Parameter selection in data-driven fault detection and diagnosis of the air conditioning system

Data-driven fault detection and diagnosis system (FDD) has been proven as simple yet powerful to identify soft and abrupt faults in the air conditioning system, leading to energy saving. However, the challenge is to obtain reliable operation data from the actual building. Therefore, a lab-scaled centralized chilled water air conditioning system was successfully developed in this paper. All necessary sensors were installed to generate reliable operation data for the data-driven FDD. Nevertheless, if a practical system is considered, the number of sensors required would be extensive as it depends on the number of rooms in the building. Hence, parameters impact in the dataset were also investigated to identify critical parameters for fault classifications. The analysis results had identified four critical parameters for data-driven FDD: the rooms' temperature (TTCx), supplied chilled water temperature (TCHWS), supplied chilled water flow rate (VCHWS) and supplied cooled water temperature (TCWS). Results showed that the data-driven FDD successfully diagnosed all six conditions correctly with the proposed parameters for more than 92.3% accuracy; only 0.6-3.4% differed from the original dataset's accuracy. Therefore, the proposed parameters can reduce the number of sensors used for practical buildings, thus reducing installation costs without compromising the FDD accuracy.

A Brief Review on Radiant Cooling Panel with Different Chilled Water Pipe Configurations

Radiant cooling systems are commonly applied in commercial applications because of their energy-saving potential. This potential can be further enhanced by evaluating the cooling performance of the radiant cooling panel in terms of flow configurations. Although studies have been conducted on the flow configurations of the radiant cooling panel, the most suitable flow configurations have yet to be determined. The conventional serpentine flow configuration does not bring out the best cooling performance of the radiant cooling panel, therefore different flow configurations are still needed to be explored. This study conducted a quick literature review on the different radiant cooling systems as well as radiant cooling panel with different chilled water pipe configurations. The objective of this review is to provide a brief comparison of the performance of radiant cooling panel with different chilled water pipe configurations and to suggest further studies for the system development. The cooling characteristics and heat transfer of the panel are investigated by using numerical study. A comparison between the designs of flow configurations is presented. In all of the cases, the plate area and flow volume are fixed. Based on the findings obtained, applying a different chilled water pipe configuration on the radiant cooling panel will affect the flow uniformity and also the temperature distribution uniformity. An optimized flow configurations for the radiant cooling panel is important for enhancing the overall efficiency of the system.

Pengaruh Variasi Insulator Saluran Chilled Water Terhadap Performansi Prototype Mini Water Chiller

The high heat transfer rate from the environment to the chilled water pipe will affect the performance of the mini water chiller prototype, so it is necessary to insulate the chilled water pipe using the right insulator to optimize the performance of the mini water chiller prototype. Therefore, this study aims to determine the effect of the chilled water pipe insulator variations: nitrile rubber expanded and polyurethane foam on the optimal temperature and cooling rate of the mini water chiller prototype cabin. The method used in this study is an experimental method with a variation of the insulator as independent variables and the optimal temperature also cooling rate of the mini water chiller prototype cabin as the dependent variables. The testing process was carried out 20 times repetition of data collection on each variation using a stopwatch, thermo gun, thermostat, ampere pliers, a bulb, and a water heating element as a tool in research. In addition, it expanded nitrile rubber and polyurethane foam spray as research material. The results obtained from this study showed that the average optimal temperature achievement of the mini water chiller prototype with polyurethane foam insulator was 11.242◦C, and with the nitrile rubber expanded insulator was 11.250◦C. Otherwise, the average cooling rate of the mini water chiller prototype cabin with polyurethane foam insulator variation was 0.001421◦C, while in the variation of nitrile rubber expanded it was 0.001032◦C, which indicates that there is an effect of chilled water pipe insulator variations on the performance of the mini water chiller prototype.