Refrigerated merchandiser with modular evaporator coils and EEPR control

An air cooling system in a commercial refrigerated merchandiser having an insulated cabinet with a product area having horizontally adjacent product zones for the display and marketing of food products, said system comprising:

• modular evaporator means having a plurality of separate coil sections of substantially equal size and heat exchange capability, said plural coil sections having a preselected length and being horizontally disposed in spaced apart, end-to-end orientation relative to each other in said cabinet;
• liquid refrigerant metering means for controlling the inlet flow of liquid refrigerant on the high side of said modular evaporator means;
• said plural coil sections of said modular evaporator means being constructed and arranged in parallel refrigerant flow relationship with each other and in series flow relationship with said liquid refrigerant metering means, and all of said coil sections having an operative cooling mode at the same time and an inoperative defrost mode at the same time;
• and
• separate air moving means associated with the respective coil sections for circulating separate air flows through said coil sections and discharging the air flows to the adjacent product zones for cooling.

The method of controlling the exit air temperature from the evaporator coil in a commercial refrigerated merchandiser for food products, in which the evaporator coil has a refrigeration mode and a defrost mode and the suction side of the evaporator coil has an electronic evaporator pressure regulator (EEPR) valve operated by a valve controller circuit, said control method comprising the steps of:

• (a) sensing the exit air temperature from the evaporator coil and generating a signal corresponding thereto;
• (b) operating the EEPR valve in the refrigeration mode of the evaporator coil by modulating refrigerant vapor flow therethrough to maintain a preselected exit air temperature;
• (c) operating the EEPR valve in the defrost mode of the evaporator coil,
• (1) by first closing the EEPR valve during a preselected de-icing period of said evaporator coil until reaching a predetermined drip temperature, and
• (2) then activating the valve controller circuit in response to detection of exit air temperatures exceeding a preselected value during a final drip period to provide limited refrigeration to maintain the preselected temperature during the remainder of the defrost mode.

An air cooling system for a commercial refrigerated merchandiser having an insulated cabinet with a product area having at least two horizontally adjacent product zones for the display and marketing of food products, said system comprising:

• modular evaporator means having at least two separate coil sections of predetermined size and heat exchange capability, said coil sections being horizontally disposed with their adjacent ends in spaced apart orientation with each other and each coil section being operatively associated with one of the product zones for the refrigeration thereof;
• first refrigerant metering means for controlling the inlet flow of liquid refrigerant to the high side of said modular evaporator means;
• said plural coil sections of said modular evaporator means being constructed and arranged in parallel refrigerant flow relationship with each other to receive liquid refrigerant from said liquid refrigerant metering means, and all of said coil sections having an operative cooling mode at the same time and an inoperative defrost mode at the same time;
• and
• separate air moving means associated with the respective coil sections for circulating separate air flows through said coil sections and being constructed and arranged with separate air flow passageways in said cabinet for discharging the air flows to the horizontally adjacent product zones for cooling.

In combination with a commercial refrigerated merchandiser having an insulated cabinet with a product area having at least two horizontally adjacent product zones of predetermined length for the display and marketing of food products, a refrigeration system comprising:

• modular air cooling and circulating means having at least two separate evaporator coil sections of predetermined heat exchange capability, each coil section having elongated coil tubing of preselected length corresponding substantially to the length of an associated one of said product zones, and further having separate air moving means for the circulation of refrigerating air flow across each of the respective coil sections;
• liquid refrigerant metering means for controlling the inlet flow of liquid refrigerant to the high side of said coil sections;
• said coil sections of said modular air cooling means being constructed and arranged in parallel refrigerant flow relationship with each other to receive liquid refrigerant from said liquid refrigerant metering means, and all of said coil sections having an operative cooling mode at the same time and an inoperative defrost mode at the same time;
• and
• said modular air cooling and circulating means being constructed and arranged in said insulated cabinet with each coil section and its air moving means being in operative relationship with its associated product zone for the circulation of separate air flows through the coil sections and the discharge of such air flows separately to the adjacent product zones for cooling.