Right now you live in a house that is pretty old and doesn’t have double- paned windows. Your heating bill in the winter and spring will be really big, and you think it might be due to the huge single-paned window in the living room. Your landlord has told you that he is willing to replace it with a double paned window but you have to cover the cost of the window. You want to do a quick calculation to see if you can recover the cost of the new window before you graduate (and hopefully move out). If electricity used for heating costs 6.90 cents per kWh, will you save enough money? Assume 120 days of winter, followed by 90 days of spring until your graduation.
The living room is 3.5
m by 4.2 m, and is 2.4 m tall. The exterior wall has the standard
20 cm of fiberglass insulation. The existing window is on the
narrower wall at one end of the living room and is 130 cm wide, 75
cm tall, and 4 mm thick. The new window is a state-of-the-art
double paned window, with two panels of 4 mm glass separated by a 2
mm air-filled gap. Use the following values of thermal
conductivity:
kfiberglass=0.04 W m−1 K−1, kglass=0.96 W m−1
K−1, kair=0.024 W m−1 K−1.
And also assume the following values for the average temperature:
Thouse=20∘C inside the house (to be maintained)
Twinter=3∘C outside the house during winter
Tspring=8∘C outside the house during spring
Finally, you estimate that the house is heated for 12 hours per day on average.
1.Calculate the heat conduction rate of the single-paned window during spring and winter.
2. With multiple layers of material with separate thickness and thermal conductivity values, the heat conduction rate must be calculated using the total resistance R.
Using the description of the double pane window, calculate its total resistance R. Give your answer in W−1 m2 K, to four decimal places.
3. Calculate the heat conduction rate of the double pane window during spring and winter.
4.calculate the total energy saved during spring and winter by switching to the double pane window in kwh
5. Using the answers above, calculate the total savings in the heating bill. Assume that the efficiency of converting electrical energy to heat is 100%. Give your answer in dollars.
In: Mechanical Engineering
A Four bar mechanism with a frame length of 200 mm, crank length of 100 mm, coupler length of 300 mm and follower length of 250 mm, if the mechanism is assembled in open cpen configuration and the input angle is 45o .
what is:
1-The coupler angle for open and crossed configuration ?
2-The output angle for open and crossed configuration ?
In: Mechanical Engineering
A thermocouple (TC) reads a temperature of 180 degrees C when placed in a large wind tunnel. The thermocouple is exposed to convection and radiation heat transfer.
Questions:
In: Mechanical Engineering
In Multi-Effects Desalination (MED) system composed of
4 effects, and 3 feed
preheaters and down condenser. List the following:
a- The mass balance in the evaporator, feed preheater and down
condenser
b- The energy balance in the evaporator, feed preheater and down
condenser
c- The Material balance in the first effect
d- The temperature profile of the feed if the intake temperature is
25ºC and
temperature of last effect is 40ºC and the temperature of first
effect is 60ºC
e- What will happen to the transfer area of the evaporator if the
motive steam
temperature is increased to 100ºC where the rest is remaining
constants.
In: Mechanical Engineering
Which of the following polymers may be produced by condensation polymerization? Choose which apply.
1) Phenol-formaldehyde
2) Poly (vinyl chloride)
3) Polycarbonate
4) Nylon
5) Polystyrene
6) Polyethylene
In: Mechanical Engineering
(a) Apply Maxwell relation and Gibb’s first equation (du=TdS-Pdv) to find the (∂u/∂P)_Trelation in terms of directly measurable properties (P, V and T). For an ideal gas, what will be the value of that partial derivative?
(b) Illustrate physical meaning of Inversion line with the help of T-P diagram.
(C) Assume that carbon dioxide (CO2) is collected from bacterial decomposition of organic matter at 5℃, and atmospheric pressure (100 kPa), and is required to be used in a process at -30℃, 40 bar. Apply theory of real gas behavior to calculate how much actual minimum work input and heat transfer is required to reach this state. Also, suggest some devices that can be used to obtain this state change
In: Mechanical Engineering
31. Write a report on advancement in wheel and tyre
technology.Also the report should be consest of 10-12
Page,Advantage disadvantage,Future scope.Plagarsim level should be
Zero.
Please don't answer if you don't know and write the report on 10-12
page minimum.
For small answer or for plagrism I will downrate your answer.So if
you know than only answer it
In: Mechanical Engineering
Consider that a 1.35 wt% C- 98.65 wt% Fe alloy. Determine the weight fraction of the following.
(a) Proeutectoid Ferrite:
(b) Proeutectoid Cementite:
(c) Pearlite:
(d) Ferrite in Pearlite:
In: Mechanical Engineering
An airplane with a total span length of b = 60 m and cord length of c = 6 m wants to land at the airport. Holiday Rentals wing profile is NACA 23012 and single slot flaps are open while landing (α = 12 °, CL, flapli = 3, CD∞ = 0.07). Airplane Find the weight (kN) of the aircraft if it lands at 1200 kW thrust (ρ air = 1.2 kg / m3 ).
In: Mechanical Engineering
what are the thermal properties of composite materials??? with references, please.
In: Mechanical Engineering
Develop a simple MIS (Management Information System)
that consists of a simple database (a text file). The system
manages to dynamically input record/data into the database. The
data from the database can be sorted, searched and updated. User
also should be able to add new records/data, remove any data and
etc.
Here are some ideas of MIS that can be developed:
1. Hotel reservation system.
2. Students management system.
3. Payroll management system.
4. Bus/Railway/Plane ticketing system.
5. Clinic record management system.
In: Mechanical Engineering
A solid propellant rocket engine gases at 3000 K stagnation temperature and 6000 kPa stagnation pressure It manufactures. The exit and throat areas of the nozzle are 0,01 m2 respectively. and 0.005 m2 Adiabatic base of the produced gases 1,4 and the gas constant is 320 J / kg.K. Find the thrust produced by the rocket at a height of 25 000 m (kN).
In: Mechanical Engineering
Give a step by step process of veryfying that a
component under a set of loads will not fail.
Soild Mechanics course question
In: Mechanical Engineering
Determine the mass flow rate of the refrigerant flowing through the condensor of a two-stage compression refrigeration cycle (in kg/s). The fraction of the refrigerant that evaporates as it is throttled to the flash chamber is 0.19. The enthalpy of the refrigerant entering the evaporator is 55.14 kJ/kg and the enthalpy of the refrigerant leaving the evaporator is 239.19 kJ/kg. The amount of heat removed from the refrigerated space is 28 kW. (Round your answer to three decimal places).
In: Mechanical Engineering
1. Residual stress refers to stresses induced by
plastic strain. T or F
2. Failure criteria is identical for ductile and brittle materials.
T or F
3. Statically indeterminate problems can be solved by using
additional equations provided by Hooke's Law. T or F.
4. To analyze stress at any point of any component or structure ,
one should consider:
5. The stress developed in a cylindrical pressure vessel along the
longitudinal axis is:
In: Mechanical Engineering