Journal of Agricultural Engineering and Biotechnology
Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
Forecasting the Thermal Load for Implementing
Solar Energy in a Model Poultry House
Esmaeil Mirzaee- Ghaleh*1, Mahmoud Omid*2, Alireza Keyhani3, Payam Javadikia4
1, 2, 3
Department of Agricultural Machinery, University of Tehran, Karaj, Iran
Department of Agricultural Machinery, University of Razi, Kermanshah, Iran
*1
mirzaeeghale@ut.ac.ir; 2*Omid@ut.ac.ir; 3akeyhani@ut.ac.ir; 4pjavadikia@gmail.com
4
Abstract- In this research, the possibility of a new hybrid method for implementing solar hot water systems in poultry houses is
discussed. Iran is located in a sunny belt and most locations in Iran receive abundant solar energy. The poultry industry plays an
important role in the economy of Iran because a huge consumption of chicken is demand. In Iran, the percent of energy consumption
in poultry industry is high and the implementation of renewable energy is an important and valuable way to cover the energy
demand. Solar hot water systems (SHWS) are used for producing hot water from solar energy. In this paper, the values of heat losses
and heat gain were determined in a model poultry house. The collector area was considered as 5.1m2. According to the collector
parameters, the quota of solar energy for warming process was calculated. Results indicated that the minimum value of solar power
was 2000 W which is 20% required energy for December.
Keywords-Solar Energy; Poultry House; Solar Hot Water System; Hybrid Method
NOMENCLATURES
m, mass of air (kg)
F, constant factor (W/mK)
Cp, specific capacity of air (J/kgK)
ρ, air density (kg/m3)
Ti, inside temperature (K)
V, ventilation rate( m3/s)
t, time (s)
Qbroiler, produced heat by broiler (W)
qsup, Supplemental heat capacity(W)
Ac, collector area (m2)
total solar radiation on collector (W/m2)
Qs, sensible heat (W/bird)
Qv, heat losses by ventilation(W)
τ, solar transmittance
Qw, heat losses from walls (W)
α , solar absorptance
Qf, heat losses from floor (W)
Qu, collected energy by collector (W)
2
A, wall area (m )
Tat, environment temperature (°c)
2
U, overall heat transfer coefficient (W/m K)
Tfi, inlet water temperature (°c)
2
R, thermal resistance (m K/W)
FR, collector heat coefficient
K, thermal conductivity (W/mK)
Qaux, auxiliary heat capacity (W)
X, thickness (m)
mb, mass of birds (kg)
P, perimeter of house (m)
I.
INTRODUCTION
Renewable energy has many benefits such as environmental benefits, economic benefits, energy security and the vital
source of energy for future generations [1]. Sun with total energy of 173,000 terawatts reaching the earth’s surface is one kind
of renewable energy with largest potential [2, 3].
Iran is located in a sunny belt between 25°and 40°N latitudes, and most locations in Iran receive abundant solar energy [4].
Alborz province in north central Iran has the ability to use this potential [5].
Solar energy has many usages in agricultural applications such as solar dryer [6], solar greenhouse [7], solar pump, dairy
processing plants [8], solar heating and cooling [9] and so on. Generally, solar hating is carried out by solar air heater or solar
water heater. Solar hot water systems (SHWSs) are well established and they have domestic and commercial applications.
These systems use solar energy to generate hot water.
- 30 DOI: 10.18005/JAEB0102001
Journal of Agricultural Engineering and Biotechnology
Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
Several configurations exist for this purpose. These configurations may be grouped into two, namely, the passive SHWS
and the active SHWS. The solar collectors which are employed in these configurations can be flat plate, concentrating, or
evacuated tube types. However, the flat-plate-type solar collectors are most common because of their low cost and ease of
design and construction [10]. The active group is more complicated and expensive than the passive group. The efficiency of
active types is normally 35-80 % more than the passive types [11]. In recent studies, the use of solar hot water system was
studied [1, 12, 13, 14].
The poultry industry plays an important role in the economy of Iran because a huge consumption of chicken is demand.
One of the most important sections in agriculture that have high energy consumption is poultry industry. Heating the poultry
house can be reduced by solar energy [15]. Some studies were done on warming the poultry house. In a research, the optimized
collector area for warming was determined [16]. The warming of poultry house by solar air heater was studied by [3, 17].
Normally the efficiency of solar hot water system is more than the solar air heater [11]. Hence, the objectives of this study are:
(1) to introduce a new method for implementing solar hot water system for warming the poultry house; (2) to predict thermal
load and the quota of solar energy in model poultry house in Karaj province, Iran.
II.
MATERIALS AND METHODS
A. The Suggested System for Warming the Poultry House
The schematic diagram of suggested system is illustrated in Fig. 1. This system can be known as a hybrid system, because
it uses two sources of energy which include solar energy and fossil fuel for auxiliary heater. This thermal system consists of
mainly four components, which are: poultry house, solar hot water system, auxiliary heater and heat exchanger.
Fig. 1 Schematic diagram of suggested system
B. Poultry House
For possible use of this new method, first, it must be evaluated on a model poultry house; therefore, this poultry house was
considered in laboratory scale with area of 12 m2, in energy laboratory of University of Tehran, Karaj, Iran. A schematic
diagram of this model poultry house is shown in Fig.2.
One of the most important parameters which must be considered in poultry house is determination of heat losses and heat
gains. Heat loss generally includes losses from walls, floor and ventilation. The source of heat gain includes sensible heat gain
from chickens, solar heat absorption and lighting [18]. In this paper heat from solar absorption and lighting are neglected. For
studying these parameters, mathematical model must be considered. This mathematical model is based on energy and mass
balance. For transient state conditions the equation can be cast as [19, 20]:
mc p
dTi
 qsup  Qs  Qv  Qw  Q f
dt
(1)
Where, m is mass of air inside the house, cp is specific heat capacity of air, Ti is indoor temperature, t is time, qsup is
supplemental heat capacity, Qs is sensible heat produced by broiler, Qv is heat losses by ventilation system, Qw is heat losses
from walls and roof and Qf is heat losses from floor.
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Journal of Agricultural Engineering and Biotechnology
Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
Fig. 2 Schematic diagram of the model poultry house
Heat conducted through the walls and roof was calculated as [21]:
Qw 
 (UA).(T  T )
i
o
(2)
Where, Qw is conduction heat transfer (W), A is wall or roof area (m2), U is overall building heat transfer coefficient
(W/m2K), Ti and To are indoor and outdoor temperature, respectively (K). The overall coefficient of heat transfer was
determined as follows:
U 
1
Rt
(3)
Where, Rt is total thermal resistance per unit area (m2K/W) and was calculated as follows:
Rt  Ris  R1  R2  R3  ... Ros
(4)
Where, Ris is inside surface unit area thermal resistance (m2K/W), Ros is outside surface unit area thermal resistance
(m K/W), and R1,2,… are unit area thermal resistance of each layer making up the building (m2K/W).
2
The unit area thermal resistance of each layer was determined as follows:
R1, 2... 
X 1, 2,...
K1, 2,...
(5)
Where, k1,2,…are thermal conductivity of each layer (W/mK) and X1,2,…are thickness of each layer of material building (m).
Heat loses from floor was determined as [22]:
Q f  F .P.(Ti  To )
(6)
Where, Qf is heat loses from floor (W), P is perimeter of the house (m) and F is a constant factor between 1.4 – 1.6
(W/mK).Heat losses from ventilation system can be calculated as follows [23]:
Q v  C p ..V .(Ti  To )
(7)
Where, Cp is specific heat of air (J/kgK), ρ is air density (kg/m3) and V is ventilation rates (m3/s). Generally, enough and
continuous ventilation is required for supplying clean air and reducing humidity in poultry house. Amount of ventilation is
depended on the age (mass) of broiler, number of them and the season of production [24]. Hence, the total heat losses will be:
Q tot  Qw Q f Qv
(8)
The total heat produced by chicken can be determined as follows [18, 25]:
Qbroiler 10.mb 0.75 (4 105 (20  Ti )3  1)
(9)
Where, mb is mass of birds (kg), Qbroiler is produced heat by birds (W/bird) and Ti is indoor temperature. Sensible heat was
determined as [18, 26]:
Q sens  Qbroiler (0.8  1.85 10 7 (10  Ti ) 4 )
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(10)
Journal of Agricultural Engineering and Biotechnology
Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
Where, Qsens is sensible heat (W/bird). And based on the Equations 1, 8 and 10, supplemental heat capacity will be as:
q sup Qtot  Qsens
(11)
Energy and mass balance models require some numerical values as input values. Table I shows input values for the models
with their dimensions.
TABLE I. INPUT PARAMETERS USED IN THE SIMULATION MODELS
Dimensions
m2
m
m
----W/mk
m3
gr
°C
°C
Numerical value
12
2.50 and 3
14
100
Cement block, foam
1.5
37.2
50 – 3000
20 -32
-15- 40
parameters
House area
Length of walls
Perimeter of house
Number of broiler
Wall materials
F
Volume of house
Mass of broiler
Ti
To
Row
1
2
3
4
5
6
7
8
9
10
C. Solar Hot Water System
In this research, an active solar hot water system is proposed. As shown in Fig.1, this system includes solar collector, solar
station, heat exchanger, tank and connections. Two flat types of solar collectors were considered. Some properties of this
collector are shown in Table II.
TABLE II PROPERTIES OF CONSIDERED SOLAR COLLECTOR
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Description
Type
Length/Width/Height
Heat transfer fluid
Aperture area
Absorber area
Gross area
Thickness of absorber sheet
Tube distance
Heat loss coefficient
Number of glazing
Solar transmittance,τ
Solar absorptance, α
Material of fluid tubes
Collector tilt angle
Tank capacity
Details
Flat Plate collector
2159/1181/90 mm
Water
2.358 m2
2.371 m2
2.55 m2
0.5 mm
95 mm
3.75 W/m2K
1
90.7 %
94 %
Copper
15°- 70°
300 Lit
The solar station includes water pump, sensors, control unit, LCD and connections. The duty of control unit is collecting
data from temperature sensors and taking appropriate decision about pumping, for collecting solar energy from collector.
Generally, effective energy from solar flat collector can be defined as [27, 28]:
Qu  Ac .FR ( I t (   )  U L (T fi  Tat ))
(12)
Where, Qu is collected energy (W), Ac is collector area (m2), FR is collector heat coefficient at temperature of Tfi,
is total
solar radiation on collector (W/m2), τ is solar transmittance, α is solar absorptance, UL is heat loss coefficient (W/m2°C), Tf i is
inlet water temperature (°C), and Tat is environment temperature (°C).
D. Auxiliary Heater and Heat Exchanger
It is obvious that sometimes solar energy is not available (such as night, cloudy days, rainy and snow conditions). Hence
there must be an auxiliary heater. A heat exchanger must transfer thermal energy from auxiliary heater to the tank. The
capacity of auxiliary heater must be equal to qsup. The energy source of this heater can be common fossil fuel such as gas, oil
etc. Normally, when the solar energy is available, the capacity of auxiliary heater is equal to:
QAUX  qsup  Qu
(13)
The water in the tank will have the constant energy (temperature). This temperature can be controlled by the solar station.
In other words, the solar station will turn off or turn down the auxiliary heater for keeping the tank temperature constant. The
heater operates only if the temperature of the output water from the tank is lower than the required value (normally 60-70°C).
The used heat exchanger is a parallel flow water-to-air type, which consists of concentric pipes. The hot fluid (water)
- 33 DOI: 10.18005/JAEB0102001
Journal of Agricultural Engineering and Biotechnology
Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
passes inside the smaller diameter pipe, while the cold fluid (air) passes through the space between the pipes. The hot fluid
transfers heat through the shell of the smaller diameter pipe to the cold fluid. Therefore, a temperature drop will occur in the
hot fluid continuously and at the same time a temperature rise will occur in the cold fluid (indoor temperature)[29].
III. RESULTS AND DISCUSSION
A. Determining of Minimum Ventilation Rate
The required ventilation rate is depended on the age (mass) of broiler, number of broilers and the season of production.
Based on the literature, for closed house and microclimate conditions (in Karaj province), minimum required ventilation rate
for winter and summer are 2.3 and 7.5 m3/h per one kg of broiler mass, respectively[24]. Considering 100 broilers in the house,
the minimum and maximum required ventilation rate were calculated (Table III).
TABLE III REQUIRED VENTILATION RATE
Time
First of period
End of period
Winter conditions
Total mass of
Required ventilation
broiler kg)
rate (m3/h)
5
11.50
300
690
Summer conditions
Total mass of
Required ventilation
broiler (kg)
rate (m3/h)
5
37.5
300
2250
Based on the results, the minimum required ventilation rate is 11.50m3/h, for the first of period and winter conditions.
While, the maximum required ventilation is 2250m3/h for end of period and summer conditions. For determining the capacity
of supplemental heater, the maximum required ventilation in winter (690m3/h) must be considered, because in winter
conditions warming is required.
B. Heat Losses and Heat Gain
The values of heat gain and heat losses were calculated using the Equations2, 3, 6, 7, 10 and Table I. These results are
shown in Table IV.
TABLE IV AMOUNT OF HEAT LOSSES AND HEAT GAIN
Parameter
Qw
Qf
Qv
Qs
Value (W)
2403.49
987
7874
1482
According to Table IV, the minimum heat loss is from floor and the maximum is from ventilation. The value of total heat
losses is 11262.49 W, about 13% of which (1482 W) will be provided by the broilers. From Table IV, it can be found that the
capacity of supplemental heater is 9782 W (the difference between heat losses and heat gain). Therefore, in suggested system,
the capacity of auxiliary heater must be at least 9782 W.
C. Solar Hot Water System
For determining the quota of solar energy for warming process, metrological data for Alborz province, for the full year of
2008, were collected from the Islamic Republic of Iran Meteorological Office data center [30]. The Alborz province was
located between 35°and 40' N latitudes, and 51°and 29' E longitude, in the north central of Iran. Mean sunshine duration and
mean daily solar radiation for selected station are shown in Figs.3 and 4, respectively.
As shown in Fig.4, the minimum solar radiation for December is 2kWh/m2day. This value, and the values presented in
Table II as well as the parameters in Equation (12) were used for calculating the quota of solar energy. Based on the results, the
total collected energy by the solar collector in these conditions will be about 2000 W. which is about 20% of total required
energy. In other words, solar radiation can provide at least 20% required energy which is for December. Also, it was found
that for supplying total thermal load in winter conditions (in December) the area of 25m2 for collector is required.
Fig. 3 Mean sunshine duration [31]
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Aug. 2013, Vol. 1 Iss. 2, PP. 30-36
Daily solar radiation
( kWh/m2 day)
Journal of Agricultural Engineering and Biotechnology
1
2
3
4
5
6
7
8
9 10 11 12
Months
Fig. 4 Mean daily solar radiation [30]
IV. CONCLUSIONS
From this research it can be concluded that:

The suggested new hybrid method can be used for warming the poultry house.
The maximum required ventilation rate for summer is 2250m3/h. While the maximum ventilation rate for winter is
3
690m /h.
 The maximum heat loss was for ventilation (7874 W) and the minimum was for floor (987W).
 Solar radiation can provide at least 20% of the required energy in December.

ACKNOWLEDGMENTS
The financial support provided by University of Tehran (research project reference number: 1305051-1-07), Iran National
Science Foundation (INSF) and National Elite Foundation is duly gratefully acknowledged.
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