Monobloc heat pumps

A monobloc heat pump uses the ambient air to generate thermal energy for heating purposes. In contrast to split heat pumps, the refrigerant circuit of monobloc heat pumps is located in a single unit. This article explains the advantages of this design and important factors when deciding on a monobloc heat pump.

What is a monobloc heat pump?

A monobloc heat pump is a type of heat pump system that is used to heat and, with some adaptations, cool buildings. In contrast to a split heat pump, which consists of an indoor and an outdoor unit, the monobloc heat pump is a compact unit in which all technical components are housed in one casing.

The monobloc heat pump consists of a compressor, a condenser, an expansion valve and an evaporator.

In a monobloc air-to-water heat pump, the outside air is fed to the heat exchanger, where the heat energy is absorbed. The refrigerant in the heat exchanger absorbs the heat energy and is vaporized in the process. The compressor increases the pressure and temperature of the vaporized refrigerant, which further increases the temperature. The hot refrigerant then flows through the heat exchanger, where it transfers its heat energy to the heating or hot water system. The cooled refrigerant flows back to the evaporator, where it again absorbs heat energy from the outside air, and the cycle starts all over again.

Monobloc heat pumps are easy to install as they only require one unit, and they take up less space compared to split heat pumps. They are often a good option for buildings where lack of space or architectural restrictions make it difficult to install a split heat pump. Common output sizes of monobloc heat pumps vary between 6 kW and 42 kW.

Which is better: monobloc or split heat pump?

The question of whether a monobloc or split heat pump is better depends on various factors, including the specific requirements and conditions of the building. In principle, both heat pump concepts can be implemented in new and existing buildings. Here are some advantages and disadvantages of both systems:

Monobloc heat pump

Advantages:

1. Simple installation: A monobloc heat pump does not require complex installation as all components are housed in one unit. This can reduce installation time and costs. No refrigeration certificate is required for installation.
2. Space-saving: As only one unit is required, a monobloc heat pump takes up less space compared to a split heat pump, which has an indoor and an outdoor unit.
3. Noise pollution: As a rule, monobloc heat pumps are installed outside. This means there is no disturbing noise inside the house.
4. No refrigeration certificate required.

Disadvantages:

1. Monoblocks installed indoors (not the rule) require more intrusive interventions in the building envelope (e.g. large supply and exhaust air ducts)
2. Noise: As the fan and compressor are housed in one unit, a monobloc heat pump can be somewhat louder than a split heat pump.
3. Due to their design,monobloc heat pumps installed outdoors are larger than the outdoor units of split appliances. This is a disadvantage if there is a lot of space inside and little outside.

Split heat pump

Advantages:

1. Flexibility: A split heat pump offers greater flexibility in the positioning of the indoor and outdoor units. This enables optimum positioning and better integration into the building.
2. Noise reduction: As the compressor and most of the noise takes place outdoors, a split heat pump can be quieter indoors than a monobloc heat pump.
3. Efficiency: Split heat pumps can operate more efficiently due to their placement, scalability and performance classes.

Disadvantages:

1. More complex installation: a split heat pump requires the installation of indoor and outdoor units and a refrigerant line between them. This can lead to additional installation work and costs.
2. Distance between outdoor and indoor unit: Longer distances between the outdoor and indoor units often involve more than 3 kg of refrigerant in the refrigerant lines. Regular inspection of the refrigerant circuit is required.
3. Refrigeration certificate required

Ultimately, the choice between a monobloc and a split heat pump depends on the specific needs, requirements and conditions of the building. It is advisable to seek advice from our specialist staff to determine the best option for your specific scenario.

How does an air-to-water heat pump in monobloc design work?

An air-to-water heat pump in monobloc design uses the outside air as a heat source and converts this energy into heat that is used for heating or hot water in a building. Here is a rough description of the operating principle of such a heat pump:

1. Absorption of outside air: the monobloc heat pump draws in outside air via a fan and feeds it into the heat exchanger. The heat exchanger consists of finned tubes that absorb the heat energy from the air.
2. Heat transfer: The absorbed heat energy is transferred to the refrigerant in the tubes of the heat exchanger. The refrigerant has a low boiling point, which can be lower than the outside temperature level depending on the conditions.
3. Compression: The refrigerant is compressed by the compressor in the heat pump, which increases the pressure and temperature of the refrigerant. This also increases the temperature of the thermal energy.
4. Heat release: The hot, compressed refrigerant flows into the second heat exchanger. There, the refrigerant releases its heat energy to the water, which is transferred via well-insulated pipes to the heat storage tanks inside the building and used for heating or hot water preparation.
5. Expansion: The cooled refrigerant flows through the expansion valve, which reduces the pressure and temperature. This allows the refrigerant to absorb heat from the outside air again and start the cycle all over again.

The process of heat absorption, compression, heat release and expansion is repeated continuously to ensure a continuous supply of thermal energy to the building.

It is important to note that this is a simplified representation of the operating principle of an air-to-water heat pump in monobloc design. The exact design and operation may vary depending on the manufacturer and model.

How do I connect a monobloc heat pump?

The exact installation of a monobloc heat pump may vary depending on the manufacturer and model. It is recommended that all settings and parameters are made according to the manufacturer's instructions. To ensure that the installation is carried out correctly and safely, we recommend that you always consult a specialist. A rough overview for connecting a monobloc heat pump is as follows:

1. Site selection: Choose a suitable location for the monobloc heat pump outdoors. Make sure that there is enough space and that the unit is not blocked by obstacles. Also check the surrounding area to ensure that there is sufficient airflow and that noise pollution is minimized.
2. Mounting the heat pump: Fix the monobloc heat pump securely to a foundation or wall in accordance with the manufacturer's instructions. Ensure that the appliance is stable and level.
3. Connecting the pipes: Normally there are supply and return pipes for the heating or hot water system. Make sure that the pipes are properly insulated to minimize heat loss and connect the pipes according to the manufacturer's instructions.
4. Electrical connection: A specialist electrical company should carry out the electrical connection. The electrical regulations and the correct voltage and current values must be observed.
5. Commissioning and settings: Observe the manufacturer's instructions for operating the appliance. This may include the selection of heating or cooling mode, temperature settings and other operating parameters. Do not forget to follow the recommendations for regular maintenance and cleaning.

We will be happy to assist you with commissioning.

Monobloc heat pump for outdoor installation only

In our opinion, a monobloc heat pump should only be installed outdoors. This allows flexible installation according to the requirements and conditions of the building.

With outdoor installation, the entire monobloc heat pump is placed outdoors. The thermal energy is absorbed from the outside air, converted into heat inside the heat pump and usually conducted to the heat storage tank in the boiler room of the house via underground pipes. This approach is particularly advantageous if there is only limited space inside the building or if an inconspicuous installation is desired.

The design therefore always depends on individual factors such as the size of the building, the accessibility of the outside area and local regulations.

Advantages and disadvantages of monobloc air-to-water heat pumps

Monobloc air-to-water heat pumps offer certain advantages and disadvantages that should be considered when deciding on a heating system. Here are some of the main advantages and disadvantages of monobloc air-to-water heat pumps:

Advantages

1. Ease of installation: Monobloc heat pumps are easier to install compared to split heat pumps as all components are housed in one unit. This can reduce installation time and costs.
2. Space saving: As only one unit is required, monobloc heat pumps generally take up less space compared to split heat pumps, which require a separate indoor and outdoor unit.
3. Reduced maintenance: Monobloc heat pumps have fewer moving parts and no refrigerant pipes to maintain or repair. This can reduce maintenance costs.

Disadvantages

1. Limited flexibility: Monobloc heat pumps have less flexibility in placement compared to split heat pumps. Long pipes to/from the appliance can lead to a risk of freezing.
2. Noise level: Depending on the heat output and quality of the pump used, the noise level can be between 30 and 60 dB. As a rule, however, monobloc heat pumps are somewhat louder than split appliances. Please find out in advance about the applicable limit values for the noise level of heat pumps. In the vicinity of hospitals and nursing homes, for example, different limits apply than in residential areas or core, mixed and village areas.
3. Lower efficiency: Due to the more compact design and the limited size of the heat exchanger, monobloc heat pumps may have a slightly lower efficiency and scalability compared to split heat pumps.

It is important to note that the advantages and disadvantages of a monobloc air-to-water heat pump depend on various factors, such as building size, heat demand, ambient conditions and individual preferences. It is advisable to seek advice from our team of experts to determine the best heating solution for your specific scenario.

Are monobloc heat pumps eligible for subsidies?

The eligibility of monobloc heat pumps can vary depending on the country, region and specific subsidy program. In many states, there are funding programs and incentives to support energy efficient heating systems such as heat pumps. These programs may include financial assistance, grants, tax credits or loans.

The government is currently creating a framework for regenerative climate solutions via the Federal Subsidy for Efficient Buildings (BEG). An investment grant of up to 40% is conceivable here. However, this is linked to various conditions. For example, the installation of a heat pump in an old building can be subsidized with 25% of the investment costs. This can be increased to 35% if you replace a functioning oil, coal or night storage heating system or a 20-year-old gas heating system. The condition here is that you no longer use fossil fuels for heating after the replacement. With a R290 heat pumpheat pump that uses propane as a refrigerant, the subsidy can be increased by a further 5% to 40%.

In addition to state subsidy programmes, local energy supply companies, municipalities or other organizations can also offer their own regional subsidies for heat pumps. It is worth asking these organizations about possible funding opportunities.

Discover our other product range

In addition to high-quality heat pumps, we also offer innovative solutions for energy storage. One brand that we particularly recommend in this area is Voltsmile. Their intelligent energy storage systems help you to take your energy independence to the next level.