Grid interactive micro-distributed refrigerated display case
The present disclosure relates to an improved open vertical display case (OVDC) which utilizes radiant cooling to cool and/or maintain food products at a target temperature. The radiant cooling is performed using a plurality of piping routed through the walls and containing a first refrigerant stream. The plurality of piping may be cooled using a refrigeration circuit. In some embodiments, a phase change material may be used for thermal energy storage and positioned between the plurality of piping and the refrigeration circuit. In some embodiments, the refrigeration circuit may be connected to heating ventilation and air conditioning (HVAC) systems and water heating systems within the building.
1. An open vertical display case (OVDC) comprising:
a backwall comprising perforations passing through the backwall;
a first side wall disposed adjacent to a first side of the backwall;
a second side wall disposed adjacent to a second side of the backwall;
a canopy disposed adjacent to a top of the backwall;
a base disposed adjacent to a bottom of the backwall;
a shelf disposed between and parallel to the canopy and the base, wherein the shelf is constructed of a perforated/porous material;
a fan disposed on the backwall to direct an air flow to a heat exchanger;
a phase change material (PCM) characterized by a high thermal conductivity and a high thermal energy storage;
a first refrigeration circuit comprising:
a first refrigerant;
first plurality of piping positioned within at least one the first side wall, the second side wall, the canopy, the base, or a combination thereof;
the first refrigerant is disposed in the first plurality of piping to cool food products on the shelf by radiant heat transfer; and
the plurality of piping is configured to thermally contact the first refrigerant with the PCM; and
a second refrigeration circuit comprising:
a second refrigerant; and
a second plurality of piping configured to thermally contact the second refrigerant with the PCM, wherein:
the heat exchanger is disposed to cool the air flow by transferring heat from the air flow to the first refrigerant, forming a cooled air flow;
the fan and the backwall comprising perforations direct the cooled air flow through the perforations into the OVDC, and
the backwall and the shelf direct the cooled air flow through the perforated/porous material of the shelf, such that the cooled air flow cools food products on the shelf by convective heat transfer.
2. The OVDC of claim 1 , wherein the PCM comprises a transition temperature below 0° C.
3. The OVDC of claim 1 , wherein the PCM comprises at least one of ammonium chloride (NH 4 Cl) or potassium chloride (KCl).
4. The OVDC of claim 1 , wherein the PCM comprises at least one of potassium fluoride tetrahydrate (KF·4H 2 O), manganese nitrate hexahydrate (Mn(NO 3 ) 2 ·6H 2 O), calcium chloride hexahydrate (CaCl 2 ·6H 2 O), calcium bromide hexahydrate (CaBr 2 ·6H 2 O), lithium nitrate hexahydrate (LiNO 3 ·6H 2 O), sodium sulfate decahydrate (Na 2 SO 4 ·10H 2 O), sodium carbonate decahydrate (NaCo 3 ·10H 2 O), sodium orthophosphate dodecahydrate (Na 2 HPO 4 ·12H 2 O), or zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O).
5. The OVDC of claim 1 , wherein food products on the shelf are cooled without an air curtain.
6. The OVDC of claim 1 , comprising a temperature differential (ΔT) of 3° C. or less between a temperature of a coolest food product on the shelf and a temperature of a warmest food product on the shelf.
7. The OVDC of claim 1 , wherein the first refrigeration system lacks an evaporator.
8. The OVDC of claim 1 , wherein the perforated/porous material comprises at least one of a mesh material, a wire material, a chain-link material, or a combination thereof.
9. The OVDC of claim 1 , wherein at least one of the first side wall, the second side wall, the canopy, the base, or a combination thereof comprises an interior side constructed of a conductive material.
10. The OVDC of claim 9 , wherein the conductive material comprises at least one of aluminum, copper, a steel, a plastic, or a combination thereof.
11. The OVDC of claim 9 , wherein at least one of the first side wall, the second side wall, the canopy, the base, or a combination thereof further comprises an exterior side constructed of an insulative material.
12. The OVDC of claim 11 , wherein the insulative material comprises ate least one of a plastic, a fiberglass, mineral wool, a polyurethane foam, concrete, or a combination thereof.
13. The OVDC of claim 1 , wherein the plurality of piping of the first refrigeration circuit is positioned to curve back and forth within the at least one of the first side wall, the second side wall, the canopy, the base, or a combination thereof.
14. The OVDC of claim 1 , wherein the cooled air flow is between greater than zero cubic feet per minute (CFM) and 664 CFM.