How to calculate the cooling capacity if you know the area and design temperature of the cold storage
The fresh-keeping warehouse is generally above the freezing point of the goods. When calculating, first calculate the weight according to the area height, and the weight * specific heat * temperature difference /24H/ purchase quantity is the required cooling capacity for one hour.
For a freezer, it's similar to this one, just above freezing point and below freezing point. The specific heat of freezing point is found from the look-up table, and the specific heat of the east and the west is also different. Generally, the specific heat at freezing point is a little more than twice that at freezing point!
Zhengzhou Yuantian Refrigeration Technology Co., Ltd. is a professional refrigeration enterprise engaged in the installation and design of refrigeration devices such as cold storage, cold storage, quick-freezing storage, low-temperature box of quick-freezing machine, medicine cold storage, experimental constant-temperature room, ultra-low-temperature experimental cold storage, ice-making project, salt pond, seafood machine and the development and research of related refrigeration products.
at the time of its establishment, the company decided to put people first and provide customers with excellent products and high-quality services. While constantly absorbing advanced management experience and scientific research achievements of domestic and foreign enterprises, it also strengthened joint cooperation with universities and scientific research units. Committed to the development of new products and the gradual improvement of enterprise management, but also trained a construction and management team with rich practical experience and perfect service system. After years of unremitting efforts, Zhengzhou Yuantian Refrigeration Equipment Co., Ltd. has produced cold storage, cold storage, frozen and quick-frozen cold storage and other devices that have been affirmed and praised by customers and won a good reputation in the industry!
The main products are cold storage, cold storage, fresh-keeping storage, fruit cold storage, medicine cold storage, seed cold storage, royal jelly cold storage, edible fungus cold storage, artificial environment room, freezing and quick freezing, low-temperature box, constant temperature experiment room, ultra-low temperature cold storage, laboratory cold storage, vaccine special cold storage, and other refrigeration equipment projects, and the agent distributes domestic and foreign famous brand refrigeration compressors and refrigeration accessories; Main business: cold storage engineering design and installation, cold storage and refrigeration equipment supporting sales. Professional design and installation: fresh-keeping warehouse, cold storage, drug cold storage, seed cold storage, fruit cold storage, medical cold storage, quick-freezing warehouse, quick-freezing tunnel, supermarket cold storage project, and undertake the maintenance and transformation of large, medium and small cold storage and refrigeration devices.
over the years, we have established good cooperative relations for frozen food enterprises, pharmaceutical enterprises, meat processing enterprises, large-scale catering enterprises, large-scale entertainment places, fruit production enterprises and distribution units, agricultural and sideline products production and distribution units, agricultural and sideline products research units, tea production and storage units and many other units, and provided high-quality products and excellent services, which have been unanimously recognized and trusted by customers. Knowing how to calculate the refrigerating capacity based on the area and design temperature of the cold storage is best accompanied by
Calculation of refrigerating capacity of the cold storage
This medium-sized cold storage is located in Guangzhou, which consists of a cold storage room and a cold storage room, with a refrigerating tonnage of 1.51 tons, and the frozen foods are pork, fish and chicken. The design temperature in the cold storage room is 118 ~ (2, phase ...
This medium-sized cold storage is located in Guangzhou, which consists of a cold storage room and a cold storage room, with a cold storage tonnage of 1.51 tons, and the frozen foods are pork, fish and chicken. The designed temperature in the cold storage room is-18~(2) and the relative humidity is 85%. Second, the calculation of the volume of medium-sized cold storage
The calculation formula of the storage tonnage of medium-sized cold storage is as follows: g: —— LQV ——. Y, where G —— storage tonnage of cold storage (tons); Yes, g: 151 tons. For meat, the average bulk density is 451 kg/m, and for this tonnage of cold storage, it is 1.5. Substituting the above data into the calculation shows that V=666m3. If the clear height of the room is 3m, the net area is f = v/h F=V／h=222m3. The total area of medium-sized cold storage is 251m3.
iii. load calculation of cooling device in medium-sized cold storage
the load of cooling device in cold room should be calculated according to the following formula:
q: QL+pq2+Q3+Q4+q5
the load coefficient p of cooling room and freezing room should be 1.3, and that of other cold rooms should be 1. Take p=1 for the cold storage room.
(1) The heat transfer of the envelope should be calculated according to the following formula:
QL = k.f.a (—ti)
where the heat transfer coefficient of k-envelope (w, m2℃);
F-heat transfer area of enclosure structure (m2);
a the temperature difference correction coefficient on both sides of the enclosure structure can be used according to the look-up table in Code for Design of Cold Storage
. A calculated temperature of the outer side of the retaining structure (℃);
tf- the calculated temperature (℃) of the inside of the envelope.
where = 31.1℃, tf-= 1 18~(2. The heat transfer area is the sum of the surrounding wall area, the roof area and the floor area. F=711m 。 Concrete pouring wall
k = 1.4w, m℃. a-1．15。
substitute and calculate QL: 15719.5w = 15.7kw
(2) The heat of goods should be calculated according to the following formula
Q2=Q2l+Q +Q +Q
where Q-food heat;
Q-heat of packaging materials and vehicles;
Q-Breathing heat when the goods are cooled;
Q-Breathing heat of goods in cold storage.
For the above formula, only fresh fruits and vegetables need to be stored in cold storage rooms, and this
cold storage room only needs to calculate the heat of food and the heat of packaging materials and vehicles
.
Q2 = Q2+Q = G (HL-H2) (TL-T2)
-+GB-
F F
G Daily purchase quantity of a cold room;
H。 The heat content of the goods when they enter the initial temperature of the cold room;
H-the heat content of the goods when they stop cooling in the cold room;
f-cooling time of goods (hours);
B-the weight coefficient of goods packaging materials or vehicles, which is 1.3 for shelving:
TL-the temperature of packaging materials or vehicles when they enter the cold room-8℃; C2-The temperature at which the packaging material or vehicle stops cooling in the cold room, which is generally the design temperature of the cold room (℃); This design is a 18~(2. For the cold storage with goods transferred from the external warehouse, the daily purchase quantity of each room in the frozen material cold storage room should be calculated as 5% of the cold storage tonnage, that is, g = 1.51 tons x 5%: 7,511 kg; When the meat is transported from the freezing room, the temperature of-8℃ is the initial temperature when the goods enter the cold room. Look up the psychrometric chart H. =76．3kJ／kg； The temperature of the cold storage room-18~(2) is the temperature when the goods stop cooling in the cold storage room, and the psychrometric chart H = 43.6 kJ/kg; The cooling time of goods is 24 hours for cold storage, and the design cold working time for cooling room and freezing room is 24 hours for this design.
q = 11156kj/h = 3.11kw
(3) The ventilation heat should be calculated according to the following formula:
Q3 = q+q3b
QVentilation heat in a cold room;
Q-fresh air heat required by the operator;
for q, only the cold rooms where the operators stay for a long time, such as processing rooms and packaging rooms, should be calculated, and the rest cold rooms can be ignored, so this design is ignored. Q after simplification is the following formula.
Q3= the heat content of outdoor air in the formula H ~, and the psychrometric chart H =88．5 kJ, kg; H-the heat content of indoor air, check the psychrometric chart H = 35 kJ/kg; N-The number of air changes per day can generally be 2-3 times, and this design takes 2 times; V-Net volume in cold storage room, 666m3；; The air in a cold storage room is heavy, 1.2 kg/m'; 24 hours a day. Q3 = 8529.8kJ/h = 2.4kW < P > calculated on behalf of the above data. (4) The execution heat of the motor should be calculated according to the following formula: < P > Q4 = n. P
where the rated power (kW) of n-motor is designed as a small-scale cold storage, and the thermal conversion coefficient is 1.2kW: ∈-and the motor is outside the cold room, and it is 1.75; P-the running time coefficient of the motor, which is taken as 1 when it is running continuously.
Q4=gkw is calculated from generational data.
(5) The operating heat should be calculated according to the following formula:
Q5=Q +Q +Q5r, where Q-lighting heat;
Q heat when the door is opened;
Q-operator's heat;
for this design, there are few operations, mainly the lighting heat
QS = QA. f
qd-the lighting heat per square meter of floor area, and it is 1.8kcal/
square meter hour in cold storage;
the floor area of f-cold room is ***251 square meters;
Q =451 451kcal//b = 1.5kw
, so the load of cooling device =Q-1 +tOz+Q,+Q4+q5 = 31.7kw
IV. Calculation of mechanical load in cold room
titq． of household appliances. Technology-1 TL; -j:, o "Kiln-one-basket repair 2O ~. O9
Qj = (NTQ,+N2Q2+N3Q3+N, Q4+NSQS) r
where QJ-mechanical load KW;
the seasonal correction coefficient of heat transfer of nt-enclosure structure has no obvious difference between light and peak seasons
, and it is 1;
n z-mechanical load reduction factor of cargo heat, and the refrigerated capacity
product of frozen matter is not too large, so take 1.6:
n3-ventilation coefficient at the same time, and take 1.8;
The synchronous operation coefficient of motor for n4-1 cold storage room is divided into 5 rooms.
According to the Code for Design of Cold Storage, N4 is 1.4;
the simultaneous operation coefficient of ns-cold room is divided into 5 parts. According to the Code for Design of Cold Storage
, n5 is 1.4;
R-equal cooling loss compensation coefficient of refrigeration device and pipeline, which is 1.12 for indirect cooling system in this design.
generation calculation
QJ = 15.7xl+1.6x3.1+1.8X2.4+1.4x.9+1.4xo.5
= 23.3kw
V. Selection calculation of refrigeration device
According to the refrigeration capacity of 23.3kw, Biesel condensing unit is selected, and its efficiency parameters are shown in the table below. The formula worked out in this way is accurate. Knowing the volume and cooling temperature of a cold storage, how to determine the cooling capacity and cooling power?
the cooling power per cubic meter is 81 watts. Newcomers ask how to calculate the refrigeration capacity of cold storage
1 = 735 W (power), 2311W (refrigeration capacity), Cold storage is 61w/71w/81w/91w/111w/111w/121w/151w/ 211w to calculate the refrigeration capacity of cold storage
how to calculate the refrigeration capacity of cold storage condenser
volume (liter) × heating degree ÷ heating time (minute )× 61 ÷1.86 (coefficient) =(W)
volume (ton or cubic meter )× heating degree ÷ heating time (hour) \
2. calculation of heat exchange area of air-cooled condenser: refrigerating capacity+compressor motor power ÷(211~251)㎡
3. The ratio of water-cooled condenser to air-cooled condenser is generally 1:15, such as 311㎡ for air-cooled condenser and 311÷15=21㎡ for water-cooled condenser. The cooling water quality difference can be appropriately reduced to about 1:11.
4. For a 61 cubic meter warehouse, the temperature is -18℃, and the ratio of air-cooled evaporator (air cooler) is generally similar to that of compressor.
5. For a 61-cubic-meter warehouse, the temperature of the warehouse is -18℃, and the evaporator is made of ceiling aluminum rows, which can be configured according to twice the bottom area of the warehouse (that is, the bottom area of the warehouse is X2). Know how to calculate the cooling capacity of air conditioner and ambient temperature. Condensed water < P > should be frozen water. Determine the temperature difference between inlet and outlet water. Qo=cpa×△t×qv, where Qo is the refrigerating capacity, cpa is the specific heat capacity of water at constant pressure, qv is the mass flow of water, and△ t is the heat transfer temperature difference between inlet and outlet water. Generally speaking, the chilled water of air conditioner is constant flow.
the condensed water flows from the water collecting tray under the evaporator of the indoor unit. Its flow rate is generally related to the moisture content of air, dew point temperature, room temperature, etc., and it can be calculated by finding a wet air enthalpy-humidity diagram. What happens when the air conditioning refrigeration capacity is greater than the room area and the air conditioning refrigeration capacity is less than the room area?
it's okay when you're older! If it is small, the air conditioner will not stop! How to calculate this temperature difference? Calculation of cold storage capacity