Micro DC Aircon - Cool & Heat

RIGID Micro DC Aircon Cool & Heat is a compact all-DC air-conditioning system designed for applications that require both cooling and heating from a 12V, 24V or 48V DC power source.

The system combines variable-speed vapor-compression refrigeration for cooling with a PTC electric heater for heating. Depending on model, cooling capacity ranges from 450W to 550W, while heating capacity ranges from 300W to 400W.

Available models include:

1. DV1910E-AC/H12V450W / 1,535 BTU/h300W / 1,023 BTU/h28.3 CFM5.0 kg;
2. DV1920E-AC/H24V450W / 1,535 BTU/h400W / 1,364 BTU/h28.3 CFM5.0 kg;
3. DV1930E-AC/H48V455W / 1,552 BTU/h400W / 1,364 BTU/h28.3 CFM5.0 kg;
4. DV3220E-AC/H24V550W / 1,876 BTU/h400W / 1,364 BTU/h28.3 CFM6.5 kg.

All four models use R134a refrigerant and are packaged in a compact 355 × 170 × 356 mm enclosure.

The Micro DC Aircon Cool & Heat is intended for telecom equipment, mobile systems, battery-powered enclosures, off-grid equipment and other compact applications where year-round temperature control and direct DC operation are required.

A combined DC cooling and heating system can provide year-round temperature control without requiring a conventional AC-powered air conditioner.

RIGID Micro DC Aircon Cool & Heat operates from:

• 12V DC
• 24V DC
• 48V DC

Cooling is provided by a miniature variable-speed BLDC compressor and vapor-compression refrigeration circuit. Heating is provided by an integrated PTC electric heater.

Depending on model, the system provides:

• Cooling capacity: 450–550W
• Heating capacity: 300–400W
• Airflow: 28.3 CFM
• Refrigerant: R134a
• Weight: 5.0–6.5 kg
• Dimensions: 355 × 170 × 356 mm

This architecture is useful for battery-powered and off-grid applications that experience both high and low ambient temperatures but have limited installation space.

The current RIGID Micro DC Aircon AC/H models use a PTC electric heater for heating.

Cooling is produced by the vapor-compression refrigeration circuit using the miniature BLDC compressor. In heating mode, the PTC heater generates heat electrically.

This is different from a reverse-cycle heat pump, which reverses refrigerant flow and uses the refrigeration circuit to transfer heat into the conditioned space.

The AC/H configuration therefore has two distinct thermal functions:

• Cooling: BLDC compressor + vapor-compression refrigeration
• Heating: PTC electric heater

The PTC heating capacity is 300W on the 12V DV1910E-AC/H and 400W on the DV1920E-AC/H, DV1930E-AC/H and DV3220E-AC/H.

Start with the available DC bus voltage, then compare the required cooling and heating loads.

For a 12V DC system, the DV1910E-AC/H provides:

• Cooling: 450W
• Heating: 300W
• Airflow: 28.3 CFM
• Weight: 5.0 kg
• Compressor: QX1901VDH

For a 24V DC system, two capacities are available:

DV1920E-AC/H

• Cooling: 450W
• Heating: 400W
• Weight: 5.0 kg
• Compressor: QX1902VDH

DV3220E-AC/H

• Cooling: 550W
• Heating: 400W
• Weight: 6.5 kg
• Compressor: QX3202VDH

For a 48V DC system, the DV1930E-AC/H provides:

• Cooling: 455W
• Heating: 400W
• Weight: 5.0 kg
• Compressor: QX1903VDH

All models use the same 28.3 CFM nominal cold-side airflow and 355 × 170 × 356 mm package dimensions.

Final selection should be based on both cooling and heating load calculations rather than voltage alone.

Current depends strongly on system voltage and operating condition.

The published specifications for the AC/H models list:

1. DV1910E-AC/H, 12V DC, Working current: 1–8A, Maximun current: 25A;
2. DV1920E-AC/H, 24V DC, Working current: 1–7A, Maximun current:16A;
3. DV1930E-AC/H, 48V DC, Working current: 1–4.1A, Maximun current: 8.3A;
4. DV3220E-AC/H, 24V DC, Working current: 1–7.1A, Maximun current:16A.

These values are particularly important when sizing batteries, DC power supplies, wiring, connectors and overcurrent protection.

However, cooling-mode compressor current and PTC heating-mode current should be evaluated separately because the two modes have different electrical loads.

For OEM integration, electrical design should be based on the confirmed maximum operating current for the selected model and operating mode.

Yes, provided the calculated cooling and heating loads fall within the capacity of the selected model.

Electronic equipment can experience two different thermal problems.

During high ambient temperatures or high internal heat generation, the refrigeration circuit removes heat from the enclosure.

During low ambient conditions, the integrated PTC heater can add 300–400W of heat to prevent the enclosure temperature from falling below the required operating range.

This makes the Cool & Heat configuration relevant to:

• Telecom cabinets
• Communications equipment
• Battery enclosures
• Mobile electronics
• Instrumentation
• Off-grid systems
• Remote equipment
• Compact control cabinets

For reliable selection, engineers should consider internal heat dissipation, maximum and minimum ambient temperatures, enclosure insulation, solar load, infiltration and the required internal temperature range.

A variable-speed DC refrigeration system can regulate cooling capacity according to changing thermal demand.

RIGID Micro DC Aircon uses a miniature BLDC rotary compressor rather than a conventional fixed-speed AC compressor.

Variable-speed operation is useful when:

• Internal heat generation changes over time
• Ambient temperature varies
• Battery power is limited
• Full cooling capacity is not continuously required
• Temperature stability is important

The AC/H configuration additionally provides PTC heating when ambient temperature falls below the application's required operating range.

Actual temperature stability depends on the control strategy, temperature sensor location, enclosure thermal characteristics, airflow distribution and thermal load.

For precision applications, RIGID can work with the OEM engineering team to develop the appropriate compressor and temperature-control strategy.

The DV3220E-AC/H provides up to 550W / approximately 1,876 BTU/h of cooling capacity, but whether this is sufficient depends on the total enclosure heat load.

An engineering heat-load calculation should include:

Internal heat generation

• Power electronics
• Batteries
• Computers
• Communication equipment
• Motors and drives
• Other electrical components

External heat gain

• Ambient temperature
• Solar radiation
• Heat transfer through enclosure walls
• Air leakage or ventilation

If the combined design heat load approaches the rated refrigeration capacity, additional engineering margin should be considered.

Enclosure volume alone is not sufficient for air-conditioner selection. A small enclosure containing 500W of electronics can require more cooling than a much larger enclosure with very little internal heat generation.

For OEM selection, provide RIGID with the internal heat dissipation in watts, maximum ambient temperature, required enclosure temperature and enclosure dimensions.

Yes. The product family is designed around direct 12V, 24V or 48V DC power.

This makes the system suitable for integration with DC battery buses used in solar-powered and off-grid equipment.

Unlike an air conditioner based on a conventional AC compressor, an all-DC refrigeration architecture can avoid adding a DC-to-AC inverter solely to power the compressor.

Typical off-grid applications include:

• Remote telecom installations
• Solar-powered equipment
• Battery-backed electronics
• Remote monitoring stations
• Mobile systems
• Field instrumentation

System designers still need to size the battery and solar array according to actual compressor consumption, PTC heater consumption, duty cycle, ambient conditions and required operating time.

Heating deserves particular attention in an off-grid system because a PTC heater converts electrical input directly into heat and can represent a significant battery load.

The hot condenser airflow must be thermally separated from the conditioned evaporator airflow.

In cooling mode, the evaporator absorbs heat from the enclosure air. The refrigeration circuit transfers this heat to the condenser, where it must be rejected outside the conditioned space.

For effective installation:

• Recirculate conditioned air through the evaporator side.
• Reject condenser heat outside the cooled enclosure.
• Keep condenser inlet and outlet airflow unobstructed.
• Avoid recirculating hot condenser discharge air back into the condenser inlet.
• Provide condensate drainage where required.
• Maintain sufficient clearance for airflow and service access.

If condenser heat is discharged into the same closed space being cooled, effective enclosure cooling will be significantly reduced.

Airflow design is therefore as important as nominal refrigeration capacity when integrating a compact air-conditioning module.

Yes. RIGID supports OEM and application-specific development when the standard Micro DC Aircon Cool & Heat models do not fully meet the project's thermal, electrical or mechanical requirements.

For engineering evaluation, provide:

• Required cooling capacity
• Required heating capacity
• DC supply voltage
• Maximum ambient temperature
• Minimum ambient temperature
• Target temperature or acceptable temperature range
• Internal heat generation
• Available installation space
• Required airflow
• Enclosure insulation
• Battery capacity
• Maximum allowable current
• Condenser ventilation conditions
• Noise requirement
• Environmental conditions
• Communication/control requirements
• Expected annual production quantity

RIGID can evaluate the thermal load, select an appropriate compressor and refrigeration configuration, develop a prototype, validate performance and support the transition to volume production.

For a new OEM project, the most useful starting parameters are DC voltage, cooling load, heating load, ambient temperature range, target temperature and available installation envelope.