Split heat pump – optimal for new construction and modernization
Sound immissions and space requirements play a significant role when it comes to air source heat pumps. Split heat pumps are among the heating systems that not only take both factors into account, but also implement them optimally in practice.
Design and mode of operation of a split heat pump
A split heat pump consists of an indoor and an outdoor unit, whereby all components that can cause noise are installed in the outdoor unit. These include the fan, the evaporator and the compressor.
Accordingly, the indoor unit is compact and can be set up very flexibly in the home. Only the condenser, the circulation pump and the control and safety technology are located indoors. It is also extremely quiet, which is not only due to the split design, but to the coordinated components and a carefully considered, noise-optimised design.
The heat generation process can be repeated at will
During operation, the fan installed in the outdoor unit actively draws in outdoor air and channels it to the evaporator (heat exchanger). A refrigerant circulates inside the evaporator, which heats up at low temperature. Once the physical state of the refrigerant has changed, it flows as warm steam to the electrically powered compressor. This compresses the steam and thus raises its temperature to the level required.
The hot steam is then transferred via thin refrigerant pipes to the condenser, which is installed in the indoor unit. There, the hot steam transfers its thermal energy to the heating system and gradually cools down. Since it is still under high pressure, it must first pass through an expansion valve that restores its initial state. Once this step is complete, the process can start again.
Scheme of a split heat pump
Split heat pumps are characterised by their separation into a quiet indoor unit and an air handling outdoor unit.
Heat from the air
 Vitocal split air source heat pump, indoor unit
 Vitocal split air/water heat pump, outdoor unit
 DHW cylinder
Benefits of the split heat pump
The key benefit of a Viessmann split heat pump is its barely audible operation. The appliance has been designed and built in such a way that deep noises that are perceived as disturbing are shifted to a higher frequency. In addition, all split heat pumps from Viessmann include a night mode in which the sound power is further reduced. Use in areas with particularly strict legal requirements for sound emissions, such as in terraced housing or in health resorts, is harmless.
Cooling and heating possible
In addition to the modest footprint indoors, plus quiet operation, split heat pumps are prepared for reversible operation. This allows them to temper rooms to the required level in the hot summer months with the help of convectors or surface cooling systems. They are also modular in design, allowing for expansion. System owners can remain extremely flexible and have additional heat pumps installed if their heating or cooling needs increase. Other benefits of split heat pumps are:
- Low running costs due to high efficiency at all operating points
- Easy to operate Vitotronic control unit with plain text and graphic display
- Ready for connection to a solar system
- High operating convenience through remote control via ViCare app and smartphone/tablet
- High subsidy amounts available
As systems for heating only, or as systems that provide heating and cooling, these split air source heat pumps from Viessmann are ideal for new build and modernisation. This design does not require costly wall outlets or the routing of air ducts.
However, assembly of both units into a closed refrigeration circuit may only be carried out by a certified refrigeration specialist. In addition, the system user must have the refrigerant circuit of larger systems checked annually for leaks by a refrigeration specialist.
Split heat pumps product range
As systems for heating only, or as systems that provide heating and cooling, these units are ideal for new build and modernisation. This design does not require costly wall outlets or the routing of air ducts.