A refrigerated space is maintained at -15℃， and cooling water is available at 30℃， the refrigerant is ammonia. The refrigeration capacity is 105 kJ/h. If the compressor is operated reversibly:
(1) What is the value of ε for Carnot refrigerator?
(2) Calculate the ε for the vapor-compression cycle;
(3) Calculate the circulation rate for the refrigerant;
(4) Calculate the rating power of the compressor.
Answer:
(1) 5.74
(2) 5.09
(3) 3.05×10⁻⁵ kg/s
(4) 0.00573 kW
Explanation:
The parameters given are;
Working temperature, [tex]T_C[/tex] = -15°C = 258.15 K
Temperature of the cooling water, [tex]T_H[/tex] = 30°C = 303.15 K
(1) The Carnot coefficient of performance is given as follows;
[tex]\gamma_{Max} = \dfrac{T_C}{T_H - T_C} = \dfrac{258.15}{303.15 - 258.15} = 5.74[/tex]
(2) For ammonia refrigerant, we have;
[tex]h_2 = h_g = 1466.3 \ kJ/kg[/tex]
[tex]h_3 = h_f = 322.42 \ kJ/kg[/tex]
[tex]h_4 = h_3 = h_f = 322.42 \ kJ/kg[/tex]
s₂ = s₁ = 4.9738 kJ/(kg·K)
0.4538 + x₁ × (5.5397 - 0.4538) = 4.9738
∴ x₁ = (4.9738 - 0.4538)/(5.5397 - 0.4538) = 0.89
[tex]h_1 = h_{f1} + x_1 \times h_{gf}[/tex]
h₁ = 111.66 + 0.89 × (1424.6 - 111.66) = 1278.5 kJ/kg
[tex]\gamma = \dfrac{h_1 - h_4}{h_2 - h_1}[/tex]
[tex]\gamma = \dfrac{1278.5 - 322.42}{1466.3 - 1278.5} = 5.09[/tex]
(3) The circulation rate is given by the mass flow rate, [tex]\dot m[/tex] as follows
[tex]\dot m = \dfrac{Refrigeration \ capacity}{Refrigeration \ effect \ per \ unit \ mass}[/tex]
The refrigeration capacity = 105 kJ/h
The refrigeration effect, Q = (h₁ - h₄) = (1278.5 - 322.42) = 956.08 kJ/kg
Therefore;
[tex]\dot m = \dfrac{105}{956.08} = 0.1098 \ kg/h[/tex]
[tex]\dot m[/tex] = 0.1098 kg/h = 0.1098/(60*60) = 3.05×10⁻⁵ kg/s
(4) The work done, W = (h₂ - h₁) = (1466.3 - 1278.5) = 187.8 kJ/kg
The rating power = Work done per second = W×[tex]\dot m[/tex]
∴ The rating power = 187.8 × 3.05×10⁻⁵ = 0.00573 kW.
1. If the correct precautions are not taken, working on automobiles can be
Hi, I have an assignment in which i needs to write a report on (Rationalization of electrical energy consumption) and i need charts and figures on any Country (USA,China,UK,...) where can I find this kind of information
Which option identifies the technology that controlled flooding in the following scenario? The Nile River in Egypt floods its banks from melting snow and heavy rains every year. Since 1970, flood control has been managed by the Aswan High Dam. terps locks polders sluice gates HELP PLEASE
Answer:
The correct option is;
Since 1970, flood control has been managed by the Aswan High Dam
Explanation:
The scenario that identifies the technology that controlled flooding is the flood control that is being managed by the Aswan High Dam
Dams alongside their reservoirs are meant control the flow water and to protect low-lying areas from disastrous floods. Damming a water way involves the construction of a standardized dam complementary standard water reservoir with the water within it being kept below a certain level to allow it accommodate water coming from floods.
Terps are artificial mounds meant for dwelling
Polders are water body reclaimed low-lying land by the construction of drainage canals and d y k e s
Sluice gates are meant to harness the power of flowing waters.
Car insurance incentives and discounts are available depending on _____. A. school attendance and driver skill B. vehicle type and driver family size C. location and driver employment status D. location, vehicle type, and driving habits
Answer:D. Location, vehicle type, and driving habits
The amount of car insurance incentives and discounts depends upon the location, vehicle type, and driving habit. Thus, option D. is correct.
What is car insurance incentive?The car insurance incentive is the extra amount being paid to the insurance holder. The amount of incentive is being set by the insurance company that shows the importance of costly and cost-friendly vehicles.
The total amount of incentive to be given to the insurance holder will depends upon the location, the type of vehicle, and the driving habits.
Therefore, option D. is correct.
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1. Unauthorized persons servicing equipment may jeopardize the safety of operators and
others due to ___ of heavy equipment.
a. mechanical failure
b. incorrect classification
C. improper signaling
d. electrical designation
Pure ethanol has an octane rating of about 113. E85, Which contains 35 percent oxygen by weight, has an octane rating of about
3. Airbags are supplemental protection and are designed to deploy in all crashes.
A. O TRUE
B. O FALSE
Airbags are supplemental protection and are not designed to deploy in all crashes. Therefore, it's false.
What are airbag?It should be noted that airbags are out in vehicles in order to reduce the impact on an individual during accidents.
Therefore, airbags are supplemental protection and are not designed to deploy in all crashes. They're designed to work with seatbelts.
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What classes I have to take before joining the lineman program?
Answer:
have a high school diploma or GED certificate, and submit an application to your local Joint Apprenticeship Training Committee (JATC). Some JATCs have additional requirements: a grade of C or better in algebra and a commercial driver's license.
Answer:
GED and a JATC
Explanation:
Create a class OperateArray in which you create a 2 x 3 integer array with all zeros in it. Allow the user to traverse the array to enter the 6 values in the array. The user will fill in the top row first, then the bottom row. The class should then subtract the bottom number from the top number in each column, and then add the results of the 3 subtractions to get a total. Enter the data shown below
| 6 5 4| Top row of array
|3 2 3| Bottom row of array
The correct answer is 7.
Answer:
The programming language is not stated; however, I'll answer this question using Java programming language.
Because of the length of the program, comments are used to explain some lines
See Attachment for program file
Program starts here
import java.util.*;
public class OperateArray{
public static void main(String [] args)
{
Scanner input = new Scanner(System.in);
//Declare Array
int arr[][] = new int[2][3];
//Fill array with 0
for(int row =0;row<2;row++)
{
for(int col=0;col<3;col++)
{
arr[row][col] = 0;
}
}
//Prompt user for input
for(int row =0;row<2;row++)
{
if(row == 0)
{
System.out.print("Enter top rows\n"); //Top rows
}
else
{
System.out.print("Enter bottom rows\n"); //Bottom Rows
}
for(int col=0;col<3;col++)
{
arr[row][col] = input.nextInt();
}
}
//Initialize difference to 0
int diff = 0;
//Print and Calculate Difference
for(int row =0;row<2;row++)
{
for(int col=0;col<3;col++)
{
if(row<1)
{
if(col<2)
{
System.out.print(arr[row][col]+" ");
}
else
{
System.out.print(arr[row][col]+" |Top Row of Array\n");
}
//Add top rows
diff+=arr[row][col];
}
else
{
if(col<2)
{
System.out.print(arr[row][col]+" ");
}
else
{
System.out.print(arr[row][col]+" |Bottom Row of Array\n");
}
//Subtract bottom rows from top
diff-=arr[row][col];
}
}
}
//Print Difference
System.out.print("Difference: "+diff);
}
}
//End of Program
BE-14 Where must registration numbers be displayed?
Bow
Stern
Engine
11
Transom
Answer:
A. Bow
Explanation:
Registration number is an evidence or authentication of registration of a vessel or vehicle. This number is very important when an emergency occurs and there is a need to trace the vessel to the owner. And this should be displayed on a vertical surface or a surface where easy view is achievable.
So it is recommended that registration numbers be displayed on the bow of the vessel. The number should be displayed in such a way that it could be read from left to right.
The practice of honoring those who have been lost in battle dates back to which two ancient
civilizations?
Without motorcycle riders are at risk of severe injury in a crash ?
Answer:
The correct option is;
A. proper protection
Explanation:
Motorcycle riders ride the motorcycle while at some level of speed while having the entire body exposed to be a major part of any collision.
Injuries sustained from motorcycle accidents are several times more severe than injuries sustained by occupants of a car that is fully protected by the metallic panel in the same and even more serious accident scenarios
Hence, motorcycle riders require adequate protection by putting on available motorcyclist safety gear
Therefore, to reduce the risk of severe injury n a crash, motorcycle riders require proper protection.
The CountLetters application is limited to counting letters in a single word. Modify the CountLetters application to count the letters in an entire phrase, which contains spaces. Care must be taken to ignore the spaces and any other non alphabetic character found in the phrase. Be sure to change comments and variable names appropriately so that the reader of the application code understands that the letters in a phrase are counted.
import java.util.Scanner;
public class CountLetters {
public static void main(String[] args) {
final int LOW = 'A'; //smallest possible value
final int HIGH = 'Z'; //highest possible value
int[] letterCounts = new int[HIGH - LOW + 1];
Scanner input = new Scanner(System.in);
String phrase;
char[] wordLetters;
int offset; //array index
/* prompt user for a phrase */
System.out.print("Enter a phrase: ");
phrase = input.nextLine();
input.close();
/* convert word to char array and count letter occurrences */
phrase = phrase.toUpperCase();
wordLetters = phrase.toCharArray();
for (int letter = 0; letter < wordLetters.length; letter++) {
offset = wordLetters[letter] - LOW;
letterCounts[offset] += 1;
}
/* show letter occurrences */
for (int i = LOW; i <= HIGH; i++) {
System.out.println((char)i + ": " + letterCounts[i - LOW]);
}
}
}
Which of the following will help sober up and lower the BAL of an intoxicated person? Exercise Black coffee Time A cold shower
Answer:
Time
Explanation: time gives the liver the chance to do its job and metabolize the alcohol. Although...exercise can help wake up the body and make a person more alert. It may also help metabolize alcohol more quickly, although the scientific evidence of this is inconclusive.
What is one way a C47 can be used on set?
Answer:
C47 may seem like a fancy word, but in the film world, it is the name of one of the simplest, most useful and versatile tools, which is commonly knows as a clothespin.
Following are major uses of C47 on a film set.
1) Lightning Purposes
C47 are used for attaching materials like gel and diffusion to the adjustable flaps, that control the direction of light
2) Adjusting Wardrobes
C47 are used to shorten, tighten or redesign a material of clothing for a specific purpose. It avoids permanent change and the hassle of sewing.
3) Modifications
These can be used for temporary repairs or to modify the set and shooting locations, e.g if a curtain is not hanging properly, C47 can be used
Luis is installing some 12 gage wire. How much resistance will there be throughout a distance of 400 feet
Answer:
0.635 m
Explanation:
When calculating the resistance R of a wire, we need its length(l), its cross-sectional area (A) and the resistivity of the material(ρ). The resistance of a wire is given by the equation:
Resistance (R) = Resistivity(ρ) × length (l) / cross-sectional area (A)
For a 12 guage wire,
Resistivity (ρ) = 1.724 × 10 ⁻⁸ ohm m, length (l) = 400 ft = 121.92 m,
Diameter (d) = 0.00205232, cross-sectional area (A) = πd²/4 = π(0.00205232)²/4 = 3.31 × 10 ⁻⁶ m²
[tex]R=\frac{\rho l}{A}=\frac{1.724*10^{-8}*121.92}{3.31*10^{-6}} =0.635m[/tex]
BE-27 In regard to waste management laws, a boat of what length or greater (in feet) is required to have an oil discharge
placard posted?
20
22
24
26
Answer: 26 feet
Explanation:
Federal law requires that when a boat of 26ft or more is on lakes, rivers, or in the ocean 3 miles from shore, it should "prominently posted" placards about garbage as well as Oil Discharges stating that oil discharges are not allowed as well as what materials can and are prohibited from being thrown from the boat into the water.
Both placards should be permanently attached with a minimum size of 5*9 inches and made entirely of durable material.
I have attached an example of the placard.
Florida's No-Fault requires owners of motor vehicles must cover the
below minimum Personal Injury Liability (PIP) insurance coverage:
o $10,000 of Personal Injury Protection (PIP)
o $30,000 of Personal Injury Protection (PIP)
o $50,000 of Personal Injury Protection (PIP)
o $100,000 of Personal Injury Protection (PIP)
Answer:
The correct option is;
$10,000 of Personal Injury Protection (PIP)
Explanation:
Personal injury protection, PIP, otherwise known as No-Fault Law coverage is a part of auto insurance that takes care of medical cost of treatment of an accident victim regardless of who is at fault
In Florida, the No-Fault Law requires motor vehicle owners to have and retain PIP providing $10,000 in medical care, resulting disability and expenses of a funeral resulting from an accident in which the motorist is involved
Therefore, the correct option is $10,000 of Personal Injury Protection.
Given half a chance, other people at work will take advantage of you.
Answer:
T
Explanation:
True
In Florida, bike lanes are painted
Answer: green
Explanation:
In Illinois, once a person has obtained their boating education certificate what is the minimum age to operate a motorized vessel without adult supervision?
Answer:
I dont really know, I am sorry, but I am going to ask my teacher
What type of damage is reduced by installing impact resistant glass functional shutters and double door top and bottom latches
Answer: you are reducing bullet damage or the damage of a person getting shattered glass all over them
Explanation: i dont
have one
On January 19, 2006, NASA launched the New Horizons mission toward Pluto; the probe
passed by Pluto on July 14, 2015, roughly 9.5 years later. Given your answers to the last
two question, on average how fast must the New Horizons probe have been traveling?
Answer:
58,536 km
Explanation:
Answer: 58,536 km
Explanation:
The driver _______
the expressway has the right of way in weave lanes.
A.On the left of
B.Merging into
C.Entering
D.Exiting
The expressway driver to the left has the right of way in the weave lane. Thus, option A is correct.
What is a weave lane?A weave lane over an expressway can be given as the lane that serves the function of being both an exit and the entrance from and to the expressway.
The lane has been termed to be the accident prone lane, as well as required much of the attention from the driver as the vehicles enter from both the side serving as entrance and exit.
The expressway has been designed with certain rules for the drivers that help in the development of the safety of the vehicles on the expressway.
This includes driving with the right of way of the expressway given to the driver at the left of the expressway. Thus, option A for the right of way on the weave lane is correct.
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