Europe’s heat pump market is rapidly shifting toward low-GWP refrigerant R290. Many OEMs only focus on nominal heating capacity during component selection, ignoring the compressor’s sustained performance under low ambient temperature and high hot water temperature. This article focuses on a mature model in Highly’s WHP series: Highly WHP32900VSKTQ9JK.
The WHP series is Highly’s dedicated rotary compressor line for heat pumps. Optimized for long-duration continuous heating, high water temperature and wide operating range, it enhances pump body, oil circuit, motor and shell pressure resistance. WHP32900VSKTQ9JK is one of the main models in this series for 15kW-class R290 air-to-water monoblock heat pumps.
1. Basic Positioning & Refrigerant Selection
WHP32900VSKTQ9JK is a DC inverter hermetic rotary compressor designed for R290 propane refrigerant. R290 features a GWP of only 3.3 with zero ozone depletion potential. It meets EU A+++ energy efficiency requirements and F-Gas regulations, making it the preferred solution for European monoblock heat pump exports.
Equipped with this compressor, the integrated air source heat pump typically delivers heating capacity in the 15kW class (varies with water and ambient temperature). It supports heating, domestic hot water and cooling all-in-one function, widely deployed in European residential and small commercial projects.
2. Core Operating Performance
WHP32900VSKTQ9JK is built for stable wide-range operation:
- Minimum ambient temperature for heating: -25°C; maximum ambient temperature for cooling: +43°C, suitable for cold climate heating in Northern and Eastern Europe.
- It can stably produce hot water up to 70°C with a short-time peak of 78°C to meet European high-temperature domestic hot water requirements. For cooling mode, the system delivers stable chilled water at 7°C with adjustable range up to 30°C.
- Wide speed inverter control delivers excellent part-load efficiency, cuts annual energy consumption and complies with European heat pump energy rating standards.
3. Structure & Reliability Design
- R290 Ignition-Proof Safety Design R290 is flammable refrigerant. The compressor terminal box and sealing components adopt ignition-proof design, complying with EU component safety requirements, serving as the foundation for the whole unit’s CE certification.
- Heat Pump-Specific Oil Return & Lubrication System Oil return becomes challenging under low-temperature and variable-load conditions. This model optimizes internal oil passages to guarantee stable refrigerant oil return at low speed and high water temperature, reducing wear from oil starvation and lowering after-sales failure rate for overseas units.
- Compact Horizontal Rotary Structure Horizontal rotary layout saves internal space, simplifies piping arrangement inside monoblock heat pumps and reduces footprint, fitting small European residential installations.
4. Practical Selection Guidelines
- Refrigerant restriction: Only R290 is permitted. R410A/R32 cannot be substituted. System and valves must match propane characteristics.
- Refrigeration oil: Must use Highly’s specified oil for WHP series. Incorrect oil type causes abrasion and shaft seizure, a common cause of overseas field failures.
- Control logic: R290 units require discharge temperature, high/low pressure and oil return protection. The controller must match the compressor’s inverter curve; air conditioner compressor control logic cannot be directly reused.
- Application limit: Designed for air source monoblock heat pumps. Not recommended for chillers, high-temperature drying or cascade systems beyond design operating conditions.
5. Market Value Summary
As EU F-Gas regulations tighten, low-carbon R290 heat pumps become mainstream. The Highly WHP32900VSKTQ9JK is not a modified air-conditioning compressor; it is a dedicated inverter rotary compressor engineered for R290, low-temperature heating and high hot water temperature.
Conclusion
The compressor is the heart of a heat pump. Most unit failures trace back to mismatched compressor operating performance. Field experience with WHP32900VSKTQ9JK proves that R290 heat pump compressors must be developed for year-round continuous heating duty instead of simple modification of air conditioning compressors.
