Sick building syndrome (SBS) is a collection of symptoms experienced by buildings occupants such as headaches, mucous, membrane irritation, respiratory problems and fatigue. A building is claimed to have SBS if more than 20% of building occupants experience symptoms. Poor indoor air quality contributes to SBS in the building. This study aims to investigate the correlation between indoor air quality and SBS symptoms in 1st and 2nd floors of the Post office building in Bandung. The study used quantitative methods with a cross sectional study design. Data collection was carried out using particle counter, thermometer, lux meter and anemometer to measure the indoor air quality, while the questionnaire utilized random sampling technique with 119 respondents. The results of the primary data were compared with the air quality standard from Minister of Health No. 1077, 2021. The results of the Statically Compare Means and Independent T-test showed that the p-values of the temperature on the 1st floor and 2nd floors were 0.437 and 0.000, respectively. Meanwhile the p-values of PM10 and PM2.5 on the 1st and 2nd floors were 0.005 and 0.290 and 0.004 and 0.364, respectively, and the p-values of the lighting on the 1st and 2nd floors were 0.002 and 0.015. It indicates that there is a significant relationship between concentrations of PM10 and PM2.5 on the 1st floor with SBS symptoms and the temperature and humidity on the 2nd with SBS symptoms. Since 29 peoples (24% of the building’s occupants) experienced SBS, the building was considered to have a significant potential to cause SBS to its occupant.

PC-based data acquisition (DAQ) systems are irreplaceable in terms of capacity and flexibility for data processing. Data acquisition systems serving IoT are a recent development trend. It is necessary to develop a remotely accessible PC-based DAQ system. In this paper, we present a PC-based DAQ system that can be accessed remotely via the internet. The system consists of several sensors connected to a microcontroller. A two-sided application is developed to set up data access, namely, a local application on the DAQ PC and a web-based application in Google Drive (GD) that can interact with applications on the PC. Local data can then be sent to GD and accessed remotely from a PC. Applications on local PCs will provide a user interface (UI) for managing the data, while those on GD will provide access from the internet. The mean time delay for sending data from a PC to Google Sheets is 2.346 s with minimum and maximum values of 0.874 and 5.863 s, respectively.

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At present, most air conditioners in an automotive use R134a as working fluid. Due to the negative impact on the environment, i.e. global warming, the refrigerant must be replaced by environmental friendly working fluid. Hydrocarbons are natural fluids, no effect on the climate, inexpensive and readily available. The hydrocarbon mixture used in the present study is R436A, composed of R290 (propane) and R600a (isobutane) with a mass ratio of 56/44. The results show that the drop-in substitute from R134a to R436A reduced COP by 4.84, 4.74 and 4.64% for the condenser temperature of 40, 45 and 50°C, respectively. To generate COP improvement on the drop-in substitute, subcooling was carried out, and results show that the COP improvement was 4.42, 5.20 and 6.09% for the condenser temperature of 40, 45 and 50°C, respectively.