Investigation on the Potential Application of Grid-connected PV

System for Food Cold Storage

Nyoman Suamir

, Wayan Temaja, Putu Sastra Negara

, and Made Ery Arsana

Mechanical Engineering Department, Politeknik Negeri Bali, Campus Street, Kuta Selatan, Badung, Bali 80364, Indonesia

Keywords: PV System, Energy Generation, Solar Cold Storage and Renewable Energy.

Abstract: The paper presents investigation on a small size solar cold storage built at Politeknik Negeri Bali. The solar

cold storage comprises a grid-connected PV system and a cold storage using R290 with power input specified

for 2.5 kW. The investigation includes potential of renewable energy generation, cold storage energy demand,

grid energy imported and renewable energy exported. The PV system is specified for a peak capacity of 3.1

kW. Average instant AC power generation during the day is 1.66 kW with maximum power generations as

high as 2.55 kW. Daily renewable energy generation in the selected highest day can reach 18.5 kWh. The

investigation results also showed the cold storage consumed 39.8 kWh electricity in a day. During the day

(PV production time), the cold storage requires for about 17.5 kWh which is lower than the energy generated

from the PV system. However, the cold storage still needs imported energy due to off and defrost cycles. It is

about 69% renewable energy generation can be applied but the rest of 31% must be exported to the grid. This

results show the use of renewable energy storage system can improve the utilization of renewable energy to

drive the cold storage.

1 INTRODUCTION

Application of integrated photovoltaic (PV) system

for commercial buildings is exceptionally favourable,

specifically in the sunny climate regions. The usage

of the PV systems is cost-effectively more attractive

due to their investment cost become cheaper and

cheaper. The PV system can provide a substantial

effect on countryside growth. PV systems can be

applied for varies applications from very small-scale

to mid-scale uses (Foley, 1995; Braun and Rüther,

2010; Feron, 2016).

Indonesia also has prospective use of solar PV

system in commercial building sector as well as in the

rural area. As a tropical country, Indonesia including

Bali Island has intensive value of solar irradiation

ranging from 4.6 kWh m

-2

to 7.2 kWh m

-2

. This

proofs that the country has high potential solar energy

sources (Rumbayan, 2012; Santika et al., 2016). On

the other hand, the utilization of solar energy in

Indonesia is only 0.03% of its total energy use which

accounted for 2.78 MW. It is about 0.41% of the total

https://orcid.org/0000-0003-0594-7511

https://orcid.org/0000-0002-1028-070X

https://orcid.org/0000-0002-6647-6621

renewable energy utilization (Yudiartono, 2018).

This shows that the segment of solar energy use in

Indonesia is insignificant.

However, there is still a shortage of publications

regarding the prospective and limitations of solar PV

implementation, specifically for food preservation

such as cold storage. An investigation on solar

refrigeration systems has testified that such systems

could be used where national grid is not continuously

available or regions are not suitably electrified

whereas refrigeration demand is life-threatening

(Aktacir, 2011).

Elias and Yilma (2019) reported that for

simulation investigation analysis and simulation of a

solar PV driven refrigeration system utilizing a

compressor with variable speed system. Energy

performance of a solar PV refrigeration can be

evaluated. However, most of the publications on solar

PV refrigeration system are based on absorption cycle

system or adsorption refrigeration cycle as published

in several researches (Suamir, 2014; He et al., 2019;

704

Suamir, N., Temaja, W., Negara, P. and Arsana, M.

Investigation on the Potential Application of Grid-connected PV System for Food Cold Storage.

DOI: 10.5220/0010951800003260

In Proceedings of the 4th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2021), pages 704-709

ISBN: 978-989-758-615-6; ISSN: 2975-8246

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

Bellos and Tzvanidis, 2017; Fellah et al., 2019; Wang

et al., 2018).

This study presents an innovative integrated solar

PV technology which is utilized to power a cold

storage refrigeration system. Indonesia weather data,

more specifically Bali Island weather data is applied.

According to Husband et al. (2020), the country and

region have the prospect of using solar PV food

refrigeration systems. The country also requires

enormous funds for energy efficient technology that

can increase the growth of food cold storage

infrastructure with various capacities. The

refrigeration demand is due to the country is

undergoing an imbalance food supply and demand.

This is one of the challenges in improving food

security and food sustainability of the country.

Indonesia is well-known as the second highest

fishery producer in the world (FAO, 2016).

Meanwhile, the growth of food cold storage for the

fishing industry is not suitable. Indonesia is also a

country within the list of low index food cold storage

(IARW, 2016). In 2016, Indonesia had food cold

storage capacity about 12.3 million m

(FAO, 2016;

IARW, 2016). This paper that present investigation

results on the potential application of grid-connected

PV System for food cold storage may encourage the

development of food cold storage infrastructure in

Indonesia.

2 MATERIALS AND METHODS

2.1 The Grid-connected PV System

The grid-connected PV system is situated at

Politeknik Negeri Bali in Bali Island, Indonesia. The

solar PV system comprises: solar power generation,

electrical power distribution, connection to the grid

and protection devices. The solar power generation

system consists of 10 solar PV panels. Each PV panel

has a 310 Wp capacity. The solar PV generation

system also includes a grid inverter of 5 kW

maximum capacity.

Specification of the solar PV panel can be seen in

Table 1. The panel has a peak power of 310 Wp at

maximum voltage 33 V and current 9.4 A. Each PV

panel has 60 mono-crystalline silicon cells. The

mono-crystalline cell has higher efficiency compared

with the polycrystalline PV cell. The cell size is 0.150

m x 0.150 m each, hence area of each panel becomes

1.35 m

. The cell has maximum efficiency of 22.96%.

The electrical power distribution and grid connection

systems are accomplished with some breakers and

one energy meter to record renewable energy

generation and also a digital power meter for

recording energy exported to the grid. The solar PV

system also incorporates protection devices to

prevent damages from lightning. The solar PV system

utilizes a fixed array installation system with 17° tilt

angle and the azimuth direction facing to the north.

The tilt angle used is an optimum tilt angle based on

solar radiation conditions in Bali Island. The

optimum tilt angle is from 10° to 18° with azimuth

direction to the north (Sugirianta et al., 2020).

Table 1: Specification of the 310 Wp solar PV panel.

Parameters Value

Maximum power P

max

(Wp) 310

Voltage at P

max

(V) 33

Current at P

max

(A) 9.4

Open circuit voltage (V) 40.30

Short circuit current (A) 9.96

Test condition (W m

-2

) 1000

Temperature test (°C) 25

Panel size (mm) 1640 x 990 x 35

Weight (kg) 19

Test condition (W m

-2

) 1000

Temperature test (°C) 25

Cells type Mono-crystalline silicon

Cell size (m x m) 0.150 x 0.150

Number of cells 60

This value is in agreement with the solar PV

system array in the regions of East, Central and West

Java. The optimum tilt angle of the solar PV array for

azimuth direction to the north of the regions are

respectively from 0º to 40º, from 1º to 34º at optimum

18º and 10º (Handoyo, 2013).

2.2 The Food Cold Storage System

A lab size innovative cold storage has been built in

Politeknik Negeri Bali. The cold storage is a

sustainable refrigeration platform for frozen food

incorporating: Grid-connected solar PV power

system, energy-efficient refrigeration system with

low emission refrigerant, instrumentation and

monitoring systems.

The schematic of the developed food cold storage

system is shown in Figure 1. In order to achieve a

complete performance testing, the cold storage test

system is completed with proper instrumentation and

monitoring systems which comprise temperature and

pressure sensors, RH sensors, flowmeter, and power

analysers. For the solar PV panels, instrumentation

will include voltage, current, power, solar irradiation,

and surface temperature measurements.

Investigation on the Potential Application of Grid-connected PV System for Food Cold Storage

705

Figure 1: The food cold storage system comprises refrigeration, cold room, innovative control, grid-tide solar PV,

instrumentation and monitoring systems.

The output signals from the instrumentation

devices are logged by a data logging system which

comprises data acquisition modules and a recording

and display system. The data acquisition modules

utilise the Datascan 7000 series from MSL

(Measurement System Ltd.) which include a

Datascan measurement processor 7320 and

expansion modules 7020. Each Datascan module

contains 16 differential input channels, individually

configurable for voltage and thermocouple

measurements. Corriolis flowmeter was used to

measure refrigerant flow rate in the system.

2.3 Experimental Test Methods

The solar PV system incorporates an IoT (Internet of

Things) based monitoring system which are

embedded with sensors, software, and other

technologies for the purpose of connecting and

exchanging data with other devices and systems over

the internet. A comprehensive data (hourly, daily,

monthly and yearly) related to system performance

can be accessed through the internet. Recorded data

in 2019 and 2020 were used for the analysis.

Some data were also recorded on site which

include solar radiation, energy generated and

exported to the grid. Solar irradiance was measured

by using a Lutron Solar Power Meter SPM-1116SD

of 10 W m

-2

accuracy. For irradiance lower and higher

than 1000 W m

-2

the resolutions can reach 0.1 W m-

2 and 1 W m

-2

respectively. The energy meters have

measurement accuracy in the range of ±1%.

Recorded data from the measurement system were

processed using spread sheet software and analysed.

Performance parameters of the solar power supply

system such as solar power generation, efficiency and

power consumption by the cold storage were

calculated and presented. Further calculations and

graphs manipulation were processed by using spread

sheet program.

Grid-tide solar PV Ssstem

10 x 310 W

Grid-tide

inverter

StV

Supply

electricity

from grid,

220 V

EEV

Power

analyser

Condenser

High

density

PU panel

100 mm

Innovative control system

Cold room system

Condensing

unit controller

𝑚



PSH/L



220

StV

ShV

Refrigeration system

Instrumentation and monitoring

system

Temperature

senso

Pressure

transducer

ShV

Evaporator

F/D

F/D = Filter dryer; SG = Sight Glass; SV = Solenoid Valve; ShV = Shut-Off Valve; StV = Straddle Valve; EEV = Electronic

Expansion Valve; PSH/L = Pressure Switch High/Low; FM = Flowmeter; SPD = Surge Protective Device; PU = Polyurethane

Data logger Computer

DC SPD

with

Breaker

AC SPD with

Breaker

Compressor

Evaporator

controller

Legend:

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

706

3 RESULTS AND DISCUSSION

3.1 Renewable Energy and Power

Generation

Figure 2 shows monthly electrical energy generation

from the PV system for one year in 2020. The figure

also shows one-year variation of the PV system

capacity factor. Monthly electrical energy generation

varies from 300 kWh to 499 kWh with average of 412

kWh. Annual energy generation of the PV system can

reach 4.95 MWh. Utilization potential of the PV

system stated as capacity factor can reach annual

average value of 38.7%. Maximum monthly

utilization potential with capacity factor value of

46.1% occurs in August, while minimum value

26.1% happens in December.

Figure 2: Monthly renewable energy generation for the

investigated year 2019 and 2020

Figure 3 shows investigation results involving

instant AC solar electrical power generation,

cumulative AC energy generation, DC power and DC

energy. The fluctuation of AC electrical power

generation during the lowest production day in

December can be seen in Fig. 3. Time of production

is about 10 hours starting from 6.30 in the morning to

4.30 in the afternoon. Average instant power

generation during production period is 274 W and

maximum power is 741 W. While cumulative AC

electrical energy generation in the selected lowest day

of production is only 2.82 kWh.

Figure 3 also shows variation of the AC power

generation together with electrical energy generation

during production period of the selected day in

August (the highest production month). Time of

production is one hour longer than the lowest day in

December which is 11 hours starting from 6.40 to

17.40. The average instant AC power generations

during production period are 1662 W. While the

maximum AC power generations, which occur at

around 12 o’clock, can reach as high as 2552 W and

cumulative energy generation can be 18.5 kWh.

3.2 Energy Consumption of the Food

Storage

The variation of power consumption of the food cold

storage in one day is presented in Figure 4. The

average power consumption is about 2.4 kW. The

figure also shows on and off cycles due to thermostat

regulation and defrost cycles.

3.3 The Potential of the Grid-connected

PV System applied for the Food

Cold Storage

Figure 5 shows power consumption of the food cold

storage in 24 hours’ test at steady operation with 15

minutes off cycle due to defrost in every 4 hours. The

investigation results also showed the cold storage

consumed 39.8 kWh electricity in a day. Daily

renewable energy generation in the selected highest

day

can reach 18.5 kWh. The investigation results

Figure 3: AC electrical power generation during the highest production day in August and the lowest production day in

December 2020.

Investigation on the Potential Application of Grid-connected PV System for Food Cold Storage

707

Figure 4: Power consumption of the food cold storage in 24 hours’ test at steady operation with 15 minutes off cycle defrost

in every 4 hours.

Figure 5: The potential use of grid connected PV system to powering the food cold storage.

also showed the cold storage consumed 39.8 kWh

electricity in a day. During the day (PV production

time), the cold storage requires for about 17.5 kWh

which is lower than the energy generated from the PV

system.

However, the cold storage still needs imported

energy due to off and defrost cycles. It is about 69%

renewable energy generation can be applied but the

rest of 31% must be exported to the grid. This results

show the use of renewable energy storage system can

improve the utilization of renewable energy to drive

the cold storage.

4 CONCLUSIONS

A lab size innovative cold storage has been built in

Politeknik Negeri Bali. The solar cold storage

comprises a grid-connected PV system and a cold

storage using R290 with power input specified for 2.5

kW. The PV system is specified for a peak capacity

of 3.1 kW. Average instant AC power generation

during the day is 1.66 kW with maximum power

generations as high as 2.55 kW. Daily renewable

energy generation in the selected highest day can

reach 18.5 kWh. The investigation results also

showed the cold storage consumed 39.8 kWh

electricity in a day. During the day (PV production

time), the cold storage requires for about 17.5 kWh

which is lower than the energy generated from the PV

system. However, the cold storage still needs

imported energy due to off and defrost cycles. It is

about 69% renewable energy generation can be

applied but the rest of 31% must be exported to the

grid. This results show the use of renewable energy

storage system can improve the utilization of

renewable energy to drive the cold storage.

500

1000

1500

2000

2500

3000

3500

4000

024681012141618202224

Power (W)

Time (hours)

Cold storage power (W)

500

1000

1500

2000

2500

3000

3500

4000

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

Power (W)

Time (hours)

Cold storage power (W) PV Power Generation (W)

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

708

ACKNOWLEDGEMENTS

The authors thankfully acknowledge Politeknik

Negeri Bali for sponsoring this publication through

funding scheme: DIPA Politeknik Negeri Bali

number: SP. DIPA-023.18.2. 677608/2021, 23

November 2020. The authors also favourably thank

the Centre of Research and Community Services

(P3M) team for administrative assistance.

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