An ideal vapor-compression refrigeration cycle that uses refrigerant-134a as its working fluid maintains a condenser at 800 kPa
and an evaporator at -20°C. Determine this system’s COP and the amount of power required to service a 150 kW cooling load. (Take the required values from saturated refrigerant-134a tables.)
1 answer:
Answer:
COP = 3.828
W' = 39.18 Kw
Explanation:
From the table A-11 i attached, we can find the entropy for the state 1 at -20°C.
h1 = 238.43 KJ/Kg
s1 = 0.94575 KJ/Kg.K
From table A-12 attached we can do the same for states 3 and 4 but just enthalpy at 800 KPa.
h3 = h4 = hf = 95.47 KJ/Kg
For state 2, we can calculate the enthalpy from table A-13 attached using interpolation at 800 KPa and the condition s2 = s1. We have;
h2 = 275.75 KJ/Kg
The power would be determined from the energy balance in state 1-2 where the mass flow rate will be expressed through the energy balance in state 4-1.
W' = m'(h2 - h1)
W' = Q'_L((h2 - h1)/(h1 - h4))
Where Q'_L = 150 kW
Plugging in the relevant values, we have;
W' = 150((275.75 - 238.43)/(238.43 - 95.47))
W' = 39.18 Kw
Formula foe COP is;
COP = Q'_L/W'
COP = 150/39.18
COP = 3.828
You might be interested in
Answer:
Kindly note that, you're to replace "at" with shift 2 as the brainly text editor can't take the symbol
Explanation:
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.layout.HBox;
import javafx.scene.control.TextField;
import javafx.scene.control.Button;
public class Calculator extends Application {
public static void main(String[] args) {
// TODO Auto-generated method stub
launch(args);
}
"at"Override
public void start(Stage primaryStage) throws Exception {
// TODO Auto-generated method stub
Group root = new Group();
VBox mainBox = new VBox();
HBox inpBox = new HBox();
TextField txtInput = new TextField ();
txtInput.setEditable(false);
txtInput.setStyle("-fx-font: 20 mono-spaced;");
txtInput.setText("0.0");
txtInput.setMinHeight(20);
txtInput.setMinWidth(200);
inpBox.getChildren().add(txtInput);
Scene scene = new Scene(root, 200, 294);
mainBox.getChildren().add(inpBox);
HBox rowOne = new HBox();
Button btn7 = new Button("7");
btn7.setMinWidth(50);
btn7.setMinHeight(50);
Button btn8 = new Button("8");
btn8.setMinWidth(50);
btn8.setMinHeight(50);
Button btn9 = new Button("9");
btn9.setMinWidth(50);
btn9.setMinHeight(50);
Button btnDiv = new Button("/");
btnDiv.setMinWidth(50);
btnDiv.setMinHeight(50);
rowOne.getChildren().addAll(btn7,btn8,btn9,btnDiv);
mainBox.getChildren().add(rowOne);
HBox rowTwo = new HBox();
Button btn4 = new Button("4");
btn4.setMinWidth(50);
btn4.setMinHeight(50);
Button btn5 = new Button("5");
btn5.setMinWidth(50);
btn5.setMinHeight(50);
Button btn6 = new Button("6");
btn6.setMinWidth(50);
btn6.setMinHeight(50);
Button btnMul = new Button("*");
btnMul.setMinWidth(50);
btnMul.setMinHeight(50);
rowTwo.getChildren().addAll(btn4,btn5,btn6,btnMul);
mainBox.getChildren().add(rowTwo);
HBox rowThree = new HBox();
Button btn1 = new Button("1");
btn1.setMinWidth(50);
btn1.setMinHeight(50);
Button btn2 = new Button("2");
btn2.setMinWidth(50);
btn2.setMinHeight(50);
Button btn3 = new Button("3");
btn3.setMinWidth(50);
btn3.setMinHeight(50);
Button btnSub = new Button("-");
btnSub.setMinWidth(50);
btnSub.setMinHeight(50);
rowThree.getChildren().addAll(btn1,btn2,btn3,btnSub);
mainBox.getChildren().add(rowThree);
HBox rowFour = new HBox();
Button btnC = new Button("C");
btnC.setMinWidth(50);
btnC.setMinHeight(50);
Button btn0 = new Button("0");
btn0.setMinWidth(50);
btn0.setMinHeight(50);
Button btnDot = new Button(".");
btnDot.setMinWidth(50);
btnDot.setMinHeight(50);
Button btnAdd = new Button("+");
btnAdd.setMinWidth(50);
btnAdd.setMinHeight(50);
rowFour.getChildren().addAll(btnC,btn0,btnDot,btnAdd);
mainBox.getChildren().add(rowFour);
HBox rowFive = new HBox();
Button btnEq = new Button("=");
btnEq.setMinWidth(200);
btnEq.setMinHeight(50);
rowFive.getChildren().add(btnEq);
mainBox.getChildren().add(rowFive);
root.getChildren().add(mainBox);
primaryStage.setScene(scene);
primaryStage.setTitle("GUI Calculator");
primaryStage.show();
}
}
Answer:
Explanation:
Our values are,
State 1
We know moreover for the tables A-15 that
State 2
For tables we know at T=320K
We need to use the ideal gas equation to estimate the mass, so
Using now for the final mass:
We only need to apply a energy balance equation:
The negative value indidicates heat ransfer from the system