Five years ago, a fellow named Bob Baker challenged NCI Leadership to give away its most carefully guarded test method. He said, ‘Offer to write an ASHRAE standard showing how to score an installed HVAC system, then gift it to the world.’ Bob coached us through the application process, then quietly passed away.
Let’s take a look at how this challenge resulted in a new industry standard. This article will also focus on how it may be used by HVAC professionals to create, build, and field verify one of the highest efficiency products that can be delivered today.
With these goals in mind, an engaged and distinguished American Society of Heating, Air conditioning, Refrigeration Engineers (ASHRAE), committee was formed. Initially, half the committee supported the test method, while the other half either opposed or questioned the concept of scoring an installed system.
The committee consisted of HVAC and mechanical contractors, engineers, PhDs, manufacturers, utilities, energy consultants, compliance personnel, and representatives from a national energy laboratory and NASA.
While maintaining mandatory ASHRAE language, the committee was instructed to write the test method ‘In the language of the common field technicians.’ These instructions led to the creation of a new breed of standard that can be used directly by field personnel.
For more than four years the committee worked vigorously to both expand and then simplify three field test methods. It received and responded to every one of nearly 300 comments during three full public reviews. This feedback greatly improved the standard’s accuracy and effectiveness.
ANSI/ASHRAE Standard 221- 2020
This standard legitimizes and details test methods enabling field technicians to publish a score that documents how well a field-installed HVAC system performs. It also reveals previously undetected system interactions and inefficiencies during live operating conditions. The same test may be applied to the system before or after repairs to quantify the impact of improvements made.
Equipment and an installed system are two separate products and should be rated or scored separately
You can find the full standard publication at the ASHRAE Bookstore: ncilink.com/ASHRAE221.
Keep in mind that 221 is not an installation standard. It is, however, an installed system test method standard that identifies losses and defects in previously built systems. When a system earns a low score, it becomes a call to action often resulting in the decision to make repairs to increase the system’s performance and score.
The standard may be used as a bolt-on to an existing installation or maintenance standard. It is employed when the technician finds it necessary to make further improvements to increase comfort and efficiency.
System or Equipment Efficiency?
For many decades, the published equipment efficiency rating number has been mistakenly interpreted to represent the installed system efficiency rating. Equipment and an installed system are two separate products and should be rated or scored separately.
Equipment is built and rated by the OEM (Original Equipment Manufacturer). It is normally packaged for sale and ultimately delivered to an installing contractor. Remember, each piece of equipment is a stand-alone product.
The installing contractor selects and fabricates many parts and pieces to assemble the selected components and build a new and different product, an HVAC system.
New ASHRAE definitions included in Standard 221 clearly separate these two different products. It does this by enabling a new field-measured and documented efficiency score for the installed system. This method honors the standards supporting stand-alone equipment capacity and efficiency ratings. Installed system scoring provides an easily understood test and documentation method that helps consumers compare their installed system to published equipment efficiency ratings.
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I applaud the use of actual measurements: this has been missing from our valuable industry for decades. However, why aren’t we making the small additional step of matching the equipment size to the actual load presented by the building? Getting the size right requires minimal additional measurement and would solve many of the customers problems with no additional repairs required. The technician would look like a genius and would get a ton of “Word of mouth advertising”.
There are many additional services that can and should be offered to a customer seeking to improve the performance of their building. Dozens of ASHRAE standards are published aimed at how to identify needed improvements.
When a system receives a low score using the ASHRAE 221 standard, it triggers the need for variety of system improvements including duct system upgrades, combustion adjustments and correcting refrigerant change,, balancing, additional duct insulation and reduced equipment capacity. A load calc should be used to properly size replacement equipment.
You are so right. Commissioning a system that is too big just leaves you with an oversized system that works like it’s supposed to. Downsizing with load calculations is far more beneficial, in my opinion.