Zhejiang Sanwei Electric Appliance Co., Ltd. is located in Ningbo, a beautiful port city with convenient transportation. It is a heating and cooling equipment manufacturer integrating R&D, production, sales, and service. The company's main products include: industrial water chillers, profile anodizing water chillers, hard anodizing water chillers, electroplating water chillers, plastics machinery water chillers, leather embossing water chillers, laser water chillers, solar photovoltaic water chillers, textile and chemical fiber water chillers, printing and dyeing water chillers, industrial oil coolers, low-temperature ethylene glycol (brine) units, low-temperature reactor units for chemical processes, water-source/ground-source heat pump units, air-source heat pump units, constant-temperature swimming pool units, constant-temperature aquaculture units, special high-temperature heat pump units for electroplating, high-temperature heat pump drying units, wood drying units, bamboo product drying units, agricultural product drying units, industrial drying units, corrosion-resistant acid/alkali chillers, special explosion-proof chillers, freezer storage, cold storage, quick-freeze storage, and constant-temperature cold storage. These products are applied across various industrial and agricultural sectors.

1. Surface Treatment Industry

Mainly used for profile anodizing, hard anodizing, electrophoretic coating, galvanizing, tin plating, nickel plating, gold plating, silver plating, copper acid plating, vacuum coating, ion plating, glass coating, etc. In anodizing, electroplating, and electrophoretic processes, the bath liquid continuously generates heat under high-frequency reactions, causing the bath temperature to gradually rise. When the electroplating solution temperature exceeds the process requirements, it significantly affects the adhesion, uniformity, flatness, and surface finish of the coating. Water chillers stabilize metal and non-metal ions, allowing metal ions to deposit onto the workpiece surface, increasing coating density and smoothness, shortening the plating cycle, reducing raw material consumption, and enabling chemical recovery while maintaining a constant bath temperature. This greatly benefits both the production process and efficiency.

2. Plastics and Rubber Industry

Includes injection molding, extrusion molding, blow molding, compression molding, film blowing, laminating, calender film, cast film, open milling, leather embossing, etc. Water chillers are used for mold cooling in plastics processing machinery. They improve the surface finish of plastic products, reduce surface marks and internal stress, prevent shrinkage and deformation, and facilitate demolding. After plastic pellets are melted and injected into molds, they solidify, and the molded parts are ejected. Continuous production requires mold cooling to shorten solidification time, improve dimensional accuracy, molding quality, and surface quality. For plastic containers, blow-molded bottles, and packaging films, if cooling is not timely, products may be underfilled, have uneven wall thickness, dull color, or fail to form, resulting in low quality. Using a water chiller significantly enhances product quality and production efficiency. In extrusion and pelletizing, the chiller's evaporator is shell-and-tube type with a closed loop to prevent water spillage. The chilled water temperature ranges from 7–18°C, and the chiller's capacity is related to the injection molding machine's shot size—larger shot sizes require greater cooling capacity.

3. Machinery Manufacturing Industry

Applied in CNC machine tools, jig borers, machining/combination machine tools, as well as lathes, grinders, milling machines, drilling machines, polishing, grinding, casting, die-casting, lasers, electronic chips, circuit board manufacturing, cleaning, printing and dyeing, ink production, papermaking, glass processing, composite flooring, concrete mixing, etc.

4. Textile and Chemical Fiber Industry

The main process stages include raw material slicing, drying, xanthation mixers, blending mixers, dissolving machines, and air purification and conditioning.

5. Pharmaceutical, Chemical, and Food Industry

Low-temperature reactor units: Used to maintain low-temperature conditions for biochemical reactions in reactors, rapid cooling of raw materials to prevent spoilage, low-temperature crystallization, extraction, and synthesis. The temperature range is adjustable from 30°C down to -110°C, with cooling capacities from 10 to 1000 kW.

Water chillers: After high-temperature processing, food products need to be cooled to packaging temperatures. Industrial chillers provide this cooling. In fermentation processes, different temperatures are required to control fermentation quality, so chillers are used for temperature control.

Air purification and conditioning units: In pharmaceutical, chemical, and cleanroom environments, temperature, humidity, and cleanliness must be controlled within specific ranges. The chiller's surface cooler is integrated with air purification devices, enabling temperature control and dust removal over large areas. Central air supply with constant temperature and humidity functions is typically adopted, making them more convenient than ordinary air conditioners.

6. Solar Photovoltaic Industry

In photovoltaic production, ancillary equipment requiring chilled water includes vacuum pumps, texturing machines, PECVD, diffusion furnaces, etching machines, screen printing machines, polycrystalline furnaces, single-crystal furnaces, polycrystalline silicon, single-crystal silicon, squaring machines, slicing machines, ingot casting furnaces, etc. The water quality requires particle sizes below 10 microns, with a supply temperature range of 15–20°C and a temperature difference of within 5°C between inlet and outlet. Piping should be stainless steel, PVC, or PPR. The chiller maintains a constant temperature within process requirements, improving production efficiency, product quality, and equipment service life. A production line with an annual capacity of 50 MW requires approximately 15 tons of chilled water per hour.

7. Industrial Oil Coolers

Industrial oil coolers are primarily used to reduce and maintain the temperature of lubricating or hydraulic oil in equipment such as machine tools, CNC machines, jig borers, grinders, machining centers, combination machine tools, hydrostatic bearings, high-speed spindles, electric spindles, and various spindle lubrication and hydraulic transmission systems. They control the required temperature, prevent thermal deformation and spindle center offset, stabilize oil pressure, prevent oil oxidation and evaporation, maintain oil viscosity, and improve machining accuracy, thereby significantly enhancing production efficiency, product quality, and extending equipment service life.

8. Marine Chiller Units

Marine chiller units are special equipment for shipboard air conditioning, refrigeration, freezing, and low-temperature seawater fresh-keeping storage. They feature innovative design, easy operation, stable operation, safety, reliability, and convenient maintenance. They are used in various passenger ships, fishing vessels, cargo ships, naval vessels, and offshore oil platforms. Custom refrigeration units can be designed according to actual user requirements, with temperature ranges from -20 to 10°C and cooling capacities from 10 kW to 1000 kW.

9. Low-Temperature Ethylene Glycol / Brine Chillers

Low-temperature chillers provide low-temperature secondary refrigerants and are suitable for various applications requiring medium-to-low temperature cold sources. They are widely used as process cold sources in non-ferrous metallurgy, chemical and pharmaceutical intermediates, petrochemicals, grain and oil, beverage and food, machinery, medicine, electronics, air separation, and other industries.

These chillers are specially designed for specific industry needs, with temperature ranges adjustable from 30°C down to -60°C and cooling capacities from 10 to 1000 kW. They are classified into three series based on temperature range: high, medium, and low.

Standard chillers: Provide 3–35°C chilled water, or use ethylene glycol solutions as secondary refrigerant to provide -5 to +5°C process coolant. They are used for ice storage, low-temperature air supply, central air conditioning, and other process cooling applications. Custom designs for large temperature differentials are also available.

Medium-temperature chillers: Outlet temperature from -5°C to -45°C, using imported semi-hermetic screw compressor sets (with economizer). They supply low-temperature ethylene glycol or brine solutions for chemical, pharmaceutical, cold storage, ice rink, and other process cold sources.

Low-temperature screw chillers: Outlet temperature from -45°C to -110°C, providing alcohol or dichloromethane chilled solutions. They employ two-stage or three-stage cascade refrigeration systems for stable operation and high energy efficiency.

10. Water-Source and Ground-Source Heat Pumps

These are used for central heating and cooling in hotels, office buildings, schools, shopping malls, villas, residential communities, and other commercial and industrial buildings. They also serve swimming pools, bathing, beer brewing, cold rolling/forging, cold storage, indoor planting, and constant-temperature cultivation. One unit can provide both cooling and heating, as well as domestic hot water. For air-conditioning systems, a single heat pump supplies two heat sources, reducing initial investment to about 60% of traditional systems. Installation is easy, with less work and shorter construction time, and modifications are also simpler. Compared to conventional air conditioning, water-source heat pumps offer the following advantages:

Energy saving: Water-source/ground-source heat pumps achieve the highest COP values among air conditioning systems. The theoretical COP can reach 7, with actual operation at 4–6. Consuming 1 kW·h of electricity, the user can obtain 4.3–5.0 kW·h of heat or 5.4–6.2 kW·h of cooling. Compared to air-source heat pumps, operating efficiency is 20–60% higher, and operating costs are only 40–60% of ordinary air conditioners.

Renewable energy utilization: These heat pumps use solar energy stored in the earth's water bodies as a heat source/sink. Available sources include groundwater, rivers, lakes, and oceans. They exchange heat with surface water without consuming water resources or causing pollution. Boiler rooms and fuel storage yards are eliminated, and the machine room occupies much less space than conventional systems, saving building space and improving aesthetics. This makes use of nearly unlimited solar or geothermal energy, making it a clean renewable energy technology with significant environmental benefits.

Stable, reliable operation and easy maintenance: Water temperature remains relatively stable throughout the year, with much smaller fluctuations than air temperature. This constant temperature ensures reliable and stable operation of the heat pump unit, system efficiency, and economy. Full computer control provides a high degree of automation. With a simple system and few components, maintenance costs are low.

11. Cold Storage

Includes freezer storage, cold storage, quick-freeze storage, and constant-temperature storage. Widely used in biology, industry, military, food, aquatic products, flowers, animal husbandry, pharmaceuticals, logistics, hotels, restaurants, food processing, and other industries for fresh-keeping and frozen storage.

12. High-Temperature Drying Heat Pumps

These are mainly used for drying wood, tobacco leaves, bamboo products, tea, medicinal herbs, fruits and vegetables, cured meat, shiitake mushrooms, sludge, industrial products, and agricultural products.

13. Air-Source Heat Pumps

Air-source heat pump water heaters, with their advantages and good economic benefits, are applied in domestic hot water for homes, villas, government offices, schools, hotels, and residential heating. Specially designed units for special applications are widely used in constant-temperature swimming pools, aquaculture, high-temperature hot water in food factories, slaughterhouses, textile and dyeing mills, electroplating plants, and other industrial hot water fields.

14. Seafood and Aquaculture

Traditional winter heating equipment in aquaculture mainly uses boilers (coal, oil) or electric heating rods. These have many drawbacks: high energy consumption, extended breeding cycles, difficult temperature control, reduced farming efficiency, harmful gas emissions, and the need for dedicated manual management.

A new generation of constant-temperature breeding units based on air-source heat pump principles uses flexible scroll compressors, special titanium alloy corrosion-resistant heat exchangers, and microcomputer automatic control. The water temperature can be adjusted between 8–30°C as needed, with control within ±1.5°C. No dedicated operator is required, saving time and effort. Compared to boilers, coal, oil, or electric heating, these constant-temperature units are more conducive to aquatic life growth, can save more than 50% of annual costs, and offer easy installation, energy savings, safety, environmental protection, and convenient unattended operation.