| Title |
Evaluation of Effect on Cooling Energy Consumption and Indoor Thermal Environment Caused by Outdoor air Enthalpy Sensor Offset Faults for Economizer during Interseason |
| Authors |
김민호(Kim, Minho) ; 장아민(Jang, Ahmin) ; 도성록(Do, Sung Lok) |
| DOI |
https://doi.org/10.5659/JAIK.2025.41.3.301 |
| Keywords |
Economizer control; Outdoor air enthalpy sensor; Offset faults; Cooling energy performance |
| Abstract |
An economizer control utilizes in cooling system outdoor air (OA) with low enthalpy to reduce cooling energy usage. The economizer
determines the OA intake rates based on measured OA enthalpy. The OA enthalpy is measured by the enthalpy sensor. The OA enthalpy
sensor is exposed to the external environment, making it prone to frequent faults. These faults cause differences between the measured OA
enthalpy and the actual OA enthalpy. This difference potentially leads to the intake of OA under unnecessary conditions or unwanted OA
intake in the cooling system. The unwanted OA intake can adversely affect cooling energy performance. Consequently, it is essential to
qualitatively evaluate the impact of increased cooling energy usage and indoor thermal environment deterioration caused by sensor faults. This
study aimed to analyze the cooling energy usage and indoor thermal environment by varying scenarios of offset faults. To achieve this,
simulations were conducted using EnergyPlus, a building energy simulation tool, by various fault occurrence scenarios. As a result of the
analysis, the negative offset case involved excessive OA intake above the maximum limit set-point. This led to increased chiller and reheat
energy usage for cooling and dehumidification. Conversely, the positive offset case was unable to intake OA below the MLSP. This led to
increased chiller for cooling. The indoor thermal environment was affected by sensor faults but remained within acceptable comfort levels.
Based on this analysis, sensor faults significantly impact cooling energy usage because sensors operate in an interconnected manner with
multiple equipment. This study highlights the importance of regular maintenance and management of sensors to ensure efficient economizer
performance. |