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Mech Eng: HVAC Exam Paper

This document contains an internal assessment for a mechanical engineering course on refrigeration and air conditioning. It includes a multiple choice section with 5 questions assessing key concepts like dehumidification and relative humidity. It also includes short answer and long answer questions assessing topics like psychrometric processes, infiltration in heat load calculations, and human thermal comfort. Long answer questions provide calculations to determine psychrometric properties or the heat transfer required to maintain a human's neutral thermal equilibrium given indoor conditions. The assessment evaluates students' understanding of fundamental refrigeration and air conditioning concepts.

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92 views3 pages

Mech Eng: HVAC Exam Paper

This document contains an internal assessment for a mechanical engineering course on refrigeration and air conditioning. It includes a multiple choice section with 5 questions assessing key concepts like dehumidification and relative humidity. It also includes short answer and long answer questions assessing topics like psychrometric processes, infiltration in heat load calculations, and human thermal comfort. Long answer questions provide calculations to determine psychrometric properties or the heat transfer required to maintain a human's neutral thermal equilibrium given indoor conditions. The assessment evaluates students' understanding of fundamental refrigeration and air conditioning concepts.

Uploaded by

coc dhinesh
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Reg.

No:

SNS College of Technology,Coimbatore-35.


(Autonomous)
B.E/B.Tech- Internal Assessment -III
Academic Year 2020-2021(ODD)
Seventh Semester
Mechanical Engineering
16ME 409 & Refrigeration and Air conditioning

Time: 11/2 Hours Maximum Marks: 50


Answer All Questions
PART - A (5 x 1 = 5 Marks)
1. What is the perfect condition for dehumidification of air?
(a) Air is heated above its dew point (b) Air is cooled up to its dew
temperature point temperature

(c) Air is heated below its dew point (d) Air is cooled below its dew
point temperature
temperature

2. When the rate of evaporation of water is zero, the relative humidity of the
air is
(a) 0% (b) 100%

(c) 50% (d) unpredictable


3. The dew point temperature is less than the wet bulb temperature

(a) saturated air (b) unsaturated air

(c) both saturated and unsaturated air (d) none of the above
4. Estimation of heat transfer rate through the building is complex due to
(a) the complex structure of walls & (b) varying indoor and outdoor
roofs consisting of wide variety of conditions

1
materials
(c) large size of the buildings (d) both A and B
5. When the outside air is introduced for ventilation purpose, there is a
(a) Sensible heat gain (b) Latent heat gain
(c) Sensible heat gain as well as latent (d) None of these
heat gain
PART - B (5 x 2 = 10 Marks)
6. Define Wet blub depression
7. Write the short notes on psychrometric chart?
8. List down the psychrometric processes.
9. What do you mean by the term Infiltration in heat load calculations?
10 List the variable which are involved in estimation of load

PART – C (14+14+7=35 Marks)


11 (a) The readings from a sling psychrometer are as follows dry bulb 14
temperature = 30°C Barometer reading 740mm of Hg Using
steam tables, determine (i). Dew point temperature (ii). Relative
humidity (iii) Specific humidity (iv) Degree of-saturation
(v) Vapour density (vi). Enthalpy of mixture per kg of dry air.
(or)
(b) Describe briefly with a neat sketch a window types of 14
airconditionger
12 (a) Explain the need for selecting design inside and outside conditions 14
with respect to a typical air conditioning system
(or)
(b) A 1.8 meter tall human being with a body mass of 60 kg performs 14
light work (activity = 1.2 met) in an indoor environment. The
indoor conditions are: DBT of 30oC, mean radiant temperature of
32oC, air velocity of 0.2 m/s. Assuming an average surface
temperature of 34oC for the surface of the human being and light
clothing, find the amount of evaporative heat transfer required so
that the human being is at neutral equilibrium.
13 (a) Enumerate the functional elements of a central unit. 7
.
2
(or)
(b) Explain the components of internal heat gains. 7

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Prepared By Verified By HoD/Mech

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