SCADA based Wireless Online Monitoring Assessment of Building Rooms on Illuminance, Temperature and Humidity

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SCADA based Wireless Online Monitoring Assessment of Building Rooms on Illuminance, Temperature and Humidity

WALUYO¹, Andre WIDURA¹

1Departmen of Electrical Engineering, Institut Teknologi Nasional Bandung (ITENAS), Jl. PHH. Mustafa No. 23 Bandung 40124 Indonesia

Abstract

In energy saving and management, environmental parameter monitoring is very important role. For supporting them, five monitoring sets were conducted in two buildings. Every set consisted of illuminance, temperature and humidity sensors, which were equipped with a 4-20 mA transmitter each. The transmitter signals entered to the PLC analogue modules and the SCADA installed computer wirelessly. The parameter quantities could be recorded automatically by the computer. The obstructions of building walls could be minimized by using router and repeater installations on some parts of network. Most of the data could be recorded properly. The average temperatures and relative humidity started to rise and decrease in the range of 6:30 until 8:40 a.m. Meanwhile, the average illuminance rose between 5:40 and 6:20 a.m. and disappeared between 5:50 and 7:20 p.m. The rooms were mostly in the warm thermal comfort. In small part of time, the rooms were in the optimal thermal comfort. The warm and optimal comforts occupied 44.4 % and 19.1 % respectively. The rest, 36.5%, exceeded the comforts. Naturally, there was not any room in cool thermal comfort. The illuminance and temperature modelling convexes upward significantly indicated by the negative constants of the quadratic time variable. To meet the standard requirement of 250 lux, the illuminance covered 65.0 %, 6.7 %, 76.7 %, 45.0 %, and 36.7 % of working time for PLC 1 up to PLC 5 respectively. In contrast, the relative humidity modelling convexes downward considerably indicated by the positive constants of the quadratic time variable. This case was also reinforced by the absolute numbers of correlation coefficients among the illuminance, temperature and humidity that were above 0.9. The parameter signals of the third PLC were the most different from the others, because the temperature and the illuminance were very high on the fourth floor.

Keywords: humidity, illuminance, SCADA, temperature, wireless

Received: 26 August 2019 To cite this article:

WALUYO, WIDURA A., “SCADA Based Wireless Online Monitoring Assessment of Building Rooms on Illuminance, Temperature, and Humidity”, in Electrotehnica, Electronica, Automatica (EEA), 2019, vol. 67, no. 4, pp. 64-74, ISSN 1582-5175.

1. Introduction

The environmental parameters of buildings, such as illuminance, temperature and humidity, are the influence of comfort sensations and result in energy consumption. Future buildings will have minimal energy consumption, but they allow maximizing performance, comfort and long term occupant satisfaction [1], [2].

The illuminance is one of significant electrical energy consumption, efficiency concerns, and occupants’

production [3-7]. A daylight illuminance will improve energy savings, which is influenced by some factors [8- 18]. Differently, the temperature, one of main factors on comfort, is also influenced by some parameters [19- 32]. It influences human activities, sleep quality and energy savings [33], [34]. Humidity is also an important factor influencing the human thermal comfort, occupant behaviour, and health impacts [35-41].

Smart buildings have a very important role to optimize the comfort and energy. The buildings usually consist of illuminance, temperature and humidity parameters. However, they change at any time, so that the comfort of rooms also changes. Generally, the measurements of environmental parameters are

conducted some of the time. The investigation on online or real time and wireless environmental parameters involving some buildings is still very rare. Thus, it is necessary to investigate the environmental parameters by monitoring and recording some rooms and buildings simultaneously, continuously and remotely. The design, implementation and analysis on the illuminance, temperature and relative humidity monitorings and recordings had been conducted on five room points in two buildings. The aim of the research was preparing a basic for further investigation for maintaining the comfortable condition, and for saving the electricity consumption. The objectives of research were to obtain the behaviours of the environmental parameters, namely the illuminance, temperature and humidity. The behaviours meant the times when the parameters started to rise and go down, when and how much they reached the peaks. Results of the research were shown in the form of curve and empirical equation modelling, and they were compared to the thermal and visual standards of human comfort. Moreover, they were also analysed by the correlation coefficients to find the closest statistical relationship.

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2. Materials and Methods

Figure 1 shows the design of monitoring diagram of the environmental parameters, with five set points consisting of illuminance, temperature and humidity sensors.

Figure 1. The monitoring diagram of the environmental parameters

Indeed, the PLCs and analogue modules were the main components. Every sensor was equipped with a 4- 20 mA transmitter. These transmitters were conformed with PLC input analogue modules, which are usually used in many industries. The signals were sent to the routers, and finally, to the server of SCADA installed computer through some repeaters wirelessly. This was the advanced of previous preliminary research [42-44].

The controllers were configured and programmed with the IEC61131-3 supported software [45], [46].

The numerical settings between the environmental and transmitter parameters adjusted to the real physical conditions [47], [48]. For 4-20 mA transmitters, the illuminance, temperature and relative humidity were 0-2000 lux, -20-60 ^oC and 0-100 % respectively.

The layout design connections of communication networks between network devices and automatic monitoring devices were implemented in wire and wireless methods. The testing results of the communication themselves have been presented [49].

The communication used Wi-Fi network [50-52].

In the first building (building 20), the server computer, PLC1, PLC2 and PLC3 were installed on the first, second, third and fourth floors respectively. Meanwhile, in the second building (building 18), PLC4 and PLC5 were installed on the second and third floors respectively

The IP addresses and SSID communications were unique on the networks and the monitoring devices. The specification of the routers and the repeaters were simultaneous 300 + 300 Mbps dual-band and at the rate of up to 300 Mbps respectively [53], [54].

There were some studies involving PLC and SCADA [55-73]. Nevertheless, they had their own distinctive features. In this research, a Power SCADA Expert V.7.40 was used for the monitorings and recordings [74]. It used a licensed dongle key, so the monitoring is continuously running. The Vijeo Citect Exploler and the Citect Project

Editor pages were for creating clusters on SCADA programming design, where the data file name was in the form ‘rtf’ extension.

The recording results were compared to the standards of thermal and visual comforts. Based on the data due to day rotation, generally they approached parabolic trends. Therefore, they were approximated by the parabolic least-square, in which the function could be stated as [75]

( ) ^x ^Ax ^Bx ^C

f

y = =

²

+ +

₍₁₎

This equation was used as the modelling on the behaviours of the illuminance, temperature and relative humidity to the time in twenty four hours.

To investigate the closeness among the three parameters, it was necessary to use the statistical correlation coefficients [76].

3. Results and Discussion

Figure 2 shows the five PLC kits sensing the illuminance, temperature and relative humidity in the five rooms.

(a) First kit (b) Second kit

(c) Third kit (d) Fourth kit

(e) Fifth kit Figure 2. Five PLC kits

They were installed on the top of windows, under the ceilings.

Figure 3(a) to Figure 3(c) show the recording results started from January 23, 2018 until February 6, 2018 for PLC 1. The lowest illuminance occurred on January 27^th, 2018, due to heavy cloud and rain. In contrast, on the next day, it was a sunny day.

ANALOG INPUT 3 x 4-20 mA PLC TM221 (Hardware & Software) (4-20mA) Illuminance Temperature

Router

Wireless (4-20mA)

(4-20mA) Humidity

SCADA (RJ45)

ANALOG INPUT 3 x 4-20 mA PLC TM221 (Hardware & Software) (4-20mA) Illuminance Temperature

Router (4-20mA)

(4-20mA) Humidity

(RJ45)

ANALOG INPUT 3 x 4-20 mA PLC TM221 (Hardware & Software) (4-20mA) Temperature

Humidity

Router (4-20mA)

(4-20mA)

Illuminance (RJ45)

ANALOG INPUT 3 x 4-20 mA PLC TM221 (Hardware & Software) (4-20mA) Temperature

Humidity

Router (4-20mA)

(4-20mA)

ANALOG INPUT 3 x 4-20 mA PLC TM221 (Hardware & Software) (4-20mA) Temperature

Humidity

Router (4-20mA)

(4-20mA)

PLC 1

PLC 2

PLC 3

PLC 4

PLC 5

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(a) Illuminance

(b) Temperature

(c) Relative humidity

Figure 3. Recording results of environmental parameters on PLC 1

Therefore, the illuminance was very high, even it was the highest in this range of recordings. Besides, the most sunny day was on January 29, 2018, as the continuation of the sunny day, and on January 26, 2018, the day before the most cloudy and rainy day. The average illuminance started to rise at 6:30 a.m. and vanished at 6:10 p.m., with 270 lux maximum value at 12:00 o’clock.

The highest temperature occurred at 30 ^oC, on January 28, 2018. This condition corresponded to the illuminance occurred on the same day. The highest temperature was followed by day 2, on January 24, 2018. The average temperature was warm comfort from the midnight until 9:10 a.m., with 26.3 ^oC minimum at

4:20 a.m. After that, it exceeded the warm comfort until 8:40 p.m., and it reached 28.8^oC maximum at 12:20 p.m. The average temperature started to rise at 8:40 a.m., reached 28.8 ^oC maximum at 12:20 p.m. and continuously decreased until midnight.

The lowest measured relative humidity was 37 % occurred on January 31, 2018. This condition corresponded to the illuminance occurred on the fifth of the sunny days. On the other hand, the high humidity days were on January 23 and 24, 2018. The maximum average relative humidity was 64.4 % at 12:50 a.m. and the minimum was 53.1 % at 11:50 a.m. In general, the relative humidity was still in the comfort range of 50-80

%, although on day 9, it reached 37 % as the minimum at 11:30 a.m. The average relative humidity started to decrease at 8:20 a.m., reached 53.3 %, the minimum, during 11:40 a.m. until 12:10 p.m.

Figure 4(a) to Figure 4(c) show the recording results of PLC 2.

(a) Illuminance

(b) Temperature

0 100 200 300 400 500 600 700

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

Illuminance (lux)

Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8

Day 9 Day 10 Day 11 Day 12 Day 13 Day 14 Day 15 Av

0 5 10 15 20 25 30 35

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM Temperature (oC)

0 10 20 30 40 50 60 70 80 90

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

Relative Humidity (%)

0 50 100 150 200 250 300 350 400

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM Time

0 5 10 15 20 25 30 35

12:00:00 AM 4:48:00 AM 9:36:00 AM 2:24:00 PM 7:12:00 PM 12:00:00 AM Time

Temperature (oC)

0 10 20 30 40 50 60 70 80

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM Time

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The lowest illuminance occurred on January 24, 2018. The fifth day, on January 27, 2018, was included into the low illuminance, due to heavy cloud and rain.

On the other hand, after that, on the sixth day, on January 28, 2018, it was a sunny day. The seventh, first and fourth days, on the 29^th, 23^rd and 26^th of January 2018, were the first, second and third sunniest days respectively. The average illuminance started to rise at 6:10 a.m. and vanished at 5:50 p.m., with 124 lux as the maximum at 12:00 o’clock. The highest temperature was 31^oC, on January 31, 2018. The second, first, sixth and tenth days, on January 24, 23, 28 and February 1, 2018, the temperatures also reached 30 ^oC as high temperature, probably due to sunny days.

These conditions corresponded slightly to the illuminance. The average temperature was warm comfort from the midnight until 8:30 a.m., with 26.3 ^oC as the minimum at 3:10 a.m. After that, it exceeded the warm comfort until 8:10 p.m., and it reached 28.9 ^oC as the maximum at 11:30 a.m.

The lowest relative humidity was 38 % on January 31, 2018, corresponded to PLC 1. Meanwhile, the high relative humidity occurred on the second, third and first days, which was on the 24^th, 25^th and 23^rd of January 2018 respectively. The maximum average relative humidity was 62.7 % at 1:00 a.m., and the minimum one was 52.3 % at 12:00 p.m.

In general, it was still in the comfort range of 50-80

%, although on day 9, it reached minimum value of 38 % at 2:10 p.m. It started to decrease at 6:50 a.m., reached 52.3 % up to 52.5 % during 12:00 p.m. until 12:50 p.m., as the minimum values.

Figure 5(a) to Figure 5(c) show the recording results of PLC 3.

(a) Illuminance

(b) Temperature

The lowest illuminance occurred on the second day, on January 24, 2018. The fifth day, January 27, 2018, was included in the low illuminance. Conversely, after cloudy and rainy day, the sixth day, January 28,2018, was a sunny day. The fourteenth day, February 5, 2018, experienced the highest illuminance followed by the third, sixth, tenth, fifteenth and twelfth days respectively. It was the highest among the remaining PLC kits. In this room, there was very large illuminance, above the standard of 250 lux. Even more, the highest illuminance reached 574 lux. It was caused by the highest position of the kit installation so that lots of light was caught by the sensor. The high illuminance was caused by not only the lighting from the sun, but also from the lamps until late at night. The average illuminance started to rise at 6:10 a.m. and vanished at 7:20 p.m., 427 lux as the maximum, at 11:20 a.m.

The highest temperature was 32 ^oC, on January 26 and 28, 2018, slightly corresponded to the illuminance.

Generally, on PLC 3, the average temperature was the highest among PLCs, due to the highest position, and lots of entered sun ray to the room. It was optimal comfort from the midnight until 8:35 a.m., with 24.43

oC as the minimum at 4:50 a.m. It was warm comfort until 9:45 p.m., exceeded the warm comfort until 6:30 p.m., and reached the maximum value of 31.75 ^oC at 1:10 p.m. It returned to the warm comfort until 10:30 p.m., and to the optimal comfort until midnight. It started to rise at 8:00 o’clock, reached 31.7 ^oC as the maximum at 13:10 p.m.

The lowest relative humidity was 34 % on January 31, 2018. On the other hand, the high relative humidity occurred on February 3 and 6, 2018 respectively. The maximum average relative humidity was 68.1 % at 6:30 a.m., and the minimum one was 49.6 % at 12:00 p.m. It was still in the comfort range of 50-80 %, although on day 9, reached 34 % as the minimum at 12:10 p.m. The average started to decrease at 7:00 o’clock, reached 49.4 % at 12:20 p.m.

Figure 6(a) up to Figure 6(c) show the recording results on PLC 4.

0 100 200 300 400 500 600

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

0 5 10 15 20 25 30 35

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

0 10 20 30 40 50 60 70 80

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

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(a) Illuminance

(b) Temperature

The lowest illuminance was on January 24, and January 29, 2018. The average illuminance started to rise at 5:40 a.m. and vanished at 6:10 p.m., with 87 lux as the maximum during 9:50 a.m. until 12:10 p.m.

The highest temperature was 29 ôC, on the seventh, sixth, eighth, ninth, tenth and eleventh days respectively. The average temperature was warm comfort from the midnight until 10:30 a.m., with the minimum value of 25.9 ôC at 7:20 a.m. It exceeded the warm comfort until 5:30 p.m., and it started to rise at 8:30 a.m and reached 28 ôC as the maximum at 2:20 p.m.

The lowest relative humidity was 41 %, on January 31, 2018, corresponded to that on PLC 1. The maximum average relative humidity was 62.7 % at 12:30, 1:10 and 4.20 a.m. and the minimum one was 54.9 % at 10:30 a.m. It started to decrease at 7:40 a.m., reached 54.9

% as the minimum at 12:30 p.m.

Figure 7(a), 7 (b) and Figure 7(c) show the recording results on PLC 5.

(a) Illuminance

(b) Temperature

The lowest illuminance occurred on the second day, January 24, 2018. Conversely, the sixth day, January 28, 2018, was a sunny day. On the fourth day, January 26, 2018, there was the highest illuminance. The average illuminance started to rise at 5:50 a.m. and vanished at 5:50 p.m., with the maximum of 127 lux at 11:30 a.m.

The highest temperature was 29 ôC occurred on the fourth, sixth and eighth days, which were on January 26, 28 and 30, 2018 respectively, slightly corresponded to the illuminance occurred on the fourth and sixth days. Meanwhile, large part of the remaining days was under the average line. The average temperature was optimal comfort from the midnight until 9:00 a.m., with the minimum value of 24.6 ôC at 5:50 a.m. It started to rise at 7:10 a.m. and it was warm comfort until 11:00 a.m. After that, it exceeded the warm comfort until 3:50 p.m., and it reached the maximum value of 27.8 ôC at 12:30 p.m. It returned to the warm comfort until 8:10 p.m, and finally, it returned to the optimal comfort until midnight.

The lowest relative humidity was 40 % occurred on January 31, 2018, corresponded to that on PLC 1.

0 20 40 60 80 100 120 140

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM Time

0 5 10 15 20 25 30 35

Temperature (oC)

0 10 20 30 40 50 60 70 80

0 20 40 60 80 100 120 140 160 180 200

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

0 5 10 15 20 25 30 35

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

0 10 20 30 40 50 60 70 80 90

12:00:00 AM

2:24:00 AM

4:48:00 AM

7:12:00 AM

9:36:00 AM

12:00:00 PM

2:24:00 PM

4:48:00 PM

7:12:00 PM

9:36:00 PM

12:00:00 AM

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In contrast, the high relative humidity occurred on the second day and the third day, which were on January 24, and 25, 2018 respectively, predicted to be sunny upto light cloudy days. The maximum and minimum average relative humidity were 72.6 % and 54%

at 2:40 a.m. and 11:40 a.m. respectively. It started to decrease at 6:30 a.m. In general, the relative humidity was still in the comfort range of 50-80 %, although on day 9, it reached minimum value of 40 % at 11:30 a.m.

Based on the standards [77], [78], the ideal illuminance on classrooms is 250 lux. For the first day (day 1), on the 23^rd of January 2018, the illuminance started to be 250 lux at around 09:00 and under 250 lux at around 15:00. It was reasonable due to the high level illuminance naturally. The high captured illuminance on PLC 3 was caused by the highest floor. Therefore, lots of light was caught by the sensor. Beside coming from the sun, high illuminance was caused by the existence of lamp lighting until late at night.

According to the Decree of the Minister of Health of the Republic of Indonesia, number 1405, 2002, on the environmental health requirements of offices and industry, the minimum illuminance in a workroom is 100 lux [79], [80]. However, the illuminance of air quality requirement in a home space is minimum 60 lux [81].

Nevertheless, the illuminance for human being (lecturers, students and technicians) to work was generally higher than the monitoring results. This case was caused that the sensors were placed on the room corners, under the ceilings. Thus, the placements of illuminance monitor have not been optimal yet. It is usually used when the students are learning. However, it was not possible if the PLC kits were placed on the tables because they would disturb students during their learning processes and the kits probably would not be safe. Thus, even though the recordings of illuminance, especially in the morning and afternoon until evening, were under 250 lux, they were higher than 60 lux, even greater than 100 lux.

In fact, they were higher than the recording of obtained data, because the kits were not placed on the desk. Therefore, it was necessary to make a corrective approach.

The corrective approach was conducted by measurements of illuminance on tables of workplace and on the installed PLC kits manually, every hour from 7:00 o’clock in the morning and 18:00 o’clock in the evening simultaneously. The average ratios of measurements on the tables and on the PLC kits were 2.56, 2.02, 1.83, 3.72, and 2.77 for PLC 1 up to PLC 5 respectively. Thus, to obtain the real illuminance on the tables of workplace, the recording results should be multiplied by the ratios of the corrective approach.

Usually, the classes start at 7:00 o’clock until 17:00 o’clock or ten hours of duration and in working time, the illuminance should be at least 250 lux, so that it met the requirement according to the standards as much as 65.0%, 6.7 %, 76.7 %, 45.0 %, and 36.7 % for first up to fifth rooms respectively.

Figure 8 shows the diagram of illuminance on the PLC installed rooms based on the averages of monitored illuminance and corrective factors.

Figure 8. Diagram of illuminance on the PLC installed rooms The illuminance in the PLC 2 installed room was very small because the window curtains were always closed, and the classroom was rather rare used. Thus, it is necessary to open some part of the curtains or design an extra lighting.

At the same time, the temperature and humidity were assumed to be uniform in the monitored rooms, so that both quantities were considered to be perceived same by the users. According to SNI (National Standard of Indonesia) of T-14-1993 and based on the standards set forth in SNI of 03-6572-2001, the zone of the thermal Comfort Standard of Indonesia is divided into three parts. They are cool comfort (20.5-22.8 ôC), optimal comfort (22.8-25.8 ôC) and warm comfort (25.8-27.1ôC), with the upper threshold of 24 ôC, 28 ôC and 31 ôC, and with the relative humidity of 50-80 %, 70 % and 60 % respectively. The healthy indoor temperature, based on Indonesia's health minister decree number 261 of 1998, is ranging from 18-26 ôC for room temperatures [82-85].

Nevertheless, according to the decree of the minister of health of the Republic of Indonesia number 1405 of 2002, on the environmental health requirements of offices and industries, the room air temperatures and relative humidity are 18ô-30ôC and 65 %-95 % respectively [86]. Meanwhile, the temperatures and relative humidity for air quality requirements in the home space are 18-30 ôC and 40 %-60 % respectively [85].

However, in the context of environment that has an air temperature of 22-35 ôC, there would be a significant relationship between several variables of ventilation and thermal comfort [86]. Based on the recording results and above standards, the temperatures and the relative humidity were almost in the ranges of 25-30 ôC and 50 %-80 % respectively. Only small part of the temperatures and relative humidity were under 25 ôC and 50 %. Therefore, the rooms were mostly in the warm thermal comfort. Nevertheless, a small part of rooms was in the optimal thermal comfort. Practically, there was not any natural cool thermal comfort room. The cool thermal comfort could be generated by facilitating the existence of air conditioning.

Figure 9 shows the diagram of thermal comforts on the PLC installed rooms based on the averages of monitored temperatures.

PLC 1 PLC 5

PLC 4

PLC 3

PLC 2

0 6 12 18 24

Time

Fulfilled illuminance standard : 36.7%

Fulfilled illuminance standard

Not fulfilled illuminance standard

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Figure 9. Diagram of comforts on the PLC installed rooms The optimal comfort and warm comfort occupied 19.1 % and 44.4 % respectively. Meanwhile, the room condition was 36.5 % exceeding the comforts. In the PLC 3 and PLC 5 installed rooms, the condition experienced the optimal comfort. It was probably caused by the high room positions, when mainly nights and early mornings, the blowing wind from outside entered to the rooms dominantly. Nevertheless, especially in the PLC 3 installed room, the temperature rose most rapidly to exceed the comfort, even it reached the highest temperature. Therefore, in future, the PLC 3 installed room will be installed air conditioners (ACs), an electric power supply should be more, approaching twice, than the remaining rooms. Nevertheless, the duration of AC running will be short.

In humid tropical climate buildings, there were many difficulties to meet the required standards. However, the air temperature outside thermal comfort could be accepted by residents. This showed that the standard was not absolutely applicable in the humid tropical climate [87].

The constants of A, B and C are indicated in equation(1). The constants of A were negative, for both illuminance and temperature, which meant that the graphs swelled upward. Both parameters rose reaching the peaks and down again as the time increased.

Generally, both parameters had achieved the peaks at mid days.

Furthermore, the constants of B were positive, which meant that the curves also went up and down again as the time increased. Nevertheless, the constants of B for both parameters were quite different. For the illuminance, they were above ten, while, for the temperature, they were under unity. This meant that the rising and decreasing illuminance were faster or steeper than the temperature one. It was also reinforced by C constants, where on the illuminance, they were high enough negative values, with the average of -0.716, and on the temperature, they were high enough. The early illuminance was very low, as - 43.47 lux in the average. Nevertheless, in the real condition, the lowest values approached zero. This meant that the illuminance variations were very high.

Meanwhile, the variations of temperature were very small.

On the relative humidity, the constants of A were low positive, under 0.1, and they are shown by the expanded downward parabolic curves. However, the

expansions were very small. They were also supported by the low negative values of B constants. However, the constants of C were high enough, and the variations were considerably low.

Figure 10(a) shows the modelling chart on the illuminance as function of time, where the curves swelled upward drastically.

(a) Illuminance

(b) Temperature

Figure 10. Modelling charts on the three room environmental parameters as time function

Thus, the illuminance variations were very high.

Figure 10(b) shows the modelling chart on the temperature, where the curves swelled upward slightly, so that the variations of illuminance were low. Finally, Figure 10(c) shows the modelling chart on the relative humidity. The figure shows that the curves swelled downward considerably. Therefore, the illuminance variations were the most significant, followed by the relative humidity and the temperature respectively.

On the other hand, the modelling could be expressed by the average mathematical models as time function.

The first and second mathematical models were the illuminance and temperature, as equations (2) and (3) respectively. The quadratic constants of variables on both equations were negative. This indicated that both curves were convex upward, although they were different in the slopes.

PLC 1 PLC 5

PLC 4

PLC 3

PLC 2

0 6 12 18 24

Time Cool Comfort: 0 Optimal Comfort: 53.5%

Warm Comfort: 26.4%

Exceed Comfort: 20.1%

Cool Comfort: 0 Optimal Comfort: 0 Warm Comfort: 70.8%

Cool Comfort: 0 Optimal Comfort: 42.0%

Warm Comfort: 21.5%

Optimal Comfort

Warm Comfort

Exceed Comfort

0 15 30 45 60 75 90 105 120 135 150

0 2 4 6 8 10 12 14 16 18 20 22 24

Time

PLC 1 PLC 2 PLC 3 PLC 4 PLC 5 Average

23.0 24.0 25.0 26.0 27.0 28.0 29.0

0 2 4 6 8 10 12 14 16 18 20 22 24

Time Temperature (oC)

50 55 60 65 70 75

0 2 4 6 8 10 12 14 16 18 20 22 24

Time

(8)

Furthermore, equation (4) represents the convex curve on the relative humidity to the bottom, as indicated by the small positive constant of the quadratic time variable. Nevertheless, the curvature was considerably low.

( )

t 0.716t 18.6t 43.47

L =− ²+ − (2)

( )

t 0.0115t 0.323t 25.12

T =− ²+ + (3)

( )

t 0.0575t 1.491t 67.84

H = ²− + (4)

The correlation coefficient between the illuminance and the temperature was 0.96499. This meant that both parameters were much correlated; the temperature increased significantly as the illuminance rose. On other hand, the correlation coefficient between the illuminance and the relative humidity was -0.99996, as the indication that both parameters were inversely and extremely correlated. The last one, the correlation coefficient between the temperature and the relative humidity was -0.96275, where both parameters were inversely and considerably correlated. Clearly, the illuminance more dominantly influenced the relative humidity inversely rather than the temperature.

4. Conclusions

The illuminance, temperature and relative humidity online monitoring and recordings could be implemented using the official SCADA software and wireless media.

By using wireless media, the data could not be 100 % transferred, due to hampered signals of building walls.

Nevertheless, this obstruction could be minimized by using router, repeater and LAN wire installations.

The average illuminance rose between 5:40 a.m. and 6:30 a.m. and disappeared between 5:50 p.m. and 7:20 p.m. The rooms were mostly in the warm thermal comfort and, in small part of time, the rooms were in the optimal thermal comfort. The warm and optimal thermal comforts occupied 44.4 % and 19.1 % respectively. The rest, 36.5 %, exceeded the comforts.

Naturally, there was not any room in cool thermal comfort. To meet the standard requirement of 250 lux, the illuminance covered 65.0 %, 6.7 %, 76.7 %, 45.0 %, and 36.7 % of working time for PLC 1 up to PLC 5 respectively. The illuminance and temperature modelling convexed upward significantly, indicated by the negative constants of the quadratic time variable.

In contrast, the relative humidity modelling convexed downward considerably indicated by the positive constants of the quadratic time variable. This case was reinforced by the absolute numbers of correlation coefficients among illuminance, temperature and humidity were very high, above 0.9. The parameter signals of PLC 3 were the most different from the others, because of very high temperature and illuminance, due to the highest installation. The research results were a basic for automation design in relation with thermal and visual comforts, and electrical energy saving.

Appendix

Nomenclatures

A Constant of x² B Constant of x

C Constant

H Relative humidity HMI Human Machine Interface IP Internet Protocol.

L Illuminance LAN Local Area Network RJ45 Registered Jack 45

SCADA Supervisory control and data acquisition SSID Service Set Identifier

SNI National Standard of Indonesia (Standard Nasional Indonesia)

T Temperature

t Time in one day (24 hours) WRP Wi-Fi repeater

WRT Wi-Fi router

x Variable

y = f(x) Function to be obtained

Greek Symbols

 Correlation coefficients

 Summation

 Components of covariance matrix

Subscripts

k Order of data N Number of data

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