Questions
This question about " Electro-Mechanical Sysrems: Simple vapor compression cycle" A simple vapor compression cycle works...

This question about " Electro-Mechanical Sysrems: Simple vapor compression cycle"

A simple vapor compression cycle works in a residential refrigerator and uses R-410a as a refrigerant. The evaporator temperature is − 20 ºC and the condenser temperature is 35ºC. Saturated vapor enters the compressor. If the refrigerant flow rate is 0.15 kg/s, calculate:
- Compressor power
- Rejected heat from condenser
- The COP of the cycle
- The increase in COP if an internal heat exchanger is used that causes the superheating of vapor to 0°C while subcooling the liquid refrigerant to 20°C.

In: Mechanical Engineering

The volumetric analysis of a certain fuel is given as C2H6 22.6% CH4 73.6% CO2 2.4%...

The volumetric analysis of a certain fuel is given as
C2H6 22.6%
CH4 73.6%
CO2 2.4%
N2 1.4%
For 100 moles and the combustion ofair is dry and in 25% excess
Calculate
1) The molecular weight of the combustion products
2) The total gas volume for complete combustion at 260oC, 1 bar
3) The dry flue gas analysis based on CO2, O2 and N2.

In: Mechanical Engineering

Q4 / A thick walled hollow cylinder having outside and inside radii of (90, and r)...

Q4 / A thick walled hollow cylinder having outside and inside radii of (90, and r) respectively, is subjected to an external pressure of (8000 bar). Find internal radius and the stresses at inner and outer surfaces. E=200GPa

In: Mechanical Engineering

Explain three stages of annealing of metallic materials by sketching their microstructures. Why annealing is used?...

Explain three stages of annealing of metallic materials by sketching their microstructures. Why annealing is used? EXPLAIN.

In: Mechanical Engineering

(a) Explain why XRD (X-Ray Diffraction) and TEM (Transmission Electron Microscopy) techniques are suitable in examining...

(a) Explain why XRD (X-Ray Diffraction) and TEM (Transmission Electron Microscopy) techniques are suitable in examining the unit cells and crystal structures of solids. (b) Calculate the expected diffraction angle (θ) for the first order reflection from the (310) planes of BCC chromium (Cr) when a monochromatic X-ray radiation of wavelength (λ) 0.757 Ao is used.

In: Mechanical Engineering

write a Fortran 77 language code for the vortex tube used in mining with its exergy...

write a Fortran 77 language code for the vortex tube used in mining with its exergy and anergy analysis using r407c refrigerant

In: Mechanical Engineering

A gaseous fuel mixture of 60% propane (C3H8) and 40% butane (C4H10) is an adiabatic The...

A gaseous fuel mixture of 60% propane (C3H8) and 40% butane (C4H10) is an adiabatic The combustion chamber is fully burned with stoichiometric amount of air. Inputs 1 atm According to the pressure and 25 ℃ temperature entering the combustion chamber and the products exit at 1 atm pressure,

a) Write the combustion equation.

b) Air-fuel ratio,

c) Dew point temperature of the products,

d) Calculate the outlet temperature of the products.

(please explain step by step)

In: Mechanical Engineering

There are 5000 CFM of outdoor air with a temp of 40F 35Fwb heated and humidified...

There are 5000 CFM of outdoor air with a temp of 40F 35Fwb heated and humidified under steady-flow conditions to a final temp of 70F and 40%RH a)find the mass of water vapor added to each pound mass of dry air b) if the water is supplied at 50F how much heat in Btu/min.

Please answer fast

In: Mechanical Engineering

Determine the properties of moist air in a region where tdb=80F,twb=70F and barometer reading of 750...

Determine the properties of moist air in a region where tdb=80F,twb=70F and barometer reading of 750 mmHg. Compute (a) dew point temperature (b) percent relative humidity (c)partial pressure of dry air (d) specific humidity (e) enthalpy (f) specific volume of moist air.

In: Mechanical Engineering

You are the manager of a healthcare facility that is considering different payment options for buying...

You are the manager of a healthcare facility that is considering different payment options for buying supplies for your facility. The annual charges for these supplies is $10,000 and the vendor is offering you three payment options to consider.

option 1: 3% discount if you make the full payment in 30 days.

option 2: quarterly payments at the beginning of each quarter with a service charge of $100 per quarter.

option 3: monthly payments at the beginning of each month with a service charge of 3% for each monthly payment.

Q1: Which of these three options provides the best value for money? Why?

Q2: Payments for these supplies are made from your bank account which has a current balance of $30,000 and earns monthly interest of 0.2%.

a. Which of these three options now provides the best value for money?

b. At what interest rate would you be indifferent between Options 1 and 2?

c. At what interest rate would you be indifferent between Options 2 and 3?

d. Consider the ending balances under each of these three options for interest rate ranging from 0.0% to 2.0%. Develop data tables to compute the ending balances for this range of interest (consider interest increments of 0.2%). Depict your results in a line graph.

In: Mechanical Engineering

Assuming standard atmospheric pressure and tdb=25 C and 90% RH. Compute (a) dew point temperature (b)...

Assuming standard atmospheric pressure and tdb=25 C and 90% RH. Compute (a) dew point temperature (b) specific humidity (c) enthalpy (d) wet bulb temperature

In: Mechanical Engineering

Joining dissimilar metal in arc welding is a difficult task. Explain why?

Joining dissimilar metal in arc welding is a difficult task. Explain why?

In: Mechanical Engineering

There are 5000 CFM of outdoor air with a temp of 40F 35Fwb heated and humidified...

There are 5000 CFM of outdoor air with a temp of 40F 35Fwb heated and humidified under steady-flow conditions to a final temp of 70F and 40%RH a)find the mass of water vapor added to each pound mass of dry air b) if the water is supplied at 50F how much heat in Btu/min.

In: Mechanical Engineering

An ACME double-threaded power screw has 45 mm major diameter, a pitch of 5 mm and...

An ACME double-threaded power screw has 45 mm major diameter, a pitch of 5 mm and thread angle 2α=29°. A vertical load on the screw reaches a maximum of 8.5 kN. The coefficients of friction are 0.05 for the thread and 0.1 for the collar. The frictional diameter of the collar is 65 mm. a) Find the efficiency of the power screw. b) Is this power screw self-locking? Explain why

In: Mechanical Engineering

18- The choice of chiller determines how the facility is prepared. Examples of parameters that determine...

18- The choice of chiller determines how the facility is prepared. Examples of parameters that determine the chiller are:
(a) Electrical requirements
(b) Ease of installation (air-cooled chillers are easier to set up)
(c) Location or available space
(d) Comfort or process cooling
(e) All of the above

19- Ventilated outdoor air can be used:
(a) for cooling of the buildings throughout the year in all locations
(b) for cooling of the buildings during many days of the year in most of the locations (c) greater potential for cooling of buildings in hot and humid areas
(d) greater potential for cooling of buildings in hot and dry areas
20- State which of the following statements are TRUE?
a) For effective utilization of outdoor air, both natural and mechanical ventilation
should be used in a building
b) Design of windows and other openings in the buildings plays a major role in
natural ventilation
c) For maximum airflow rate, the openings should be as close to the neutral pressure
level as possible
d) All of the above.
21- In comfort-cooling applications, cooling loads are often satisfied by air handlers equipped with coils to transfer heat from the conditioned space air to circulating
chilled-water. Heat transferred ways:
a) Three-wayvalve
b) Two-wayvalve
c) Variable-speed pump
d) All of the above.
from the loads can be controlled in a number of
22- An air handler supplies 5,000 CFM (2.36m3/s) at a temperature of 13°C. The air handler was designed for 1,000 CFM of outside air at 31°C DB and 26°C WB. The remaining return air from the space is at 25 °C DB and 55% relative humidity. What are the entering conditions of the air into the coil, in DB and WB?
(a) 26 C ?BT, 20 C ?BT
(b) 26 C ?BT, 15 C ?BT
(c) 29.5 C ?BT, 23.5 C ?BT (d) 29.5 C ?BT, 24 C ?BT
23- In variable air volume systems:
(a) In single duct, variable air volume systems, the supply air flow rate remains
constant, but the temperature of the supply air is varied depending upon the load (b) Variable air volume systems generally consume less power compared to constant
volume systems
(c) Variable air volume systems occupy less space compared to constant volume
systems
(d) Variable air volume systems always ensure adequate ventilation and good room
air distribution

24- For air-water system, Which of the following statements are TRUE?
(a) An air-water system uses both air and water in the thermal distribution system (b) In an air-water system, all the latent load on the building is handled by the
primary air only
(c) In an air-water system, the cooling coil kept in the conditioned space operates
under dry conditions
(d) Compared to all water systems, an air-water system is difficult to maintain
25- For fan coil unit ,Which of the following statements are TRUE?
(a) A fan coil unit is used with all water systems only
(b) A fan coil unit can be used either with an all water system or with an air-water
system
(c) It is possible to control the cooling capacity by controlling either liquid flow rate
or air flow rate in a fan coil unit
(d) A fan coil unit used in an all water system requires a provision for draining the
condensed water
26- For a convector, Which of the following statements are TRUE?
(a) In a convector, heat transfer takes place by forced convection
(b) Convectors are commonly used for heating applications
(c) In a radiator, heat transfer takes place by both radiation and convection (d) A unit ventilator is a fan coil unit with a provision for fresh air entry
27- For Small unitary systems, Which of the following statements are TRUE?
(a) Small unitary systems have air cooled condensers, while larger systems can be
either air cooled or water cooled
(b) A split type room air conditioner should be used when the room does not have an
exterior wall
(c) A split type air conditioner is more reliable compared to a window air conditioner (d) It is possible to provide fresh air in a window air conditioner, whereas this is not
possible in a split air conditioner

In: Mechanical Engineering