Solar Heating System for Building – Water Heating, Pipe Dimension and Insulation over Pipe

IDL - International Digital Library Of
Technology & Research
Volume 1, Issue 5, May 2017 Available at: www.dbpublications.org
International e-Journal For Technology And Research-2017
IDL - International Digital Library 1 | P a g e Copyright@IDL-2017
Solar Heating System for Building – Water
Heating, Pipe Dimension and Insulation over
Pipe
Satish Kumar Maurya1 & Dr. Jeeoot Singh2
1.P.G. Student, 2. Associate Professor Mechanical Engineering, Department, MMMUT
Gorakhpur, India
Abstract: This paper presents the performance of
a solar water heating system equipped with flat plate
solar collector panels of numerically identical surface
area but of different geometric configuration. The
amount of heat acquired from collectors of solar
energy depends primarily on the surface area that is
exposed to the solar irradiance. The solar thermal
water heaters with Thermo-syphon systems using Flat
Plate Collectors (FPC) to heating water. The hot water
supply through steel pipes and insulation must be
necessary to saving heat energy, losses by atmosphere.
Polyethylene is the insulating material which is used
to insulate over steel pipe. Approximately, 50%
efficiency of the solar water heating system (SWHS)
was gained when the insulation was used. They
efficient and the cost effectiveness are according to the
designs of the systems. The places and the climate of
the buildings where they locate are the main
considerations of the system design.
Keywords: flat plate collector, solar energy,
residential buildings, steel pipe, insulating material,
geometrical orientation.
1. INTRODUCTION
One of the essential requirements in modern buildings
is the uninterrupted provision of heating water. Flat
plate collector absorbs radiated energy from sun and
converts it into heat energy. A lot of work is being
done on solar collectors to increase efficiency of these
systems. These systems can be used for hot water
demands, space and room heating for household, large
buildings, and power sector. A solar water heater
consists of solar collector, hot water storage tank,
control unit and pump station.
The hot water in storage tank heated by flat plate
collector and supplied to building for different
purposes. The storage tank is requiring of insulation to
save heat energy otherwise heat will be transfer or loss
to atmosphere. The supply of hot water through pipe at
required location in building, the pipe is also require of
insulation because at long distance transfer of hot
water decreases its heat or water temperature drop, so
for saving heat, insulation over pipe must necessary.
SWH can play vital role in reducing effects of
environmental pollution caused by fossil fuels.
There are numerous types of the solar collector which
are available commercially such as flat-plate
collectors. The flat plate solar collector best fit for
sunny and warm temperature zones, so during cold,
cloudy, and breezy weather.
2. FLAT PLATE COLLECTOR:
• A device may be used for absorb radiations to
produce heat like water heater. The device in which

the collection is achieved is called a flat-plate
collector.
• The flat plate collector is usually held tilt in a fixed
position and has no moving parts on a supporting
structure, facing south if located in the northern
hemisphere.
• The collector having a face area of 2 m2 with the
length being usually larger than width and the
temperature of hot water delivered ranges from 50 to
70o C. The storage tank being located above the level
of the collector, if natural circulation is applied for
heating small quantity of water.
• Absorber plate made of sheet metal and thickness
range from 0.2 to 1 mm. Generally, Aluminium or
Copper is used for both absorber plate and tube due to
high thermal conductivity.
3. BASIC PARTS OF FLAT PLATE
COLLECTOR:
A.Insulated Container:A layer of insulation, which
reduces conduction losses. An enclosure to contain the
different elements.
B.Transparent Cover: These are one or more sheets
made of glass for trapping the heat received by the
absorber plate. It helps in reducing the convective and
radiative heat losses.
C.Pipe/Tube: Flow tubes through which the heat
transfer fluid circulates.
D.Absorber Plate: Absorber plate is used to grasp and
absorb solar radiation. The plate is usually metallic
(copper, aluminum or steel), sometimes plastics have
been used in some low temperature applications.
4. DIRECTION OF FLAT PLATE
COLLECTOR TILT ANGLE:
5. STORAGE TANK:

The storage tank is located slightly at higher level with
the solar collector which is located on stand. The cool
water flow inside the tank and these water flows
through collector. The collector heated this cool water
due to low density of hot water than cool water, the
hot water flow inside the tank. In storage tank, the hot
water will up side and cool water will down side due
to low and high density of water. The storage tank
capacity is 1000 liters.
6. STORAGE TANK INSULATION:
In general terms, the more thermal insulation will
better since it reduces standby heat loss. Hot water
tank is available with various insulation ratings but it
is possible to add layers of extra insulation in the form
of a blanket or 'jacket' on the outside of an uninsulated,
hot water tank to reduce heat loss, to increase energy
efficiency and, in extreme conditions, the hot water
tank itself might be wholly enclosed in a specially
constructed insulated space.
The most commonly available type of water heater
blanket is fiberglass insulation with a vinyl film on the
outside, the insulating blanket being wrapped around
the tank fixed in place with tape or straps, adding
insulation to an already well insulated tank may cause
condensation leading to rust, mould, or other
operational problems so some air flow must be
maintained, usually by convection caused by waste
heat. Most modern hot water tank have applied
polyurethane foam (PUF) insulation.
7. THERMOSIPHON SYSTEM:
For storing water, a storage tank is needed. A very
simple way of doing this, making use of gravity is
shown in above the thermosiphon system. The
principle of the thermosiphon system is that cold water
has a higher specific density than warm water, and so
being heavier will sink down. Therefore, the collector
is always mounted below the water storage tank, so
that cold water from the tank reaches the collector via
a descending water pipe. If the collector heats up the
water, the water rises again and reaches the tank
through an ascending water pipe at the upper end of
the collector. The cycle of tank–water pipe–collector
ensures the water is heated up until it achieves an
equilibrium temperature. The consumer can then make
use of the hot water from the top of the tank, with any
water used being replaced by cold water at the bottom.
The collector then heats up the cold water again.
Due to higher temperature differences at higher solar
irradiances, warm water rises faster than it does at
lower irradiances. Therefore, the circulation of water
adapts itself almost perfectly to the level of solar
irradiance. A thermosiphon system‟s storage tank must
be positioned well above the collector, otherwise the
cycle can run backwards during the night and all the
water will cool down. Furthermore, the cycle does not
work properly at very small height differences. In
regions with high solar irradiation and flat roof
architecture, storage tanks are usually installed on the
roof.
Thermosiphon systems operate very economically as
domestic water heating systems, and the principle is
simple, needing neither a pump nor a control.
However, thermosiphon systems are usually not
suitable for large systems, that is, those with more than
10 m² of collector surface. Furthermore, it is difficult
to place the tank above the collector in buildings with
sloping roofs, and single circuit thermosiphon systems
are only suitable for frost-free regions.
Thermosiphon System [adopted from 4]

8.CALCULATION:
The quantity of solar energy striking the Earth's
surface (solar constant) averages about 1,000 watts per
square meter under clear skies, depending upon
weather conditions, location and orientation. However
on the solar flat plate collector (FPC) available at
present you will only gain roughly 15-20% efficiency
at best. For flat plate collector, the useful heat gain
(Qu) can be calculated by,
9. FLOW RATE:
The suitable flow rate used in this project was set to
1000 liters per hour in major pipe and 100 liters per
hour in minor pipes, Working fluids is allowed to flow
steady enough to ensure the heat from the absorber
plate is transferred uniformly. Temperature difference
between the inlet and the outlet are easily measurable
when the fluid temperature is already in steady state
condition. The velocity of water inside pipe will be
depending on the height of storage tank. In this project
we use more bend pipes, Where bend loss is affect to
velocity of water inside pipe. The pipe may be
horizontal, vertical and inclined in direction. The
velocity of water inside pipe used in this project was
set to 0.1 m/sec.
10. DIMENSION OF PIPE:
A.Major Pipe:
The major steel pipe is connected from hot water tank.
The major pipe is require to discharge 1000 liters
water per hour.

B.Minor Pipe:
The minor steel pipes are connected to major
pipe. The minor pipe installed in 10 rooms and
each room is requiring to 100 liters water per
hour.
11. INSULATING MATERIAL:
In this paper, we will use polyethylene foam to
insulate over steel pipes for both major and minor
pipes. These properties are -
Polyethylene Foam:
 Polyethylene is a flexible plastic foamed insulation
that is widely used to prevent freezing of domestic
water supply pipes and to reduce heat loss from
domestic heating pipes.
 It is usually a mixture of similar polymers of
ethylene with various values of n and the chemical
formula (C2H4)n.
 Polyethylene is of low strength, hardness and
rigidity, but has a high ductility and impact strength as
well as low friction.
 The thermal-conductivity of HDPE (high-density
polyethylene) and LDPE (low-density polyethylene)
are 0.50 w/mk and 0.33 w/mk respectively.

CRITICAL RADIUS CASES:
1. If, R1 < Rc
The heat transfer increases by adding insulation till R2
= Rc. If insulation thickness is further increased, the
rate of heat loss will decrease from this peak value.
This happens when R1 is small and Rc is larger then
the thermal conductivity of the insulation K is high
(poor insulating material) and heat transfer co-efficient
h is low.
2. If, R1 > Rc
The heat transfer decreases by adding insulation. This
happens when R1 is large and Rc is small then the
thermal conductivity of the insulation K is low (good
insulating material) and heat transfer co-efficient h is
high.
13. THE FUTURE OF SOLAR THERMAL
ENERGY:
The passive and active solar will become the main
source of low temperature heating systems. The
integration of solar energy into the building is a trend
of the building energy development. The tendency of
designing energy efficient and cost effective building
is the main direction in the next few decades [9]. For
the electricity, it will rely on the concentrating solar
power (CSP). Refer to the experts, a minimum
reduction of 50% of greenhouse gases have to be
achieved in the coming fifty to a hundred years in
order to protect the global climate [10]. According to
some studies, the number of CSP plants around the
world will increase. The CSP plants will be mainly
built in the sunny areas. In the less sunny places, there
will be mixing of local energy production with less
contribution of CSP electricity from nearby CSP
plants in the sunnier places [11]. As the energy
production from the CSP is not sufficient to the
demand, the solar-hybrid energy systems are the trend
in the short-term development. For the long-term
development, the solar power tends to be the major
energy source.
14. CONCLUSION:
In this study, the simulations demonstrated the solar
thermal water heater (STWH) on the residences. The
hot water supply at the rate of 1000 liters/hour in
buildings. There are requiring to 155 solar flat plate
collectors for heating these water. The comparison of
without insulation and with insulation is of great
importance. Without insulation knew a 50% of energy
losses in the transfer pipe. As a result, the energy
stored in the hot water tank reaches 167.2 MJ/hour.
Thanks to the insulation of transfer pipe. Still, even
though there is insulation the reduced losses are high.
The problem goes back to the long pipe that connects
the tank with the collector.
15. REFERENCES:
1. M. S. Hossain, R. Saidur, H. Fayaz, N. A. Rahim,
M. R. Islam, J. U. Ahamed, and M. M. Rahman,
'Review on solar water heater collector and thermal
energy performance of circulating pipe,„ Renew
Sustain. Energy Rev., vol. 15, no. 8, pp. 3801–3812,
2011.
2. S.P. Sukhatme, "Solar Energy- Principles of
Thermal Collection and Storage", 2008, the McGraw-
Hill Companies.
3. http://iniflex.com/Benefits.html
4. http://www.appropedia.org/Thermosiphon
5. S. IRFAN SADAQ, S. NAWAZISH MEHDI,
ISHRATH M.M, AFROZ MEHAR, NBV. LAKSHMI
KUMARI, “PERFORMANCE ANALYSIS OF
SOLAR FLAT PLATE COLLECTOR” Third IRF
International Conference, 2015, India, ISBN: 978-93-
82702-74-0.
6.http://www.engineersedge.com/heat_transfer/convec
tive_heat_transfer_coefficients__13378.htm
7. R.K. RAJPUT, “Heat And Mass Transfer”, 2006, S.
Chand & Company Limited.
8.https://en.wikipedia.org/wiki/Hot_water_storage_tan
k.

9. U.S. Department of Energy - Energy Efficiency &
Renewable Energy, web
page:http://www.eere.energy.gov/
10. Werner W. and Gottfried P., 2000, Technology
Portrait Thermal Solar Energy, source: energytech.at,
web page:http://energytech.at/solar/portrait.html
11. Technology Roadmap - Concentrating Solar
Power, source: International Energy Agency (iea).

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