RETROFITTING OPEN REFRIGERATION CASES

By using proper reconfiguration to retrofit open refrigeration cases with doors, you can significantly reduce your energy usage. 

According to a publication of the U.S. Department of Energy’s (DOE’s) Better Buildings Alliance, “if performed properly, retrofits of open cases with glass doors will lead to sizable reductions in infiltration loads, reducing overall case heat loads by 50-80 percent as compared to the original open case performance. Additional system improvements performed concurrently, such as upgrading fan motors, installing higher-efficiency lighting, and raising case saturated evaporator temperatures, can further reduce the heat load from the refrigerated display case.”  Trust Ruscor, Inc with the details of your grocery or retail refrigeration cases.

Below are our proper steps for reconfiguration.

Load-Profile Evaluation: 

A thorough analysis of the load profile should be completed first as part of the initial engineering assessment in the pre-planning phase of the retrofit.

Refrigerant Reclamation: 

Before beginning work on a refrigeration system, it is imperative to prevent all leaks or accidental punctures. Refrigerant should be evacuated and recycled per the appropriate guidelines. 

Compressor Rack and Control Configuration: 

Failure to properly configure the rack to best match the case load profile will result in a mismatch between the load steps of the rack and the actual loads from the cases, resulting in excessive compressor cycling.

Controls and Calibration: 

During the retrofit, it is important to ensure that existing control systems are re-calibrated to ensure proper performance. This is a good time to upgrade existing controls as needed. 

Hot Gas Defrost: 

If the rack is equipped with the capacity to accommodate hot gas defrosting of coils, the solenoid valve on the main liquid line or the discharge differential valves should be evaluated for compatibility.

Heat Reclaim:

Calculations should be performed to evaluate the new heat output of the rack when operating in conjunction with the newly retrofitted cases.

Refrigerant Piping and Expansion Valves:

The significant decrease in refrigeration load due to the addition of doors on cases has the potential to affect many components of the refrigeration system, including the refrigerant line runs and the case expansion valves.

Condensers:

In some instances, removal of excess condenser capacity may be warranted due to extreme climatic factors.

Discharge Risers:

This is the piping from the compressor rack outlet to the condenser. It should be evaluated for proper sizing.

Winter Control:

Some condensers may be equipped with a device, known as winter control, which regulates the head pressure to prevent it from falling below optimal condensing pressure during low ambient temperature conditions.

Subcooling:

Subcooler sizing should be checked in relation to the case heat load. 

Unitary Condensing Units:

In systems featuring unitary condensing units, with a single display case being served by a dedicated remote condenser, the issue of load reduction is likely to have a more pronounced impact than in multiplex rack systems. 

Electrical Units:

Case electrical consumption may be reduced due to changes in lighting and fan power. Due to the changes in energy efficiency the existing circuit breakers could be grossly over-sized. Care should be taken to evaluate the electricity supply and building codes.

System Recharging:

Prior to restarting the system, the contractor should make sure all refrigeration levels are accurate.