Implementation of Fault Detection and Diagnostic Technology - In-field Diagnostics

Fault detection and diagnostics technology has the potential to make a positive impact on the cost of operating buildings. That is, to lower utility bills, service and maintenance costs and extend equipment life.  Buildings use a significant amount of the energy used in the United States and around the world, and heating, cooling and lighting buildings consume most of the power used in buildings.  The roles fault detection and diagnostics play includes finding, analyzing, documenting, and communicating the existence of a fault, degradation or operational anomaly. 

Implementation of Fault Detection and Diagnostic Technology

In-field Diagnostics

Common initial approach

When applying diagnostic tools in the field, there are two approaches customers commonly choose in non-incentivized environments.  One is to authorize a pilot program; often five to ten locations chosen based on some criteria related to energy cost or perceived chronic reliability problems.  A second common approach is to add the diagnostic capability to a regularly scheduled visit, usually a maintenance inspection.  These attempts at implementing diagnostics have the objective of gathering data, assessing opportunities, effectively addressing issues and reporting achieved benefits. Please Press "Read More"

Another implementation approach to in-field diagnostics has been through utility energy efficiency incentive programs.  These programs have the goal of reducing energy use and peak demand by making HVAC systems perform better.  Because ratepayer or taxpayer funds are employed, as a rule utility programs cannot make use of proprietary technologies.  The unintended consequence of this policy is that patented, market-ready FDD products such as Field Diagnostics’ can go unused or unsupported by program implementers for years while less effective technologies and approaches in the public domain are supported.

Despite this barrier, the use of Field Diagnostics’ two in-field FDD platforms have been very useful in gathering data about the general condition of equipment in service and the effectiveness of various approaches to diagnostics. They have supported research into the prevalence, the magnitude and the root cause of inefficient system performance. 

Field Diagnostics has participated is many utility incentive programs over the years. While meeting the program requirements, Field Diagnostics has delivered analytics and services that exceed most program requirements.  The most notable and significant improvement over standard issue publicly-funded programs delivered by Field Diagnostics’ approach has been the documentation of both 1) proof that faults have been eliminated by the work done, and 2) the performance gains made by those improvements in terms that make sense to customers  The Field Diagnostics approach has been to analyze each refrigeration cycle and apply the services needed to achieve a “Safe and reasonable” diagnosis and at least a 90% efficiency estimate at each unit, based on the Service Assistant™/SA Mobile™ assessment.  This methodology is gaining acceptance in the incentive program world and is moving the utility incentive program industry to adopt specifications more along the lines of the Field Diagnostics approach.

Implementation challenges

HVAC provides several kinds of challenges to facility managers.  These include comfort complaints from internal and external clients, perceived and actual high service and energy costs, capitol planning and the complicated decision-making around selecting candidates for replacement, and service provider selection and management.  The metrics used to make choices and to judge success are often subjective or poorly focused because of a relative lack of dependable data. There is a need for a simplified and scalable process for interpreting the data that is available.  Those in the position to make HVAC maintenance, service and replacement decisions many times are not technical or analytical experts and usually have a different skill set than their “professional energy manager” colleagues where maintenance usually is not considered an energy management measure. 

Sometimes, effective implementation of advanced diagnostic techniques are challenged from the onset  because objectives are poorly defined, or because the approach requires service providers to behave in ways that unnecessarily increase costs or reduce the value of the outcome. 

Some common in-field diagnostic implementation strategies that lead to disappointing results include:

1.       Assuming that service providers are already skilled in the new technology and do not require more than a few hours of training.

2.       Using an incumbent service provider that is unsuited or not interested in advanced technology or change itself.

3.       Selecting a small group of sites based on some criteria other than evidence of a savings opportunity that is capture-able through maintenance. These may include selecting sites near their office or sites where the HVAC equipment is beyond reasonable repair.

4.       Setting expectations that each unit at a selected site will be working “perfectly” when the work is complete, this means expending valuable resources on units that are performing adequately, merely because they exist at the same site as poor performers and therefore are under added scrutiny during the project.

Lessons learned

HVAC equipment’s current performance, relative to design expectations is highly variable because of a range of factors.  These include the equipment’s age, how well it is maintained, how much it runs and, how well the system it is a part of was originally designed and constructed.  Some fleets of equipment are well maintained while others less so.  Experience has shown that the best maintained equipment may have as few as 10% of the fleet performing poorly.  However there are some fleets where essentially every unit has serious performance problems.  On average, in a normally maintained fleet of HVAC units, about a quarter to a third of the units will represent 80%-90% of the energy savings and bill reduction opportunity.  Finding and documenting the units that are performing poorly, prior to applying a basket of services is a good initial approach. Auditing the entire fleet and producing an accurate current inventory with enough data to detect and rank opportunities is a definite best practice.

Establishing achievable goals for the implementation and then designing an approach that takes into account the condition of the equipment, the budget available for investment in performance improvement and the capabilities of the people and systems involved in implementing the solution greatly increases the probability of success.  There are many variables that make defining a cookie-cutter solution that will work everywhere difficult. However there are some characteristics of a successful plan including:

1.       Define the group of units that are performing poorly and have the better opportunities for measurable improvement and return on investment.

2.       Target that group in a way that focuses most of the effort on the units with the performance problems.  Some examples might be a plan where only the units identified as poor performers are addressed, or a plan where the performance of all the units at a site are averaged and the sites are ranked and a common basket of services are applied to all units at the sites with the most savings opportunity.

3.       Understand that customers have budgets and package solutions that do not exceed them.  By ranking the units or sites and focusing on the larger opportunities, the budget can be managed to produce the best return with the available investment and the project can pause when the budget is exhausted.

4.       Be clear with the service provider about the goals of the program, how success is being measured and how to communicate unexpected information early in the process. Bring the service provider into the planning process and get agreement to the plan from the whole team.

5.       Be flexible when unanticipated obstacles arise.  Very often the best answer is to temporarily bypass a problematic site or unit and then re-engage it when the issue is resolved.  Some examples of this may include sites with access problems or sites or units that need repairs outside the scope of the program like compressor or fan motor replacement. 

6.       Train the people that are doing the work.  This includes training on the use of the technology, effective testing procedures and equipment performance prior to the audit and then training on effective cleaning and adjustment procedures when remediation work has commenced.  Write clear step-by-step instructions and make them available on a single laminated page for use in the field.  Do not assume that any technician, regardless of how much experience they have will know what the expectations are and what the definition of success is for a job.

7.       Have a plan for reporting results and an expectation that there will be a formal meeting where final results are delivered to the people that will make the judgments about the effectiveness of the program. Work to get explicit agreement about the resources expended and the benefits produced.

Benefits produced

There are a range of benefits that could be expected from the implementation of in-field diagnostic technology in a HVAC maintenance program.  These include:

1.       A current and accurate equipment inventory

2.       Data about the condition and performance of each unit that can be processed into effective reporting:

a.        Exception reports showing unfulfilled maintenance requirements

b.      List of units that are inoperable and what is required to return them to service

c.       Ranked list of opportunities to save energy

d.      Ranked list of opportunities to resolve problems that lead to service interruptions and premature compressor failures

e.      Ranked list of replacement candidates based of a pre-determined selection formula