ABSTRACT
In the mechanical Engineering department of institute of management and technology there and many machines but not all in are good shape or form. This may be due to inadequate maintenance, which is evident in the breakdown of air conditioner. In the case of machine maintenance, the quality and effusiveness of material were well noted. Also not left behind was the cost of maintenance which was minimized and yet getting to a highly successful repairs too. In so long, during the repairs and rehabilitation of a faulty air conditioner appropriate tools, cost and quality of material were well considered.
TABLE OF CONTENT
CHAPTER ONE
1.1 literature review
CHAPTER TWO
2.1 air conditioning maintenance
CHAPTER THREE
Reference
CHAPTER ONE
1.1 LITERATURE REVIEW
Air conditioning is a process whereby heat received from a low temperature region is transferred to a higher temperature region. Then a negative net work is being done in the system. Air conditioning system has four basic components which are the compressor, condenser, metering device or thrilling valve and an evaporator. When any of these component is faulty or damaged it will cause the air condition system not to function well or not functioning at all.
In the first place the faulty air conditioner was rehabilitated as a project by a group of students in the department of mechanical engineering 2004/2005 session.
Before working in the air conditioner by the group in the year 2005 the following fault were dictated.
The compressor is the heart of all air conditioning system. It pumps the refrigerant to the whole system.
The metering device or the expansion device meters a given quality of refrigerant required for each unit.
In this case most of these essential components of the air conditioner which seems to be very delicate, need not be handled carelessly, when it developed any fault and again, it should not be handled by non-exports in the field of air conditioning and refrigeration.
The last group that handled the project are classified as non-exports in the field of air conditioning. We say this because an air conditioning system that has the problems outlined above needs not be repaired as they had done without replacing some of the components with a brand new spare parts and the normal size that is the size of the machine air conditioner
For instance a compressor that has low pumping action, we verified that the compressor which supposed to b e two horse power (2hp) compressor. This under sized compressor has low pumping action, 6to the air conditioning set. Because the capillaries for the two horse power compressor for the bigger than that of 1.5 horse power air conditioning set.
Again the volume of air conditioning gas being pumped was too negligible to bring about the desired cooling.
The capacitors which was bad that is not good at all.
The drier which was blocked up by impurities was changed and replaced with a new one. As a result, its caused by poor cycling of refrigerant through. The copper capillary of the air conditioner which we repaired by replacing the drier with a new one. Through we can still be in a good condition.
A repaired and rehabilitated equipment is supposed to be sound both internally and externally. The people who worked in the air conditioner before, were unable to spray the air conditioner which has many scratches as a result of their work.
Sincerely speaking and other criteria that contributed immensely to the braked own of the air conditioner was poor maintenance.
Plant maintenance is the upkeep of plant safe working state. Plant maintenance is divided in to planned preventive and breakdown maintenance were sub-divided.
Thus this report encomprises, urges the series of job done to arrive at a meaningful randy to breakdown problem.
Considering space, volume and relevance we will limit our write up (thesis) to the direct and practiced work of all the air conditioner.
In the first place we used the basic procedure in tracing a fault like diecking of leakage with soap solution was done, flushing of the condenser which revealed the fault of the drier (filter) was done using vacuum pump. The compressor was tasted, there was no fault only that the size was 1.5 horse power (hp) and they have opened the compressor before and welded it which is not advisable to do.
The general dean up of all dust compacted parts was done particularly without any problems following by the changing of the plug which supply electricity to the system.
The sequence of operation and fools used during the repair is recorded in ascending order over leaf.
CHAPTER TWO
High = 16.20 bars (150psi)
Low = 9.65 (300psi)
Using freon 22 as refrigerant
At 16.2 bar = 02.50c
Hf = h3 = 9.8.5kj/kg
Hg = h2 = 209.86 kj/kg
Sf = s3 = 0.34395 kj/kg
Sg = s2 0.6756 kj/kg
At = 9.65 bars – 400c
Hf = 74.5 kj/kg
Hg = 203.20 kj/kg
Sf = 0.2718 kj/kg
Sg = 0.6825 kj/kg
From s1 = s2 =S
S = sf + x (sg + sf)
X = 0.6756 – 2718 = 0.438 = 0.983
0.6828 0.2718 0.4107
hi = hf + x (hg -hf)
= 74.59 + 0.985 (203.2 – 74.59)
= 74.59 + 0.938 (120.61)
= 201.10kj/kg
from s3 – s4 = S
s=sf + x4 (sg - sf)
0.3495 = 0.2718 + x4 (0.6825 – 0.2718)
X4 = 0.34395 – 0.2718 = 0.7215 = 0.176
0.6825 0.2718 0.4107
h4 = hf + x4 (hg - hf)
H4 = 74.59 + 0.176 (203.2 – 74.59)
H4 = 74.59 + 0.176 (129.61)
H4 = 97:23 Kj/Kg
From S1 =S2
S = Sf + X (Sg - Sf)
0.6756 = 0.2718 + (0.6825 – 0.2718)
X1 = 0.6756 – 0.2718 = 0.4038 = 0.983
0.6825 0.2718 0.4107
h1 = hf + x1 (hg - hf)
h1 = 74.59 + 0.983 (203.2 – 74.59)
= 74.59 + 0.983 (128.61)
= 201.01 kj/kg
From S3 = S4 = S
S = sf + x4 (sg - sf)
0.34395 = 0.2718 (0.6825 – 0.2718)
X4 = 0.34395 – 0.2718 = 0.176
Or = 0.6825 – 0.2718 = 0.4107
H4 = hf + X4 (hg - hf)
H4 = 74.95 + 0.176 (203.2 – 74.59)
H4 = 74.59 + 0.176 (128.01)
H4 = 97.23 kj/kg
coefficient of performance (c.o.p)
= Q41 = hf – h1 = 201.01 – 97.23
W12 h2 – h1 209.86 201.01
= 103.78 = 11.73
8.85
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