How to select the refrigeration unit? How to select a refrigeration unit?

Kedley answers:

Choose a chiller.

Considerations:

The purpose of the building.

Performance and characteristics of various types of chillers.

Local water source (including water quantity, water temperature and quality), power source and heat source (including type, nature and grade of heat source). The building's annual air-conditioning cooling load (heat load.

The law of distribution. Initial investment and running costs.

to Freon. Duration of refrigerant refrigerant restrictions and the possibility of using alternative refrigerants.

2) Precautions for the selection of chillers:

After fully considering the above factors, the following points should also be paid attention to when choosing a chiller:

1. For the cold source of large-scale centralized air-conditioning system, it is advisable to choose compact structure, small footprint, compressor, motor and condenser.

The evaporator and automatic control elements, among others, are assembled on the same frame for the chiller. For small full air conditioning systems, direct evaporative compression condensing units should be used.

2. For places with suitable heat sources, especially places with waste heat or waste heat, or places with lack of electricity, it is advisable to use absorption chillers.

3. Refrigeration units are generally suitable for 2 or 4 units, 2 units for small and medium-sized scales, 3 units for larger units, and 4 units for extra-large units. The possibility of mutual standby and switching between units should be considered. In the same machine room, a combination of different types and different capacities of units can be used to save energy consumption.

Among the units running in parallel, at least one unit with a high degree of automation, good regulation performance, and can ensure efficient operation under partial load should be selected. When choosing a piston chiller, it is advisable to give preference to a chiller with automatic joint control of multiple heads.

4 When choosing an electrically driven chiller, the cooling capacity of a single air conditioner.

When 1163kw, centrifugal type should be selected; When 582 1163kw, centrifugal or screw type should be selected; When 582kw, piston type should be used.

5 Refrigeration coefficient of an electrically driven chiller.

COP has a higher thermal coefficient than absorption chillers, which is more than twice that of the latter. The order of energy consumption from low to high is: centrifugal type, screw type, piston type, and absorption type (the screw type of foreign units is ranked before the centrifugal type). However, each type of unit has its own characteristics and applies its strengths.

6. When choosing a refrigerator, it should consider its pollution to the environment: first, noise and vibration, to meet the requirements of the surrounding environment; The second is the effect of the refrigerant CFCS on the atmospheric ozone layer.

and produce the greenhouse effect.

size, pay particular attention to the CFCS disabling schedule. Absorption refrigerators have clear advantages in the direction of preventing CFCS contamination.

Design and selection of combined cold storage compressor units:

1. No matter what brand of compressor unit, the selection is determined according to the evaporation temperature of the active cold storage and the effective working volume of the cold storage, and the condensation temperature, storage volume, and frequency of goods in and out of the warehouse should also be referred to.

2. Usually the formula for calculating the refrigeration capacity of high-temperature active cold storage is: the volume of cold storage is 90 positive deviation, and the positive deviation is determined according to the condensing temperature of frozen or refrigerated items, the storage volume, and the frequency of goods entering and leaving the warehouse, with a range of 100-400W;

3. The formula for calculating the refrigeration capacity of the medium-temperature active cold storage is: the positive deviation of the cold storage volume is 95, and the positive deviation range is between 200-600W;

4. The formula for calculating the refrigeration capacity of the compressor unit of the low-temperature active cold storage is: the volume of the cold storage is 110 positive deviation, and the positive deviation range is between 300-800W.

The selection principle is to see how large the storage volume and purpose of the cold storage is, and then select the corresponding refrigeration compressor and related equipment.

A chiller is a machine that transfers the heat of a cooled object with a lower temperature to the ambient medium to obtain cold capacity. The amount of heat transferred from a lower temperature object is customarily referred to as cold volume.

The working fluid involved in the thermodynamic process change (energy conversion and heat transfer) in the chiller is called the refrigerant. The temperature range of refrigeration is usually above 120K, and below 120K is in the range of cryogenic technology.

Compression chillers. The pressure of the refrigerant is increased by the compressor to achieve the refrigeration cycle.

Absorption chillers. Relying on the action of the absorber-generator group (thermochemical compressor) to complete the refrigeration cycle, it can be divided into three types: ammonia absorption, lithium bromide absorption and absorption diffusion.

Steam jet chillers. The refrigeration cycle is completed by the action of a steam ejector (jet compressor).

Refrigeration is a science and technology that reduces the temperature of a space or object to a lower temperature than the surrounding environment and keeps it in a specified low temperature state.

Semiconductor coolers. The thermoelectric effect of semiconductors is used to produce cooling capacity.

The main performance indicators of the refrigerator are the operating temperature (evaporation temperature and condensation temperature for vapor compression refrigerators, the temperature of the cooled object and the temperature of the cooling medium for gas compression refrigerators and semiconductor coolers), and the cooling capacity (the amount of heat removed from the cooled object per unit time of the refrigerator).

Power or heat consumption, refrigeration coefficient (an index that measures the economy of a compression chiller, which refers to the amount of cooling that can be obtained by consuming a unit of power) and thermal coefficient (an index that measures the economy of absorption and steam jet chillers, which refers to the amount of cooling that can be obtained by consuming a unit of heat), etc. Modern refrigerators are most widely used in vapor compression refrigerators.

Abstract】After satisfying the basic needs of food, clothing and warmth, people's dietary quality has been further improved, and then, our refrigerators have appeared in our lives and contributed to the quality of our diet. Today, Xiao Ruo will introduce to you the selection knowledge of refrigeration units, an important part of the electric ice orange trace rock box.

Because reform and opening up have made indelible contributions to the economy of our motherland, the problem of feeding more than one billion people has been solved, and people have paid attention to improving the quality of their diet. In recent years, a new industry in China has emerged, food refrigerated logistics, which can reduce the loss of nutrients in the process of transporting our food, and at the same time the safety of our food has also been guaranteed, and the refrigeration unit plays a vital role in ensuring its stable operation in food refrigerated logistics, as its core equipment, the selection of refrigeration units is extremely important. In its more than 100 years of development history, it has developed refrigeration units and become a leader in the refrigeration and transportation unit industry, continuously accumulating rich application experience.

How to select refrigeration units

1. Calculation theory of unit cooling capacity

Choosing the right unit is one of the factors in the selection of the unit, we not only want to make the refrigeration capacity of the unit in the temperature of the transported goods in the box to be guaranteed, but also to prevent the waste of resources, according to the type of transport, the size of the humidifying box, the thermal conductivity of the insulation material, as well as the temperature value set in our compartment and the area used by the vehicle to determine the amount of cooling.

2. Select the unit in the quick selection table

It is too troublesome to use the formula for selection, it is difficult for non-professional industry insiders to complete, and there are many uncertain factors, resulting in the correctness of the selection effect is not very high, so we can use the rapid selection table to select, the rapid selection table is based on the theoretical calculation formula and in the practical application of Carrier, so as to develop the unit rapid selection table, so that our refrigerated car factory and our end customers application.

3. Selection of various specific demand units

The above unit selection is only for the cooling capacity matching unit, and in our actual application, different practical applications for the functional requirements of the unit are not the same, only when the function of the unit can make the user's use needs to be satisfied, the refrigeration unit to ensure the safety of the transported goods can play its greatest role.

When selecting the unit in our actual life, our users should also select the most appropriate refrigeration unit according to their actual use needs, so as to ensure food safety and improve food quality in a real sense.

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Refrigeration unit selection method.

Estimation and selection through the power and calorific value of the equipment

a. If it is used for spindle cooling, the cooling capacity of the refrigeration unit can be estimated according to 30% of the power of the spindle motor.

Example: Motor, optional or cooling capacity of the refrigeration unit;

b. The injection molding machine can be estimated according to the cooling capacity per ounce.

a.Direct cooling: that is, the plating solution directly enters the evaporator of the freezer through the filter or filter screen for cooling and then returns to the oxidation tank.

Advantages and disadvantages of this cooling method: short cooling time and good effect; The disadvantage is that the evaporator needs to be treated with anti-corrosion (generally titanium alloy), and the evaporator is easy to scale and needs to be cleaned regularly, otherwise the refrigeration effect and machine operation will be affected.

b.Indirect cooling: titanium tubes are laid in the oxidation tank, and the chilled water is carried away by the titanium tubes to achieve the purpose of cooling; If it is inconvenient to lay titanium tubes, you can add a heat exchanger (which needs to be made of titanium alloy) to take the plating solution while taking chilled water.

I'll give you a web page, please take a look at it yourself.

First of all, it is divided into two categories: 1. electric cooler 2. Lithium bromide absorption unit.

There are electric coolers: screw machines, centrifuges, compressors, piston machines, etc.

Bromine coolers include: steam engines, direct-fired engines, fuel engines, flue gas engines, multi-energy engines, etc.

There are many ways to classify them;

According to the type of circulation: absorption type and compression circulation type;

According to the type of compressor, the compression cycle type can be divided into: centrifugal, screw, piston, scroll, etc.;

Semiconductor refrigeration, volumetric compression, absorption, separation.

There are also absorption types, which only heat without compressors.

What equipment or environment do you need to buy and use, whether the company is equipped with cooling towers or pools, what is the temperature control range, and how much cooling capacity is needed.

Is there any requirement for the flow pressure of chilled water, and other parameters, we must confirm it before we can give the plan and

According to the capacity of the cold storage (the required cooling capacity), the temperature of the cold storage.

Cold storage cold capacity (cold ton), cold storage temperature, and some requirements of users.