Answer:
a) 4.1 kw
b) 4.68 tons
c) 4.02
Explanation:
Saturated vapor enters compressor at ( p1 ) = 2.6 bar
Saturated liquid exits the condenser at ( p2 ) = 12 bar
Isentropic compressor efficiency = 80%
Mass flow rate = 7 kg/min
A) Determine compressor power in KW
compressor power = m ( h2 - h1 )
= 7 / 60 ( 283.71 - 248.545 )
= 4.1 kw
B) Determine refrigeration capacity in tons = m ( h1 - h4 )
= 7/60 ( 248.545 - 107.34 )
= 16.47 kw = 4.68 tons
C) coefficient of performance ( COP )
= Refrigeration capacity / compressor power
= 16.47 / 4.1 = 4.02
Attached below is the beginning part of the solution
Answer:
The specific volume of the super heated steam is 0.2139 m³/kg.
Explanation:
Super heated steam is the condition where only compressed vapor of water present. This is not containing any liquid form of water. Super heated steam has very high pressure depending upon temperature. If heat supplied increases after saturation vapor condition of the water, the water fuses into steam completely. Properties of super heated steam are taken from the super heated steam table.
Given:
Temperature of superheated steam is 300°C.
Pressure of the super heated steam is 1.2 Mpa.
Calculation:
Step1
Value of specific volume of the super heated steam is taken from superheated steam table at 300°C and 1.2 Mpa as follows:
Specific volume is 0.2139 m³/kg.
Step2
All other properties are also taken from the table as:
Internal energy is 2789.7 kj/kg.
Enthalpy is 3046.3 kj/kg.
Entropy is 7.034 kj/kgK.
The part of table at the temperature 300°C and pressure 1.2 Mpa is shown below:
Thus, the specific volume of the super heated steam is 0.2139 m³/kg.
Answer:
The correct option is;
Loose cords
Explanation:
Based on the 2011 Census of Occupational Injuries, which is published by the Bureau of Labor Statistics, one of the leading causes of injuries at work is slips, trips and falls which may lead long duration of time down and large huge amount of claims for compensation. Slips trips and falls are also comes fourth in the reasons of fatality at work
Trip hazards are hazards that causes trip and fall by stopping and locking the movement of the step of people walking along traffic lanes
Items that cause trips mainly include item used for work. The correct option is therefore loose cords, which should be kept under cable bridges for safety.