Description
Thermal energy storage · fireclay core · 7–8 hours charge window
Store surplus electricity as useful room heat
TECHNOTHERM TTB-E 7 Duo 26+ converts electricity into heat inside a substantial fireclay storage core. The offered model uses 2.55 kW charging input and stores approximately 20.4 kWh during its nominal cycle. It is designed for projects where electricity is available before the heat is needed—particularly photovoltaic surplus, time-of-use tariffs and controlled charging periods.
This is energy storage, not an ordinary portable electric heater. The charging element heats the core, the cabinet releases stored energy gradually, and a separate direct-heating element can cover short-term demand. The result is a controllable thermal load that can move part of the building’s electricity consumption into a more favourable time window while maintaining room comfort.
Why thermal storage
A practical destination for photovoltaic surplus
A battery stores electricity and returns electricity. A thermal store converts electricity into heat and returns heat. Where space heating is a real building load, that conversion can be an efficient and economically direct use of surplus generation. It avoids using an electrochemical battery cycle for energy that would ultimately be converted into heat anyway. The two technologies can also complement each other: batteries support electrical loads, while the storage heater absorbs planned thermal demand.
TECHNOTHERM TTB-E 7 Duo 26+ is sized for approximately approximately 20 m² only as an early orientation. Actual selection depends on the calculated room heat loss, insulation, outside design temperature, desired indoor temperature, available wall position, electrical connection and the duration of the charging window. A renovated room may need much less input than an uninsulated room of the same area. WodaTherm therefore confirms the heat requirement before finalising the model.
Charge when energy is available
The 7–8 hours charging concept can be coordinated with PV surplus, a tariff window or an energy-management relay.
Fireclay storage core
A substantial fireclay mass absorbs electrical energy as heat and releases it gradually instead of producing only short-lived direct heat.
Quiet heat delivery
Radiant and natural convective output provide comfortable room heat without a continuously running fan.
Direct-heating reserve
The integrated direct element can respond when the stored heat alone is not enough, subject to the selected control programme.
Only 18.5 cm deep
The shallow cabinet places meaningful thermal mass close to the wall while preserving usable floor space.
Sized for the room and charging window
This 26+ version is selected for the room heat loss and available charging power, not by room area alone.
Operating principle
Charging, storing and controlled heat release
During an authorised charging period, resistance elements convert electricity into heat inside the fireclay core. The mass stores that heat and the insulated cabinet moderates how quickly it reaches the room. Heat is delivered through radiation from the housing and controlled air movement through the appliance. Charging and room temperature are coordinated by the electronic control rather than by repeatedly switching a simple plug thermostat.
The 7–8 hours version is selected according to the energy window available to the project. A shorter window needs more instantaneous charging power to place the same approximate amount of heat into the storage mass. A longer window spreads the electrical demand over more hours and may suit steady PV diversion or a wider low-price tariff period. This version charges at 2.55 kW; the electrical design must reserve that load in addition to any direct-heating element.
Stored heat continues to enter the room after active charging has stopped. The direct-heating element is available for rapid correction when occupancy or weather produces more demand than expected. Good control strategy prevents that direct element from masking an undersized storage calculation or consuming expensive peak electricity without need.
Technical data
Dimensions, power and storage capacity
TTB-E cabinets look similar across several sizes and charging variants. The values below apply to TECHNOTHERM TTB-E 7 Duo 26+. Width, mass, heater input and direct-heating output change between versions. The room-size indication is not a substitute for a heat-loss calculation, and connection details must be checked against the current manufacturer manual supplied with the appliance.
| Model | TTB-E 7 Duo 26+ |
|---|---|
| Charging input | 2.55 kW |
| Nominal charging window | 7–8 hours |
| Nominal stored charge | 20.4 kWh |
| Maximum nominal charge | 23.2 kWh |
| Direct-heating element | 750 W |
| Indicative room size | approximately 20 m²; verify by heat-loss calculation |
| Dimensions W × H × D | 885 × 715 × 185 mm |
| Approximate weight | 124 kg |
| Storage-stone packs | 6 packs |
| Supply | 230 V, 1/N/PE, 50 Hz |
| Protection class | Class I |
| Cabinet depth | 185 mm |
| Finish | RAL 9003 white |
| Control | Electronic thermostat with daily/weekly programmes and supported app functions |
| Heat delivery | Radiation and natural convection with designed upper/lower air paths |
| Installation | Permanent mounting and electrical connection by qualified professionals |
Energy management
Use the storage heater as a controllable load
A PV meter, dynamic-tariff controller or building energy-management system can identify favourable charging periods. The control concept must still respect the heater’s permitted inputs and the room’s required stored charge. A simple surplus contact may be adequate in one project; another may need staged control, load limitation or coordination with an EV charger and battery inverter.
The objective is not to force every spare watt into the heater. It is to charge enough heat for the expected room demand at the most suitable times. That approach avoids unnecessary overheating, reduces peak demand and makes the storage mass an intentional part of the building’s energy plan.
Comfort
Radiant and convective output
The warm cabinet contributes radiant heat while the designed air paths support natural convection. This mixed output produces a more even sensation than a small, high-temperature fan heater. The appliance is suitable for living, working and transition spaces where quiet operation matters.
Daily and weekly programmes, adaptive control and open-window detection can reduce avoidable energy use. The best programme reflects occupancy and the building’s thermal response. A heavy room and a lightweight room do not cool down at the same rate, even when their floor area is identical.
Installation
The mass, wall and electrical circuit must be planned together
This appliance is heavy. The finished wall, floor and anchors must accommodate the model weight and the manufacturer’s mounting geometry. Required clearances must be maintained around furniture, curtains and other heat-sensitive materials. The intended position should be agreed before delivery because moving an assembled storage heater is not comparable to moving a panel radiator.
A qualified electrical professional must provide the 230 V connection, protective conductor, circuit protection, isolation and control wiring. The charging input and direct-heating input must be included in circuit and load calculations. Where an external energy-management contact is used, its function and fail-safe behaviour must be verified during commissioning.
Commissioning should confirm the product designation, installed storage stones, thermostat operation, charge permission, direct-heat response and temperature limits. The installer must follow the current TECHNOTHERM manual. Do not cover the appliance, obstruct air paths or operate it before the storage core and cabinet have been assembled correctly.
Delivery and scope
Made-to-order planning without hidden assumptions
Made to order; estimated delivery 2–4 weeks. Because the heater is heavy and made to order, WodaTherm confirms the delivery address, access route and unloading conditions. The order is accepted online at the displayed price; supplier confirmation establishes the final dispatch date.
The order includes the specified heater and manufacturer-supplied components stated in the confirmation. Electrical installation, energy-management hardware, building work, special carrying service and commissioning are included only when explicitly quoted. Storage stones and transport packages must be handled according to the manufacturer instructions.
Product photographs represent the TTB-E family. Cabinet width changes with size, and minor control or grille details can change with the production revision. The order number in the technical table identifies the heater being purchased.
Verified references
Manufacturer product data
TECHNOTHERM product family · Installation and operating manual
WodaTherm’s explanation is original editorial content based on current manufacturer material. The linked documents remain authoritative for installation and can be updated by TECHNOTHERM.
