Use renewable energies and reduce the use of fossil heat carriers as much as possible: With the BRUNNER central heating system (BHZ), your heating system becomes an intelligent heating system. We have drawn on decades of experience, the needs of our customers and trade partners, as well as the latest technical developments in the design of the BHZ. The result is a convertible and expandable system that intelligently controls modern heating. A heating system of the future.
The use of regenerative heat sources is not only appealing, but also provided for by law. The resulting combination possibilities are great. A heating solution in a new building will differ from that of a refurbishment in an old building. The living situation determines which operating effort can be managed. The system storage and hydraulic box can be directly coupled together or spatially separated from each other. Whether simple or complex - it can be realised in any case with a BRUNNER heating system.
For the version with fossil heat generators, the operator decides whether they are to be used as a thermal backup or as the main heating system. Here, too, the concept is clearly defined: Use regenerative energies and reduce the use of fossil heat carriers as much as possible. Should life situations change, the choice of heat generators and consumers can be adjusted accordingly.
Remuneration for self-generated solar power is getting lower and lower, while electricity prices for private use continue to rise. Owners of photovoltaic systems are looking for ways to not only generate household electricity, but also to heat with their own electricity. With the BRUNNER heating system, surplus solar power can be used as an additional heat source. BRUNNER has developed a simple plug & play solution for the trade. Without any special knowledge, photovoltaic systems from 3 kWp can be universally integrated into the heating concept of the BRUNNER central heating system. All the necessary components (electricity meter, power controller) are matched to each other.
The plate heat exchanger installed in the BRUNNER central heating system heats the water to the desired temperature only when required. Only the amount of hot water required is heated - no more and no less. Depending on the design, tap rates of up to 40 l/min are possible. This means that hot water can also be used in several bathrooms or wellness areas at the same time without temperature fluctuations occurring.
A quick glance at the display is enough and the current heat situation of the building is recorded. If the buffer tank is "blue", it is time to heat the wood boiler with wood. The solar system currently provides heat, but too little for the winter day. Using regenerative energies and reducing the use of fossil heat carriers as much as possible is the core idea of the heating concept for many families. Of course, a cold log boiler can be pre-loaded with wood at any time. The integrated kindling starts the combustion automatically when the buffer tank is "cold" and a heat demand is present. Info content, operation and setting options are designed to make it easy to heat a house with regenerative yields. All family members can and should participate. The learning effect is guaranteed.
The additional display in the entrance or living area
A second display can be installed up to 50 metres away from the main board in a flush-mounted box. The touch display is available with a black or white glass front.
Here, all heat flows are collected, stored and released as required
This buffer tank is designed as a stratified charging storage and optimised for the use of regenerative heat carriers. The aim of stratified storage is to avoid mixing of the storage water during load and discharge. Because hot and cold water have different densities, a stable temperature profile is achieved. Hot water is lighter and rises to the top. Colder water accumulates at the bottom. This thermal stratification profile is maintained if all heat generators and consumers are coordinated without any high inflow and outflow speeds and the yields are exclusively fed into the storage area in terms of the adequate temperature level. By using a separating plate and stratified pipe, high volume flows can also be controlled and mixing effects minimised under extreme conditions of use.
It's all about the right size. buffer tanks with a capacity of 750-4,000 litres are available. The larger boilers as of 3,000 litres are used when a particularly large amount of heat is to be generated and stored - usually in conjunction with a log gasifier.
The interplay of the heat flows is coordinated in order to produce three temperature zones in the stratified storage tank The upper, hottest area (190 - 265 litres) is intended exclusively for heating the drinking water and is, so to speak, untouchable for the heating systems. Underneath is the area from which the heating circuits draw their heat. In the lower section, the cooler heating water is fed to the returns.
Priority 1: Drinking water heating
Priority2: Storage area for heating circuits
Priority 3:Return water zone
The issue of heat losses plays a decisive role in the design of the system storage tank. The design as a stratified storage tank minimises the internal mixing losses. The individual connector design prevents turbulence from occurring in the storage tank in conjunction with the pump control. Heat losses via the cylinder surface are reduced to a minimum by the tight fibre insulation. All connection lines of the system storage as well as the ball valves are insulated or embedded in insulated coating to keep thermal losses as low as possible.
Conventional hot water systems use large drinking water storage tanks or boilers (150 - 300 litres) in which the hot water often stands for several days. The plate heat exchanger installed in the BRUNNER heating system heats the water to the desired temperature only when required. Only the amount of hot water required is heated - no more and no less.
Depending on the design, tap rates of up to 40 l/min are possible. This means that hot water can be used in several bathrooms or wellness areas at the same time without temperature fluctuations. Three temperature sensors and one flow sensor are installed in the fresh water module. The internal logic is such that the plate heat exchanger uses almost all of the heat from the heating water for DHW heating. The water flowing back into the system storage is "cold" and is fed into the return water zone. The electronic anti-scald device can be set via the user interface. A necessary safety feature, especially for families with small children.
Pellet boilers save the work of lump supplies and make you independent of the price development for oil, gas and electricity. Of course, a pellet boiler can also be operated in summer. In practice, the combination with a solar system has proven its worth. It does not have to be large, as the focus is on heating domestic hot water. The concept of the BRUNNER heating system supports thermal as well as photovoltaic solar systems.
In new buildings, pellet condensing boilers are installed, and in old buildings, when the oil heating system is replaced, pellet boilers are placed. The oil tank room can be easily converted and holds enough pellets for the whole winter. In new buildings, 2 m3 are sufficient to store a year's pellet supply because of the low heat demand. The operating costs of a pellet heating system are extremely low. The notice to empty the ash box will be sent 3-4 times during the heating season. All other activities are covered by the maintenance contract.
Logs are the most commonly used wood fuel and the oldest form of wood heating. Depending on the size and output of a wood gasification boiler, combustion starts every 2-3 days during the heating season. In combination with a solar system, the boiler does not have to be fired in the summer months for the provision of hot water.
Wood gasification boilers are installed in the output range of 12-50 kW (filling quantity 40-80 kg). For high heat yields, the heating system is combined with an lateral expansion storage tank. The storage volume can be up to 4,000 litres. Due to the size, the wood boiler and the expansion tank can also be located in a building separately from the central heating system. In such cases, the system storage of the BRUNNER heating centre is loaded via a long-distance line.
In new buildings, heat pumps are a matter of course today. Air-to-water heat pumps have the highest market share because they require less installation work. Their operating principle: they extract heat from the outside air and transfer it to the heating system. With only one kilowatt of operating current, up to five times as much heating output can be achieved with today's technology.
When the outside temperatures drop, the efficiency of the heat pump decreases. At that moment, it is not only a pleasure to heat the stove in the house, but it also makes sense. A plus of the heating system is the integrated boiler in the stove/fireplace, which heats the heating water. The perfect assistant to compensate for the "efficiency weakness" of the heat pump on frosty days. What's more, this combination can definitely extend the lifetime of your heat pump.
Non-kit system heat pumps can be hydraulically connected to the system storage of the BRUNNER central heating system. It works, but is not perfect. A good heat pump heating system requires a concept where all components are not only hydraulically but also control-technically coordinated with each other. This is essential in ensuring that all heat generators and consumers in a single-family house function as a common heating solution. The system storage and hydraulic box of the BRUNNER central heating system are specially designed to meet the requirements of the BRUNNER heat pump. A central control system with common software. Only in this design can the heating system and other heat generators be combined to form a turnkey heating concept.
The BRUNNER heat pump can do more. It is not only a supplier, but is integrated into the interaction of the heat generators: When a water-bearing stove is heated, the BRUNNER heat pump waits to see whether the expected heat output is sufficient. If the photovoltaic system generates surplus energy, a decision is made as to whether this energy is multiplied by the operation of the heat pump or whether it is used to directly heat the electric rod in the system storage tank. And if heat is needed, the temperature level is adapted. Only as much as needed.
The idea behind BRUNNER's central heating system was to develop an effective and, above all, easy-to-use heating solution for the central control of all the components in a modern heating system. The result is a system that efficiently links different heat generators and integrates them according to eco-hierarchical principles. The kit system storage can also be installed under a staircase to save space. The hydraulic box is located in the boiler room and the control unit in the entrance area.
The modular design of the BRUNNER heating system allows you to adapt the heating system to your individual living situation. Only the version currently required is ordered and purchased. The hydraulic box can be expanded at any time and directly at the customer's premises with little installation work. Our idea was to develop a future-proof hybrid heating system that intelligently couples different heat generators. The control software specially designed by BRUNNER is permanently modified and can be updated quickly and easily.
At BRUNNER, we define the hydraulic box as the coordinated, compact basic installation of all technical components that are necessary for a buffer tank-based heating system. In other words, the perfect interplay between generating, collecting and distributing heat. Neatly packaged in the smallest of spaces: The hydraulic box measures just 108 x 40 cm, but in its case all the connections for heat generators, heating circuits or hot water systems are accommodated in a space-saving and clearly arranged manner. The hydraulic register functions like a socket strip for heat connections.
The front cladding of the BRUNNER heating centre is made of powder-coated steel sheet. The upper part of the panelling can be folded open and locked in the open position. The front element underneath can be removed from the front. This makes all parts of the hydraulic box easily and quickly accessible. The rear and side panels are also made of steel sheet and are bolted directly to the register frame.
In principle, the BRUNNER heating centre uses energy-saving pumps (made by Wilo) based on the Ecodesign Directive for the protection of resources. The models are speed-controlled and particularly powerful. In the solid fuel boiler and in the domestic hot water circuit, the pumps are controlled directly and according to demand by PWM signals; in the solar circuit, the classic control by means of phase control is used.
Two controlled heating circuits are usually sufficient for a detached house. With the BRUNNER heating circuit extension, two additional mixed heating circuits can be connected to the side - and thus outside the heating centre. The extension consists of the extension board, a thermally separated distributor bar and the respective pump group "heating circuits" with integrated high-efficiency pump. The extension board is connected to the main board of the BRUNNER heating centre by means of a bus cable.
If the power fails, the combustion in a log boiler continues, but in this case the hot water is no longer discharged via the buffer tank charge pump. To prevent the pressure in the boiler from becoming too high, cold water is fed in via the thermal discharge safety device. This means loss of heat energy. In addition, a craftsman is required to reset the safety temperature control afterwards. A power failure becomes a safety risk if the house has its own well and the well pump is also affected. No cold water is supplied and the boiler can only release steam uncontrollably via a valve. The consequence: water damage and great danger to persons in the room. These fatal consequences are prevented by the BRUNNER emergency power supply.
The special NV 500/1000 charge inverter secures the power supply for a log boiler with heating system during a burn-down phase. The buffer tank charge pump continues to run normally; the heating water is discharged from the boiler via the pump. Technically, the NV 500/1000 is a charger for a 12-volt lead-acid battery. A voltage converter from 12 volts DC to 230 volts AC is integrated. The principle is simple: the boiler or BRUNNER heating centre (BHZ) is connected to the NV 500/1000 and only then to the mains. In mains operation, the input voltage is switched through directly to the output without any loss. In the event of a power failure, internal relays react within ten milliseconds and switch over to battery operation.
Any standard 12-volt car battery with a capacity between 65 Ah and 125 Ah can be connected to the NV 500/1000. The higher this charging capacity, the longer the operating times in battery mode. One thing is certain: The started combustion in the log boiler runs in a controlled manner and the energy is transferred from the boiler to the buffer tank. If the system is set up with a BHZ, it can maintain the heating function for up to 24 hours, depending on the number of pumps. If the battery capacity is almost exhausted before the mains voltage returns, the NV 500/1000 automatically switches off the operation of the log boiler via deep discharge protection. When the mains voltage kicks in, the battery is recharged and the power supply to the system is available again via the mains.
Here all energy flows are collected, stored and released as required. The BRUNNER system storage, also known as a buffer tank, is a stratified storage tank that has been optimised for regenerative heat transfer media. The aim of stratified storage is to avoid mixing of the storage water during charging and discharging. Because hot and cold water have different densities, a stable temperature profile is achieved. Hot water is lighter and rises to the top; colder water accumulates at the bottom. This thermal stratification profile is maintained if all heat generators and consumers are coordinated without any high inflow and outflow speeds and the yields are exclusively fed into the storage area in terms of the adequate temperature level. By using a separating plate and stratified pipe, high volume flows can also be controlled and mixing effects minimised under extreme conditions of use.
The storage contents can be easily doubled by lateral standard tanks The BRUNNER standard storage tank is connected as an expansion storage tank to the four 5/4" connections of the BRUNNER system storage. Parallel loading and unloading has proven itself in practice. The combination with an extended storage tank of the same content is intended. An extended buffer tank is useful for large, thermal solar systems, biomass boilers with an output of more than 25 kW or heat pumps with more than 15 kW. Expansion and leading storage tank of the BHZ 3.0. The hydraulic connection takes place via the four 5/4" connections.
The standard storage tank is equipped with an internal pipe heat exchanger for connection to a solar thermal system.
The hot water storage tank is equipped with internal pipe heat exchanger for connection to a solar thermal system with additional pipe heat exchanger in the upper buffer tank area for domestic hot water heating.
The remuneration for self-generated solar power is getting lower and lower, while at the same time electricity prices for private use continue to rise. Owners of PV systems are looking for new ways to make good use of the surplus solar power and to integrate it efficiently into the heating systems. The BRUNNER solution as another module of the BHZ strictly stratifies the solar yields; even with low solar irradiation. No further auxiliary energy, for example pumps, is required to store the surplus solar power. There are also no radiation losses due to external components. In the event of higher or longer solar irradiation, a speed-controlled high-efficiency pump in the BRUNNER heating centre ensures reliable stratification of the system storage. With a heating output that is continuously regulated from 0.1 to 9 kW, surplus solar power output is stored at usable temperature levels in the buffer tank. This ensures high or even predominantly solar coverage. This output control fulfils all requirements of the technical connection conditions of German grid operators and energy suppliers. Customers and heating engineers benefit equally from the photovoltaic integration. The result is a visually and technically flawlessly installed boiler room at comparable costs to a conventional installation. Despite its complexity, the BRUNNER heating system can be easily operated and understood via a single control - the basis for effective operation. At the same time, the desire for rational use of surplus solar power is professionally taken into account. All BRUNNER heating systems are guaranteed to work and to last. The pre-assembled hydraulics avoid installation errors and possible functional impairments due to mismatched components or different controls. With the BHZ, the heating industry can offer the end user a new, solid solution for the use of surplus solar energy. The interfaces of the heating plant to the electrical plant are also clearly streamlined and clearly defined.
Converting solar power into heat can be so simple. The BRUNNER heating centre has been awarded the Innovation Prize and the Bavarian State Prize of the Ministry of Economic Affairs for the sensible integration of surplus solar electricity at usable temperature levels without supply losses or auxiliary energy requirements. In addition, heating optimisation with a BHZ is generously subsidised by the Federal Office of Economics and Export Control (BAFA).
... in a lateral hot water tank:
When renovating a heating system, functioning hot water tanks can continue to be used. It makes sense to use them if many bathrooms are used simultaneously. In such cases, a larger drinking water reserve is required.
... with fresh water module:
Conventional hot water systems use large hot water tanks (150 to 300 litres) in which the hot water often stands for several days. The generously dimensioned plate heat exchanger installed in the BHZ heats the water to the desired hot water temperature only when required. Tapping rates of up to 25 litres/minute can be covered without temperature fluctuations. This is due to a regulated pump for flow rate and temperature control. Only the required amount of hot water is heated - no more and no less.
Solar thermal systems heat buffer tanks to 80 °C and more during the summer months. If hot water is tapped via the plate heat exchanger in these situations, you can be seriously scalded without a safety device. To prevent this from happening, an adjustable thermal mixing valve BM is installed between the cold and hot water circuits, which limits the hot water temperature to around 55 °C.
Make an appointment for a free consultation and let us work together to determine the ideal heating device for your home. We look forward to your visit.
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