I. Product Overview
The Danfoss HRM series scroll compressors are a complete line of light commercial scroll compressors developed specifically for R22 refrigerant, covering cooling capacities from small entry-level models to large-capacity, high-temperature optimized models. This series includes U-suffix models adapted for standard air conditioning conditions, and T-suffix models custom-upgraded for high condensing temperature environments. The full model range covers HRM032U4, HRM034U4, HRM038U4, HRM040U4, HRM042U4, HRM045U4, HRM047U4, HRM048U4, HRM051T4, HRM051U4, HRM054U4, HRM058U4, HRM060T4, and HRM060U4, meeting diverse selection needs from small HVAC equipment and medium-sized constant-temperature units to tropical high-temperature cooling systems.
Built on mature scroll compression technology, the product balances compact structure, continuous stable operation, and safety protection performance. Equipment manufacturers can select the appropriate model based on cooling requirements and on-site heat dissipation conditions to build air conditioning, heat pump, and cooling systems adapted to different operating environments.
| Feature Dimension | Description |
| Brand | Danfoss |
| Technology Type | Hermetic Compliant Scroll, Fixed Speed |
| Power Range | 2.7 HP – 5.0 HP |
| Displacement Range | 43.6 – 81.0 cm³/rev |
| Refrigerant | R22 |
| Lubricant | Alkylbenzene Oil (160ABM) |
| Power Supply | 3φ, 380-415V/50Hz, 460V/60Hz |
| Core Positioning | R22 AC main platform, flexible U/T dual-version adaptation |
Model Grouping Logic
| Group | Models | Displacement (cm³/rev) | Nominal HP | Cooling Capacity (W) | Core Positioning |
| Small Group | HRM032U4 – HRM045U4 | 43.6 – 61.5 | 2.7 – 3.8 | 7,850 – 10,940 | 2.5–4HP AC workhorse, compact & efficient |
| Large Group | HRM047U4 – HRM060U4 | 64.1 – 81.0 | 3.9 – 5.0 | 11,500 – 14,820 | 4–5HP AC flagship, large capacity & high efficiency |
II. Full Series Comprehensive Parameter Comparison Table
| Group | Model | Nominal HP | Displacement (cm³/rev) | Cooling Capacity (W) | Cooling Capacity (Btu/h) | Input Power (kW) | COP | EER | Oil Charge (L) | Net Weight (kg) |
| Small | HRM032U4 | 2.7 | 43.6 | 7,850 | 26,790 | 2.55 | 3.08 | 10.5 | 1.06 | 31 |
| Small | HRM034U4 | 2.8 | 46.2 | 8,350 | 28,490 | 2.66 | 3.14 | 10.7 | 1.06 | 31 |
| Small | HRM038U4 | 3.2 | 46.2 | 9,240 | 31,520 | 2.94 | 3.14 | 10.7 | 1.06 | 31 |
| Small | HRM040U4 | 3.3 | 54.4 | 9,710 | 33,120 | 2.98 | 3.26 | 11.1 | 1.06 | 31 |
| Small | HRM042U4 | 3.5 | 57.2 | 10,190 | 34,770 | 3.13 | 3.26 | 11.1 | 1.06 | 31 |
| Small | HRM045U4 | 3.8 | 61.5 | 10,940 | 37,310 | 3.45 | 3.17 | 10.8 | 1.33 | 31 |
| Large | HRM047U4 | 3.9 | 64.1 | 11,500 | 39,250 | 3.57 | 3.23 | 11.1 | 1.33 | 31 |
| Large | HRM048U4 | 4.0 | 64.4 | 11,510 | 39,270 | 3.57 | 3.23 | 11.1 | 1.57 | 37 |
| Large | HRM051T4 | 4.3 | 68.8 | 12,390 | 42,280 | 3.67 | 3.37 | 11.5 | 1.57 | 37 |
| Large | HRM051U4 | 4.3 | 68.8 | 12,800 | 43,690 | 3.83 | 3.34 | 11.4 | 1.57 | 37 |
| Large | HRM054U4 | 4.5 | 72.9 | 13,390 | 45,680 | 3.97 | 3.37 | 11.5 | 1.57 | 37 |
| Large | HRM058U4 | 4.8 | 78.2 | 14,340 | 48,930 | 4.25 | 3.37 | 11.5 | 1.57 | 37 |
| Large | HRM060T4 | 5.0 | 81.0 | 14,570 | 49,720 | 4.28 | 3.40 | 11.6 | 1.57 | 37 |
| Large | HRM060U4 | 5.0 | 81.0 | 14,820 | 50,580 | 4.40 | 3.37 | 11.5 | 1.57 | 37 |
Conditions: 50Hz, R22 refrigerant. Full series max. pressure (PS): high side 31.1 bar, low side 26.2 bar; IP protection class IP22. HRM051T4 speed: 2900 rpm at 50Hz, 3500 rpm at 60Hz; RLA 8.3 A, MCC 13 A, locked rotor current 60 A, max. refrigerant charge 5.44 kg.
III. Detailed Analysis
Feature
Small and medium models adopt a compact scroll structure with unified base mounting dimensions, built-in motor overload protection, and support for 50/60Hz dual power frequency, designed specifically for R22 refrigerant matching. The fixed and orbiting scroll plates are precisely machined with stable meshing clearance. Medium and large models upgrade the internal oil circulation and oil separation structure, with increased winding margin to support long-duration full-load operation. T-suffix models (HRM051T4, HRM060T4) adopt a high compression ratio tuning scheme paired with reinforced high-temperature motor insulation; large-capacity U models adopt a large-displacement scroll structure with reserved high/low dual-pressure protection interfaces.
Advantage
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Smaller internal footprint; standardized mounting holes reduce equipment casing modification work; integrated protection module automatically shuts down under overheating or overload risks.
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Low operating vibration and noise; stable oil return under low spring/autumn part-load conditions, avoiding dry wear of scroll plates from oil starvation; motor temperature rise is controllable during 24-hour full-load continuous operation of medium models.
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T models can withstand up to 54.4℃ condensing temperature, with controllable energy efficiency attenuation in extreme high-temperature environments; large-displacement design increases exhaust volume, and reserved protection ports allow external pressure switch linkage protection.
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Compared with traditional reciprocating compressors, it offers superior COP values, helping end-users save on electricity costs in the long term.
Benefit
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Simplifies structural design of small and medium HVAC equipment, shortening new product development cycles; supports quick on-site replacement and repair, effectively reducing after-sales labor hours and service costs, making it more contractor- and service team-friendly.
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Achieves low-noise comfortable operation in office spaces, guesthouses, and other human-occupied environments; stable part-load performance extends compressor service life, reducing downtime losses from continuous operation of constant-temperature equipment.
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T models deliver stable cooling output in tropical regions and rooftop units with poor heat dissipation, avoiding frequent high-pressure shutdowns; large-capacity models reduce the number of compressors per unit, simplifying piping and electrical control systems, lowering spare parts procurement and overall assembly costs for large cooling equipment; dual protection mechanisms safeguard the compressor under abnormal conditions such as line blockage or cooling failure, preventing permanent damage.
IV. Application Quick Selection Guide
The Danfoss HRM full series covers multiple light commercial HVAC and cooling scenarios:
| Application Category | Recommended Models | HP Range | Typical Scenarios |
| Small Capacity | HRM032U4 ~ HRM042U4 | 2.7–3.5 | Small commercial split AC, residential air-source heat pumps, small air-energy water heaters, laboratory constant-temp cooling equipment, convenience store all-in-one refrigeration AC |
| Medium Capacity U-Type | HRM045U4 ~ HRM051U4 | 3.8–4.3 | Medium air-cooled heat pump units, office building standalone central AC, pool constant-temp heat pumps, food processing workshop constant-temp AC, small server room precision cooling units |
| Large Capacity & High-Temp Optimized | HRM051T4, HRM051U4, HRM054U4, HRM058U4, HRM060T4, HRM060U4 | 4.3–5.0 | Tropical rooftop AC units, high ambient temp heat pumps, large supermarket split central AC, industrial equipment cooling systems, air-energy units operating in extreme high-temp environments |
Selection Quick Reference: 2.7HP → HRM032U4 · 2.8HP → HRM034U4 · 3.2HP → HRM038U4 · 3.3HP → HRM040U4 · 3.5HP → HRM042U4 · 3.8HP → HRM045U4 · 3.9HP → HRM047U4 · 4HP → HRM048U4 · 4.3HP → HRM051T4/U4 · 4.5HP → HRM054U4 · 4.8HP → HRM058U4 · 5HP → HRM060T4/U4.
V. Frequently Asked Questions (FAQ)
Q1: Can U-suffix and T-suffix compressors with the same nominal capacity be directly interchanged?
Direct interchange is not recommended. U models are calibrated for standard AC conditions, while T models are optimized for high condensing temperatures, with different internal oil circuits and protection logic. Direct replacement will cause a sharp drop in energy efficiency under high-temperature conditions and frequent unit protection shutdowns.
Q2: Are HRM compressors suitable for heat pump systems with frequent winter defrost cycles?
The compressors support standard heat pump cycles and defrost functions. As long as the electrical control scheme follows Danfoss official defrost timing and proper liquid return protection is in place, normal defrosting will not damage the compressor. However, liquid slugging caused by defective defrost logic will result in permanent compressor damage.
Q3: What is the difference between HRM060T4 and HRM060U4?
Both share the same displacement (81 cm³/rev) and nominal 5HP rating. HRM060T4 delivers 14,570 W cooling capacity with 4.28 kW input power and COP 3.40; HRM060U4 delivers 14,820 W cooling capacity with 4.40 kW input power and COP 3.37. HRM060T4 offers higher energy efficiency, while HRM060U4 delivers greater cooling capacity.
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III. Detailed Analysis
