To study the relationship between the saturation pressure and temperature of water/steam in the range 0 – 14 bar (gauge) and to study the change in temperature of a body when being heated or cooled.

Safety

The apparatus is a pressure vessel. The pressure must not exceed 14 Bar (gauge)!

Background

1)In order to carry out a heat transfer experiment simultaneously with measurement of vapour pressure, it is required that the rates of heating and cooling of the pressure vessel, the rate of energy addition by the heater and the ambient temperature are recorded.

2)Study the following derivation of a simplified 1st Law (energy) equation relating the temperature of the boiler to time as it is heated and cooled.

Assumptions

i.The temperature is uniform throughout the boiler. Thus the outside surface temperature of the boiler is the same as the steam temperature, T.

ii.Newton’s Law of cooling applies – the rate of heat transfer from the surface is proportional to the surface area, As, and to the temperature difference between the boiler surface and the surroundings ( T- T).

Thus,

where (kW/m2K) is called the heat transfer coefficient for heat transfer between the boiler surface and the surroundings. By Newton’s law of cooling it is assumed constant.

The 1st law balance for the boiler at time t (secs) is

+ Rate of change of internal energy of the boiler and contents.

Therefore,

Where MC (kJ/ K) is the heat capacity of the boiler which in this simplified development is assumed constant.

So, when being heated,

(1)

and when cooling,

(2)

At a value of T1 on the lot of the measured heating curve and at a value T2 on the cooling curve, the respective slopes,

and

are determined by construction. The value of dQ/dt may be calculated from tabulated measurements of electrical energy consumption (kWh) versus time (hrs), or from a...

...Solutions (Week-01)
Chapter-01
1-12 A plastic tank is filled with water. The weight of the combined system is to be determined.
Assumptions The density of water is constant throughout.
Properties The density of water is given to be = 1000 kg/m3.
Analysis The mass of the water in the tank and the total mass are
mw =V =(1000 kg/m3)(0.2 m3) = 200 kg
mtotal = mw + mtank = 200 + 3 = 203 kg
Thus,
1-14 The variation of gravitational acceleration above the sea level is given as a function of altitude. The height at which the weight of a body will decrease by 1% is to be determined.
Analysis The weight of a body at the elevation z can be expressed as
In our case,
Substituting,
1-30 The gravitational acceleration changes with altitude. Accounting for this variation, the weights of a body at different locations are to be determined.
Analysis The weight of an 80-kg man at various locations is obtained by substituting the altitude z (values in m) into the relation
Sea level: (z = 0 m): W = 80(9.807-3.32x10-60) = 809.807 = 784.6 N
Denver: (z = 1610 m): W = 80(9.807-3.32x10-61610) = 809.802 = 784.2 N
Mt. Ev.: (z = 8848 m): W = 80(9.807-3.32x10-68848) = 809.778 = 782.2 N
Chapter -02
2-4C In electric heaters, electrical energy is converted to sensible internal energy.
2-11C A process during which a system remains almost in equilibrium at all times is called a quasi-equilibrium process. Many engineering...

...ENGINEERING
THERMODYNAMICS
Dr. Tamer A. Tabet
Course Code: KC1702 and Mechanical Eng.
Programme, KM21102.
SEMS-1-2011/2012
Lecture 6. Tue. 15 / 10/ 2012
Lecture Room DKP 10
Engineering Thermodynamics
Lecture 6: Evaluating Properties
Using the Ideal gas
OUTLINE:
Real gases, specific heats,
internal energy, enthalpy
In this section the ideal gas model is introduced.
The ideal gas model has many applications in
engineering practice and is frequently used in
subsequent section of this text.
Ideal gas Equation state
From the Generalized compressibility chart show that the state
where the pressure p is small relative critical pressure Pc (low
PR), and the temperature T is large relative to the critical
temperature Tc (high Tc ).
The compressibility factor Z =Pv/RT , is approximately.
At such state we can assume with reasonable accuracy that Z=1,
or:
Pv =RT
Known as the Ideal gas equation of state.
Generalized Compressibility chart
Generalized Compressibility chart
Compressibility Factor Equation
Engineering calculations often require a tradeoffs between ease of
use and accuracy. The ideal gas equation is very easy to use, but of
questionable accuracy for many cases. Virial and cubic equations of
state are accurate, but not particularly convenient. A good
compromise is a generalized compressibility factor equation.
The "compressibility factor", z, is defined so that
Consequently, z=1 for an ideal gas. There are a...

...Chapter 15
(not much on E)
Thermodynamics:
Enthalpy, Entropy
& Gibbs Free
Energy
Thermo 2
Thermodynamics:
thermo = heat (energy)
dynamics = movement, motion
Some thermodynamic terms chemists use:
System: the portion of the universe that we are
considering
open system:
energy & matter can transfer
closed system:
energy transfers only
isolated system: no transfers
Surroundings: everything else besides the system
Isothermal: a system that is kept at a constant
temperature by adding or subtracting heat from the
surroundings.
Heat Capacity: the amount of heat energy required to
raise the temperature of a certain amount of material by
1°C (or 1 K).
Specific Heat Capacity: 1 g by 1°C
Molar Heat Capacity: 1 mole by 1°C
Thermo 3
Calorie: the amount of heat required to raise the
temperature of 1g of water by 1°C.
specific heat of water = 1 cal/g °C
1 calorie = 4.18 joules
Specific Heats and Molar Heat Capacities
Substance
Specific Heat (J/°Cg)
Molar Heat (J/°Cmol)
Al
Cu
Fe
CaCO3
0.90
0.38
0.45
0.84
24.3
24.4
25.1
83.8
Ethanol
2.43
112.0
Water
4.18
75.3
Air
1.00
~ 29
important to:
engineers
chemists
EXAMPLE: How many joules of energy are needed to raise
the temperature of an iron nail (7.0 g) from 25°C to 125°C?
The specific heat of iron is 0.45 J/°Cg.
Heat energy = (specific heat)(mass)(T)
Heat energy = (0.45 J/°Cg)(7.0...

...Enthalpy changes can be calculated using average bond enthalpy data.
i) The enthalpy change to convert methane into gaseous atoms is shown below.
[pic]
Calculate the average bond enthalpy of a C—H bond in methane. [1]
ii) Use the data in the table below and your answer to (a)(i) to calculate the enthalpy
change for
[pic] [3]
[pic]
b) The standard enthalpy of formation of 1,2-dibromoethane, CH2BrCH2Br, is – 37.8 kJmol-1.
Suggest the main reason for the difference between this value and your calculated value in (a)(ii).[1]
2. . a) Define the term standard enthalpy of combustion. [3]
b) Write an equation for the complete combustion of ethanol, C2H5OH [1]
c) The following table gives some standard enthalpies of formation.
[pic]
Use these data to calculate a value for the enthalpy of combustion,∆Hc , ofpropan-1-ol, C3H7OH
C3H7OH(l) + 4 O2(g) → 3CO2(g) + 4H2O(l) [3]
d) State how you would expect the value obtained in part (c) to differ if gaseous water, rather than liquid
water, is formed. [1]
e) In an experiment 0.92 g of propan-1-ol, C3H7OH, was burned and the heat given off used to raise the temperature of 250 g of water. The temperature rise was 16 °C. The specific heat capacity of water is 4.2 JK–1 g–1.
Calculate a value for the enthalpy of combustion of one mole of propan-1-ol. [4]
f) Suggest why the experimental value of the enthalpy of combustion obtained in part (e) is less...

...Grading Sheet
~~~~~~~~~~~~~~
MIME 3470—Thermal Science Laboratory
~~~~~~~~~~~~~~
Laboratory №. 17
Refrigeration Cycle Analysis
Students’ Names / Section №
POINTS
SCORE
TOTAL
PRESENTATION—Applicable to Both MS Word and Mathcad Sections
GENERAL APPEARANCE
5
ORGANIZATION
5
ENGLISH / GRAMMAR
5
ORDERED DATA, CALCULATIONS & RESULTS
TABLE OF PROPERTIES FOR THE 8 STATES
10
PLOT IDEAL CYCLE (W/ BLOCK ARROWS) USING PRESSURES 3 & 8
10
PLOT ACTUAL CYCLE (W/ BLOCK ARROWS)
10
CALCULATE &
10
TECHNICAL WRITTEN CONTENT
DISCUSSION—GENERAL DISCUSSION OF CALCULATIONS
5
EXPLAIN IN TERMS OF 1ST & 2ND LAWS THE DISCREPENCIES
BETWEEN THE TWO PLOTS ABOVE
10
ARE THE DISCREPENCIES IN THE PROPER DIRECTION(S)?
10
SHOULD THERE BE DIFFERENCES BETWEEN THE ACTUAL &
IDEAL CYCLES?
10
CONCLUSIONS
5
ORIGINAL DATASHEET
5
TOTAL
100
COMMENTS
GRADER—d
MIME 3470—Thermal Science Laboratory
~~~~~~~~~~~~~~
Laboratory №. 17
Refrigeration Cycle Analysis
~~~~~~~~~~~~~~
Lab Partners: Name Name
Name Name
Name Name
Section №
Experiment Time/Date: Time, date
~~~~~~~~~~~~~~
OBJECTIVE—of this exercise is to determine the various coefficients of performance, COP....

...CHEMISTRY 110 GENERAL CHEMISTRY I INFORMATION SHEET Fall 2011
Instructors:
Professor Ashok Kakkar Otto Maass Chemistry Building, room 313 Tel: (514) 398-6912 Office hours: By appointment, e-mail via WebCT to arrange meetings. E-mail: use webCT Professor Scott Bohle Otto Maass Chemistry Building, room 233A Tel: (514) 398-7409 Office hours: By appointment, e-mail via WebCT to arrange meetings E-mail: use webCT Professor Bryan Sanctuary Otto Maass Chemistry Building, room 224 Tel: (514) 398-6930 Office hours: By appointment, e-mail via WebCT to arrange meetings E-mail: use webCT Professor Ariel Fenster Otto Maass Chemistry Building, room 110 Tel: (514) 398-2618 Office hours: By appointment, e-mail via WebCT to arrange meetings E-mail: use webCT
Course information:
All Course Related Information on WebCT Vista at: http://www.mcgill.ca/mycourses/ "Mycourses" can also be reached through myMcGill from the main McGill page Login: McGill ID AND Minerva PIN OR McGill username AND McGill password For information on the use of webCT go to https://home.mcgill.ca/mycourses/students/start/ Select General Chemistry 1 - Fall 2011 - CHEM-110-001 - Cross-Listed If you are having trouble logging on to WebCT, please contact IST Customer Services (ICS) (514) 3983398 or by e-mail from the WebCT page: http://www.mcgill.ca/webct/students/help/ Please do NOT email the lecturers as they will not be able to help.
Lectures:
CHEM 110, Section 1 Monday, Wednesday and Friday 10.35 to 11.25,...

...Thermoelectric powered car is a powerful and efficient method to drive the car with the help of temperature difference, that one side of the peltier plate involved is heated and other side is cooled by placing appropriate heat sink over it that is cooled with the help of normal atmospheric air while the car will be moving.
3. PRINCLIPLE OF OPERATION BEHIND THERMOELECTRIC POWERED CAR
This concept is very useful in terms that it adds up to other renewable sources of energy and can be used in place of other non-conventional sources of energy like wind, solar, tides, geothermal heat, etc. This is a new concept for electricity generation using temperature difference between junctions of a peltier element to be used in our project. The complete Thermo Electric Generator would be based on Seebeck Effect that is reverse of peltier effect. The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice-versa. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when a voltage is applied to it, it creates a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side, similar to a classical gas that expands when heated; hence inducing a thermal current. A Peltier cooler can also be used as a thermoelectric generator. When operated as a generator, one side of the device is...

...I. Objective
The first objective of the measurement of thermal conductivity & one-dimensional heat conduction experiment was to identify three different metal specimens by comparing their experimentally determined thermal conductivities to known thermal conductivity values of existing metals. The second objective of the experiment was to establish a connection between the thermal conductivities & temperatures of the metal specimens. Thirdly, the contact resistance of the interfaces between the specimens was to be determined.
II. Theory
Particles of a substance always interact with each other. There’s a transfer of energy with each of there interactions. The energy is transferred from the higher excited particles to the lesser excited particles, which this energy transfer is called conduction. Fourier’s Law governs conduction, which deems that the heat transferred through a substance is proportional to the change in temperature over the substances thickness. The ability to transfer heat through conduction is dependent on the substances thermal conductivity, which is denoted as k. The property k is dependent on the substances atomic structure & temperature, which will be verified in this experiment. The governing law of conduction, known as Fourier’s Law of Heat Conduction is represented by the equation: [4]
Qcond= -kAcdTdx
(1)
Qcond represents the rate of heat conduction; Ac represents the cross-sectional area that the heat is being transferred...