INTEGRATION OF SOLAR PANELS INTO RESIDENTIAL ARCHITECTURE

IN NIGERIA

Prepared by

AMINU, TAOFIK OLADIMEJI

ARC/10/3121

Submitted to

Department of Architecture,

Federal University of Technology, Akure

In partial fulfillment of the award of Master Degree (M. TECH) in

Architecture

Course instructor

Prof O. O. Ogunsote

Date: August, 2011.

ABSTRACT

Solar panels are devices used to convert solar energy to electrical energy for use in buildings be

it residential, commercial or industrial. This energy can be converted in three ways namely:

biochemical, electrical and thermal. Some of the devices used in collecting the solar energy

include flat plate collectors, concentrating or focusing collectors and photovoltaic collectors.

TABLE OF CONTENT

Title page

Abstract i

Table of content ii

Chapter One 1

1.0 Introduction 1

1.1 Study Area 1

1.2 Research methodology 1

1.3 Aims and Objectives 2

Chapter Two 3

2.0 Integration of Solar Panels in residential architecture 3

2.1 Appraisal of Solar panel 4

2.1.1 solar panel 5

2.1.2 grid connected 5

2.2 Energy from solar panel 6

2.3 Factors affecting the amount of energy reaching the solar panels 7

2.4 Reducing the power need of a solar paneled home 8

2.5 Making up the power deficit 8

Chapter Three 9

3.0 Installation method of solar panel 9

3.1 Uses of solar energy 10

Chapter Four 12

4.0 Conclusion and recommendation 12

References

Appendix

CHAPTER ONE

1.0 INTRODUCTION

The need for stable and constant power supply in Nigeria of today where Power Holding

Company of Nigeria (PHCN) has made the electricity supply the alternate to generator has

actually called for a more reliable and effective means of power generation. In order to meet

our daily power requirements, solar energy can provide all or most of building energy

requirements at little or no cost if properly harnessed.

The sun, the main source of energy on earth produces energy free of charge and practically

endlessly. This energy from the sun can be converted to domestic use in residential

architecture.

Solar panels are form of photoelectric or thermoelectric processes of conversion of solar energy

directly to electrical energy. In Nigeria, the use of solar panels in power generation in

residential architecture has not been too encouraging but of late. This may be due to the cost,

technology or awareness. Basically, the technology is imported into Nigeria not too long ago,

but the prohibitive cost of buying and installation has greatly reduced the general acceptance

of the technology.

1.1 STUDY AREA

The study area for the assignment is Akure in Ondo State, in the western part of Nigeria and

Abuja, the Federal Capital Territory (FCT).

1.2 RESEARCH METHODOLOGY

In order to accomplish the stated aim and objectives of the study, there is need for a research

methodology. If one should go by John Ratcliff’s statement that “Planning must be based upon

knowledge, knowledge depends upon information and information depends upon survey”

then, the need for logical and objective approach to the job at hand cannot be over-

emphasized.

The methodology used in this research includes:-

DATA COLLECTION: Data were collected through secondary and primary sources.

Primary Information: This is direct information from the study areas. This includes

interview, observation and photographs.

Secondary Information: This is second hand information obtained to

complement the primary information. It was gathered through Literature reviews

which are research works published in journals, newspapers, literatures etc.

1.3 AIMS AND OBJECTIVES OF THE STUDY

The aim of this study is to know the extent of acceptability or the integration of solar panels in

residential architecture in Nigeria.

CHAPTER TWO

2.0 INTEGRATION OF SOLAR PANELS INTO RESIDENTIAL

ARCHITECTURE

Solar panels can be integrated into residential architecture to provide electricity for the

building, to power the bulbs, television sets, fans, refrigerators, air-conditions and other electric

using mechanical devices. This is not very common in Nigeria due to very high cost of purchase

and installation.

The most commonly use of solar panels in electricity generation is for street lightening by

various tiers of Government.

In the alternative, inverters are more acceptable and comparatively cheaper in Nigeria, hence

its acceptability. This may be due to the fact that the maintenance cost is almost zero.

Most of the solar panels are integrated into the building through the roof. The panels are

placed in such a way that they will harness or collect enough solar energy which will be

converted to electrical energy.

In integrating solar panels into buildings, calculations to know the energy requirements of the

entire building has to be done and this will determine the number of panels, size of storage,

size and position of collectors to be installed to generate the required energy.

2.1 APPRAISAL OF SOLAR PANEL

Solar electric systems—also commonly referred to as photovoltaic systems—utilize

photoelectric cells to convert the photons of the solar light spectrum directly into electricity.

Solar electric cell technology has been developing since the early 1950s, in the first applications

in the space industry, where solar cells have been used to power space satellites. Solar cells are

now a common power source for portable appliances and battery chargers, evident in remote

installations, including boating and road sign illumination.

An increasing improvement in solar electric cell technology and an increased awareness of the

need to reduce fossil-fuel dependent means of producing power has resulted in the increased

economic viability of solar electric installations. This study describes one of the primary

applications for buildings, the design of solar electric systems for residences.

In this study, utility independent systems are emphasized, in which case solar panels or electric

collectors provide electric energy for direct use and for an on-site battery storage system. Grid-

connected systems for both residences and commercial buildings—which may or may not

include an on-site battery storage system—are technically feasible and also may be

economically attractive, off-the-grid (independent) systems can be installed without such

interface requirements. Residences have a relatively manageable demand for electricity year

round, which also makes them reasonable candidates for photovoltaic systems.

In developed countries, a solar electric system usually offers a means to provide electric power

for a residence that is not connected to the electric utility power grid. In many instances, the

solar electric system is the only practical option for someone planning to live some distance

from the electric power grid, because the cost of bringing in commercial power is prohibitive.

In other instances, an owner may choose to be independent of the utility infrastructure. When

many people begin to investigate solar electric systems, they are often skeptical that an array of

solar electric collectors can deliver more than a small fraction of the electrical energy.

2.1.1 Solar panel

The term “off-the-grid” is commonly used to refer to electric power installations that are not

connected to the electric utility power lines that supply electricity to the vast majority of

buildings. Electricity for off-the-grid installations must come from some other source than the

public utility lines. In recent years, however, thousands of houses have been built and powered

with off-the-grid solar electric systems, also referred to as “stand alone” systems.

2.1.2 Grid-connected

The vast majority of residences are connected to electric power lines served by a public electric

utility company known as Power Holding Company of Nigeria (PHCN), the primary advantage to

this source of power being that the infrastructure already exists. For those planning a new

residence, electricity from a public utility is, in most cases, readily available. It is usually the

least first cost option. In most cases, there is an installation fee that a potential user must pay

to connect to the power lines. In the case of either an existing or a new residence, the high first

(installation) cost of a solar electric system is difficult to justify if that justification is based solely

on savings in electricity costs. There are more cost effective ways to reduce electricity costs.

These include “reducing the electric energy load” by replacing inefficient electric appliances

with those that are more efficient and/or replacing high demand electric appliances, such as

refrigerators, with efficient fuel-fired appliances.

In some instances, other factors such as the need for total reliability and availability of power

supply, may outweigh the high first cost of a solar-electric system for a grid connected home. In

Nigeria generally, the supply of public utility power is sufficiently unreliable, unstable and

ineffective that many people have installed generators to carry critical loads until the public

utility power has been restored. However, in Nigeria where public power outages occur several

times a year, then a solar electric system is a viable alternative to generator.

In the other climes, space heating is the single largest end use for energy in residences.

Domestic water heating is next largest, after space heating.

2.2 ENERGY FROM SOLAR PANEL

To appreciate the importance in photovoltaic system design of “reducing load” or minimizing

electricity consumption, it is helpful to know how much energy to expect from an array of solar

electric collectors.

Climate, latitude, collector tilt and collector orientation all affect the amount of energy

produced by an array of solar electric collectors.

On a clear day at noon, the equivalent of about 1000 watts/sq. meter strikes a surface held

perpendicular to the sun’s rays. The exact amount of solar energy striking the earth varies with

the time of year and the distance that the sun’s rays must travel through earth’s atmosphere.

With current technologies, the amount of energy available from an array of collectors is a

fraction of that available from the sun. An efficient solar electric collector can deliver between

12 to 15 % of the sun’s energy at noon on a clear day. Thus, a solar electric collector can deliver

about 120 watts/10sqm.

One widely used solar electric collector module measures 33 cm x 140 cm or (5.1sqm); its rated

output is about 55 watts at noon on a clear day. Two of these modules would have an area of

slightly less than 9sqm.

The electricity from the solar electric collector module is available in either 6 volts direct

current (dc) or 12 volts dc. Direct current is the same type of electrical current that comes from

a battery. The 6 and 12 volt output values are nominal voltages. The collectors are designed to

deliver somewhat more than the nominal voltage.

Usually more than one collector is required for most residential applications. The collectors can

be wired in either series or parallel configuration, as desired to increase voltage and or

amperage.

2.3 FACTORS AFFECTING THE AMOUNT OF SOLAR ENERGY

REACHING THE SOLAR PANELS

climate,

latitude,

collector tilt

orientation

For generalized calculations, solar collector receives the most solar energy on an annual basis

when it is mounted at a tilt angle which, when measured from the horizontal, is equal to the

local latitude. This presumes that solar intensity at any particular site would approach this

average, while in fact it varies as a function of daily and monthly sky conditions. The

presumption of tilt angle equal to local latitude is nonetheless a good one for both solar electric

and solar domestic water heating installations. In addition, like a solar thermal collection, the

solar collector is mounted in an equatorial-facing orientation, that is oriented so that it receives

the most irradiation for any fixed position. In order to simplify the sizing of solar electric

systems, the term “sunhours” is used to express the effect of climate, latitude and tilt. Different

tilts are used because the latitude is different.

The sun-hour term is convenient for roughly approximating the output of a solar electric

collector or an array of collectors.

For example, the output of one 55 watt solar electric collector on a clear day, between

11:30 AM and 12:30 PM is 55 watt-hours.

The simple approach to calculations given above is sufficient for rough estimates of the output

of a solar electric system. One significant aspect of solar electric collector performance that this

approach does not account for is the variation of photovoltaic cell performance with

temperature. Typically, the output of a cell is rated at 77F (25C). As the temperature of a cell

decreases below this rated value, the output of the cell increases. Conversely, the higher the

temperature of a cell, the lower is its output. Several computer programs are available to

accurately account for the variation of cell output with temperature over the period of a year.

2.4 REDUCING ELECTRIC POWER NEEDS OF A SOLAR PANELLED

HOMEIf a solar electric system is to be feasible, the electricity requirement of a typical single family

dwelling must be reduced significantly.

There are a number of ways to reduce electric energy consumption in the average dwelling.

Different measures required to cut electric power consumption are given below. They are

grouped as follows:

• Substitute a fuel-fired appliance for an electric appliance.

• Eliminate high wattage loads.

• Use high efficiency electrical appliances.

• Schedule the use of certain heavy electric loads

2.5 MAKING UP THE DEFICIT

In most solar panel residences, it is the norm that more energy is required in the house than is

supplied by the solar system. The deficit is usually made up with a generator in developed

world where a typical residence require a 5 to 7 kW generator. But in Nigeria, the deficit of

energy supplied by generator or solar panels is made up with the energy from the utility

company (PHCN).

CHAPTER THREE

3.0 INSTALLATION METHOD OF SOLAR PANEL

• The roof of a house is usually the preferred place to mount the solar collectors because in

that location they are least likely to receive shade from surrounding trees. In addition, a roof is

often a ready-made mounting surface for the collectors thereby eliminating the cost of a

separate mounting structure. A draw-back to putting the panels on the roof is that access to

them may be limited.

• If the collectors are to be mounted on a house roof or on a ground mount they should face in

a southerly direction and have a tilt from the horizontal of 40 degrees or more. The roof tilt can

be less than 40 degree, but the lower tilt will result in the system collecting varying degree of

energy at different times. A higher tilt than 40 degree increases the winter collection.

Generally, if the roof is not tilted at the optimum for the solar collectors then a collector

mounting frame can be used to increase the collector tilt.

• When wiring the house the electrician should provide at least two ac panel (circuit breaker)

boxes. The main panel will serve the heavy electrical loads that will be carried only by the

energy supplied by the utility company (PHCN). The second panel will carry the loads served by

the solar electric system.

• There are a number of reasons to use conventional (ac) appliances and wiring in the house.

The fact that the wiring in the house will be conventional will simplify the electrical contractor’s

task. In addition, the consumer has a far greater selection of ac powered appliances than direct

current (dc) powered appliances. The ac appliances are easily repairable and competitively

priced. The wire sizes can be much smaller in the ac powered house than in the dc powered

house. The dc wires must be large to reduce the resistance losses in them.

• Battery Charging: The inverter (dc to ac device) used with the solar panel system is available

with an integral, high quality, battery charger. This charger is used when the batteries are

discharged and the solar array cannot keep up with the rate of discharge.

• The batteries most commonly used with solar electric systems are the lead-acid, deep cycle

type. The deep cycle designation means that they can be drawn down to some fraction of their

total capacity, repeatedly, with little harm done to them. The type of battery used for starting

automobiles is not appropriate for this application because several deep discharges will ruin

that type of battery.

• Two inverters are desirable for solar panel systems. One is for all the expected loads except

the well pump, and the other is for the well pump or similar high amperage load.

• Most dimmer switches will not work with the ac power produced by the ac inverter used with

solar panel systems.

• Variable speed motors, such as those used in ceiling fans will buzz on ac power from the type

of inverter used with off-the-grid systems. This causes no harm to the motor.

• Battery powered AM band radios are preferred to the plug in type because of the radio

frequency interference broadcast by the inverter. Keeping the radio 3 to 5m from the inverter

helps diminish the noise picked up on the AM band.

• There are a number of small electrical loads in a typical dwelling that can significantly reduce

the efficiency of solar panel. The effect of these loads is disproportionate to their actual

wattage. Inverters for solar panel systems operate in the range of 85 to 95% efficiency for loads

of 10% of rated capacity, or greater. Some of the small loads that are responsible

for this power loss are: electric clocks, clocks in stoves, TV’s, cordless phones, power cubes for

devices such as phone answering machines and door bells; and electronic typewriters.

3.1 USES OF SOLAR ENERGY

Solar energy can be used in residences in various ways including but not limited to electricity

production, cooking, heating and cooling.

a. Electricity generation : electricity can be generated from solar energy in two ways. The

direct conversion by photovoltaic or thermoelectric processes. Alternatively, solar

energy can be used to produce mechanical work which will then be used to drive

electric generators.

b. Water heating : solar panels produces energy that heats up water in a water heater for

domestic use in the kitchen and bathroom. In swimming pool, it is done by using

thermo-siphon principle. The water is heated in the collector, rises and is replaced by

cooler water.

c. Cooking : solar energy can be used for cooking using either the direct (focusing) cooker

or the box (oven) type solar cooker. In the focusing cooker, the pot containing the

foodstuff is placed at the focus of a parabolic mirror. The solar oven is an insulated

chamber with a window on one side to admit radiation.

d. Distillation : distillation of non-potable water for drinking using the box type distiller.

e. Space heating : this is the use of solar energy for heating of buildings through the use of

buildings as collectors or the use of special building elements or collectors.

f. Space cooling : this can be done through mechanically driven compression type

refrigeration or by using absorption type refrigeration. The energy to run these plants is

obtained from the sun.

g. Drying : drying of various agricultural crops or products is achieved through exposing

them to the sun in a covered tray of some sort or by blowing hot air through or over

them.

CHAPTER FOUR

4.0 CONCLUSION AND RECOMMENDATION

Integration of solar panels in residential architecture in Nigeria to generate electricity will

reduce the problem associated with electricity supply by PHCN and makes homes seeking

minimum comfort and convenience achieve it without much fuss.

The most basic solar electric system for a family would be a single solar panel, charge

controller, battery and inverter depending on the energy requirements of the residence.

A solar electric system consultant should be retained to design and install the system. Electrical

contractors, who are able to size and install the wiring for an alternating current system, are

often familiar with direct current systems.

Some solar equipment sales companies offer training for people who are interested in learning

to install their own solar electric system. In the past five or six years, there is a high demand for

the rapidly developing solar electric industry which serves as alternative to the epileptic energy

supplied by PHCN.

Government should encourage Nigerians and enlighten them on the use of solar panels in

electricity generation by crashing the cost and thereby helping in achieving the Government

target of providing stable electricity in the country.

REFERENCES

Callender, J. H. (1999). Time-Saver Standards for Architectural Design Data. Seventh edition.

McGraw-Hill Book Company.

Ernst and Peter Neufert, (2000). Architects’ Data. Third edition

Ogunsote, O. O. (1991). Introduction to building climatology: a basic course for Architecture

students. Ahmadu Bello University Press, Zaria.

APPENDIX

Sources: Time-saver standards for architectural design data

Sources: Time-saver standards for architectural design data

Figure showing comparison the arrangements of typical flashlight batteries and solar panels in

series and in parallel.

Sources: Architets’ data