Canadian Pizza Magazine

News
Patent approved for defrosting technology


March 24, 2008
By Canadian Pizza

Master-Bilt, manufacturer of a full line of premier
commercial refrigeration systems for over 65 years, recently announced
patent approval for its innovative reverse cycle process. This
proprietary technology involves a reverse cycle valve added to the
condensing unit that reverses the direction of refrigerant flow during
defrosts.

Master-Bilt, manufacturer of a full line of premier commercial refrigeration systems for over 65 years, recently announced patent approval for its innovative reverse cycle process. This proprietary technology involves a reverse cycle valve added to the condensing unit that reverses the direction of refrigerant flow during defrosts. The reverse cycle is automatically activated by the master controller electronic control system, saving the user energy and money and providing added convenience.

When the master controller demand defrost feature determines a defrost is necessary, the reverse cycle valve is automatically activated and the high temperature refrigerant flow is reversed through a unique multi-step process. Once triggered, the refrigerant flows back through the evaporator coil, heating it along its entire length and completely eliminating frost buildup. In contrast, traditional electric defrost heaters only heat a certain amount of the coil, leaving ice deposits that weaken the evaporator’s performance.

“While other reverse cycle methods exist, ours is unique because it is controlled by the electric expansion valve found within the master controller system. Other systems rely on mechanical components, such as check valves and extra thermostatic expansion valves, to control the reverse cycle valve,” says Pat Melvin, engineering manager.

There are several advantages to reverse cycle technology. First, the process uses less energy than electric defrost heaters, resulting in an 80 per cent reduction in defrost energy usage. This savings, coupled with that from the demand defrost, dramatically reduces electrical bills.

Reverse cycle technology also eliminates not only the need for defrost heaters, but also head pressure control valves, check valves and thermostatic expansion valves. Removing these components reduces the cost of the evaporator itself and saves on installation and wiring.

Additionally, defrost time is dramatically lessened. The average time using defrost heaters is 20-30 minutes. However, reverse cycle performs a completely clean defrost in three to five minutes.