-- Miniature BLDC Rotary Refrigeration Compressors

    RIGID miniature rotary compressors are the result of a breakthrough in vapor compression technology featuring low vibration and low noise operation. Its tiny device is the first real innovation in micro-compressor technology for a century. They can be utilized in many thermal management applications from compact recirculating chillers, small coolers, medical cooling, electronic cooling, and mini-chilled water systems. RIGID mini compressors with cooling capacities range from 100W up to 800W (2,800Btu) by our patent drive board. The drive board is continuously speed-controllable via the frequency of a square wave signal, with variable speeds from 2000rpm to 6500rpm.


    Compressors are a key component of refrigeration products, it is the “heart” of such appliances, comparable to a car engine or even the human heart. RIGID Technologies now presents the lightest, ultra-compact, and more efficient Mini Rotary Compressor. The mini compressor is a new type of innovative micro dc compressor. Its compact and lightweight design makes it ideally suited for mobile and small cooling applications. Today, RIGID has successfully developed the 5th generation miniature compressor, which adopts our patented sine wave driver board.


    To maintain our technological edge, RIGID re-invests a large portion of corporate earnings back into R&D each year. PDF Download


      Miniature DC Compressors

      Mini Compressor

      • 12V & 24V & 48V DC
      • Liquid Water Cooling
      • Liquid Chiller Module
      • Small Air Conditioning
      • Laser, medical, semiconductor & military applications
      • Miniature & Mobile Refrigeration / Small Cooling systems
      R134a R410A Compressors

      Small AC Rotary Compressors

      • 110~120V/50~60HZ;  220~240V/50~60HZ
      • R134A, R410A, R290 Compressor
      • Dehumidifier
      • Air Conditioning
      • Refrigerator and Freezer

      Miniature DC Compressors


      •     Brushless motor
      •     12V / 24V / 48V DC
      •     Refrigerant R134A / R290
      •     Capacity 100W ~ 800W (2,800Btu)
      •     Variable speeds range from 2,000 to 6,000rpm
      •     Low vibration and noise, sine wave controller
      •     High efficiency, high capacity, lightweight, smallest footprint
      •     Robust design is ideally suited for mobile & compact applications



      R134a R410A Compressors

      Typical Applications

      •    Micro Cooling
      •    Medical Device
      •    Small Refrigerators
      •    Beverage Cooling
      •    Electronic Components
      •    Portable Cooling Systems
      •    Mini-Chilled Water Systems
      •    Portable DC Air Conditioner
      •    EV / Automotive Lithium-ion Battery 
      •    Aesthetic & Medicine Device
      •    Telecommunications Cooling
      •    Portable and Small Cooling Applications

      Miniature Compressor List -RIGID HVAC


      RIGID rotary refrigeration compressor is characterized by very small size and high performance. It is a variable capacity DC Compressors driven by drive board. Its volume is very small like a coke can, and the weight is only 720g. The current models use a single-cylinder configuration under standard ASHRAE conditions, which can produce a cooling capacity of up to 450W to 800W.


      Compatible with R134A and R290A refrigerants, it can run at 12, 24, 48V DC, and other voltages or AC power supply can be converted by AC and DC. RIGID's newly developed Miniature BLDC Rotary Refrigeration Compressors have begun a new trend, providing unparalleled cooling capabilities in various compact mobile cooling systems and other small footprint countertop appliances.


      Up to a 40% reduction in overall energy consumption and a 5 dB(A) average noise level reduction were measured applying Variable Capacity Compressors as compared to conventional fixed-speed compressors.



      New Enabling Technology for Mini Refrigeration & Air Conditioning Applications

      12 Voltage

      Commercial Cooling Systems

      24 Voltage

      Medical Device Cooling Systems

      48 Voltage

      Electronics Cooling Systems

      R290 Series

      Beverage Cooling Systems


    • Miniature Inverter DC Compressor

      Miniature Inverter Compressors

      12/24/48V DC Mini Compressors are ideally suited for compact & mobile refrigeration applications.

      Drive Board & Display Panel

      It is easy to integrate the drive board (PCB) & display panel into your application if you need sophisticated functions, or want to control by your software.

      R134A R410a Compressor for Dehumidifier

      R134A R410A R290 Compressors

      115V~240V / 50~60Hz AC Compressors for Compact Refrigeration & Air Conditioning.


      We have our own R&D department and manufacturing facilities. Thereby, we control the complete process from the first idea to the delivery of finished cooling products to customers. If you don’t see what you are looking for in our product lineup, do not hesitate to talk to us about your system. Apart from standard cooling systems, RIGID also provides custom solutions. We have developed solutions for medical devices, life science, laboratory, electronics, laser, Lithium battery, and electric vehicle customers. We can design a miniature cooling system to meet the requirements of your application. To learn more, go to our Design & OEM page. Or, please contact us for a free evaluation of your application.

    • FAQ


      Mini compressor is a key component of refrigeration and air conditioning applications. Compressors are the “heart” of such appliances, comparable to a car engine or even the human heart. A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. RIGID Technologies now presents the lightest, more compact and more efficient BLDC Inverter Compressor.


      The selection of a compressor should be considered the following factors:

      Evaporator Temperature
      Cooling Capacity
      Refrigerant Type
      Ambient Temperature
      Electrical Power Available
      Compressor and Drive Cooling


      Super small volume: 56.5 x 78 mm (LxH)
      Super lightweight: 720g (1.6lbs)
      Use brushless motor, 12V, 24V, and 48V are available
      Driver board: variable speed ranges from 1800 to 6500 rpm
      Low vibration with anti-vibration cushion
      High-temperature working conditions can work under 52-degree ambient temperature.


      The minimum evaporating temperature and the condensing temperature allow RIGID mini compressor to apply to the application (LBP, MBP, or HBP).

      Low Back Pressure systems such as freezers have evaporator temperatures below -20ºC (-4ºF). Medium Back Pressure systems such as food coolers or beverage dispensers have evaporator temperatures higher than -20ºC (-4ºF). High Back Pressure systems such as chillers and air conditioners have evaporator temperatures higher than -5ºC (+23ºF).


      QX1901VDL (12V );
      QX1902VDL (24V );
      QX1903VDL (48V );
      QX3202VDL (24V );


      6.1 Cooling Capacity
      This is usually defined as the specified nominal cooling capacity at normal working conditions of the system in watts, according to evaporating and condensing temperatures. The capacity is determined by the mass flow rate of the refrigerant, which depends on the compressor’s displacement, RPM, and volumetric efficiency. RIGID miniature compressor refrigeration capacity ranges from 100W to 800W.


      6.2 Refrigerant Type
      Refrigerant selection can be made on the basis of availability, performance, and ecological considerations. RIGID BLDC rotary compressors have been verified for use with R134a refrigerant.


      6.3 Ambient Temperature
      The compressor must be selected in order to ensure it’s suitable to operate at the highest expected ambient temperature. RIGID mini compressors are usually intended for indoor use, and a minimum of +5ºC is required in order for proper lubrication. In 2017, RIGID has successfully developed T-tropical series mini compressor, which is able to work in 52-degree ambient temperature.


      6.4 Electrical Power Available
      RIGID DC compressors are used in mobile or portable refrigeration systems. Its DC power is produced by batteries, fuel cells, vehicle alternators, solar panels, or from an AC inverter power supply. The compressor must be selected for use according to the DC voltage available. RIGID compressors are available in 12V, 24V and 48V versions.


      6.5 Size and Cooling
      RIGID mini compressors are extremely small, high-performance rotary refrigeration compressors. Its size is only an adult's fist and weighing only 1.6 to 2.2 lbs. Current models produce as much as 100W to 800W of cooling under standard ASHRAE conditions, using a single-cylinder configuration. Compatible with various refrigerants and running on 12, 24 and 48VDC, or AC power through an AC-DC conversion, the new compressors are starting a new trend in various compact mobile cooling systems as well as small foot-print countertop appliances with cooling or ice-making capabilities.


      6.6 RIGID Mini Compressor Cooling Capacity and COP

      Coefficient Of Performance: Up to 3.25W/W


      The attached photo Table 1. shows the comparative sizes of RIGID miniature rotary compressor with a reciprocating DC compressor. RIGID mini dc compressor (right) is about 30 percent less size than that of a traditional reciprocating compressor (left), which has been widely used around the world for a long time. It is almost inconceivable to most people at first glance that the small compressor on the right (1.5 lbs) actually has a 30 percent higher capacity than the larger compressor on the left (9.5 lbs)! Comparison of key performance parameters is also shown in

      Table 2. For appliance designers, an important but seldom used (since they were pretty much all the same!) parameter is that of cooling power density, both volumetric and weight.


      RIGID tiny compressor is a new type bldc rotary compressor. It has 17 times the cooling power for the same volume, and 10.5 times the cooling power for the same weight. An obvious conclusion to be drawn from this realization is that large space and weight savings can be achieved using the miniature compressor. Such factors have historically been prized in mobile refrigeration systems only. Now, even though highly unusual for a DC-powered compressor, due to the weight and volume, the miniature compressors are being considered in various stationary applications, such as household countertop appliances; beverage dispensers; ice makers; ice cream machines, coffee machines, etc., where the small compressor size is highly desired to make the footprint of the appliance small.


      When RIGID miniature compressor is used in a refrigeration system together with a high-performance condenser and evaporator, the complete refrigeration system can be incorporated within a package as small as 100 in3 (1.64 liters). This allows a major space reallocation in the cabinet, namely much less volume for the refrigeration system and considerably more volume for product storage space. There’s also a weight reduction of approximately 10 lbs (4.54 kg) just from the use of mini-compressors. But for the most part, the space savings are usually considered more important than weight savings in most refrigerated appliances.


      A small vapor compression cooling system using RIGID miniature compressor would have even larger performance and efficiency advantages over thermoelectric coolers often used in various products in the absence of small compressors before. Above the cooling capacity range of 100W, the vapor compression-based system will be far superior to the thermoelectric systems: ¼ to ½ the weight and volume, and 1/3 to ½ the power consumption compared to the thermoelectric systems.


      RIGID tiny compressor is very well-received by the market. Numerous refrigerated appliances can benefit from the size and weight reduction of a compressor. Some of the relevant refrigerated appliances are listed below:

      • Water Dispenser
      • Beer Dispensers
      • Beverage Cooling
      • Beverage Dispensers/Refrigerated
      • Cabinets/Refrigerated
      • Commercial Refrigerators/Freezers
      • Cooled Display Cases
      • Countertop Appliances/Refrigerated
      • Drawers/Refrigerated
      • Household Appliance
      • Ice Cream Cabinets/Dispensers
      • Ice Storage Bins/Chests
      • Yacht Refrigerators
      • Medical Product Storage
      • Milk Coolers/Dispensers
      • Mini Portable Air Conditioners
      • Mini-Bars
      • Overclocking of Personal computers
      • Portable Spot Coolers
      • Reach-In Freezers
      • Refrigerated Buffet Units
      • Solar-Powered A/C & Refrigerator
      • Vaccine/Medical Transport
      • Wine Coolers
      • Yogurt/Smoothie/Slush Machines


      RIGID’s compressors are built to order. Prior to installation, compressors should be stored in an upright position to prevent oil from entering the suction or discharge tubes. If compressors are to be stored in inventory for long periods of time, they should be stored in climate chambers or storage areas that can control both temperature and humidity.

      RIGID compressors are built with high precision parts that are susceptible to chemical attack and corrosion from contaminants in ambient air. Compressors are always shipped with a low-pressure nitrogen blanket sealed with rubber plugs to maintain this pressure and prevent internal parts from exposure to moisture and other contaminants. If long shelf life is anticipated, it is important to maintain the inert atmosphere to prevent internal corrosion or chemical attack.


      All compressors shipped from RIGID are charged with 25cc of RL-32H oil, are evacuated, sealed with low-pressure nitrogen, and capped. In addition to the compressor, other system components should be internally dried, sealed, and stored in an inert atmosphere until installation, preferably no more than 15 minutes from assembling of components.

      Remove the compressor from its packaging while keeping it in an upright position. Failure to keep the compressor upright can result in the flow of oil into the suction accumulator and process connections, which can cause brazing problems. The compressor must also remain upright while assembling the grommets in the mounting bracket to the base plate.


      The cleaning and removal of solid substances and non-condensible and the removal of moisture and other gas contaminants in all components of the refrigeration system are key to successful compressor operation and long life. In addition, the use of R134a with new polyester oils has been accompanied by new stricter standards in comparison with CFC or HCFC refrigerants. Any non-compatible products that can contaminate these refrigerants and polyester oils including chlorine compounds and non-ester-based oils need to be eliminated. Other system components such as tubing, evaporators, condensers, receivers, valves, capillaries, and separators need to have these contaminants removed before the system is assembled.


      RIGID recommends that all components remain sealed as long as possible before assembly, performing the brazing no more than 15 minutes after exposure to ambient.


      It is important to avoid residual oil during brazing by blowing out components with nitrogen or dry air, with a dew point lower than -40ºF. Internal oil on surfaces of the suction or discharge tubes can cause difficulty in brazing, and even more hazardous, it can introduce contaminants into the system from ‘cracking of oil’.


      The filter drier needs to be protected from absorption of ambient humidity during assembly of the system components using the following practices:


      Remove protective caps just prior to brazing
      For filters supplied without protective caps in hermetic boxes, these must also be protected to avoid moisture absorption before brazing.

      If the drier does not have complete water absorption in the molecular sieve, then moisture can circulate freely in the system with the following effects:

      Ice Buildup: Reduces the cross-sectional area of a capillary tube or TX valve
      Acid Buildup: Causes serious attack in a compressor and to the molecular sieve in filter drier
      Oil Contamination Acidification reduces lubrication, changes oil color, a buildup of sludge, and poor lubrication of compressor

      RIGID is not responsible for damage to its compressors from the introduction of such contaminants.


      RIGID compressors have been designed and tested for operation with R134a refrigerant. Some users may want to employ other refrigerants or refrigerant blends, and other refrigerants may perform quite well. However, due to case design pressure considerations, refrigerants that have a maximum working pressure greater than 350 psi (24.13 bar) are not recommended. If other refrigerants are to be used, the compressor should be thoroughly tested and evaluated with those refrigerants to verify reliability with expected conditions in the intended application. Because of the wide differences in refrigeration systems with different working fluids, the reliability of all equipment should be evaluated for appropriate life through field tests.

      Rotary compressors perform best when the pressure ratio between the high and low sides of the compressor is less than 8:1. When the pressure ratio exceeds this value, the compressor’s coefficient of performance (COP) is adversely affected. Good refrigeration practice requires that careful evaluation of the refrigeration system and evaporator conditions be specified and that an appropriate refrigerant is selected to avoid excessive pressure differential.

      12.1 R134a Refrigerant

      R134a (tetrafluoroethylene) is a replacement for R12 in applications with medium and high evaporator temperatures in Aspen’s compressors.

      Its physical properties are: Molecular Weight – 102 Critical Temperature – 101.1ºC Critical Pressure – 40.6 bar Boiling Point -26.5ºC


      This refrigerant also requires the exclusive use of polyester oil (POE) as a lubricant. R134a refrigerant is associated with strict requirements for the internal cleanliness of the cooling system. In addition to chlorine and water, solid residues must be carefully removed including dust, metal particles, etc., which can damage the compressor. The recommended lubricating oil is POE RL 68H. This lubricant is highly hygroscopic (water absorbing) which can cause the formation of acid residues. When present, these acid residues can create a blockage in the capillary tube and reduced lubricity in the compressor.


      The level of moisture in the refrigeration system should be below 40 ppm. It is recommended that a filter dryer compatible with R134a and POE be installed with the capability to remove moisture from the system to below 20 ppm. The compressor and other components should remain sealed until they’re ready to use. The compressor and other system components should not be open to the ambient for more than 15 minutes. Good refrigeration practice also calls for system evacuation of both low and high sides, achieving a minimum vacuum level of 0.14 bar (100 ! Hg).

      12.2 Refrigerant Charge

      Following the system evacuation, it must be charged with refrigerant. For a low capacity system, as little as 40 grams might be used, while as much as 120 grams might be used in a high capacity system. After refrigerant is pumped into the system, it is wise to wait 5-10 minutes before starting the compressor to allow refrigerant evaporation and avoid the ingestion of liquid into the compressor. For high charge levels, the system should be equipped with a liquid receiver. An accumulator should always be used with rotary compressors to minimize liquid intake in the compressor.

      For each system, the optimum refrigerant charge should be determined by controlled testing in order to obtain the best working conditions and to avoid the return of liquid refrigerant to the compressor. In order to evaluate system performance, instrumentation should be added at certain locations to record key data. Recommended data points to be recorded include the following:


      Even the most experienced refrigeration technicians need to read these instructions carefully since the quantity of oil used in RIGID compressors is much less than found in other types. Some lubricating oil will travel with the refrigerant in any refrigeration system. Thus, it is imperative that they be miscible and fully soluble in one another at all temperatures. This provides good oil return and lubricity for the compressor while avoiding heat transfer losses in the evaporator. During the prototyping of the refrigeration system, it is vital that the proper amount of oil in the system be determined. RIGID compressors are all shipped with 25cc of POE RL 68H. This has been found to be adequate for many compact cooling systems.


      There is no sight glass to visualize oil flow within the compressor. Therefore, the following procedures are highly recommended to ensure that adequate oil is present at all times. Keep in mind that oil entertainment occurs in all compressors, and typically is a function of compressor speed (RPMs). All RIGID cooling systems have been designed to be fully drainable with no traps in heat exchangers, and contain refrigerant refill valve where coolant or oil can recharge.

      12.4 Oil Charging

      Using a syringe (see photo below) load the compressor with adequate (RL 68H, Viscosity: 300SUS, recommended or equivalent) refrigerant oil through the discharge port. Make sure the syringe is inserted just far enough to reach the inner chamber to allow air to purge but not to contact internal electrics, which might cause damage.

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