How does two-stage heating work?

PVT modules preheat the medium, and the main heat source raises the temperature to the required working value.

PVT modules preheat the medium, and the main heat source raises the temperature to the required working value.

Higher COP pump

PVT preheats the medium, thanks to which the heat pump operates in more favorable conditions. This improves seasonal efficiency and reduces electricity consumption.

Lower gas consumption

In the gas system, the boiler heats up the already raised temperature of the medium. The burner works less and less frequently, which reduces fuel consumption and operating costs

Stable operation of the system

Two-stage heating reduces load spikes and stabilizes the operation of the entire installation. The system maintains parameters more smoothly even with variable consumption

Less energy loss

With high demand for CWU, the installation responds faster to changes and works more effectively. This translates into less energy loss during peak hours.

Configuration no 1

PVT+ gas boiler

This is the basic variant of the system for buildings with a gas boiler room.

Description of operation:

PVT: preheating

PVT modules produce electricity and preheat the medium, offloading the main heat source.

Heat pump: main source

The system achieves better annual efficiency thanks to a lower heat pump load.

Boiler: the peak role

The gas boiler acts as a peak or emergency source, stabilizing the system at demanding moments.

Due to preheating of water by PVT:

PVT: preheating

PVT modules produce electricity and preheat the medium, offloading the main heat source.

Heat pump: main source

The system achieves better annual efficiency thanks to a lower heat pump load.

Boiler: the peak role

The gas boiler acts as a peak or emergency source, stabilizing the system at demanding moments.

Thanks to the preheating of water by PVT

The boiler consumes less fuel

The working time of the burner is reduced

decreases the load on the installation during peak periods

Nature of the solution

modernization of existing infrastructure

low degree of interference in the installation

reduction of gas consumption without changing the main heat source

transitional solution in the energy transition process

Configuration no 2

PVT + gas boiler + heat pump

In this variant, the system is expanded with a heat pump, which takes over the role of the main heat source in typical operating conditions.

Description of operation:

Preheating by PVT

PVT modules produce electricity and at the same time preheat the medium, relieving the main heat source.

Heat pump as a primary source

The heat pump (air or ground) takes over the role of the primary heat source for CWU and/or CO.

Gas boiler as a security

The gas boiler acts as a peak or backup source, supporting the system during high demand or in exceptional situations.

Two-stage heating in this configuration increases the efficiency of the heat pump because:

Better compressor operating conditions

Thanks to the preheating of the medium by PVT, the compressor operates at a higher inlet temperature, which improves the stability of the system.

Higher seasonal COP

Two-stage heating increases the efficiency of the heat pump over the entire season, improving system performance in daily operation.

Lower electricity consumption

The heat pump requires less energy to achieve operating parameters, which translates into lower costs and better installation economics.

Nature of the solution

significant reduction of operating costs

operational flexibility

peak power security through gas

the possibility of gradually reducing the share of fossil fuels

Configuration 3

PVT + heat pump (without gas)

A variant intended for investments focused on maximising the share of renewable energy.

Description of operation:

Energy from PVT modules

PVT modules simultaneously generate electricity and thermal energy, providing real support for the operation of the entire heating system.

Heat pump as the core

The heat pump, also in a high-temperature version according to our design, serves as the only main heat source.

Stability through buffers

Enlarged domestic hot water tanks and a central heating buffer stabilise the operation of the installation and maintain parameters even under variable sunlight conditions.

Intelligent system automation

The control automation optimises energy flows between PVT, the heat pump, and heat storage, increasing the efficiency of the system.

In this configuration, energy is obtained from:

solar radiation (PVT)

outdoor air (heat pump)

Nature of the solution

no gas infrastructure

high annual energy efficiency

reduction of CO₂ emissions

preparation of the building for low- and zero-emission standards.

See also:

Hybrid HVAC systems with Ice Energy Storage (ICE) and PVT modules

Hybrid HVAC systems with Ice Energy Storage (ICE) and PVT modules

2026-03-19|0 Comments