Question

2) For the studying of the performance of a concentrating solar collector used for water distillation shown in the figure, a mumber of measurements are required. iyDefine these measurement and suggest the device which is used each meas urement. ii)Give a focus Tepla on the temperature measurement devices suitable for this study and explain briefly the method which should be used for mounting theses devices,their locations and themethod of calibration Solar Energy Evaporator Ded weam 197 Reflector Distillate Water Condenser Aomatir flaw Thurmo ad tranceducer y Tanp

Answer 1

The experiment is conducted to determine the efficiency of the collector and the efficiency of the collector and to determine the efficiency of the distillation process. here it is concentrated for determination of the performance of the solar collector used for the process. we can concentrate on that.

To determine the performance of a solar collector we need certain measurements. that are the temperature of water inlet to the solar collector, temperature of water outlet to the collector, the flow rate of the water, the solar intensity at the surface of the solar collector, and the Aperture area of the collector.

the equation to determine the performance of collector is

$\eta _{collector}=\frac{mc_{p}(T_{out}-T_{in})}{IA\rho }$

These are the measurements used for the experiment

1

definition of measurements

1) the Temperature - it can be define as the degree or intensity of heat present in a material. here we need to determine the temperature of the water inlet and outlet of the collector. The device that used for measure the temperature are of different kind. the number of devices used usually are thermometer, thermocouples etc. Here for the experiment usually used device are themocouples. the thermocouple that suitable for this experiment are k- Type thermocouples. which can be connect to a monitoring device to measure.

2) flow meter - the flow meter is used to measure the mass flow rate of the water flowing through the collector. the amount of mass passing through unit time is called mass flow rate. the flow meter is introduced to the outlet flow of the water from the solar collector. most common device used is Rotameter.

3) solar intensity of sun - it is the rate of solar energy falling on the surface. unit of solar intensity is W/m² . the device that can be used for the experiment is Luxi meter. which is a simple and easy use instrument to measure solar intensity. which can be placed near to the solar collector surface and take measurement.

2

  the temperature measurement device used are K type thermocouple. two thermocouples need to use here. one for to determine the inlet water temperature and the other for determine the outlet water temperature from the solar collector. the thermocouple are of different shape. we can used a spherical tip one. To install the thermocouple first make a hole in the inlet and outlet water pipe. then insert the themocouple in it and seal using suitable sealant like silicon base. them connect the thermocouple wire end to the monitoring devise.

the calibration of the themoucouple can be done using mercury thermometer at different temperatures. the common calibration is at ice point and boiling point. placing the thermocouple in different temperature medium and taking value and measure same measium using mercury thermometer. plotting calibration curve and correct the measured value from the experiment using equation.

ice point calibration is taking a jar of ice and place the thermocouple and thermometer in it. and taking the value. next take a 50⁰ C water and measure using both thermometer and thermocouple . them take a boiling water and measure using two device and plot a chart. then take the equation of curve. we can calibrate by this procedure.