Dimensioning method for precharged membrane expansion vessels for pressure maintenance of hydronic systems
Loading...
Authors
Author (Corporation)
Publication date
27.03.2025
Typ of student thesis
Course of study
Type
05 - Research report or working paper
Editors
Editor (Corporation)
Supervisor
Parent work
Special issue
DOI of the original publication
Link
Series
Series number
Volume
Issue / Number
Pages / Duration
Patent number
Publisher / Publishing institution
Institut Nachhaltigkeit und Energie am Bau, Hochschule für Architektur, Bau und Geomatik FHNW
Place of publication / Event location
Muttenz
Edition
Version
Programming language
Assignee
Practice partner / Client
Abstract
Effective pressure maintenance is essential to ensure fault-free and energy-efficient operation of hydronic systems. Precharged membrane expansion vessels (MEV) are widely used for this purpose. A membrane within these MEVs separates the liquid connected to the circuit from the fixed amount of gas. Several standards provide dimensioning methods. However, these methods have two main disadvantages. First, pressure measurement uncertainties are not considered. Second, changes in the MEV temperature are neglected. The resulting uncertainties in dimensioning, commissioning, and maintenance can lead to malfunction and damage. Based on the extremal states of both the circuit and the MEV, an improved and generalized dimensioning method was derived. The change in the gas temperature within the MEV is accounted for. The measurement uncertainties of preset- and system pressure, as well as average MEV and circuit temperature, are considered. Furthermore, this method accounts for temporary process volumes that can occur, for example, during vacuum degassing or the stagnation of solar thermal circuits. By applying the new method, operational failures owing to incorrectly dimensioned MEVs, or faulty maintenance can be avoided. For simple commissioning and maintenance, corresponding software is provided as a free, open-source tool.
Keywords
Subject (DDC)
Event
Exhibition start date
Exhibition end date
Conference start date
Conference end date
Date of the last check
ISBN
ISSN
Language
English
Created during FHNW affiliation
Yes
Strategic action fields FHNW
Zero Emission
Publication status
Published
Review
No peer review
Open access category
License
Citation
Eismann, R. (2025). Dimensioning method for precharged membrane expansion vessels for pressure maintenance of hydronic systems. Institut Nachhaltigkeit und Energie am Bau, Hochschule für Architektur, Bau und Geomatik FHNW. https://doi.org/10.26041/fhnw-14718