Experiment 1.
Familiarisation with the functions of the collector and the heating circuit
Identifying the solar trainer components layout
Supposing that you recognize the diagram’s symbols, identify the
components.
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
Version 2.1
Experiment 1. Familiarisation with the functions of the collector and the heating circuit
Identify, on the manufacturer’s label, the technical characteristics
of the main components.
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
The most important parameters are:
Version 2.1
Experiment 1. Familiarisation with the functions of the collector and the heating circuit
- Active area (Superficie utile) - 1.84 m2
- Maximum thermal agent pressure (Max. pressione di esercizio) -
10 bars
- Maximum thermal agent temperature (Temperatura massima) -
2340C
- The diameter of the primary network coupling system (fittings
diameter).
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
The following components are present on the panel:
- Pr: 230V power supply socket.
- K1: RS232 connector to which the supplied RS232/USB adapter
is connected.
- BC: 2mm terminals, connected to probes S1 to S6, C1, S12.
They allow measuring the voltage variation when the
temperature varies.
- J1: Automatic magneto-thermal differential switch.
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Experiment 1. Familiarisation with the functions of the collector and the heating circuit
- J2: Normal/forced switch. It allows the operation of the system
even when in low light conditions, by switching to "forced".
0
- C: cooling system simulator for excessive temperature. The
lamp lights on when approximately 90 ° C are reached on S3 in
the tank. This simulation is also indicated for the collector
temperature.
- P3: DHW circulation simulator in a heating system. The lamp
lights on when 40 °C on S3 are reached.
- TC: control unit; the circulation pumps of the main circuits are
controlled, in terms of start/stop processes, by an electronic
control unit that receives the temperature information from
the sensors located at different key points through which the
liquid flows.
IV.4.1.1 Collector installation- making ready to heat water
Ones you have fixed the Advanced Solar Heating trainer properly for
heating capturing, you can proceed with the next major step: filling
both circuits with water.
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
Version 2.1
Experiment 1. Familiarisation with the functions of the collector and the heating circuit
Secondary circuit (domestic) charging
First, identify the circuit:
Then, find the most convenient way to fill the tank with water. In our
testing system, we made this connection.
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
The dashed line suggest the waterway from the supply tap to the
output outlet for draining it.
At the end of the filling process, some water might be wasted. We
drained that little water in a sink, or collector recipient.
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Experiment 1. Familiarisation with the functions of the collector and the heating circuit
Primary circuit charging
First, identify the primary circuit and its components.
The air vent valve placed on the collector is
equipped with a tap that is kept open during the
charging of the system and closed when the
system is under pressure.
It can be opened later to discharge the residual air and then
closed again. Should the pressure drop, it must be restored via
taps 6.
Insert the rubber hoses in the two side taps 6, close the ball valve 7,
turn the ring of the thermometer T as shown and let the water in
that will come out from the lower tap 6 (drain).
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
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Exercise 2. Available solar energy estimation
Available energy estimation
Locations of Solar Collectors and their Latitude: 27.947 (°N)
Total Energy Absorbed by Solar Collectors throughout the Year:
2377.554396 [kWh/m2]
Maximum and Minimum values of Solar Flux throughout the year
with Day (Energetic flux):
[kWh/m2 day] Time
Min. value 8.3158 18-Jun
Max. value 4.2515 20-Dec
Some typical conditions:
Hot water demand: 500 l/day
Cold water: 20°C
Hot water (storage) 60°C
Version 2.1
Thermal Solar Energy Study- Advanced trainer.
Experimental section
1. Collector yield calculation Cy
It is influenced by the efficiency of the collector (ηk=0.61, for
collector’s capacity below 200 l) and the efficiency of piping, storage
(ηsys=0.81, for storage capacity below 3000 l).
where Cy is [kWh/m2]
The energy demand is calculated by:
where:
Heat capacity of water = 1.16 [kWh/m3K]
ΔT is the temperature difference between hot water and cold
water [K]
Then, the energy demand is
The area: A = 1.84 m2
Local irradiation energy: I = measured by the sensor
The collector performance is described by the equation for the power output q
[W]:
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Experiment 5. Standalone experiments. Determining the collector efficiency
by entering the local operating conditions:
I - Solar irradiance on collector plane - 2200 [W/m²], to be measured
dT - Temperature difference between the collector average fluid temperature and
the ambient air temperature - 50 [K] (Kelvin)
and the collector performance parameters:
n0 - Optical efficiency (combined efficiency of the transparent cover and the
absorber)
a1 - 1st order heat loss coefficient (heat loss coefficient at collector fluid
temperature equal to the ambient temperature [W/K])
a2 - 2nd order heat loss coefficient (temperature dependent term of the heat loss
coefficient [W/K²]).
The area: 1.84 m2
Local irradiation energy.
The collector performance is described by the equation for the power output q
[W]:
by entering the local operation conditions:
I - Solar irradiance on collector plane - 2200 [W/m²]
ΔT - Temperature difference between collector average fluid temperature and ambient
air temperature - 50 [K] (Kelvin)
collector performance
First condition :
Sensor Value
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
At 2 L/MIN
Sensor Value
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
AT 4L/MIN
Sensor Value
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
Experiment 5. Standalone experiments. Determining the collector efficiency
Our calculations
Cy= energy* eff collector * eff system
= a*i*0.61*0.81
=1.84*2100*0.61*0.81
=1,909.2024Wh
=1.909KWh
For tank
Q=v Cv * ∆ t
= 150*1.16*4
=696 Wh
=0.696kwh
Qnet=Qincident-Qoverall losses
Qincident= a*effoptical*I-a1*dt-dt 2❑*a2
=1.84*.8*2104- 3.5*40-0.02*40^2
=3097-140-32
=2925.088 w
Qlosses=40*1.84*3
=220.8
Qnet=2925.088-220.8=2704.88
Eff=Qnet/i*a*eff o=0.87
dt=(s1+s2/2)-Tambient= 61-21=40
