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Why Controls should drive the Ref/MEP design in Supermarkets
By Larry Herman – President Redline Control Design, LLC,
I have been designing, installing, and integrating Energy Management and Electronic Control Systems in Supermarkets for over 35 years, and I have seen several major changes during that period. Since their onset, electronic controls have always been adapted or integrated into refrigeration, mechanical and electrical design. Due to a long-overdue acceptance of the latest control objectives, that needs to change. Control systems should now take the forefront, and the other MEP systems need to be designed around those capabilities.
When they first arrived on the scene in the early 1980s, electronic controls were quickly accepted by the more progressive chains and owners. They provided a tighter range of control, some energy savings through floating suction setpoint, and certainly the quickly accepted way to achieve product loss prevention through sophisticated alarming abilities. They were typically retro-fitted, either during a new installation, remodel, or as part of a rollout program. In the ensuing years, individual “rack controllers” with better compressor control strategies lead to the refrigeration manufacturer’s factory installing them to better run racks using dissimilar horsepower compressors. At a later point, much of the old mechanical controls and clock that were retained as “backup” were eliminated due to better controls reliability, a greater prevalence of replacement parts, and a general reduction in the build cost and complexity of the racks.
This is the point in time where most new and remodeled stores received some sort of “EMS” as a general design parameter. Rack controls were typically supplied by the manufacturers, and architects designed sensor layouts and HVAC controls as part of the systems. The general build of a supermarket stayed pretty much the same. As the capabilities of the systems improved, many new control features were added, including standard and digital unloaders and VFD control of compressors and fan motors. All of these features, though, are evolutionary. The real revolution, which started many years ago in fits and spurts, is finally here, DISTRIBUTED CASE CONTROL.
Pioneered by EMC and EIL back in the late ’90s, distributed case-control has finally been improved to the point where now many companies specify that as the method they want to operate the refrigeration in their stores going forward. Danfoss, Emerson, and Micro Thermo all have sophisticated and reliable case controller systems to run electronic expansion valves and produce dramatic operational performance and cost reductions. What hasn’t changed, not quite yet, is the Ref/MEP design of the store. Many stores are still being designed the old way, with centrally located refrigeration racks and electrical distribution systems. This is what is causing so many discrepancies between the refrigeration/electrical system design and the control design.
The ability of the new EMS to have truly distributed control requires that the MEP designers understand or consult with those who know the capabilities of these systems. This is a crucial area for the “build for less” crowd to identify and embrace. Being able to put smaller refrigeration racks closer to the cases they serve can save tens of thousands in piping costs. Eliminating centrally located electric defrost panels and embracing single-point power to all cases can also save many tens of thousands of dollars in electrical build costs. All of this, though, requires that the full abilities of the selected EMS be understood and utilized. Using all of what the controls can do should drive how the mechanical and electrical systems are designed, not the other way around. This will eliminate many of the headaches and cost over-runs now encountered when the electricals are designed for a conventional store, and the refrigeration is via case-control. Going forward, this must be the norm in order to provide the lowest cost of installation as well as the lowest cost of operation. Please feel free to contact me about any design or integration assistance that you may need.
About the author – Larry Herman has spent his career in the Refrigeration and Controls industry, was at the inception of computer-based EMS in the early 1980s, and has been a Business Entrepreneur, Contractor, Operations Manager, and Consultant over the last 40 years.
I have been designing, installing, and integrating Energy Management and Electronic Control Systems in Supermarkets for over 35 years, and I have seen several major changes during that period. Since their onset, electronic controls have always been adapted or integrated into refrigeration, mechanical and electrical design. Due to a long-overdue acceptance of the latest control objectives, that needs to change. Control systems should now take the forefront, and the other MEP systems need to be designed around those capabilities.
When they first arrived on the scene in the early 1980s, electronic controls were quickly accepted by the more progressive chains and owners. They provided a tighter range of control, some energy savings through floating suction setpoint, and certainly the quickly accepted way to achieve product loss prevention through sophisticated alarming abilities. They were typically retro-fitted, either during a new installation, remodel, or as part of a rollout program. In the ensuing years, individual “rack controllers” with better compressor control strategies lead to the refrigeration manufacturer’s factory installing them to better run racks using dissimilar horsepower compressors. At a later point, much of the old mechanical controls and clock that were retained as “backup” were eliminated due to better controls reliability, a greater prevalence of replacement parts, and a general reduction in the build cost and complexity of the racks.
This is the point in time where most new and remodeled stores received some sort of “EMS” as a general design parameter. Rack controls were typically supplied by the manufacturers, and architects designed sensor layouts and HVAC controls as part of the systems. The general build of a supermarket stayed pretty much the same. As the capabilities of the systems improved, many new control features were added, including standard and digital unloaders and VFD control of compressors and fan motors. All of these features, though, are evolutionary. The real revolution, which started many years ago in fits and spurts, is finally here, DISTRIBUTED CASE CONTROL.
Pioneered by EMC and EIL back in the late ’90s, distributed case-control has finally been improved to the point where now many companies specify that as the method they want to operate the refrigeration in their stores going forward. Danfoss, Emerson, and Micro Thermo all have sophisticated and reliable case controller systems to run electronic expansion valves and produce dramatic operational performance and cost reductions. What hasn’t changed, not quite yet, is the Ref/MEP design of the store. Many stores are still being designed the old way, with centrally located refrigeration racks and electrical distribution systems. This is what is causing so many discrepancies between the refrigeration/electrical system design and the control design.
The ability of the new EMS to have truly distributed control requires that the MEP designers understand or consult with those who know the capabilities of these systems. This is a crucial area for the “build for less” crowd to identify and embrace. Being able to put smaller refrigeration racks closer to the cases they serve can save tens of thousands in piping costs. Eliminating centrally located electric defrost panels and embracing single-point power to all cases can also save many tens of thousands of dollars in electrical build costs. All of this, though, requires that the full abilities of the selected EMS be understood and utilized. Using all of what the controls can do should drive how the mechanical and electrical systems are designed, not the other way around. This will eliminate many of the headaches and cost over-runs now encountered when the electricals are designed for a conventional store, and the refrigeration is via case-control. Going forward, this must be the norm in order to provide the lowest cost of installation as well as the lowest cost of operation. Please feel free to contact me about any design or integration assistance that you may need.
About the author – Larry Herman has spent his career in the Refrigeration and Controls industry, was at the inception of computer-based EMS in the early 1980s, and has been a Business Entrepreneur, Contractor, Operations Manager, and Consultant over the last 40 years.
