion flame which can lead to excessive flame failures, nuisance trips and cycle losses.

The P-K Analysis

Realistic boiler modulation rates have helped improve the overall boiler system efficiency from reduced cycle losses and increased thermal effi­ciencies. Extreme turndown produces the opposite effect. Boil­er plant designs must factor in actual (not extrap­olated) boiler efficiencies through the firing range of the equipment and matching the expected plant loads with the right boiler size selections.

Interested in learning more? Reach out to us at sales@buymeinc.com

Going to be at the 2019 AHR Expo?

Dave Connors, Patterson-Kelley’s Trainer and National Accounts Manager will be giving an exclusive presentation at the 2019 AHR Expo. Be part of his “The Dirty Little Secret Associated with High Turndown” presentation to get a new perspective on the controversial topic.

Join Dave Connors on Wednesday, January 16th between 1:45 PM and 2:05 PM at Theater A – Room C101 of the Georgia World Congress Center. 

As an owner or as a design engineer, you want to be sure that your boiler selection will operate at peak efficiency, under all conditions. Thermal efficiency is simply the chemical energy added to the boiler, divided by the energy added to the boiler water. As more energy is transferred from the hot gas into the boiler water, the thermal efficiency increases and the temperature of the hot gas decreases. Turndown ratio plays a key role in this energy transfer. Many engineers and owners have been intentionally misled regarding turndown ratio’s and this article will dispense with the misleading information and down right nonsense about turndown ratios and efficiencies!

Patterson-Kelley, one of our most trusted brands of boilers, has published a blog post on the advantages and disadvantages of high turndown. We are sharing that post below as well as their explanation of how Patterson-Kelley will introduce 10:1 turndown without sacrificing system efficiency.

Commercial Boiler Efficiency

Placing system efficiency at the forefront of commercial boiler acquisition continues to be a trend in the heating and water heating industry. Manufacturers are racing ahead to push the limits of technology by offering aggressive turndown capabilities approaching, and even exceeding 20:1, at the detriment of system efficiency.

In an age where energy conservation is important and condensing boilers are increasingly being adopted, the dewpoint plays an important role in system efficiency because it determines whether the boiler will condense or not, as well as how much condensation will occur. The dewpoint is the atmospheric condition below which water droplets condense and dew can form, releasing heat that can then be absorbed back into the system. Condensation can occur at up to 130º F depending on pressure and humidity. The returning water in the heating system is used as the cooling medium; as the temperature of the returning water drops, the amount of condensate increases.  The potential amount of condensate estimated at 100,000 BTU’s per hour is one gallon, if the boiler is operating at reduce temperatures.

Heating System Flexibility

Although heating systems are designed to meet peak loads, they spend most of their run-time hours off peak. Along with efficiency, flexibility is an important factor in boiler operation. As the building loads change, the heating system must be flexible enough to change with it. In the instance where the heating system is sized at a higher capability than is required, the flexibility of a boiler could accommodate the imbalance by turning down the input to match the load. This has become the key driving factor in the high turndown story.

Traditionally, turndown has been the limiter of efficiency. To maintain stable flames, excess air is introduced which depresses the dewpoint of natural gas. The dirty little secret associated with high turndown is that, in most cases, the boiler is no longer condensing.

Aggressive turndown capabilities usually lower the dewpoint and reduce the window of opportunity to condense due to excess air. The 970 BTU/lb. of condensate that engineers expect to get from the system, will continue to go straight up the flue.

Excess air to achieve highest possible efficiency:

  • 5 – 10% for natural gas
  • 5 – 20% for fuel oil
  • 15 – 60% for coal

A Patterson-Kelley Solution

Due to technology improvements, Patterson-Kelley will introduce 10:1 turndown capabilities for the first time during 2019. Patterson-Kelley has achieved higher turndown with a unique process that allows the gas valves to reliably turn down without adding large amounts of excess air, resulting in flexibility and efficiency. This method delivers a 10:1 turndown rate while preserving the dewpoint of a 5:1 turndown rate, which helps maintain high condensation levels. This higher turndown capability will provide designers the ability to match input to building loads without sacrificing reliability. No more nuisance flame failures that have traditionally plagued high turndown boilers.

You can see the original post here.

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