reflective array solar water heater for milk pasteurization

131Environmental Research, Engineering and Management 2020/76/4

Reflective Array Solar Water Heater for Milk Pasteurization

EREM 76/4Journal of Environmental Research, Engineering and ManagementVol. 76 / No. 4 / 2020pp. 131–137DOI 10.5755/j01.erem.76.4.24411

Reflective Array Solar Water Heater for Milk Pasteurization

Received 2019/10 Accepted after revision 2020/11

http://dx.doi.org/10.5755/j01.erem.76.4.24411

Budhy Setiawan, Riska Nur Wakidah*, YuliantoState Polytechnic of Malang

*Corresponding author: [email protected]

The solar water heater is a method of utilizing solar thermal energy by storing heat energy in water which can be used directly. Solar thermal energy has a high utility potential. It has a power of 1 kW/m2 on average on the surface of the earth with energy up to 7 kWh/m2/day on average per year. One of the uses of the solar water heater is that it can be implemented in the milk pasteurization system. The research equipment consists of an accumulator vessel with an area of 2x2 m2 and a water pipe collector. The water that had been heated in an accumulator (thermos) was used directly as the heating source in the milk pasteurization process. Meanwhile, the most common heating method used in the pasteurization process is electricity and gas energy. The result showed that using 82oC of accumulator water, it took 12 minutes (14.48–15.00) to reach the milk temperature needed in the pasteurization process which is 70oC for 6.75 litres of milk. The efficiency of solar heat energy absorption by an accumulator is 47%. This value can be increased by increasing the volume of water.

Keywords: solar water heater, reflective array method, milk pasteurization

IntroductionThe world’s fossil energy reserves (oil, gas, and coal) have declined since 2008 (World Oil Reserve, 2009). One of the renewable alternatives is solar energy that is free and everlasting. Solar energy has a power of 1 kW/m2 on average on the surface of the earth with energy up to 7 kWh/m2/day on average per year (Budhy and Andrew, 2014). Solar energy is generally converted to electricity, but it also can be stored as heat energy using liquid ma-terial and dry material (EBTKE). One of the implementa-tions of solar energy is as a solar water heater.

The implementation is very relevant and effective to use. It is related to Indonesia’s geographical position in the tropical coordinate region, which has high solar en-ergy, 1600 kWh/m2/per year (Dang, 2017). In addition, this implementation has a high efficiency of collecting and storing heat energy up to 70% (Brian, 2013).

One of the uses of a solar water heater in the industri-al is milk pasteurization system. Milk pasteurization is done to prevent damage to pathogenic bacteria in milk. The milk pasteurization process is mostly done with

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Environmental Research, Engineering and Management 2020/76/4132

thermal method. The thermal method is conventional food processing using heating temperature between 60–100oC (Yinghao, 2011). In general, the heater used to perform the pasteurization process utilizes electri-cal or gas energy. On the other hand, many developing countries do not yet have an abundant electricity supply and this should be a concern (Tuszyński, 1983). The re-search is expected to be able to reduce the use of elec-trical and gas energy needed in the milk pasteurization process and for the welfare of an area that still lacks an electricity supply (Atia, 2010).

The equipment used in the research is a heat accumu-lator that has a 3.8 m2 width vessel and a 3.8 m2 flat plate collector inside, and also a 3.8 m2 reflective array. The heat energy of the accumulator will be absorbed by water inside the flat plat collector. The heated water will be used directly as a milk heating medium in the pasteurization process.

Modelling of the System

Solar water heater method

Research on the conversion of solar energy shows that changes to heat energy have the highest efficiency of 80% (EBTKE; Quijera, 2011). In the study of the imple-mentation of solar thermal energy, the method intro-duced heat storage in liquid material temperature using salt, oil reaching 300℃, and water reaching 60℃ (EBT-KE). Heat storage using dry material reaches a tempera-ture of 120℃ (Brian, 2013).

Air heat accumulator utilizes the greenhouse effect method (EBTKE). In the greenhouse method, water and ground are used as heat-absorbing materials. Mean-while in this study, the solar heater used water media as an absorber and storage of heat energy trapped in the greenhouse (Brian, Charles, Ferenz George, and Kilkis,2013).

In Fig. 1, to maintain absorbed energy, the accumulator is utilized by a reflective array controller (reflective array method). The way method works as follows: if the heat power in the accumulator is smaller than solar power, the array will open, and the array will close if the solar power is smaller than heat power in the accumulator.

The materials of the array are stainless steel with a 78% reflectivity efficiency, and the controller array is driven by a low energy DC motor, 12 watts. Arrays and motors were placed below the vacuum glass. The vacuum glass is made of tempered glass (capable of up to 300oC).

The system of utilizing heat energy can be carried out directly by storing it in water media. Water was stored in a spiral pipe placed in the vessel with an area of 3.8 m2. With this ability, water was flowed and used to heat milk in the pasteurization process. Heating milk in this pro-cess required the water to be 82oC. Water that had been heated in the accumulator was poured into a double jacket pan by an electric motor pump.

Fig. 1. Array reflective solar water heater method

2

In Fig. 1, to maintain absorbed energy, the accumulator is utilized by a reflective array controller (reflective 1 array method). The way method works as follows: if the heat power in the accumulator is smaller than solar power, 2 the array will open, and the array will close if the solar power is smaller than heat power in the accumulator. The 3 materials of the array are stainless steel with a 78% reflectivity efficiency, and the controller array is driven by a 4 low energy DC motor, 12 watts. Arrays and motors were placed below the vacuum glass. The vacuum glass is 5 made of tempered glass (capable of up to 300oC). 6

The system of utilizing heat energy can be carried out directly by storing it in water media. Water was stored 7 in a spiral pipe placed in the vessel with an area of 3.8 m2. With this ability, water was flowed and used to heat 8 milk in the pasteurization process. Heating milk in this process required the water to be 82oC. Water that had been 9 heated in the accumulator was poured into a double jacket pan by an electric motor pump. 10 11

Flat plat Accumulator

glass Array

Motor Pump

12 Fig. 1 Array reflective solar water heater method 13

14 Data collection method of solar water heater energy capacity 15

16 The purpose of the data collecting is to find the energy capacity and parameters involved. This research is 17

very important in the optimization and calculation of solar energy storage. 18 Equations (1) – (5) are expressed in the application programme that is connected directly to the sensor via 19

DAQ DT-9813 interface to obtain data and graphs for analysis. This research is also to obtain the absorption 20 efficiency of the accumulator. The empirical measurement method is applied as seen in Fig. 2. 21

The absorption efficiency of the accumulator can be calculated by Equation (1): 22 23

%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31

Where: p = stored energy efficiency [%]; 32

accE = accumulator energy [kWh]; 33

wm = water mass [L] 34

wC = specific heat capacity of water [kJ/oK]; 35

wT = water temperature [oC]0;0 36

sE = solar energy [kWh]; 37

Data collection method of solar water heater energy capacity

The purpose of the data collecting is to find the energy capacity and parameters involved. This research is very important in the optimization and calculation of solar en-ergy storage.

Equations (1) – (5) are expressed in the application pro-gramme that is connected directly to the sensor via DAQ DT-9813 interface to obtain data and graphs for anal-ysis. This research is also to obtain the absorption ef-ficiency of the accumulator. The empirical measure-ment method is applied as seen in Fig. 2.


The absorption efficiency of the accumulator can be cal-culated by Equation (1):

2




glass Array

Motor Pump







%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31







(1)

Where,

2




glass Array

Motor Pump







%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31







(2)

2




glass Array

Motor Pump







%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31







(3)

3

sP = solar power [W]; 1

sI = solar intensity [Lux]. 2 3

4 Fig. 2 Measuring data method 5

6 Results and Discussion 7

8 The analysis is carried out to determine the ability of the accumulator and heat supply in the milk 9 pasteurization process. This capability is shown by several sensors converted by Arduino. Furthermore, the output 10 of the sensor is fed to the data retrieval instrument DAQ (data acquisition) DT9813. 11 The research was conducted at Malang State Polytechnic, Malang, East Java, precisely at the coordinates 12 of 7o 56'44.57'' south latitude and 112o 36'53.20" east longitude, located at an altitude of 499 m above sea level, 13 on 22 October 2018 with a state of sunlight shown in Fig. 3. 14 15

0

100

90

80

7060

5040

30

20

10

07.00

08.00

09.00

10.00

11.00

12.00

13.00

14.00

15.00

16.00

Intensity (Lux x 1000)

Time

16 Fig. 3 Solar intensity on 22 October 2018 17

18 The light intensity at that time was relatively low with a maximum intensity of 90,000 Lux, which was 19

reached at 11.45–12.00 local time. From 08.00–11.00 local time, there was no significant increase. Then there was 20 a decrease and fluctuation until 15.00 local time. And until 15.00–16.00 local time, the intensity decreased to 21 10,000 lux. Furthermore, the relative intensity fluctuated and decreased. Light intensity monitoring was carried 22 out by the light intensity sensor module GY-30 BH1750. 23

24 Reflective solar water heater capability in the milk pasteurization process 25

26 It can be seen from Fig. 4 that using 82oC takes 12 minutes (14.48–15.00) to reach the milk temperature 27

needed in the pasteurization process, which is 70oC and for 6.75 litres of milk. This shows that a reflective solar 28 water heater can be used for the pasteurization process. The attainment of the temperature can be increased by 29 increasing the water discharge from the accumulator to the pan used in the pasteurization process. 30

And from Fig. 5 it is known that to increase the milk temperature, the accumulator’s heat energy decreases by 31 1.9 kWh. This value can be calculated by Equations (2) and (3). The decreasing energy is large, which is 43% of 32 the energy absorbed in the accumulator. This decrease can be reduced by increasing the volume of water in the 33 accumulator so that the energy that can be absorbed by the accumulator is greater. 34

Fig. 2. Measuring data method

And

2




glass Array

Motor Pump







%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31







(4)

2




glass Array

Motor Pump







%100s

accp E

E (1) 24

Where, 25

wwwacc TCmE (2) 26

01 www TTT (3) 27 And, 28

dtPEt

t ss 1

0 (4) 29

luxIP ss 121/ (5) 30 31







(5)

Where: ηp= stored energy efficiency [%]; Eacc = accumu-lator energy [kWh]; mw = water mass [L]; Cw = specific heat capacity of water [kJ/oK]; Tw = water temperature [oC]0;0; Es = solar energy [kWh]; Ps = solar power [W]; Is = solar intensity [Lux].

Results and DiscussionThe analysis is carried out to determine the ability of the accumulator and heat supply in the milk pasteurization process. This capability is shown by several sensors con-verted by Arduino. Furthermore, the output of the sensor is fed to the data retrieval instrument DAQ (data acquisi-tion) DT9813.

The research was conducted at Malang State Polytech-nic, Malang, East Java, precisely at the coordinates of 7o 56’44.57’’ south latitude and 112o 36’53.20” east longi-tude, located at an altitude of 499 m above sea level, on 22 October 2018 with a state of sunlight shown in Fig. 3.

The light intensity at that time was relatively low with a maximum intensity of 90,000 Lux, which was reached at 11.45–12.00 local time. From 08.00–11.00 local time,

there was no significant increase. Then there was a de-crease and fluctuation until 15.00 local time. And until 15.00–16.00 local time, the intensity decreased to 10,000 lux. Furthermore, the relative intensity fluctuated and decreased. Light intensity monitoring was carried out by the light intensity sensor module GY-30 BH1750.

Reflective solar water heater capability in the milk pasteurization process

It can be seen from Fig. 4 that using 82oC takes 12 min-utes (14.48–15.00) to reach the milk temperature needed in the pasteurization process, which is 70oC and for 6.75 litres of milk. This shows that a reflective solar water heater can be used for the pasteurization process. The


Fig. 3. Solar intensity on 22 October 2018

3

sP = solar power [W]; 1

sI = solar intensity [Lux]. 2 3

4 Fig. 2 Measuring data method 5

6 Results and Discussion 7

8 The analysis is carried out to determine the ability of the accumulator and heat supply in the milk 9 pasteurization process. This capability is shown by several sensors converted by Arduino. Furthermore, the output 10 of the sensor is fed to the data retrieval instrument DAQ (data acquisition) DT9813. 11 The research was conducted at Malang State Polytechnic, Malang, East Java, precisely at the coordinates 12 of 7o 56'44.57'' south latitude and 112o 36'53.20" east longitude, located at an altitude of 499 m above sea level, 13 on 22 October 2018 with a state of sunlight shown in Fig. 3. 14 15

0

100

90

80

7060

5040

30

20

10

07.00

08.00

09.00

10.00

11.00

12.00

13.00

14.00

15.00

16.00

Intensity (Lux x 1000)

Time

16 Fig. 3 Solar intensity on 22 October 2018 17

18 The light intensity at that time was relatively low with a maximum intensity of 90,000 Lux, which was 19

reached at 11.45–12.00 local time. From 08.00–11.00 local time, there was no significant increase. Then there was 20 a decrease and fluctuation until 15.00 local time. And until 15.00–16.00 local time, the intensity decreased to 21 10,000 lux. Furthermore, the relative intensity fluctuated and decreased. Light intensity monitoring was carried 22 out by the light intensity sensor module GY-30 BH1750. 23

24 Reflective solar water heater capability in the milk pasteurization process 25

26 It can be seen from Fig. 4 that using 82oC takes 12 minutes (14.48–15.00) to reach the milk temperature 27

needed in the pasteurization process, which is 70oC and for 6.75 litres of milk. This shows that a reflective solar 28 water heater can be used for the pasteurization process. The attainment of the temperature can be increased by 29 increasing the water discharge from the accumulator to the pan used in the pasteurization process. 30

And from Fig. 5 it is known that to increase the milk temperature, the accumulator’s heat energy decreases by 31 1.9 kWh. This value can be calculated by Equations (2) and (3). The decreasing energy is large, which is 43% of 32 the energy absorbed in the accumulator. This decrease can be reduced by increasing the volume of water in the 33 accumulator so that the energy that can be absorbed by the accumulator is greater. 34

Fig. 4. Reflective ability of a solar water heater to increase the temperature of milk

4

1 Fig. 4 Reflective ability of a solar water heater to increase the temperature of milk 2

3

4 Fig. 5 Heat energy required by milk in the accumulator 5

6 From the data above, the calculation of the frequency of peak solar energy used to heat 6.75 litres of milk 7

using the accumulator reflective array software [14] is shown in Fig. 6. 8 With the ideal intensity, it was found that the accumulator was able to be used in the milk pasteurization 9

process of 6.75 litres of milk as many as 5 times a day. The energy requirements of 6.75 litres of water are 1.9 10 kWh and the accumulator will be used when the temperature is 82oC. 11

12

13 Fig. 6 The frequency of milk pasteurization in a day 14

15 16 17

Absorption of solar thermal energy by accumulators 18 19

attainment of the temperature can be increased by in-creasing the water discharge from the accumulator to the pan used in the pasteurization process.

And from Fig. 5 it is known that to increase the milk tem-perature, the accumulator’s heat energy decreases by 1.9 kWh. This value can be calculated by Equations (2) and (3). The decreasing energy is large, which is 43% of the

energy absorbed in the accumulator. This decrease can be reduced by increasing the volume of water in the ac-cumulator so that the energy that can be absorbed by the accumulator is greater.

From the data above, the calculation of the frequency of peak solar energy used to heat 6.75 litres of milk using the accumulator reflective array software [14] is shown in Fig. 6.


Fig. 6. The frequency of milk pasteurization in a day

4


3





12


15 16 17


Fig. 5. Heat energy required by milk in the accumulator

4


3





12


15 16 17


With the ideal intensity, it was found that the accumulator was able to be used in the milk pasteurization process of 6.75 litres of milk as many as 5 times a day. The en-ergy requirements of 6.75 litres of water are 1.9 kWh and the accumulator will be used when the tempera-ture is 82oC.

Absorption of solar thermal energy by accumulators

Fig. 7 explains that the accumulator’s absorption of solar thermal energy is 47%. This value can be calcu-lated by Equation (1). This value can be increased by


Fig. 7. The accumulator capability to absorb solar heat energy by accumulator

5

Fig. 7 explains that the accumulator’s absorption of solar thermal energy is 47%. This value can be calculated 1 by Equation (1). This value can be increased by increasing the volume of water. With greater absorption, it is 2 expected to decrease the accumulator energy when used for smaller pasteurization processes. 3 4

5 Fig. 7 The accumulator capability to absorb solar heat energy by accumulator 6

7 Conclusions 8

9 The proposed reflective solar water heater was presented. The result showed that using 82oC of accumulator 10

water, it took 12 minutes (14.48–15.00) to reach the milk temperature needed in the pasteurization process, which 11 is 70oC for 6.75 litres of milk. Meanwhile, the efficiency of solar heat energy absorption by an accumulator is 12 47%. 13

14 Acknowledgements 15

16 The authors express deep gratitude to Malang State Polytechnic and CV. Karya Brawijaya for the industrial 17

cooperation funding provided to this research. 18 19

References 20 21 22

World Oil Reserve, http://www.galtstock.com, /Peak-Oil-$.html/ Jan 2009. EBTKE, Director-general Energi Baru Terbarukan dan Konservasi Energi (EBTKE) Ministry of Energy and Mineral Resources Kardaya Warnika, RI oil reserves run out in 10 years,

Budhy Setiawan, Mauridhy Heri P, M Ashari. A High Precision Angle Compensation Controller for Dish Solar Tracker installed on a Moving Large Ship, International Review of Automatic Control (IREACO), Vol 7, No 1, Italy, ISSN: 1974-6059, pp 695-700 Terindeks : Scopus, Jan 2014

Andrew L. Thomas, Anastasia Becker, and Richard J. Crawford, Jr., An Energy-Efficient Solar-Heated Greenhouse, Produces Cool-Season Vegetables all Winter Long, University of Missouri-Columbia, Community Food Systems and Sustainable Agriculture, Southwest Research Centre, Mt. Vernon, Missouri

Dang, M. Q. (2017). Potential of Solar Energy in Indonesia. Brian Harits, Lutfi Rozaqi, mentored by Budhy Setiawan, Designing a heat accumulator prototype of 1 m2, Final Report of State Polytechnic of Malang, 2013

Tuszyński, W., Diakowska, E. A., & Hall, N. S. (1983). Solar energy in small-scale milk collection and processing (No. 39). Food & Agriculture Org.

increasing the volume of water. With greater absorp-tion, it is expected to decrease the accumulator energy when used for smaller pasteurization processes.

ConclusionsThe proposed reflective solar water heater was present-ed. The result showed that using 82oC of accumulator water, it took 12 minutes (14.48–15.00) to reach the milk

temperature needed in the pasteurization process, which is 70oC for 6.75 litres of milk. Meanwhile, the efficiency of solar heat energy absorption by an accumulator is 47%.

AcknowledgementsThe authors express deep gratitude to Malang State Pol-ytechnic and CV. Karya Brawijaya for the industrial coop-eration funding provided to this research.

References World Oil Reserve, http://www.galtstock.com, /Peak-Oil-$.html/ Jan 2009.

EBTKE, Director-general Energi Baru Terbarukan dan Konser-vasi Energi (EBTKE) Ministry of Energy and Mineral Resources Kardaya Warnika, RI oil reserves run out in 10 years,

Budhy Setiawan, Mauridhy Heri P, M Ashari. A High Precision Angle Compensation Controller for Dish Solar Tracker installed on a Moving Large Ship, International Review of Automatic Control (IREACO), Vol 7, No 1, Italy, ISSN: 1974-6059, pp 695-700 Terindeks : Scopus, Jan 2014

Andrew L. Thomas, Anastasia Becker, and Richard J. Crawford, Jr., An Energy-Efficient Solar-Heated Greenhouse, Produces Cool-Season Vegetables all Winter Long, University of Missou-

ri-Columbia, Community Food Systems and Sustainable Agri-culture, Southwest Research Centre, Mt. Vernon, Missouri

Dang, M. Q. (2017). Potential of Solar Energy in Indonesia.

Brian Harits, Lutfi Rozaqi, mentored by Budhy Setiawan, De-signing a heat accumulator prototype of 1 m2, Final Report of State Polytechnic of Malang, 2013

Tuszyński, W., Diakowska, E. A., & Hall, N. S. (1983). Solar ener-gy in small-scale milk collection and processing (No. 39). Food & Agriculture Org.

Atia, M. F., Mostafa, M. M., Abdel-Salam, M. F., & El-Nono, M. A. (2010). Solar energy utilization for milk pasteurization (Doctoral dissertation).


Quijera, J. A., Alriols, M. G., & Labidi, J. (2011). Integration of a solar thermal system in a dairy process. Renewable Energy, 36(6), 1843-1853.https://doi.org/10.1016/j.renene.2010.11.029

Yinghao Chu, Review and Comparation of Different Solar Ener-gy Technologies, Global Energy Network Institute (GENI), www.geni.org, August 2011.

Republika, 01 October 2014, Electricity Production Indonesia still counts on Fossil Energy, interview with ESDM minister Susilo Siswoutomo. 2020 125 MW is currently 50MW, coal is the backbone of electrical energy besides fuel.

Charles Wyman, James Castle and Frank Kreith (), A Review of Collector and Energy Storage Technology for Intermediate Ap-plications, Solar Energy, Vol. 24, pp 517-540 [A valuable review paper.], 1980.https://doi.org/10.1016/0038-092X(80)90352-7

Ferenz Rákóczi† and Zsuzsanna Iványi, Water vapour and green-house effect, GEOFIZIKA, VOL. 16-17, pp 65-72, 1999-2000.

Frank W. Schmidt and A. John Willmott (), Thermal Energy Storage and Regeneration, Hemisphere Publishing Corpora-

tion. [Another reference on the thermal energy storage], 1981, https://doi.org/10.1115/1.3266227

George A. Lane (), Solar Heat Storage: Latent Heat Materi-al, Volume I, CRS Press, Florida. [A useful reference book for phase change materials.], 1983.

Kılkış and H. Yüncü, Editors, Energy Storage Systems: Funda-mentals and Applications (B.), Advanced Study Institute, June 27-July 8, İzmir, Turkey p. 541-549. [It includes a series of de-tailed useful articles], 1988

Setiawan, B., Wakidah, R. N., Edy, P. R., Maulidia, D. A., Yulianto, Y., & Widjanarko, W. (2018). Empirical base solar reflective array accumulator design simulator. In MATEC Web of Conferences (Vol. 197, p. 11017). EDP Sciences https://doi.org/10.1051/matecconf/201819711017

Riska Nur Wakidah. (2018). Control system energy for hybrid egg hatching machine with solar accumulator. Thesis of magis-ter electrical engineering. State Polytechnic of Malang

This article is an Open Access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 (CC BY 4.0) License (http://creativecommons.org/licenses/by/4.0/ ).

https://doi.org/10.1016/j.renene.2010.11.029

https://doi.org/10.1016/0038-092X(80)90352-7

https://doi.org/10.1115/1.3266227

https://doi.org/10.1051/matecconf/201819711017

https://doi.org/10.1051/matecconf/201819711017

reflective array solar water heater for milk pasteurization

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