FOOD COOLING METHOD

Abstract

A food cooling method includes: a dehumidifying step of performing mainly a dehumidifying process on food by cooling the food with cool air of a first blow-out temperature at which no frost is generated on fins of the heat exchanger; and a cooling step of performing mainly a cooling process on the food by cooling the food having undergone the dehumidifying step with cool air of a second blow-out temperature which is lower than the first blow-out temperature and at which frost may be generated on the fins.

Claims

1. A food cooling method comprising: a dehumidifying step of performing mainly a dehumidifying process on food by cooling the food with cool air of a first blow-out temperature at which no frost is generated on first fins of a first heat exchanger; and a cooling step of performing mainly a cooling process on the food by cooling the food having undergone the dehumidifying step with cool air of a second blow-out temperature which is lower than the first blow-out temperature and at which frost may be generated on second fins of a second heat exchanger.

2. The food cooling method according to claim 1, wherein the first temperature falls within a range of 10 C. to 20 C., and the second temperature falls within a range of 5 C. to 0 C.

3. The food cooling method according to claim 1, wherein a pitch of the second fins falls within a range of 2 mm to 5 mm.

4. The food cooling method according to claim 2, wherein a pitch of the second fins falls within a range of 2 mm to 5 mm.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is an explanatory illustration of processes according to one embodiment of a food cooling method of the present invention.

[0015] FIG. 2 is a psychrometric chart showing the state of cool air in the food cooling method of the present invention.

[0016] FIG. 3 is an explanatory illustration of processes of one example of a conventional food cooling method.

DESCRIPTION OF EMBODIMENT

[0017] In the following, with reference to the drawings, a detailed description will be given of the food cooling method of the present invention. Note that, the present invention is not specified to the examples, and instead is shown by the scope of claims and includes all changes which are equivalent to the claims in the meaning and within the scope of the claims.

[0018] FIG. 1 is an explanatory illustration of processes of a food cooling method according to one embodiment of the present invention. In the present embodiment, hog carcasses which are food are cooled. Hogs undergo a slaughter process and a skin process before splitting through which each of the hogs is disassembled to be carcasses. The carcasses obtained by the disassembling undergo a dehumidifying process for about 24 hours in a carcass hanging room 1, so that the moisture contained in the carcasses is removed.

[0019] The carcasses dehumidified in the carcass hanging room 1 is cooled in a carcass refrigerator 2 for 48 hours to 72 hours, for example, until the core temperature of the carcasses reaches about 4 C. Each of the cut meat are processed to be cut meat in a process room 3 downstream to the carcass refrigerating room 2.

[0020] The carcass refrigerator 2 according to the present embodiment is divided into three zones, namely, a zone A, a zone B, and a zone C in sequence from the entrance side of the carcass refrigerator 2. The zone A and the zone B, and the zone B and the zone C are respectively partitioned by partitions 4a, 4b. The carcasses are each hung on a hook (not shown) travelably set in a rail 5 installed in the zones. The carcasses carried in from an entrance 6 of the zone A undergo a dehumidifying and cooling process in the carcass refrigerator 2, and carried out from an exit 7 of the zone C. The partitions 4a, 4b are each provided with a door 9 which is openable for allowing the carcasses to pass through.

[0021] A plurality of indoor units 8 are installed along the wall of the zones. In the present embodiment, three pairs having the carcasses interposed, that is, six indoor units 8 in total are installed in each zone. The indoor units 8 blow out cool air into the space of the zones, which cool air carries out the latent heat process and the sensible heat process on the carcasses.

[0022] In the present embodiment, mainly the dehumidifying process is performed (a dehumidifying step) in the zone A. In the dehumidifying step, as a process preceding the cooling of the carcasses, mainly the dehumidifying process is performed on the carcasses in which the carcasses are cooled with cool air of a first blow-out temperature, which is for example about 10 C., at which no tiny ice crystals or frost occur on the fins of the heat exchanger in each of the indoor units 8. Accordingly, the indoor units 8 installed in the zone A are each a reheat dehumidifier which is capable of reheating. In the zone A, as shown in the following Table 1, control is exerted so that, for example, the intake temperature becomes 15 C. and the blow-out temperature becomes 10.3 C. In FIG. 2, a1 indicates the intake air in the zone A and a2 indicates the blow-out air.

[0023] Here, assuming that the evaporation temperature of the refrigerant in the heat exchanger is about 5 C., the airflow volume is 256 m.sup.3/min, and the specific volume is 0.827 m.sup.3/kg, the dehumidification volume is (25660)/0.827(0.00850.0070)27.9 kg/h.

TABLE-US-00001 TABLE 1 Zone A Zones B, C Capacity [kW] 43.1 31.5 Airflow volume [m.sup.3/min] 256 256 Intake Temperature, humidity 15 C., 0 C., RH80% RH80% Specific volume [m.sup.3/kg] 0.827 0.777 Specific enthalpy [KJ/kg] 36.53 7.56 Absolute humidity [kg/kg] 0.0085 0.0030 Blow-out Temperature, humidity 10.3 C., 4.1 C., RH88% RH85% Specific enthalpy [KJ/kg] 28.2 1.82 Absolute humidity [kg/kg] 0.0070 0.0024 Dehumidification volume [kg/h] 27.9 11.9

[0024] In the zone B and the zone C, mainly the cooling process (a cooling step) is performed. In this cooling step, as a process subsequent to the dehumidifying step, mainly the cooling process is performed on the carcasses in which the carcasses are cooled with cool air of a second blow-out temperature, which is for example about 4 C., which is lower than the first blow-out temperature in the dehumidifying step and at which frost may occur on the fins of the heat exchanger installed in each of the indoor units 8. In the zone B and the zone C, as shown Table 1, control is exerted so that, for example, the intake temperature becomes 0 C. and the blow-out temperature becomes 4.1 C. In FIG. 2, b1 indicates the intake temperature in the zone B and the zone C, and b2 indicates the blow-out temperature.

[0025] Here, assuming that the evaporation temperature of the refrigerant in the heat exchanger is about 10 C., the airflow volume is 256 m.sup.3/min, and the specific volume is 0.777 m.sup.3/kg, the dehumidification volume is (25660)/0.777(0.00300.0024)11.9 kg/h.

[0026] In the zone A, the set temperature is raised to be higher than that in the conventional cooling method so that the dehumidifying process is performed with the air of higher absolute humidity. Therefore, the present embodiment improves the dehumidifying capacity per unit time as compared to the conventional cooling method. The present embodiment improves the dehumidification volume per unit time as 27.9/11.92.3 times as great as that in the zone B or the zone C (the conventional cooling method).

[0027] Furthermore, in the present embodiment, mainly the latent heat process is performed at the temperature at which no frost is generated, and thereafter the sensible heat process is performed at the temperature at which frost may be generated. This reduces the amount of frost attached to the fins of the heat exchanger of each of the indoor units 8 in the zone B and the zone C. As a result, this improves the efficiency of the heat exchangers of the zone B and the zone C, and reduces the frequency of the defrosting operations. Consequently, the cooling efficiency improves. This saves energy and reduces the running costs.

[0028] By virtue of the reduction in the amount of frost to be attached, the fin pitch of each heat exchanger can be smaller than that in the conventional heat exchanger. For example, the conventional pitch of about 6 mm to 10 mm can be reduced to about 2 mm to 5 mm. This downsizes the heat exchanger, and consequently each indoor unit. The downsizing reduces the costs of the indoor units. In the present embodiment, the fin pitch of each heat exchanger in the zone A is 4 mm, and the fin pitch of each heat exchanger in the zone B and the zone C is 4 mm.

[0029] Other Variations

[0030] The present invention is not specified to the embodiment described above, and various modifications can be made within the scope of claims.

[0031] For example, in the embodiment, while the carcass refrigerator is divided into three zones, the number of division may be two or four or more, so long as there are a zone in which mainly the dehumidifying process is performed and a zone in which mainly the cooling process is performed.

[0032] Furthermore, in the embodiment, while the first blow-out temperature at which no frost is generated is 10.3 C., this temperature may be changed as appropriate according to the content and amount of the food to be cooled. For example, it may be 10 C. to 20 C. Similarly, while the second blow-out temperature at which frost may be generated is 4.1 C., this may also be changed as appropriate according to the content and amount of the food to be cooled, and the set cooling temperature of the food. For example, it may be 5 C. to 0 C.

[0033] Furthermore, in the embodiment, while the food to be cooled is exemplarily hog carcasses, the present invention is not limited thereto. For example, the food cooling method of the present invention is also applicable to other food such as cattle carcasses.

REFERENCE SIGNS LIST

[0034] 1: CARCASS HANGING ROOM

[0035] 2: CARCASS REFRIGERATOR

[0036] 3: PROCESS ROOM

[0037] 4a: PARTITION

[0038] 4b: PARTITION

[0039] 5: RAIL

[0040] 6: ENTRANCE

[0041] 7: EXIT

[0042] 8: INDOOR UNIT

[0043] 9: DOOR

[0044] 51: CARCASS HANGING ROOM

[0045] 52: CARCASS REFRIGERATOR

[0046] 53: PROCESS ROOM

[0047] 54: RAIL

[0048] 55: ENTRANCE

[0049] 56: INDOOR UNIT

[0050] 57: EXIT