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Heat Pump DH1

The DH1 is an all-electric driver cabin HVAC unit with reversible heat pump technology, delivering efficient heating, cooling, and windscreen demist/defrost for zero-emission vehicles.

Designed for bus, coach, off-highway, special vehicles and commercial vehicles, it provides reliable cabin comfort across extreme conditions, while reducing energy consumption compared to PTC-only systems.

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Overview

The DH1 Heat Pump combines driver climate comfort and safety-critical windscreen clearing in one compact, plug-and-play system. Using reversible heat pump technology, it delivers efficient heating in low ambient temperatures, supported by optional PTC elements for operation down to -15°C.

All major components (electric compressor, heat exchangers, controller, and complete refrigeration system) are packaged into a single assembly, supplied pre-charged for fast installation with no on-site commissioning. Integrated CAN J1939 communication ensures seamless vehicle integration and control.

Configurable to your platform needs, the DH1 can operate in heat pump-only mode or heat pump + air conditioning mode, with fresh air, recirculated, or mixed airflow. Designed for durability and quick service exchange, it minimises vehicle downtime and total cost of ownership.

Features

Developed for driver and cabin HVAC, our heat pumps combine effective climate control with dependable year-round operation.

  • Reversible heat pump technology: Efficient heating in cold climates reduces reliance on energy-intensive PTC heaters.
  • All-in-one packaged system: Compressor, heat exchangers, controller, and refrigeration circuit supplied as a single assembly.
  • Plug-and-play installation: Pre-charged with refrigerant, requiring only HV, LV, and CAN connections.
  • PTC heating option: Provides reliable low-ambient heating and defrost capability down to -15°C.
  • Flexible airflow modes: Available in fresh air, recirculated air, or a combination to suit application needs.
  • Integrated CAN J1939 control: Ensures smooth communication and control within vehicle systems.
  • Designed for service exchange: Enables rapid replacement to minimise downtime and reduce maintenance costs.
  • High efficiency COP: COP >2.0 at -5°C ambient, reducing energy draw in real-world operation.
Technical

Every component in the system supports precise temperature regulation, improving efficiency and ensuring reliable performance in service.

  • High Voltage range: 420 – 750V DC (Compressor)
  • Nominal High Voltage: 600V DC
  • Nominal Low Voltage: 24V DC (Blowers / Control)
  • Refrigerant: R407C (1.3kg)
  • Heating performance*: 8kW @ 0°C ambient, COP 1.95 / 6kW @ -5°C ambient, COP 1.98
  • Cooling performance**: 3.5kW @ 40°C ambient, 18°C air-off temperature
  • Dimensions (L x W x H) (mm): 1155.5 x 288.5 x 544
  • Weight (kg): 53kg
  • Minimum operating temperature: -15°C (with PTC assist)
  • Maximum operating temperature: +45°C
Model Variations

Available in a choice of specifications, our heat pump range offers flexibility to match vehicle type, thermal demand, and layout constraints.

  • 3F-10002-0F02: Heat pump only, 4kW PTC heating, recirculated air (no AC, PEPA-F filters)   
  • 3F-10009-0D02: Reversible heat pump, no AC 2kW PTC, 95% fresh air        
  • 3F-10009-0D03: Reversible heat pump with AC, 2kW PTC, 95% fresh air
Heating Capacity

8kW @ 0°C ambient

Delivers high-capacity heating and defrost for driver cabins in cold environments.
Voltage Range

420–750V DC

Compatible with a wide range of high-voltage architectures.
Cooling Capacity

3.5kW @ 40°C

Provides efficient cabin cooling and windscreen demist at high ambient.
Operating Temperature Range

-15°C to +45°C

Designed to perform reliably in both low and high ambient conditions.
Download Full Specification Sheet
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Compatible Applications

Product Benefits​

See why OEMs have selected Grayson’s DH1 Heat Pump to deliver reliable climate control for drivers in all conditions.

All-In-One Packaged System

Complete refrigerant circuit and control system integrated into one unit for easy specification and integration.

Quick and Simple Installation

 Complete reversible heat pump system supplied pre-charged with gas for easy installation and no commissioning required.

Flexible Configuration

Heat pump-only or heat pump + AC mode, with airflow tailored to platform needs.

Low-Ambient Operation

Optional PTC heaters ensure heating and defrosting down to -15°C ambient.

Contact Us

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For over four decades, Grayson Thermal Systems has been trusted worldwide to deliver dependable thermal management solutions. Our expertise ensures vehicles stay efficient and reliable, year after year.