Cold Connection


Energy Efficiency Projects: The Best Bang For Your Buck

Guest post written by GCCA Strategic Partner, Refrigerating Engineers & Technicians Association (RETA)

RETA’s Certified Refrigeration Energy Specialist (CRES) is gaining popularity, and the entire industry wants to join in the movement to reduce energy costs at their facility. The following guidelines help explain energy saving activities and how to work on them for CRES certification. With just a little more information, you’ll be saving energy – and money – in no time!

So what’s CRES all about and why do you need to think about energy efficiency?

CRES is gaining traction in the marketplace because it provides direct energy efficiency knowledge, opportunity to achieve energy cost-savings, and is an excellent review of industrial refrigeration operations and safety topics. CRES-credentialed professionals can reduce energy use and costs while maintaining production, safety and reliability.

Are energy efficiency projects expensive?

No – CRES focuses on low- and no-cost activities to manage energy in your facility. RETA uses the word activities instead of projects on purpose – there should be no need to secure capital funding to improve efficiency. Though a capital project would certainly qualify for CRES, the best return on investment often occurs when the activity involves operations and maintenance items.

Example low- and no-cost activities

A few low- or no-cost CRES activities include:

  • Defrost Optimization: Common steps to defrosting evaporators include a pump out, soft gas, hot gas, equalize and cool down periods. Some sequencing durations may seem arbitrary at the controller, but it is important to understand each setting. For example, consider the pump out sequence. To ensure an adequate defrost is performed on a given coil it is important to rid the coil of liquid refrigerant to maximize the work accomplished during hot gas. A good indicator of a proper pump out period is equalized temperatures across an evaporator. A sufficient pump out period allows the system to perform a hot gas defrost more efficiently and potentially allows for reduced hot gas duration, reducing the amount of heat added to the cold environment. Simply put: for every two minutes of hot gas the compressors must operate approximately three minutes to remove the heat that is dissipated from the hot metal coils into the cold environment.
  • Lift Reduction: One of the easiest activities to accomplish is simple setpoint changes at the microprocessor panel or control system. Reducing the lift across a compressor results in greater operating efficiency. For example, reducing the minimum head pressure setpoint (e.g. from 120# to 100#) will save energy when ambient conditions and refrigeration load allows. However, mind the system design: if applicable, are DX coils going to receive adequate differential pressure across thermostatic expansion valves to properly meter liquid? Will liquid injection screws receive enough refrigerant for adequate oil cooling? Replacing mechanical expansions devices with electronic counterparts may help alleviate some of these concerns.
  • Sensor Calibration: Calibrating items such as temperature sensors, pressure transducers and slide valve and volumetric index position indicators can positively impact the operation and performance of a refrigeration system. For example, a slide valve that does not modulate to a fully loaded position can handicap the operating efficiency of a screw compressor. Optimally, a fixed speed screw should be used as the base load machine in the presence of a variable speed unit on the same suction group. If that base load (or variable speed) machine is not performing at 100% slide valve position whenever possible, the user is wasting energy.

Sounds great, but why now?

Start your energy efficiency activities now: not only are they a required step in becoming CRES certified, but they help manage energy use and improve the bottom line right away. Top companies are focusing more and more on energy efficiency and sustainability practices – to manage costs, stand out in the market, and respond to their customers’ requests for documented sustainability.

For more information on CRES activities, along with other RETA certifications, visit the website of Refrigerating Engineers & Technicians Association:

About GCCA Strategic Partners

Global Cold Chain Alliance Strategic Partners are global food industry associations, government bodies, and trade press formally aligned with GCCA, who participate in information exchange, programs, or projects, and share common cold chain interests and objectives. Learn More.

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