Solar thermal instalation

2011/2012
Solar Thermal Instalation


INDEX

* Introduction to solar thermal power plants

* Description of the project

* Aim of the project

* Measurements

* Calculations

* Final conclusions

INTRODUCTION TO SOLAR THERMAL POWER PLANTS

Solar thermal electric power plant generates heat by using lenses and reflectors to concentrate the sun's energy. Becausethe heat can be stored, these plants are unique because they can generate power when it is needed, day or night, rain or shine.
The sun's heat can be collected in a variety of different ways: Solar Parabolic Troughs consist of curved mirrors which form troughs that focus the sun's energy on a pipe. A fluid, is circulated through the pipes which are used to drive a conventional generator tocreate electricity. Solar Parabolic Dish systems consist of a parabolic-shaped concentrator (similar in shape to a satellite dish) that reflects solar radiation onto a receiver mounted at the focal point at the center. The collected heat is utilized directly by a heat engine mounted on the receiver which generates electricity. Solar Central Receivers or "Power Towers" consist of a tower surrounded by alarge array of heliostats. Heliostats are mirrors that track the sun and reflect its rays onto the receiver, which absorbs the heat energy that is then utilized in driving a turbine electric generator.
Solar thermal power plants create two and one-half times as many skilled, high paying jobs as do conventional power plants that use fossil fuels.
Utilizing only 1% of the earth's deserts toproduce clean solar electric energy would provide more electricity than is currently being produced on the entire planet by fossil fuels.

DESCRIPTION OF THE INSTALATION

Solar thermal power plant absorbs energy from the sun’s rays to heat water to 150ºC. Then the water circulates through the pipes so it can transfer heat to the working fluid of the other circuit. The working fluid is convertedinto mechanical energy in a turbine and into electrical energy by a generator couplet to the turbine.
Initial parameters:
* Heat generated by collectors, Qd = 270 kW
* Pressure of water, Ps1 = 6,9 bar
* Outlet temperature from collectors, Ts1 = 150 ºC
* Inlet minimum temperature of water to collectors, Ts3 = 50 ºC

AIM OF THE PROJECT

The aim of the project is to compare theefficiency and power that we obtained from our solar power plant, when we use different working fluids.
The study is based in three different working fluids:
* R-227
* Toluene
* RC-318
We will sweep temperatures from 10 ºC below the critical temperature, to a temperature 10 ºC above the condensation temperature, varying the temperature at intervals of 10ºC.
With the help of NISTREFPROP program, we can obtain all thermodynamic properties of each fluid in each temperature.
Once we have the thermodynamic properties of each fluid, we can begin to calculate the parameters sought, performing energy balances in our organic Rankine cycle (ORC). This is the general scheme of Rankin cycle:

MEASUREMENTS
R – 227
Nº | T [ºC] | P [Mpa] | h [ kJ/kg] | s [kJ/kg K] | ts3 | 65,75999076|
1 | 95,00 | 2,5558 | 368,67 | 1,5012 | | |
2s | 41,61 | 0,6111 | 352,36 | 1,5012 | | |
3 | 35,00 | 0,6111 | 240,66 | 1,1389 | | |
4s | 36,21 | 2,5558 | 242,09 | 1,1389 | | |
5 | 95,00 | 2,5558 | 325,38 | 1,3836 | | |
| | | | | | |
Nº | T [ºC] | P [Mpa] | h [ kJ/kg] | s [kJ/kg K] | t3s | 64,14542484 |
1 | 85,00 | 2,0688 | 369,36 | 1,5085 | | |
2s | 43,88 |0,6111 | 354,66 | 1,5085 | | |
3 | 35,00 | 0,6111 | 240,66 | 1,1389 | | |
4s | 35,92 | 2,0688 | 241,73 | 1,1389 | | |
5 | 85,00 | 2,0688 | 308,16 | 1,3379 | | |
| | | | | | |
Nº | T [ºC] | P [Mpa] | h [ kJ/kg] | s [kJ/kg K] | ts3 | 57,98369565 |
1 | 75,00 | 1,6649 | 366,67 | 1,5074 | | |
2s | 43,51 | 0,6111 | 354,32 | 1,5074 | | |
3 | 35,00 | 0,6111 | 240,66 |...