Voltage unbalances exceeding more than 2 percent in three-phase systems can cause current unbalance among the windings. These voltage and current unbalances can cause an increase in winding temperature and an overheating problem that can be detrimental to the motor.
Measuring the evaporator’s superheat value is an important part of analyzing a system’s performance. If a lower-than-normal value is measured, too much refrigerant is entering the evaporator for the heat load. If a higher-than-normal value is measured, too little refrigerant is entering the evaporator for the heat load.
The aggressive environmental and regulatory positions in Sacramento have caused the rest of the U.S. to monitor policymaking and enforcement out West. And, more often than not, those policies have ended up as the blueprint for federal regulations.
CO2 is primarily used in cascade systems that include ammonia, in booster systems in supermarkets, and as a stand-alone refrigerant for transcritical-configured systems.
Everyone talks about what it initially costs a supermarket to switch to a 100 percent CO2 commercial refrigeration system. But start thinking about the costs that come next — on everything from electricity to regulatory compliance — and the return on investment on CO2 begins to make a great deal of sense.
Danfoss’ 22nd EnVisioneering Symposium was titled “Refrigerants2Sustainability,” and focused on the challenges reshaping the refrigeration landscape. These include climate change, increased regulatory pressure, ever-increasing energy costs, contractor training on new low-GWP systems, and more.
So, supermarket owners want refrigeration systems that are energy efficient to hold down costs and pro-environmental for political correctness. But for engineers, contractors, and technicians that approach may not be all that easy, whether bringing a new store online or retrofitting an existing one.
A demonstration of complex — but ultimately valuable — developments when it comes to supermarket refrigeration is a project conducted by the Oak Ridge National Laboratory (ORNL) and the U.S. Department of Energy (DOE).
This is my last Point of View commentary for The NEWS’ FROSTlines eNewsletter. By the time you read this, I will have been retired for several weeks. FROSTlines was a new venture for The NEWS when it began a few years ago. It was set to focus totally on refrigeration and it would be online only.