Static evaporator

Types of Static Evaporators

Static evaporators are used in commercial refrigeration systems to absorb heat from the surrounding space into the refrigerant, leading to cooling. While working efficiently and quietly, they come in various types.

• Direct expansion evaporator static coils

  Direct expansion (DX) evaporators allow refrigerant gas to directly expand within the air-carrying coil. DX coils are often utilized in air-conditioning and refrigerating applications. Refrigerants typically used include R-22, R-410A, and R-134A. DX evaporators are, without question, the most prevalent.

• Dry expansion evaporator static coils (also known as mushy evaporators)

  (Also called “soggy evaporators” wet expansion evaporators are opposite mushy ones. Only a thin film of water continually covers wet exchangers, which are generally used in dehumidifying cooling applications. Because moisture on wet exchangers enhances thermal conductivity, they are often more compact than mushy ones. The main drawback is that they frequently chill air below the dew point, which can generate a dropping problem.

• Flooded static coil evaporators

  Flooded evaporators maintain a constant refrigerant liquid level within them, in contrast to dry evaporators where the coils are only partially flooded. Because of this, the entire evaporator surface area is used for heat exchange, making it a very effective design. Flooded evaporators, however, need a constant pump operation to maintain the refrigerant level, making them more suited to the industrial sector.

• Finned evaporators

  Another common design is the use of thin metal plates to spread out like fins around the coil. Due to the increasing surface area, heat absorption by the refrigerant in the coil is accelerated, leading to enhanced cooling.

• Sucker box/static evaporators

  Sucker box static evaporators typically have the evaporator housed in a rectangular box. The single-pass, square-cornered boxes are typically found under the condenser fan shroud. This is, in fact, a way that appears stuck in the past. Because there is only one way for air to circulate through the evaporator, static suckers frequently exhaust exchanges, which can sometimes be performed only with the optimistic theory.

• Crossflow evaporators

  Crossflow evaporators, in contrast to counterflow evaporators, direct the airflow across the coil, which causes the air to move perpendicular to the movement of the refrigerant. Crossflow evaporators are frequently more compact and are easier to incorporate into systems where space is at a premium. But in terms of efficiency, counterflow evaporators frequently outperform them.

Specifications and maintenance of a static evaporator

Specifications of static evaporators may vary depending on the specific model or type. However, the following are some common specifications that buyers may expect to find when looking for a static evaporator.

• Sizes and capacities: Static evaporators are generally available in a wide variety of sizes and capacities to meet different storage needs. Whether it's a small showcase for a retail store or a large cold room for industrial use, static evaporators can provide the appropriate size and capacity to accommodate different quantities of goods.
• Temperature range: Static evaporators usually have a specific temperature range to ensure that the stored goods maintain the appropriate refrigeration state. The temperature range may vary depending on the model and specification, and buyers can select an appropriate temperature range according to their refrigeration needs.
• Box body materials: The box body materials of static evaporators are commonly made of metal or stainless steel, which ensures the durability and stability of the equipment. Meanwhile, box body materials usually have good thermal insulation performance to keep the internal temperature constant and prevent external heat from entering.
• Compressor power: The compressor power of static evaporators determines the refrigeration capacity and efficiency of the equipment. High compressor power can provide stronger refrigeration capacity, while low compressor power is more energy efficient. Buyers can choose the appropriate compressor power according to the usage scenario.
• Fan speed: For static evaporators equipped with fans, they might offer options for different fan speeds. The high fan speed can provide more substantial air refrigeration, while the low fan speed is relatively quieter. It is crucial to choose the appropriate fan speed according to different usage environments.

Proper maintenance can ensure the efficient operation of a static refrigerating evaporator and prolong its lifespan. The following is a brief introduction to the static evaporator's cleaning and maintenance tips.

• Dust removal: Regularly dust the external surface of a static evaporator to ensure the condensate's smooth operation. Dust and dirt on the surface can block the heat exchange and affect refrigeration efficiency.
• Cleaning of the internal space: Periodically clean the internal space of a static evaporator and dispose of rubbish and odours. This practice helps to maintain the internal hygiene and prevent cross-contamination of goods.
• Inspection of doors and windows: Regularly check if the doors and windows of static evaporators are in good working condition to make sure they are sealed tightly. If there are any problems, get them fixed promptly to avoid heat leakage and waste of electricity.
• Checking the inline goods: For merchandise with static evaporators, it is necessary to periodically check their statuses, such as whether there are goods staying too long, deformation, etc. If problems are found, transfer or handle them in time to avoid equipment damage and good loss.
• Coil cleaning: The coil is a significant heat transfer part of the static evaporator. Its cleanliness directly affects refrigeration efficiency. Therefore, it is essential to clean the coil and remove dust and dirt on its surface.

Scenarios

Static evaporators are used in various industries, mainly for food products. Here are a few examples of how different industries and businesses utilize static evaporators in their operations.

• Food Industry: Static evaporators are commonly found in food processing plants, mainly to produce concentrated fruit juices, dairy products, syrup, sauces, and liquid food items. The evaporator's ability to preserve flavor and nutritional value makes it an ideal choice for such applications. Also, the refrigerated static evaporator is used to freeze food to prevent spoilage and extend the shelf life of food items, such as fruits, vegetables, and meats.
• Chemical and Pharmaceutical Industry: In the chemical and pharmaceutical industries, static evaporators are often used to concentrate chemical solutions, extracts, and medicinal liquids. Chemical and pharmaceutical companies prefer the static evaporator overother types because it is less likely to damage heat-sensitive products. Additionally, static evaporators extract solvents fromchemical compounds during the production process.
• Dairy Industry: Dairy companies utilize static evaporators to concentrate milk, cream, cheese, and other dairy products. The evaporators help them reduce the volume of liquids for transportation, storage, and further processing. The concentrated dairy products are then used to prepare cheeses, ice creams and reconstituted milk.
• Textile Industry: Static evaporators in the textile industry concentrate dye solutions, chemical treatments, and other liquid additives. Textiles often go through dyeing processes, and the static evaporator helps make the dye liquids more viscous, thus simplifying application procedures. In addition, textile companies use evaporators to recover valuable chemicals and water from textile processing effluents to minimize waste and conserve resources.

How to choose static evaporators

When choosing static evaporators for commercial needs, consider various factors such as the designed application, available refrigerants, and potential energy savings of the system.

• Designed application: Commercial buyers need to match the intended application to the type of static evaporator they plan to buy. For example, a static evaporator with a finned tube is great for cold storage warehouses, while a flooded evaporator may suit processing facilities that cool liquids.
• Available refrigerants: Not all static evaporators work with every refrigerant. Make sure the chosen evaporator can efficiently use the selected refrigerant, like ammonia or CO2, for economic and environmental benefits.
• Energy efficiency: Opt for static evaporators with features that enhance energy efficiency. This includes fan motors that have variable speed and tube designs for optimal heat transfer. Energy-efficient evaporators can lower operational costs significantly.
• Maintenance needs: Consider the maintenance requirements of the evaporator being considered. While some static evaporators have complex designs usually requiring professional help, others are simpler and allow users to handle routine maintenance.
• System compatibility: Ensure that the chosen static evaporator will work with the existing refrigeration system in the commercial space. Consider the evaporator's dimensions, capacity, and design to avoid any installation issues.
• Budget constraints: Commercial buyers need to consider the upfront costs and long-term operational expenses of the static evaporator. Though some models may have a low initial price, they could lead to high energy and maintenance costs over time. Invest in a quality unit with a good balance of performance, efficiency, and affordability.

Q&A

Q1: How do static evaporators work?

A1: Static evaporators work by the flow of refrigerant into the evaporator coil, lowering the temperature of the coil. Air from the refrigerated space then passes over the coil, removing heat from the air and cooling it.

Q2: What are the two main types of static evaporators used in refrigeration?

A2: The two main types of static evaporators are the plate evaporator and the shell-and-tube evaporator. The plate evaporator comprises several thin plates, while the shell-and-tube evaporator comprises a large cylindrical shell with two matching tube bundles inside.

Q3: Why are static evaporators preferred in certain refrigeration systems?

A3: Static evaporators are preferred in certain refrigeration systems due to their simplicity, space-saving design, lower cost, and low maintenance requirement. Static evaporators are generally easier to maintain than evaporators with fans or other moving parts.