FAQ General overview
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Series of publications on quality management for Biomass DH Plants
Ist in «Standardschaltungen – Teil I» ab der 2., erweiterten Auflage und in «Standardschaltungen – Teil 2» integriert und damit überflüssig.
This FAQ on installations without energy storage has been removed and will not be replaced.
Included in ‘Standard Circuits – Part I from the 2nd expanded edition onwards and in ‘Standard Circuits – Part 2’ and therefore redundant.
Corrected in ‘Standard Circuits – Part I from the 2nd expanded edition and therefore superfluous.
This topic is covered in section 7.2.2 of the QM Planning Manual for QM for Biomass DH plants.
In ‘Standard Circuits – Part I [2], the pumps are shown at the boiler inlet and the pressure reducer is connected behind the pumps, on the main return. Are these types of connections mandatory?
The standard ‘Standard circuits – Part I [2] requires sequential control based on the main variable for all installations with multiple boilers. What is sequential control?
In the standard circuit VVE3 ‘Dual-fuel wood-fired heating system without storage tank’ according to ‘Standard circuits – Part I’, the main flow temperature T341 (main control variable) is measured before the bypass; measurement after the bypass at T342 is only provided as a variant with maximum priority given to the return temperature at T344. Why not measure systematically after the bypass and then regulate to the lowest possible value (e.g. maximum instantaneous heat demand)?
The installation of a gas condensing boiler is shown in Figure 13.10 of the QM for Biomass DH Plants Planning Manual.
It is quite common for an existing oil/gas boiler to need to be connected to a heating system that is not located in the boiler room with the wood-fired boiler. How do you connect such an external oil/gas boiler?
The control system for the storage charger is described in the document ‘Standard Circuits’.
The topic has been included in section 13.5.1 of the QM Planning Manual for Biomass DH Plants
In the event of low load (operation in summer, transition period, prolonged phases with reduced operation), it is often advisable to fill the tank completely and then empty it completely. How do I activate and deactivate the FILL/DRAIN operating mode?
The topic has been included in section 7.5.2 of the QM Planning Manual Biomass DH Plants.
This topic is covered in Chapters 3 and 5 of the Thermal Networks Planning Guide (Thermal Networks).
Included in ‘Standard Circuits - Part I’ [2] from the 2nd expanded edition under WE7 and WE8, it has therefore become redundant.
The topic has been included in section 13.7.2 of the QM Planning Manual for Biomass DH Plants (Wood-Fired Heating Plants).
The topic has been included in section 5.8.1 of the QM planning manual for Biomass DH Plants.
This topic is covered in the QMstandard advanced course.
There is no standard circuit for monovalent installations with three boilers (neither in Part I [2] nor in Part II [5]). In Switzerland, monovalent three-boiler systems with combustion power control (in accordance with Part I) are mainly built because they allow wood to be used for heating even in summer and during the transition period with the smallest boiler (compliance with the minimum load). How can the sequential switching circuit for such a monovalent three-boiler system be implemented in principle?
The topic has been included in section 7.5.1 of the QM planning manual for Biomass DH Plants.
This topic has been included in section 5.8.1 of the QM Planning Manual for Biomass DH Plants.
The Excel spreadsheet ‘Situationserfassung’ (inventory) makes this assessment easier and is available in the downloads section.
This topic is covered in section 8.14 of the Thermal Networks Planning Guide.
In addition to heat metering in the wood boiler circuit according to standard diagrams [2] [5], simplified metering can also be carried out via the wood boiler's API or control system. What are the options for heat metering in a wood boiler circuit?
QM for Biomass DH Plants provides the basic control concept with standard circuits [2], but no requirements for the individual controllers, let alone control parameters. However, experience shows that experienced manufacturers of wood-fired boilers and control devices are certainly capable of implementing stable control, but often only after demonstrating (as part of operational optimisation) that the control is not sufficiently stable. What requirements must controllers and control parameters meet for load-dependent power control?
Storing large quantities of wood chips poses a fire risk. What should be done to prevent fires in chip silos and outdoor storage areas?
In the standard circuit VVE3 ‘Dual-fuel wood-fired heating system without storage tank’ according to ‘Standard circuits – Part I’, the main flow temperature T341 (main control variable) is measured before the bypass; measurement after the bypass at T342 is only provided as a variant with maximum priority given to the return temperature at T344. Why not measure systematically after the bypass and then regulate to the lowest possible value (e.g. maximum instantaneous heat demand)?
This topic is covered in section 3.1 of the thermal network planning manual.
This topic is covered in Chapter 5.5 of the thermal network planning manual.
This topic is covered in section 5.4.7.3 of the thermal network planning manual.
In practice, the use of solar thermal energy is often desirable. On the producer side, this usually involves a single large solar surface, while on the consumer side, there are typically many small solar surfaces. How can solar collectors be integrated?
This topic is covered in Chapter 5.3 of the thermal network planning manual.
This topic is covered in Chapter 5.3 of the thermal network planning manual.
This topic is covered in Chapter 5.7 of the district heating network planning manual.
The new EN ISO 17225 standard ‘Solid biofuels - Specifications and fuel classes’ replaces the old EN 14961-4:2011 standard. The classification of fuels and particle sizes must be adapted to standard EN ISO 17225-1:2014 ‘Part 1: General requirements’ and standard EN ISO 17225-4:2013 ‘Part 4: Classification of wood chips’.
This topic is covered in section 3.7.3 of the thermal network planning manual.
How is the availability of electrical separators (electrostatic precipitators) defined and determined?