SOLAR HEAT ACCUMULATOR CONTROL APPLYING REFLECTIVE
ARRAYMETHOD FOR ENERGY OPTIMIZATION
Budhy Setiawan
1, Wirawan
2and Herman Hariadi
11
Electrical Engineering Department, State Polytechnic of Malang, Indonesia
2Mechanical Engineering Department, State Polytechnic of Malang, Indonesia
E-Mail: [email protected]
ABSTRACT
This paper presents solar heat accumulator with reflective plate arrays method for heat supply of hybrid solar hatching machine. The arrays method is driven by a dc geared motor that is controlled by MCU (Microcontroller Unit Atmega), in which, include an appropriate hysteresis method to handle the driver. In the experiment, the hysteresis method has shown its capability to absorb and regulate the sun heat up to 57.46% solar energy.
Keywords: solar heat accumulator, reflective array, hysteresis.
1. INTRODUCTION
The world's reserves of fossil energy (oil, gas and coal) has decreased since 2008 [World oil Reserve], and predicted by 2020 have been exhausted [EBTKE]. One of the alternative renewable energy is solar energy that is both timeless and free. Solar energy has a power of 1 KW/m2 in average on tropical surface of the Earth with energy up to 7 KW hour/m2/day average per year [Andreev, Daniel]. Solar energy technologies are generally converted to electric. However, it is also converted to heat energy that can be stored in liquid and dry materials [Ercan]. One of the implementation of solar energy can be utilized in the incubator.
The implementation is very relevant and effective use, the thing with regard to Indonesia's geographical position on the region's tropical coordinates that have solar energy is high enough, 5 Kwh/m2/day average per year [NASA]. With the efficiency of collection and storage of heat energy of 70% [Brian] (when using the method of collection and storage of the heat), then it brings the heat energy of 5.3 KWh/m2 per day.
In the community and industry, hatcher machines almost entirety using electrical energy. The machinery with regard to the procurement of food of poultry meat and eggs would be a society that is on the rise and have easy access of electricity on the other party of Government’s Electric Company. Indonesia has stated that fossil energy will be depleted by 2020 [EBTKE]. Ironically, in this decade, in Indonesia, an increase in the procurement of electrical energy relies on fossil energy as raw electrical energy [Republika].
This research is expected to reduce the use of electric energy on the use of hatching machine or incubator.
With hopes of a reduction in energy use by 60% annually accumulator from this research; East Java province can reduce electricity consumption for all of 821.1 MWj/year or 2.26 MWj per day.
Because the incubator requires heat energy, it is wise, utilizing solar thermal energy as a complement. The proposed method such as heat storage solar accumulator have an efficiency up to 80% on energy conversion [Ercan],compare to electric energy, that spent fossil energy
or solar cellthat was only able to convert a maximum of 20% [Andreev].
Road map beginning with the utilization of solar energy heat storage material using the paddy hull with manual controls [Sukatmi] and the utilization of energy hybrid electric and solar paddy hull [Eni]. On the development of advanced solar energy storage research on SWH (Solar Water Heater) to supply heat energy hatching machine [Kuye]. Solar energy conversion to electricity using Photovoltaic has maximum efficiency 20% [Andreev]. In the research, the heat of the Sun stored in accumulator, and the heat storage material are concrete blocks [Brian]. Flat collectors to be utilized in electric hybrid hatching machine have efficiency up to 70% [Brian, Ercan]. Storage method of hot air superiority lies on the conversion efficiency; it is particularly high. The technology of collectors and accumulators are easy and cheap. Simple and cheap are also obtained from electronic control role in maximizing the heat energy absorbed.
2.PROPOSED METHOD
In contrast to previous research, a research on hybrid hatcher in this paper has traits as follows:
a) a storage method is conversion of sun light energy to heat, thathas high-efficiency, 70%-80% [Ercan].
b) method of the collector is also an accumulator at the same time, so the loss of energyis low and there is no energy transferloss.
c) solar energy storage method using dried material, so that it is expected big energy save and capacity,and also its technology will be easy and cheap.
2.1.Hysteresis method for arrays
Open the lid of the collector is implemented using a reflective Array placed in the space vacuum glass.
Figure-1. The working principle of hysteresis.
DL > DTU
DL < DTTL
DTU=DT+range
DTL=DT-range
D0=0 D1=1
LST=1
DT=m.c.(T-40)
DL=L.l/100
closed
opened
Y
Y
D0=1 D1=0 D0=0 D1=0
Y
LSB=1 D0=0 D1=0 Y
D0=0 D1=0
PBT=1
PBB=1 D0=0 D1=1
PBT=1
opened
Y
Y
D0=1 D1=0 D0=0 D1=0
Y
PBB=1 D0=0 D1=0 Y
L = Ligh (LDR)
T = Temp (LM35)
M = Mass (Pot)
C = Coefisient (Pot)
W=Width (Pot)
UTP/LTP Range (Pot)
PBs=1 Display 0 closed Y PB s=0 Y Display 1 start
Figure-2. Hysteresis method algorithm.
The reflective arrays are rotated by motor with an electronic control, UTP/LTP method. Open and close limits determined by the magnitude of the intensity of the light outside (the sky and the Sun) against infrared intensity in the accumulator. The intensity of the infrared has correlation with direct heat. When the intensity of the
outside is greater than the intensity of the infrared, hence Array is opened, so that the Sun's light energy absorbed by dry storage materials in the accumulator. When the outer lower intensity (night or cloudy), hence the array closed. The closure means the intensity of infrared in the accumulator need to be maintained. If the arrays keep it open, then the intensity of the infrared heat accumulator will be radiated outward, so that the energy in the accumulator will be off and decline.
Hysteresis in principle method is the determination of output-positive or negative depending on the level of the input against the level reverence. Figure-1. Vin is change the input level (simulated sine) against a reference level (flat-line). Vout are describing the condition
of the output, arrays’ motor which is controlled for turning CW (clock wise) or CCW (contra clock wise).
The hysteresis is formed into algorithm as Figure-2.
2.2. Thermal energy storage
Storage methods of some solar thermal has been published. Ercan in the article mention the existence of the three-way thermal energy storage, one of whom is the dry material. On the research methods of solar thermal energy storage with dry material, using concrete block instead of water or other fluids. The ability of storing energy (Joules) per gram on a material depend on temperature increment on T1 to T2 is determined by the specific heat capacity of
the heat storage material, as an expression of equation 1).
T
C
m
E
TT p
21
(1)
Note:
E = saved energy (Joules)
m = the mass (in grams) of the material
Cp = specific heat capacity of the material (J/g/oK)
T = temperature change [Ercan, Frank, George, Marc]
Specific heat capacity ofconcrate block
Heat storage material in the research isconcrete blocks. In search of the literature study of specific heat capacity material is 1130 J/Kg K. and density of 2240 Kg/m3 [Ercan].
2.3. The parameters of solar thermal energy
Energy storage period is per day, as the solar cycle. Storage capable to accumulate light energy Sun’sinfra red received by area collectors during the day, so that the heat energy can be supplied to hatching machine with capacity xxxx eggs for 1 ½ days can be fulfilled. The compliance is determined by the area of the capture of sunlight by collectors and volume capacity save heat energy by accumulator chaff.
incubator. Thermal energy is an incubator determined by how many eggs will be hatched.
Incubator energy
i t t
i
P
J
E
24
/
(2)Note:
Ei = Energy incubator per day (Watt hours)
Pt = Power needed grain of certain poultry eggs (Watts)
Jt = The number of eggs in incubator I = efficiency incubator
Energy accumulatorconcrete block
i
a
E
E
1
.
5
energy accumulators, prepared for 1 ½ days (3)
a s s
a
m
C
T
E
/
(4)Ea = energy accumulator for 1 ½ days
(Watt hours)
ms = time concrete block (kilogram)
Cs = specific heat capacity concrete block (KJ/Kg/oK)
∆T = change in temperature aefficiency = accumulator
Concrate block Specifications
Specific heat capacityconcrate block1.3-2 Kj/Kg/oK
Heat Conductivityconcrate block= 0271 BTU (0.0794 watt hours)
Bulk dencityconcrate block(BDs) = 125 kg/m3
Volume of accumulatorconcrate block
a s s
a
m
C
T
E
/
(5)T
C
E
m
s
a
a/
s
(6)s s
s
m
BD
V
/
(7)Note:
Vs = Volumeconcrate block(m3)
BDs = bulk dencityconcrate block(125Kg/m
3
)
Collectors width
i
k
E
E
(8)k m k
k
L
D
t
E
/
(9)t
D
E
L
k
a
k/
m
(10)Note:
Lk = broad catches the sunlight (m2)
Ea = energy accumulator for 1 ½ days (Watt hours)
Dm = Solar Power per meter2
∆t = time intensity of 80% Im peak (HRS)
k = efficiency of the collector [Sukhatme]
3.SYSTEM MODEL
Physic of collector- accumulator
Figure-4 the collectoris physically vacuum Conservatory that can be penetrated by the light.
Figure-3. Thermal energy storage: as collector and accumulator.
The vacuum spaces intended as an insulator for heat accumulator below. The light that is acceptable not only direct solar light but also diffuse light (all the light in the sky other than direct sunlight). The design follows the method of Flat collector.
Temperature in the collector
In the greenhouse, the incoming sunlight energy in the glass-enclosed space, so that energy into heat and energy trapped inside. The temperature in the greenhouse can be calculated based on the measurement results. The relationship between the powers of sunlight with temperatures can effectively be expressed as the following formula [Ferens],
𝑺 𝟏−∝ 𝜋𝑅 = 𝜎𝑇𝑒44𝜋𝑅 , (11)
Note:
S = Solar Power W/m2 R = radius of the Earth = albedo,
Te = effective temperature, so the equation is
obtained,
𝑇𝑒= [𝑆 −𝛼4𝜎 ]
1
4 (12)
Note
x 10-8
Accumulator Vessel contains concrateblock with the design capabilities of air pressure 1.2 bar. The entire surface of the vessel it layered with heat insulators, except parts of them are glass-capable pressure 4 bar anyway. Methods of work of the vessel followed the method of the greenhouse effect, where light enters a vessel will be caught. At the time of heat energy outside of the vessel is greater than the energy of the heat radiation in it, a reflective array mechanically cover vessels.
Heat is essentially infrared, so the heat transfers in media presence, known air conduction and radiation properties. In conduction, accumulator, the air through pipe transfer (host) with heat insulating material coated.
Mechanical design of accumulator follows rule of law coefficients of the air.
C = PV/T (13)
Note
C = coeffisient
P = barometric pressure V = the volume of the vessel T = temperature
Given the volume of the vessel is still being accumulated the temperature therein increasing by solar heat from the collector, then an increase in air pressure.
4.CONTROL DESIGN
In electronics block diagram, the hardware accumulator control can be seen at Figure-4.
ATmega 8 D0
D1
Opto H Bridge
Drive
M
ADC 0 SC Intensity (LDR)
ADC 1 SC Temperature (LM35)
ADC 2 / Mass (Pot)
ADC 3 / Coefisient (Pot)
ADC 4 / m2 (Pot)
ADC 5 / UTP/LTP (Pot)
12V
LST
LSB
PBT
PBB
Figure-4. Block hardware.
Figure-5. DC motor drive circuit.
There are three big majors block. The first one is MCU in which the algorithm is written in a program to be inserted to ROM of the MCU to control second block, Motor Drive and the third, temperature and intensity sensors.
As the MCU work as a controller with low voltage (5 Volt) and low current, it is required a driver for the motor. Figure-5 the driver capable to turn on and of the motor, and also to rotate Clock Wise and Contra Clock Wise
5.ACCUMULATOR SET UP
Reflective Arrays are set up as Figure-5. The reflective plates arrays when they closed, they cover all of the collector surface. From one side, reflective arrays are vertical when open to receive sun light, but closed when they reflect the incoming light and reflect the heat inside of the accumulator.
159.00
1
1.
0
0 16
11.00
16 A.
B.
C.
Figure-5. Reflective array on collector.
6. EXPERIMENT RESULT AND DISCUSSION
R(Ohm)
I (Lux)
Figure-6. LDR, intensity sensor characteristic.
Figure-6. Characteristic identification of the individual LDR sensor, shown on its nonlinearity (dot) in between intensity absorbs (Lux) and resistivity (Ohm). However, the problem is calibrated by applying three linear (lines) program that represent the nonlinear characteristic of LDR sensor component. The three linear algorithms are held due to the incapability of the MCU, At mega to solve nonlinear problem.
VT(Volt)
T(oC)
Figure-7. PT100, temperature sensor characteristic.
On the other hand, the characteristic identification for temperature sensor, PT100 shown its linearity. Finally, its analog voltage output has represented its temperature measured.
6.2. Resources and empirical energy
On August 4, 2016, the experiment was carried out in koordinat7o 56' 44.57"South latitude; 112o 36’, 53, 20"East longitude and height of 499 meters. Figures 8 and 6.5 are based on empirical data that are recorded by DAQ (Data Acquisition Interface) as a data logging.
Figure-8. Solar intensity (Lux).
Figure-8 indicates the intensity of the Sun's behavior received by collector accumulator from 09:00 to 16:20. Not bright sunlight conditions on intensity peak, i.e. of 94,830 Lux or equivalent power 948.3 Watts at 11:54. Peak price drop happened until 17:00 approximately 10,000 Lux. On the duration of the hour 13:00 to 13:28 sun rays are diffuse overcast covered is still pretty bright, 40, 000 Lux.
Figure-9. The temperature in the accumulator.
In the Figure-9 it looks towards its peak temperature rise behavior in the accumulator to exceed the peak time the intensity of the Sun. It shows the presence of heat energy accumulated and trapped in the depository materials. After 12:10, it looks slightly decrease because of the drop in temperature of the existence of a decrease in the average intensity of the Sun. The intensity decreases due to the time setting of the Sun and the emergence of light rain.
Figure-10. Solar power each minute.
Figure-11. Heat power of the accumulator.
Figure-11 is the result of temperature measurement in the accumulator within the time duration. The amount of heat power in accumulator is 98% equal to intensity power measurement in every minute sampling.
Figure-12. Energy accumulation.
Figure-12 illustrates the behavior of the addition, the accumulated heat energy stored in the accumulator for 5 hours, 20 minutes, to sunset; compared with the accumulation of solar energy.
At first, the heat energy accumulator is as great as the energy of the Sun. However, after 15:00 hours, there was a decrease in the intensity of sunlight. Decrease the accumulation of energy is not visible on the energy accumulator. Even on the contrary increased energy accumulation. It indicates that the accumulator is trapping heat energy inside. Of the graph can be deduced also energy absorption efficiency is up to 57.46%
7. CONCLUSIONS
The research Equipment in the form of the accumulator can be used with the ability to provide captured heat energy of the sun.
Accumulator solar thermal collector flat reflective array methods shows its ability to absorb and store heat energy from the sunlight. Absorption efficiency of energy accumulator can reach57.46%.
Advice: research information held within the control of reflective array to optimize thermal energy stored in the accumulator, and the research will be continued in the implementation of the accumulator on the energy supply of solar hybrid hatching machine.
APPENDIX
a. The accumulator System
b. The arrays system
c. The electronics controller
ACKNOWLEDGEMENTS
Highly appreciation and tank you to Indonesian Higher Education, Kemenristek for the research completion, that is supported financially through Penelitian Hibah Bersaing 2016 program.
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