I. Product Overview

The screw-type ultra-low temperature air source heat pump is a large-scale heating unit centered around a twin-screw compressor. Specifically developed for centralized heating needs in severe cold regions, it can operate stably at ambient temperatures as low as -35°C, with a maximum outlet water temperature of up to 70°C. The single-unit maximum heating capacity can reach 315 kW or more, capable of replacing 0.5-ton or larger coal-fired or gas-fired boilers. It is a leading product for clean heating projects in cold regions.

II. Working Principle

The screw-type ultra-low temperature air source heat pump operates on the reverse Carnot cycle, with a closed-loop system consisting of four main components: the evaporator, compressor, condenser, and expansion valve. Its core lies in the breakthrough of compression technology.

In heating mode, the liquid refrigerant absorbs heat from the outdoor air in the evaporator and evaporates into a low-temperature, low-pressure gas. The gaseous refrigerant then enters the screw compressor for two-stage compression. The refrigerant is divided into two stages for compression, and through vapor injection enthalpy enhancement technology, medium-pressure refrigerant is injected into the compressor chamber during the compression process—significantly increasing the refrigerant enthalpy and ensuring sufficient heat extraction even in ultra-low temperature environments.

The compressed high-temperature, high-pressure refrigerant gas enters the shell-and-tube condenser, where it releases heat to the circulating water, heating it to 35–70°C before supplying it to the heating terminals. After releasing its heat, the refrigerant condenses into a liquid, passes through the expansion valve to reduce pressure, and returns to the evaporator to begin the next cycle. The entire process consumes only a small amount of electrical energy to drive the compressor, resulting in far superior energy efficiency compared to direct electric heating methods.

In addition, the unit is equipped with an intelligent defrosting control system that automatically adjusts defrosting criteria and parameters based on changes in outdoor temperature, time since last defrost, and frost accumulation—without requiring manual intervention. This ensures adaptability to various climates and effectively guarantees continuous heating capacity in low-temperature environments.

III. Core Features

Ultra-Low Temperature Stable Operation:
With two-stage screw compression technology combined with a vapor injection enthalpy enhancement system, the unit can operate stably at ambient temperatures as low as -35°C—significantly expanding the application range of air source heat pumps to cover winter heating needs in Northern Europe, North America, Russia, Central Asia, East Asia, and other cold regions.

High Outlet Water Temperature for Wide Applicability:
The outlet water temperature range covers 35–70°C, allowing flexible matching with various heating terminals including underfloor heating, radiators, and fan coil units—meeting the heating needs of diverse building types.

Large Heating Capacity for Boiler Replacement:
Single-unit heating capacity can reach 300 kW to over 1,000 kW. Multiple units connected in parallel can meet centralized heating demands for buildings covering tens of thousands of square meters. This makes it an ideal replacement for coal-fired, oil-fired, and gas-fired boilers, particularly suitable for environmental retrofitting projects where traditional boilers must be phased out.

High Energy Efficiency:
Two-stage compression cycles improve efficiency by over 10% compared to single-stage cycles. Combined with dual variable frequency drives and adjustable Vi technology, the system can precisely match output under partial load conditions—avoiding energy waste. Some products achieve an annual integrated COP of over 3.15, demonstrating significant comprehensive energy efficiency advantages.

Intelligent Control and Remote Management:
Equipped with a microprocessor-based intelligent control system, the unit supports stepless regulation from 25% to 100%, automatically adjusting output based on actual heat load. The system also supports IoT cloud platform connectivity, allowing users to monitor real-time operating status, energy consumption data, and receive fault alarms via computer or mobile devices—enabling remote monitoring and scientific energy management.

Reliable Operation and Easy Maintenance:
The dual-compressor design provides mutual backup. When one compressor requires maintenance, the other continues to operate—ensuring uninterrupted heating. The screw compressors feature a semi-hermetic design for smooth operation and long service life, with oil separation efficiency reaching 99.9%—ensuring long-term stability of the lubrication oil circulation system.

Environmentally Friendly Refrigerants for Green and Low-Carbon Operation:
R410A and other environmentally friendly refrigerants are used, with an Ozone Depletion Potential (ODP) of zero. This meets the requirements of international environmental agreements on refrigerants and contributes to global greenhouse gas reduction targets.

IV. Main Applications

Screw-type ultra-low temperature air source heat pumps are widely used in various centralized heating projects in cold regions, including large residential communities, office buildings, commercial complexes, schools, hospitals, and other public buildings. In the industrial sector, they are used for large-area heating in factory workshops and warehousing logistics centers. Additionally, they have proven applications in special scenarios such as mine shaft anti-freeze heating, ensuring safe production in extremely cold weather conditions.

The units typically also offer cooling functionality, enabling dual-purpose use—meeting summer air conditioning needs as well. This makes them particularly suitable for comprehensive building projects that require both winter heating and summer cooling.