Environmental Engineering Reference
In-Depth Information
Figure 9. Location of measuring sensors in block F.
The analog signals from the resistance-to-voltage converters, as well as the pulse output
signal from the PCU were connected to the DAS for recording and printing and for transfer to
a PC computer system via an RS-232 interface cable. The pulse output signal was integrated
over a period of one hour and scanning of the data was made every 15 minutes.
The inlet and outlet temperature measurements (
T
A
and
T
B
) of each of the 12 arrays
making up block F were measured using copper-constantan thermocouples which were
attached to the array header pipes as shown in figure 9. The assembly of these thermocouples
into the array supply and return pipes, as well as the locations of the 24 (2 x 12 arrays)
thermocouples used are also shown in this figure. The mV output signals from these
thermocouples were recorded on an hourly basis. The heat collected by the 12 arrays was
calculated by multiplying the temperature difference,
T
A
-
T
B
, by the flow rate and the
specific heat in a manner similar to that used for estimating the block heat collected.
A remote converter-type vortex flowmeter (model YF105, Yewflo by Yokogawa) is used
with a model YFA11 vortex flow converter are used for flow measurement. This vortex flow
meter measures the flow rates and converts the measurements to a 4 to 20 mA DC output
signal. The accuracy of the instrument is ± 1.0% of reading plus ± 0.1% of full scale.
A solar radiation sensor (pyranometer)- model H 201 manufactured by Nakaasa
Instrument Co.- is used to measure the global insolation on the collector absorber plate. The
sensor has a measuring range of 0 to 2 kW/m
2
and has an accuracy of ± 0.5% of full scale.
The mV output signal from the sensor is first amplified before being converted into a pulse
signal for connection to Thermodac 32 data logger. This signal is integrated over hourly
intervals in order to obtain the hourly values of the solar radiation. The ambient temperature
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