A scientific study has highlighted the potential of thermal storage for photovoltaics, dynamic electricity tariffs and flexible electricity usage.
How can electric heating systems be better integrated with renewable energy and photovoltaic systems in the future, given fluctuating electricity prices? What impact do different heating systems have on thermal comfort and temperature distribution within a room?
Dresden University of Technology (TU Dresden) investigated these questions in a comprehensive metrological and energy-related study. On behalf of LUCHT LHZ Elektroheizung GmbH & Co. KG, various electric heating systems were examined under controlled and comparable conditions.
Particular emphasis was placed on the storage heater TECHNOTHERM Dynamo. This system’s dual-storage technology is designed to store electrical energy as heat, decoupling electricity consumption from actual heating demand over time.
The study confirms that the TECHNOTHERM Dynamo provides consistent thermal comfort while enabling a significant proportion of electricity consumption to be shifted to cheaper periods.
Aim of the study
The energy transition is creating new demands for electricity consumers. Electricity generated from photovoltaic and wind power is not always available when it is needed. At the same time, dynamic electricity tariffs mean that prices can vary considerably throughout the day.
Electric heating systems with thermal storage can play a key role in addressing this issue. They absorb electrical energy, convert it into heat, and store it for later use.
Dresden University of Technology therefore focused its research on:
- how evenly various heating systems heat a room
- how the perceived temperature changes at different positions within the room
- how much electrical energy is consumed during the period of use
- how prior storage charging affects subsequent electricity consumption
- what potential exists for time-of-use load shifting
- and how different electricity prices and the use of self-generated PV electricity can affect costs.
Testing under controlled conditions
The measurements were carried out at the Combined Energy Laboratory at Dresden University of Technology. This enabled environmental conditions to be controlled and different thermal loads to be simulated in a realistic setting.
Various electric room heating systems were compared, including:
- the TECHNOTHERM Dynamo with dual-storage technology
- a conventional electric storage heater
- and infrared heaters in various configurations.
The systems were tested under several load conditions. The analysis did not focus solely on the measured room air temperature. The so-called perceived temperature is also crucial for actual thermal comfort. In addition to air temperature, it takes into account the radiant temperatures of surrounding surfaces.
This made it possible to assess whether the heat was distributed evenly throughout the room, or if the perceived temperature varied significantly depending on where a person was standing.
Consistent thermal comfort throughout the room
A key finding of the study was the highly homogeneous temperature distribution achieved by the TECHNOTHERM Dynamo.
In the load cases examined, the maximum difference in perceived temperature for the Dynamo was just 0.25 to 0.45 Kelvin. This resulted in a remarkably consistent perceived temperature at the various measurement points throughout the room.
The partial storage heating system tested also achieved largely uniform heat distribution. By contrast, the wall-mounted infrared heating system produced differences in perceived temperature ranging from 3.8 to 4.6 Kelvin depending on the load case and occupant position.
These results highlight the significant difference between radiant heating, which acts predominantly at specific points, and a heating system designed to evenly heat the entire room.
According to the study’s findings, the Dynamo and the partial storage heater provide particularly uniform thermal conditions in rooms where people occupy different positions.
Storing heat before it is needed
The particular strength of the TECHNOTHERM Dynamo lies in its integrated thermal storage unit.
In the test, the storage unit was charged electrically prior to the usage period. Under the selected test conditions, it took the unit approximately 1 hour and 15 minutes to fully charge.
This energy was stored as heat within the unit and released into the room in a controlled manner over a longer period. This meant that a significant proportion of the electrical energy required for space heating could be used earlier.
This is the key difference compared to conventional direct heating systems, where electricity consumption and heat release must take place at the same time.
Proven potential for load shifting
During the four-hour usage period, the TECHNOTHERM Dynamo consumed less electrical energy than the systems used for comparison in all three examined load cases.
This was due to the heat stored in the unit prior to use. Subsequently, the Dynamo was able to heat the room considerably using its thermal storage.
Taking the 60 per cent load case under investigation as an example, the following values were measured during the four-hour operating period:
- TECHNOTHERM Dynamo: 1,752.5 Wh
- Partial storage heater: 2,813.0 Wh
- Wall-mounted infrared heater: 3,236.1 Wh
A further 1,490.7 Wh was required to charge the storage system before the usage period began in the case of the Dynamo. Therefore, the study does not show that charging the storage system generally results in lower overall energy consumption.
The key advantage lies in the fact that a significant proportion of electricity consumption can be shifted to an earlier, specifically selectable time.
This temporal flexibility is of great importance for an energy system based on renewable energy sources.
Potential for dynamic electricity tariffs
With these tariffs, the price of electricity fluctuates throughout the day. Hours when there is a high supply of electricity can be significantly cheaper than periods of high demand.
An electric heating system without significant storage capacity must draw most of its electricity at the moment heat is needed. The TECHNOTHERM Dynamo, on the other hand, can be charged during cheaper time slots and release the stored heat later.
In a sample scenario analysed by TU Dresden, the initial charging period was assumed to cost 0.15 euros per kilowatt-hour and the subsequent usage period 0.40 euros per kilowatt-hour.
Under these assumptions, operating the Dynamo was more cost-effective than operating partial storage or infrared heating systems in most cases.
However, the actual savings depend on factors such as the building, heat demand, usage pattern, control system and available electricity tariffs. Nevertheless, the study generally demonstrates the economic potential of targeted time-shifted load management.
Your own solar power can be used for heating
Another potential application arises in conjunction with a photovoltaic (PV) system.
While PV electricity is often available at midday, a building’s heating requirements may be higher in the early morning or evening. Without a storage system, therefore, not all of the solar power generated can be used for space heating.
The TECHNOTHERM Dynamo can be charged during periods of surplus PV electricity. This electrical energy is converted into heat, stored in the unit, and can be used for space heating at a later time.
In another calculation scenario, TU Dresden considered charging the storage tank with self-generated PV electricity at an assumed cost of €0.08 per kilowatt-hour. Under these conditions, the economic benefit of pre-charging was further enhanced.
Thus, the thermal storage system can help increase the self-consumption of a photovoltaic system and reduce the purchase of more expensive grid electricity during subsequent usage.
Implications for buildings and the electricity grid
Electric heating systems with thermal storage have the potential to do more than just generate heat. With intelligent control, they can be developed into flexible consumers within the energy system.
Ideally, charging should take place at times when:
- there is sufficient self-generated PV electricity available;
- there is a high level of renewable energy available on the electricity grid;
- overall electricity demand is low,
- or when dynamic electricity prices are particularly favourable.
Conversely, during periods of high grid load or high electricity prices, electricity consumption can be reduced while stored heat remains available for room heating.
Thus, the study by TU Dresden demonstrates the potential of decentralised thermal storage systems for grid-friendly and cost-effective electrical energy use.
An overview of the key findings
The study by TU Dresden shows that:
- The TECHNOTHERM Dynamo ensures a very uniform perceived temperature throughout the entire room under investigation.
- The maximum spatial temperature difference for the Dynamo was only between 0.25 and 0.45 Kelvin.
- Under the test conditions, the thermal storage unit could be fully charged in around 1 hour and 15 minutes.
- During the subsequent four-hour operating period, the Dynamo required less additional electrical energy than the comparison systems in all three examined load cases.
- A significant proportion of the electricity consumption could be shifted to before the usage period.
- This allows the Dynamo to benefit from favourable time slots in dynamic electricity tariffs.
- When combined with a photovoltaic system, self-generated solar power can be stored as heat and used at a later time.
- The economic benefits primarily arise from the timing of electricity consumption rather than from a blanket promise of lower overall energy consumption.
- Electric heating systems with thermal storage can contribute to more flexible electricity usage, which benefits the grid.
Conclusions of the study
The study, conducted by Dresden University of Technology, confirms the basic technical principle of the TECHNOTHERM Dynamo. Electrical energy can be absorbed before the heating phase begins, stored within the unit, and released as heat into the room as and when required.
At the same time, the Dynamo achieves an even temperature distribution throughout the room, providing a high level of thermal comfort.
Its key advantage lies in its flexibility in terms of timing. Electricity can be used primarily when it is cheap, such as when using self-generated PV electricity, or when large quantities are available from renewable sources.
The TECHNOTHERM Dynamo thus meets three essential requirements for future-oriented electric space heating:
High thermal comfort, thermal storage, and flexible control over electricity consumption.
Download the study
“Metrological and Energy Analysis of Room Heating Using Various Electric Heating Appliances and Their Potential for Load Shifting”
Dresden University of Technology, Institute of Energy Technology
Final report, 2 June 2026
