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PROJECT: DESIGN OF A RENEWABLE ENERGY

SYSTEM (PV) TO POWER A HOUSE

ELEC 6421- Renewable Energy Systems

Submitted By: Md. Sami Refayet

ID-27668600

Submitted to

Dr. Jonathan Maisonneuve

Department of Electrical & Computer Engineering

Concordia University

April 01.

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Table of Contents

Introduction................................................................................................................................................4

Background……………………………………………………………………………………………………………………………………………5

Solar home system type…………………………………………………………………………………………………………………………6

Operating Principal………………………………………………………………………………………………………………………………..7

Standalone solar home system………………………………………………………………………………………………………………8

Project Objective: ...................................................................................................................................... 9

Specification of the house......................................................................................................................... 10

Layout of the house………………………………………………………………………………………………………………………………11

Power consumption chart 1………………………………………………………………………………………………………………….12

Power consumption chart 2………………………………………………………………………………………………………………….13

Solar Panel Selection..................................................................................................................................14

INVERTER... .............................................................................................................................................15

Datasheet of inverter…………………………………………………………………………………………………………………………….16

BATTERY.....................................................................................................................................................17

Datasheet of battery……………………………………………………………………………………………………………………………..18

DC-DC Converter....................................................................................................................................... 19

Cable specifications................................................................................................................................... 20

PV Panel orientation................................................................................................................................ .21

Detailed Wiring drawing............................................................................................................................21

Conclusion................................................................................................................................................22

References…..............................................................................................................................................22

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Introduction:

Solar Energy is defined by the radiant energy which is produced by the sun. The energy

can be received in the form of light and heat. Rapid deployment of renewable energy and energy

efficiency is resulting in significant energy security, climate change mitigation, and economic

benefits. 174 peta watts (PW) of solar radiation is received by the earth at the upper atmosphere.

There are certain ways to use this energy for producing electricity. Solar photovoltaics’ is one of

the most cost effective means to provide small amounts of electricity in areas without a grid.

Especially when people live in scattered homes, the costs of alternatives to provide electricity are

usually prohibitively high. Solar home systems (SHS) are small systems designed to meet the

electricity demand of a single household. A Solar home system always consists of one or more

photovoltaic (PV) modules, a battery, and a load consisting of lights, and one or more sockets for

radio, television or other appliances. A battery charge regulator is usually added to control

charging and discharging of the battery.

Background:

Early in 1999, about one million solar home systems were in use in the world, and this number is

rapidly growing. This is a strong indication that this technology provides desired services to rural

households in non-electrified areas. However, technical and non-technical problems often arise,

which can hamper the further wide-scale application of solar home systems in rural

electrification.

Despite of large potential of solar system in Bangladesh, utilization of solar energy has been

limited to traditional uses such as crop and fish drying in the open sun. Solar PV are gaining

acceptance for providing electricity to households and small businesses in rural areas. In 1988,

Bangladesh Atomic Energy Commission (BAEC) installed several pilot PV systems. The first

significant PV-based rural electrification program was the Norshingdi project initiated with

financial support from France. Three Battery charging stations with a total capacity of 29.4kWp

and a number [36] of standalone SHSs with a total capacity of 32.58kWp were installed. REB

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owned the systems and the users paid a monthly fee for the services. Since 1996, penetration of

SHSs increased rapidly, mainly due to the efforts of GS, which sells PV systems on credit to

rural households through its extensive network. Several other NGOs such as CMES and BRAC

are also engaged in promoting PV technology. PV modules are generally imported, while there

are a few private companies manufacturing PV accessories [36] found that 82% of them are also

interested in marketing SHSs in surrounding areas if some sorts of favorable financing

arrangements are available. Below, there is a percentage analysis of the solar home systems in

different districts of Bangladesh.

14%

21%

22%

17%

8%

6%

12%

BarisalChittagongDhakaKhulnaRajshahiRangpurSylhet

Fig: Distribution of the SHSs (Solar Home System) in seven divisions in Bangladesh [39]

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Solar home system Types:

Solar home system are usually classified according to their utility and operative requirements, their

component configuration and how the equipment is connected to other power sources and electrical loads.

The systems can be designed to DC or AC power service, can operate connected with or independent of

the utility grid and can be connected with other energy sources and energy storage system. Two principal

classifications are grid connected and stand-alone system.

Operating Principal:

The crucial element in gird connected solar home system is the inverter or power controlling unit (PCU).

PCU converts the DC power produced by the PV array into ac power consistent with the voltage and

power quality requirements of the utility grid and automatically stop supplying power to the grid when

the utility grid is not energized. a bidirectional interface is made between the PV system ac output circuits

and the electric utility network, naturally at an onsite distribution panel service entrance. This allows AC

power produced by the PV system to either supply on site electrical loads or back feed the grid when the

PV system output is greater than the onsite load demand. At night and during other periods when

electrical loads are greater the PV system output, the balance of power is required by the loads is received

from electric utility. This security feature is required in all grid connected solar home system and ensures

that PV system will not function and feed back into the utility grid when the grid is down for provision or

renovation.

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Solar PV System

Grid connected System Stand –alone System

Stand alone solar home system:

Project Objective:

The main objective of this project is to scheme a photovoltaic (PV) system for my house where I was

born. The location (latitude and longitude) and size of my house needs to be specified. The size of the

house and its electric loads has to be determined. The PV panels will be located on the roof of the house

and the batteries storing the energy should be somewhere in the basement. Solar panels must be selected

on the assumptions that on the shortest day of the year, there are no clouds or dust and the maximum

power generated by the solar panels must at least be equal to the sum of the loads. RET Screen software is

used to find the annual radiation at the specified location and conduct the calculations regarding this.

Realistic assumptions are to be made regarding the tools like panel efficiency, battery, DC-DC converter,

charge controller, wiring etc. Energy will be be stored in 24V batteries. Size and manufacturer of the

panels, DC-DC converter, inverter and cables must be specified. Lastly, a detailed drawing of the system

must be presented so it can be wired up by a technician.

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Specifications of my house:

Address: House-29, Road-16(new), Dhanmondi-1207

Location/Place of birth: Dhaka

Country: Bangladesh

Voltage supply: 220V, 50Hz

Length of house: 42ft

Width of house: 35 ft

Total area of house: 1430sq.ft

Total number of rooms: 4

Latitude: + 23°45'14.6"N

Longitude: + 90°22'16.8"E

Time Zone: UTC/GMT +6 hours

Bangladesh has a tropical monsoon-type climate, with a hot and rainy summer and a dry winter. April is

the hottest month in my country. The maximum summer temperatures range between 38 and 41 °C (100.4

and 105.8 °F). January is the coolest month, when the average temperature for most of the country is 16–

20 °C (61– 68 °F) during the day and around 10 °C (50°F) at night .

The dimension of the house: The dimensions are in square feet.

Bed Room 1 18' x 16' = 288 sq ft. Bed Room 2 16 x 14' = 224 sq ft.Living Room 22 x 12'= 264 sq ft.Dining Room 24 x 14' =336 sq ft.Kitchen 9 x 12' =108 sq ft.Washroom 1 5' x 13' =65 sq ft.Washroom 2 6' x 10' =60 sq ft.Balcony 5' x 17' =85 sq ft. Total = 1430 sq ft.

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The layout of my house is as follows:

So, my house is situated in the Latitude of + 23°45'14.6"N and the Longitude of + 90°22'16.8"E. The

total area of my house is 1430 sq ft. The loads are mentioned in the layout above.

Total Rated Power, Current and Units consumption per day is shown in the following chart-

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Total Rated Power, Current and Units consumption per day (at 220V in the Dhaka, Bangladesh)

Dry Season (March-June):

Cooling appliance like ceiling and table fan are mostly used in this season.

Here,

Total Wh/Day= (55+60+44+60+22+80+33+33+88+5.5+440+2160+220+960) = 4260.5 Wh/Day

Total Power= (11+20+11+20+11+20+22+11+22+11+110+180+110+240) = 799 W

Total Ah/Day= (0.25+0.27+0.2+0.1+0.36+0.135+0.27+0.2+0.025+2+9.84+1+0.92)= 15.84 Ah/ Day

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Load Total unit Power(W) Current(A) Hour/Day Wh/Day Ah/DayBedroom 1 Light (CFL)

1 11 0.05 5 55 0.25

Bedroom 1 Light(Tube)

1 20 0.09 3 60 0.27

Bedroom 2 Light (CFL)

1 11 0.05 4 44 0.2

Bedroom 2 Light (Tube)

1 20 0.09 3 60 0.27

Living room Light(CFL)

1 11 0.05 2 22 0.1

Living room Light(Tube)

1 20 0.09 4 80 0.36

Washroom Light(both,CFL)

2 11*2=22 0.09 1.5 33 0.135

Kitchen Lights(CFL)

1 11 0.09 3 33 0.27

Dining room lights(CFL)

2 11*2=22 0.05 4 88 0.2

Balcony Lights(CFL)

1 11 0.05 0.5 5.5 0.025

Television 1 110 0.5 4 440 2Refrigerator 1 180 0.82 12 2160 9.84Computer 1 110 0.5 2 220 1Ceiling fan 4 60*4=240 0.23 4 960 0.92

Cold season (November-February):

In Bangladesh January is the coolest month, when the average temperature for most of the country is 16–20 °C (61– 68 °F) during the day and

During this time it gets cold, so no heater is used. The loads get rather lower because of no/very limited uses of fan.

Here,

Total Wh/Day= (55+60+44+60+22+80+33+33+88+5.5+440+2160+220+) = 3300.5 Wh/Day

Total Power= (11+20+11+20+11+20+22+11+22+11+110+180+110+) = 599 W

Total Ah/Day= (0.25+0.27+0.2+0.1+0.36+0.135+0.27+0.2+0.025+2+9.84+1+)= 14.92 Ah/ Day

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Load Total unit Power(W) Current(A) Hour/Day Wh/Day Ah/DayBedroom 1 Light (CFL)

1 11 0.05 5 55 0.25

Bedroom 1 Light(Tube)

1 20 0.09 3 60 0.27

Bedroom 2 Light (CFL)

1 11 0.05 4 44 0.2

Bedroom 2 Light (Tube)

1 20 0.09 3 60 0.27

Living room Light(CFL)

1 11 0.05 2 22 0.1

Living room Light(Tube)

1 20 0.09 4 80 0.36

Washroom Light(both,CFL)

2 11*2=22 0.09 1.5 33 0.135

Kitchen Lights(CFL)

1 11 0.09 3 33 0.27

Dining room lights(CFL)

2 11*2=22 0.05 4 88 0.2

Balcony Lights(CFL)

1 11 0.05 0.5 5.5 0.025

Television 1 110 0.5 4 440 2Refrigerator 1 180 0.82 12 2160 9.84Computer 1 110 0.5 2 220 1Ceiling fan 4 60*4=240 0.23 0 0 0

RETscreen simulation of the loads with the panel output:

We are considering the peak load that is 745W in summer season and considering the shortest day of the year which is 21st December to have the most efficient system.

RETscreen simulation of the loads with the panel output is as follows-

Peak consumption = 799W

Solar Panel Manufacturer = OSM Solar.

Model = mono-Si-OSM72M-OSM270W

Number of Panels from the simulation= 4

PV Panel orientation:

The angle of declination δ = - 23.38°. Latitude φ = 23.8103 (Dhaka, Bangladesh).

Therefore, The slope or Zenith angle, θZ =φ - δ = 23.81 - (-23.38) = 47.2°

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Here we see Total Load consumption is 1080W (considering the loss with real load consumption) and for each Panel Capacity per Unit is 270W. So Total 4 Panel is required.

Battery, DC/DC converter, inverter, cable specifications with data sheets.

INVERTER:

The load specification of the house is as below-

Peak load consumption: 799W

Current: 2.75 A

Total energy demand: 4.22 kWh/day

Total current demand: 4260.5 Wh/day

Load voltage: 220 V (AC)

Frequency: 50 Hz

Inverters are used to convert the DC voltage from the battery to AC voltage that will be supplied to the

loads. Here, the DC batteries are implemented as inputs for the inverter. For this solar panel the inverter

that is used is, ‘Energizer EN900 900W power inverter’. It works soothingly with the specifications of the

PV panels and the battery.

From the product specification we see that the efficiency of the inverter is given at 90%. The inverter is

capable of supplying a continuous power output of 900 watts and can convert from 24V to 220V. So it

can supply 900 X 0.9 = 810W. Which is somewhat larger than the peak load (799 W). The inverter is well

capable to supply the loads of the house

The power converter data sheet is given below-

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BATTERY:

Here, we have the following measurements-

Total energy consumption: 4260.5 Wh/day

Charge discharge efficiency of the battery: 90%

Battery efficiency to nameplate rating: 95%

Depth of discharge (DOD): 80%

AC wiring efficiency: 98%

The DC bus voltage of batteries is going to be 24V.

Now, total current per day= (4260.5/24) = 177.52 Ah/day

Now, we have to consider the wiring efficiency (0.98) and charge-discharge efficiency (0.9) of battery.

The energy supplied from DC to inverter = 177.52 / (0.98 x 0.9) = 201.27 Ah/day.

Then, we compute the real energy supplied by considering the depth of discharge (0.8), and the battery operating efficiency (0.95) compared to nameplate rating due to temperature.

The battery will need to supply = 201.27/(0.8 x 0.95)= 264.83 Ah/day

Now, we need to consider the days of autonomy. It is 3 from RETscreen). Which signifies that we are bearing in mind that for 3 days it might be be rainy, cloudy, no sun, etc. So the battery will have to be capable to supply for that time too.

So, considering the days of autonomy the battery needs to supply = 264.83 x 3 = 794.49 Ah

In this project, we need to store the energy from the PV panels in 24V batteries. We take two 12V batteries and connect them in series to make a 24V battery pack. The battery chosen to be appropriate for this project is EPL-300AH-12V-SLIM. Which is rated at 12V and 300Ah. So connecting two such batteries in series gives rise to a 24V DC bus.

Now, when the batteries are connected in series, current remains same in the branch. So each branch of the battery must provide 300 Ah. Taking account the voltage, the voltage 2 batteries needs to be connected in series for each branch.

Therefore, numbers of batteries required to supply the current are = 794.49/300 = 2.65 ~ 3

Since there are 2 batteries in each branch,

Total number of batteries are = 3 x2 = 6 batteries.

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DC-DC Converter

The voltage from the panels needs to be kept fixed to 24V. The reason is that the DC bus of the battery banks are at 24 V. We need a DC-DC converter to prevent overcharging or undercharging of the batteries. A charge controller which includes a dc-dc converter is necessary for all power systems that charge batteries, whether the power source is PV, wind, hydro, fuel, or utility grid. Its purpose is to keep the batteries safe for the long term, also prevent battery over discharge, protect from electrical overload, and/or display battery status and the flow of power.

The PV panels in this project have a short circuit current of 6.9 A. We need twelve panels to supply the total load, so total short circuit current is (6.9 x 12) = 82.8 A

So we need a charge controller which has an output current of at least equal to the maximum current produced by the panels.

For this project we are using Xantrex C60 charge controller that operates at 24V, and has a load current of 60A and peak current rating of 85A

Cable Specifications:

Assuming that the house is already wired up to the loads, our total cable requirements are from the PV panel array to the inverter (or the distribution panel). The peak current flowing through the cables at each part has to be calculated and cables selected such that they can handle those currents. For our project we are using Relicab Multicore Round Flexible Cable.

Connections Cable length Voltage capacity Current capacity Size of cable

PV panel array to charge controller

50 24V DC 34.5 A 12 sq.mm with current rating of 45 A

Charge controller to battery banks

35 24V DC 34.5 A 10 sq.mm with current rating of 45 A

Battery bank to Inverter

20 24V DC 22.5 A 8 sq.mm with current rating of 33A

Inverter to distribution panel (MCB)

15 220 V AC 2.45 A 1 sq.mm with current rating of 11 A

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PV Panel orientation:

For best results, the solar panels should be inclined at an angle where it is most perpendicular to

the sun. The latitude of Dhaka is 23.8103 degrees. Since the declination angle is negative, it

means the panels must be angled at an angle of 23.8103 degrees facing south to generate

maximum amount of power.

Detailed Wiring drawing

The following figure presents the detailed wiring diagram which can be used to wire up the entire system

in the house. The PV panels produces the voltage and are connected to the charge controller which

ensures the DC bus of 24V is maintained for the battery. The inverter converts the DC to AC before

supplying it to the distribution panel at 220V, 50Hz.. We have already assumed before that the house is

already wired up to the loads and the loads are able to draw power from the distribution panel.

Fig: Wiring diagram of the Solar Photovoltaic System of the house.

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Conclusion

Photovoltaic system design for my house has been successfully done. I could successfully design a renewable energy system in the place where I was born. The size and manufacturers of the solar panels, batteries, dc-dc converter, charge controller, inverter has been mentioned and shown. All necessary calculations were also shown.

The interesting and informative thing we saw in the project was that in a tropical country like Bangladesh, it is very convenient and important to provide power for a house through solar energy harvesting using solar panels and it is also very convenient from the user and distributor end. I could do it in my city, Dhaka, very efficiently. So it should be a step taken all over our country to provide us with cheap and abundant source of energy. In a developing country like Bangladesh, it is a viable solution to produce clean energy through PV panels. It can change our country, hence change the world energy system.

References:

https://www.amazon.ca/Energizer-EN900-Power-Inverter-900-Watt/dp/B00APL78W2

http://enerdrive.com.au/product/300ah-slim-lithium-battery- 12v/

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