VEHICLE AIR CONDITIONER (VAC) CONTROL SYSTEM BASED ON PASSENGER COMFORT: A PROOF OF CONCEPT

The air conditioning system (AC) in passenger cars requires precise control to provide a comfortable and healthy driving. In an AC system with limited manual control, the driver has to repeatedly change the setting to improve comfort. This problem may be overcome by implementing an automatic control system to maintain cabin temperature and humidity to meet passenger's thermal comfort. Therefore, this paper presents the development of a laboratory-scale prototype air conditioning control system to regulate temperature, humidity and air circulation in the cabin. The experimental results show that the control system is able to control air temperature in the range of 21 °C to 23 °C and cabin air humidity between 40% to 60% in various simulated environmental conditions which indicate acceptance for comfort and health standards in the vehicle. In conclusion, this method can be applied to older vehicles with reasonable modifications. ABSTRAK: Sistem penyejuk udara (AC) pada kenderaan penumpang memerlukan ketepatan kawalan bagi menyediakan keselesaan dan kesejahteraan pemanduan. Melalui sistem AC dengan kawalan manual terhad, pemandu perlu berulang kali mengubah penyesuaian latar bagi meningkatkan keselesaan. Masalah ini dapat diatasi dengan menerapkan sistem kawalan automatik bagi menjaga suhu dan kelembapan kabin agar memenuhi keselesaan suhu penumpang. Oleh itu, kajian ini merupakan pembangunan prototaip sistem kawalan AC skala laboratari bagi mengawal suhu, kelembapan dan peredaran udara dalam kabin. Hasil eksperimen menunjukkan sistem kawalan ini mampu mengendali suhu udara pada kitaran 21 °C hingga 23 °C dan kelembaban udara kabin antara 40% hingga 60% pada pelbagai keadaan persekitaran simulasi yang menunjukkan penerimaan standard keselesaan dan kesejahteraan kenderaan. Sebagai kesimpulan, cara ini dapat diaplikasi pada kenderaan lama dengan modifikasi bersesuaian.

Flow Disturbing to Enhance Heat Transfer Inside a Duct: an Experimental Study

In the present experimental work, the effect of air circulation on increasing heat transfer rates within the duct was studied. Three air circulation speeds are implemented: 2400, 1800, and 1200 rpm. In addition, the effect of the distance between the heat source and the location of the circulating fan on heat transfer rates was investigated using three different distances: 20, 40, and 60 cm. The Exhaust fan, placed at the outlet of the duct, changed its speed to three values: 2850, 2140, and 1425 revolutions per minute. The Reynolds range ranged from 65,000 to 175,000. The results showed that the best thermal performance is achieved when the exhaust fan speed, air circulation speed, and the distance between the heat source are 1425 rpm, 2400 rpm, and 60 cm, respectively.

Phytoremediation of Formaldehyde in Indoor Environment With Common House Plants and Pseudomonas Chlororaphis

Low light survivor house plants were assessed for their formaldehyde removal capacity from indoor environment. Low ventilation leading to poor air circulation in indoor environment has become a matter of grave concern as it leads to health issues. Phytoremediation technology is being studied in such situations. The capacity of plants in absorbing indoor pollutants can be enhanced through use of bacteria helping phytoremediation process. The gaseous formaldehyde of about 5 ppm was released into the static chamber of volume 1 m3 . Selected test plants were Aglaonema commutatum, Chlorophytum comosum, Sansevieria trifasciata and Epipremnum aureum. Medium in which plants were growing was inoculated with Pseudomonas chlororaphis, which helps the process of phytoremediation. Activated charcoal was also added in the medium, to increase the absorptive surface. The exposure given was for 24 hours. Experiment was replicated for three times. Air quality in the chamber was monitored on advanced Formaldehyde meter, at the start of the experiment and after 24 hours. Leaves of the plants were analysed by DNPH on LCMS method for quantification of Formaldehyde. Quantification of Formaldehyde from leaves ranged between 0.03–4.7 ppm. Formaldehyde meter showed reduction in formaldehyde quantity ranges from 1.999 to 0 ppm in 24 hours. This clearly indicates that selected plants have enhanced limited capacity of formaldehyde absorption in synergy with Pseudomonas chlororaphis.

A Study on The Healthy Rental-Housing for College Students According to World Health Organization: Evidence from Surabaya City in Indonesia

Introduction:Many college students live far from their parents to study to get a better higher education, so they occupy a rental-housing. However,many rental-housings do not meet the health standards according to the World Health Organization (WHO). Therefore, this study aiming at evaluating the rental-housing quality used by college students in Surabaya, Jawa Timur, Indonesia.Methods:This type of research is an observational study conducted with a descriptive observational design. The sample in this study was 52 college students who originated from outside Surabaya and currently living in the rental-housing in Mulyorejo, Surabaya, Indonesia.Results:The results present observational data from 52 student respondents who live in boarding houses including the overview of boarding houses condition, ventilation and air circulation condition, trash management, clean water and wastewater management, and toilet condition.Conclusion: Under the circumstance, this study was conducted to assess healthy rental-housing quality for college students, using the WHO's evaluation indicators. While some college students could afford to stay in proper and healthy rental-housing, some of them still suffer from lousy ventilation, the absence of clean water, and terrible trash management.

Upper air circulation and thermal anomalies over India and neighbourhood vis-à-vis Indian summer monsoon activity

The three dimensional circulation and thermal anomaly features associated with droughts and floods India are examined using 20 year of upper wind data over India and neighbourhood. The analysis reveals that years of droughts (floods) in India are associated with cyclonic (anticyclonic) circulation anomalies and cold (warm) thermal anomalies in the troposphere between 500 hPa and 200 hPa over northwestern India. In drought years (flood years) upper tropospheric westerly (easterly) anomalies are observed in the lower latitudes in the months of May and June. Tibetan anticyclone shifted to east of its normal position in drought years , during the month of June. The correlation coefficient between the meridional component of the wind at 200 hPa over northwestern India and the summer monsoon rainfall found to be -0.72 which is significant.

Prototipe Pengendalian Kualitas Udara Indoor Menggunakan Mikrokontroler dengan Sensor MQ135, DHT-22 dan Filter HEPA

Indoor air pollution is a very serious health issue in comparison with outdoor air conditions. The current pandemic of COVID-19 causes people to remain indoors at all times. It is unimaginable that during this pandemic a smog-related disaster could occurs that could aggravate human respiratory diseases, thus requires additional air quality monitoring which can filter clean air into the room. The purpose of this study is to produce a prototype of air quality control that can provide a good air circulation system and hold the temperature and humidity in the room. This research was conducted with an Arduino Uno microcontroller and an MQ-135 gas sensor to detect CO2 gas and a DHT-22 sensor for measuring room temperature and humidity by comparing the results of using a HEPA filter. The research results of the prototype make it possible to generate the room temperature using a HEPA filter and air humidifier whose average is 27.7°C. Another parameter that is performed is the CO2 measurement, it is found that the average CO2 in the test using a HEPA filter and an air humidifier is 496 PPM.

Assessment of the Potential Use of Shallow Geothermal Energy Source for Air Heating and Cooling in the Kingdom of Saudi Arabia

A large part of the total energy consumption in buildings in the Kingdom of Saudi Arabia (K.S.A.), is devoted to air cooling. This leads to high electricity costs for residents and a high amount of equivalent CO2 emissions. The work presented in this paper aims at evaluating and applying shallow geothermal energy for cooling and heating to reduce cost and environmental issues in the Kingdom. The system is based on the earth-air heat exchanger (EAHE) equipped with an air circulation fan. In this study, six cities have been selected; Madinah city, where our university is located, and five other cities representing five different climatic zones. A new parameter called “geothermal percentage” is proposed to calculate the ratio of geothermal energy to the cooling/heating total load. It has been shown that the proposed system covers part of the cooling load and the total heating needs for almost all the country’s territory. However, both heating and cooling needs can be fulfilled by the EAHE for few cities such as Guriiat and Khamis, characterized by a moderate climate.

QPF model for Sabarmati basin based on Synoptic analogue method

The paper formulates a synoptic analogue model for issuing Quantitative Precipitation Forecast (QPF) for Sabarmati basin based on 10 years data (2000-2009) during southwest monsoon period. The model was verified with the actual Average Areal Precipitation (AAP) for the corresponding synoptic situations during 2010.The performance of the model were observed Percentage Correct (PC) up to 71%. The cases out by one or two stage were due to variation in the intensity of the system especially upper air circulation (S3) over the basin. The synoptic analogue model was able to generate accurate QPF 24 hrs in advance to facilitate flood forecasters of Central Water Commission.

Ice in caves and its effect on thermal inversion and permafrost in the case of the Velika ledena jama v Paradani, Smrekova draga and neighbouring dolines

In the Velika ledena jama v Paradani, in the karstic blowholes on the slopes of Smrekova draga and in the nearby dolines I measured and interpreted air temperatures and the effect of the summer outflow of cold air from them into the surrounding area. In winter, cold air enters the cave, radically cooling the entrance part of the cave, where for this reason there is permanent cave ice. The summertime circulation is reversed: emerging from the inner part of cave, which has an average temperature of around 4° C, is air which only when it transits through the sub-cooled entrance part is then cooled to around 1° C. This air comes to the surface and in the hollow at the cave entrance maintains a distinct thermal inversion during the warm part of the year. There is a similar air circulation and similar development of annual temperatures observed at the vents, where cave air emerges through rubble spread over cave entrances on slopes or at the bottom of dolines. The stable summer air temperatures of around 1° C in the vents where I conducted measurements indicate that underneath them there is also permafrost or sub-cooled rock and permanent ice. This is created and preserved, just like in the caves, due to the advection of cold air in winter. In Trnovski gozd, such karstic permafrost is found at an altitude of 1,100 m above sea level. The outflow of cold air from the vents in the summer, just like inside the cave, causes a distinct thermal inversion in dolines on the surface.