Sporlan has released its next generation of CDS conversion kits solution for converting SPORT evaporator pressure regulators on refrigeration equipment into stepper motor-driven CDS valves. According to Sporlan, nearly all A8 and SPORT pressure regulators can now be converted into Sporlan stepper motor valves using only one of three kits, in a retrofit that only takes about 30 minutes.
Sporlan CDS valves are electronically operated step motor evaporator pressure regulating valves. Synchronized signals to the motor provide discrete angular movements of the rotor, which translate into precise linear positioning of the valve piston through a lead screw attached to a series of gears. Valve pistons and ports have an engineered profile, providing high resolution flow performance, and are easily interfaced with microprocessor-based controllers.
“As supermarket refrigeration equipment moves toward greater electronic control, Sporlan’s new conversion kit enables the conversion of a wider range of older mechanical valves toelectronic valve control,” said Dustin Searcy, product manager, electric valves, Sporlan Division, Parker Hannifin.
According to Sporlan, A8 and SPORT valves, over time, may fail to operate due to system contamination or develop external leaks at one of the several gaskets. Converting these valves using electronic CDS conversion kits is often preferable to rebuilding a mechanical valve. Conversion also reduces valve complexity and can usually be done in less time than it takes to rebuild a mechanical valve.
“With the short-term advantage of reduced installation labor costs coupled with the longer term benefits associated with upgrading to an electronic modulating valve, it is no surprise that these CDS conversion kits have become very popular within the supermarket refrigeration industry,” Searcy said.
Other advantages of converting, according to Sporlan, include:
• Energy savings. Laboratory testing and field trials indicate a 6 to 10 percent refrigeration system energy savings is possible after converting EPRs to electric CDS valves. The exact amount of savings is difficult to determine because so many variables are present in a real-world supermarket refrigeration system; however, Sporlan has concluded that there is a direct correlation between energy savings and deviation from set point of a mechanical valve.
• Improved control and oil management. Mechanical valves require a pressure drop through the valve to function properly and (because they are not always set correctly in the field), refrigerant and/or oil may back up into the condensing unit or evaporator. Because CDS electric valves are easy to set properly, and do not require pressure drop to operate, these backups do not occur and the refrigerant and oil is free to return to the compressors.
• Conversion allows accurate setting of the valve at any time of year. Since a direct correlation exists between the pressure and temperature of a refrigerant because of its thermodynamic properties, outdoor ambient temperatures must be considered when determining set points for mechanical head pressure control valves. It is not uncommon for a supermarket refrigeration system to need adjustments when the ambient temperature changes with the seasons in order to maintain consistent case temperatures. For mechanical valves, this requires a refrigeration technician to be on site making the required adjustments, but this is not necessary for electric valves. Since electric valves are electronicallycontrolled, their algorithms are able to adapt the valve operation to ensure case temperature is maintained throughout all seasonal changes in the ambient conditions.
• The temperature and pressure controls allow precise control of air temperature and pressure. Electronic sensors have very tight tolerances, which ensure very high accuracy in valve performance. In addition, by using an electric CDS valve in place of a mechanical pressure regulator, the refrigeration system control is able to modulate the valve position based on case temperature rather than refrigerant pressure. This offers an advantage to the temperature pull down time when a case comes out of a defrost cycle. Rather than modulating to a specific pressure set point, which is always attained before the case temperature set-point has been satisfied, the electric CDS valve remains open for case pull down. The end result is a quicker pull down, and increased product integrity. Controlling off discharge air temperature also allows the case to utilize the available pressure drop to ensure that the temperature is maintained, even if the case is not running optimally, without experiencing an energy penalty.
• Eliminating “blind” components. CDS conversion kits are compatible with standard Sporlan KelvinII Pressure and Temperature Controls and can be integrated into enterprise control systems via MODBUS and BACnet communication protocols. Temperature control is recommended for suction applications to maintain case temperature, and pressure control is recommended for high side head pressure control applications. Mechanical valves must be physically set by a technician on site, while electric valves can be set remotely and monitored in real time through an enterprise control system.
“Complex refrigeration systems can especially benefit from centralized control, saving time and money on service calls and labor costs,” Searcy said. “For example, commissioning a new supermarket refrigeration system typically takes a two or three person team one week to set all the mechanical valves. With electric CDS valves, all the settings can be uploaded to the enterprise control system in a fraction of the time.”
• No brazing required to complete the conversion.Just as in the SORIT-to-CDS conversion kit, Sporlan’s next-generation electric CDS conversion kit utilizes the existing valve body installed in the refrigeration system. This means no brazing is required to complete the conversion.
According to Sporlan, valves that qualify for conversion include Refrigerating Specialties mechanical pressure regulators such as the A8A, A81, and A82 and SPORT valves. Conversion kits can be driven directly by Sporlan’s Micro Thermo control systems or other common third-party enterprise control systems. Installation typically takes about 30 minutes.
“Once the retrofit is complete, the solution pays for itself through improvements in system performance and improved future serviceability and diagnostic capabilities,” Searcy said. “Payback is dependent upon the type of application and system-specific details, including how well the store is set up or maintained. In general, however, return on investment is typically about two years or less, followed by improved performance, continued energy savings, and reduced maintenance for years to come.”