Now showing 1 - 10 of 11
- PublicationExponential pattern recognition for deriving air change rates from CO2 dataA novel procedure for automated determination of air change rates from measured indoor CO2 concentrations is proposed. The suggested approach builds upon a new algorithm to detect exponential build-up and decay patterns in CO2 concentration time series. The feasibility of the concept is proved with a test run on synthetic data that shows a good reproduction of the previously defined air change distribution. The demonstration continues with test runs on CO2 datasets measured in the kitchen and the sleeping room of two residential buildings. The derived air change rates were within the expected distributions and ranges in both cases when natural or mechanical ventilation was used.
254 216Scopus© Citations 3
- PublicationTowards non-invasive temperature measurements in HVAC: A characterization and correction approachThe existing building stock within the European Union is responsible for a considerably huge amount of the total energy consumed. This has prompted legislative actions that focus on increasing the efficiency of Heating, Ventilation and Air Conditioning facilities by employing building automation and electronic monitoring systems. The fluid flow temperature in the hydraulic grid of a building is therefore an essential parameter to be measured, where clamp-on temperature sensors are often applied due to their simple and cost-effective installation. As the plumbing industry heads towards non-metal pipe materials with low thermal conductivity, the applicability of non- invasive measurement procedures diminishes. In this context, a characterization approach of non-invasive temperature measurements that is linked to a thermal resistance model is experimentally validated. Based on that, a correction algorithm to reduce the deviation between measured surface and the fluid flow temperature for steady state conditions is derived and tested. The presented approach provides sufficient characterization and correction performance, albeit several limitations have to be taken into consideration.
423Scopus© Citations 1
- PublicationA Thermal Flow Sensor Based on Printed Circuit Technology in Constant Temperature Mode for Various Fluids(MDPI, 2019)
;Glatzl, Thomas ;Beigelbeck, Roman ;Cerimovic, Samir ;Steiner, Harald ; ;Sauter, Thilo ;Treytl, AlbertKeplinger, FranzWe present a thermal flow sensor designed for measuring air as well as water flow velocities in heating, ventilation, and air conditioning (HVAC) systems. The sensor is designed to integrate the flow along the entire diameter of the pipe also quantifying the volume flow rate of the streaming fluid where the calorimetric principle in constant temperature operation is utilized as a readout method. In the constant temperature mode, a controller keeps a specific excess temperature between sensing elements at a constant level resulting in a flow dependent heater voltage. To achieve cost-effective sensors, the fabrication of the transducer is fully based on printed circuit board technology allowing low-cost mass production with different form factors. In addition, 2D-FEM simulations were carried out in order to predict the sensor characteristic of envisaged setups. The simulation enables a fast and easy way to evaluate the sensor’s behaviour in different fluids. The results of the FEM simulations are compared to measurements in real environments, proving the credibility of the model. 452Scopus© Citations 7
- PublicationTowards distributed enthalpy measurement in large-scale air conditioning systemsAir conditioning systems are among the major energy consumers in buildings. Energy-efficient operation of AC systems is an important step towards better energy management in building automation, but requires efficient monitoring of the energy or enthalpy flows within the AC installation, which is currently still difficult because of the lack of appropriate equipment. This paper introduces a distributed data acquisition system for large-scale AC systems based on low-cost flow sensors implemented by means of standard printed circuit board technology and interconnected via a wireless sensor network. A critical issue for the system installation is the placement of the sensors in the air ducts to obtain representative measurements of the air flow. To this end, extensive aerodynamical simulations are carried out to analyze the flow distributions in typical building blocks for air ducts, particularly with respect to turbulences. The simulation results are compared with experimental data from the literature and are shown to be reliable.
144Scopus© Citations 7
- PublicationGetting Fit for the Future: Optimizing Energy Usage in Existing Buildings by Adding Non-Invasive Sensor NetworksOptimizing energy usage is becoming an economic necessity for existing buildings. Non-invasive sensors and sensor networks are key technologies for efficiently achieving this goal, since it is of utmost importance that existing hydraulic systems are not changed and the engineering effort for installation remains minimal. This paper presents a data-driven approach that should allow low-cost installation of sensors at arbitrary points of the building and then retrieve the structure of the hydraulic system from the recorded sensor values. The architecture as well as first preliminary results from field test buildings are presented.
403Scopus© Citations 1
- PublicationNumerical and experimental characterization of a novel low-cost thermal air flow sensorTo enable highly efficient operation of large scaled ventilation systems a continuous measured and well located air flow monitoring for control purposes and energy management is needed. The air flow monitoring solution is targeting low manufacturing cost as well as sufficient accuracy when operating near complex duct flows like pipe bends and tees. Therefore, a novel, low-cost, thermal air flow sensor, which takes non-uniform velocity profiles into account, is presented and characterized due to its application in heating, ventilation and air conditioning systems. Extensive numerical simulations and experimental investigations in an operating ventilation system show reasonable results and prove basic feasibility of the suggested novel sensor concept.
79Scopus© Citations 3
- PublicationDigital Twin with Multi-Input and Multi-Output optimisation for Air-Conditioning Systems