Maintenance Resources

Tuesday, December 8, 2009

Hot Water from Heat recovered from Air conditioner and chiller


Saving energy is on air. Awareness is increasing on global warming. Every body, as individual or as corporate are trying to contribute to save energy to stop global warming.

Saves 1 KWH in consumer end is equal to saves 2 KWH in generating end. So, if you save 1 KWH at your home or industry, you are contributing to save natural resource depletion and stopping generating of green house gases by saving Coal or gas which require to produce 2 KWH (Including line loss).

Here is an idea to recover heat from split unit ACs compressor , compressors of chillers. By which

1.      @ 4 Liter per minute flow, water can be heat up to 65 to 90 degree .
2.      Electricity consumed by compressor is reduced by around 15% due to better cooling.
3.      Compressor load reduced and so life increase.
4.      Saving in LPG require for water heating
5.      Savings in KWH require for water heating and AC consumption also got reduced
6.      Maximum payback period is 6 month to 1 year according to size.
Bellow is the normal operation of a Air conditioner system.


The compressor “sucks” the refrigerant from point 4 through tubing in the evaporator
Coil. This action causes the liquid refrigerant to “evaporate” and become cold (≈45ºF).
The evaporating refrigerant inside the tubes cools the air being circulated over the outside
Of the tubes and fins by the indoor fan.
• In order to move the refrigerant from point 1 to point 2, it must be raised to a higher
Pressure by the “compressor”. The compressing causes the refrigerant to become hot (a
similar effect occurs with an air compressor and this can be verified by quickly and
carefully touching the discharge line).
• The hot refrigerant is sent through the tubing inside the condenser. Outdoor air circulated
by the fan cools the refrigerant and causes it to return to a liquid (condense). Even
though the air may be warm (80-100ºF) it is cooler than the hot refrigerant (100-160ºF).
In some cases, water can be used to cool the hot refrigerant if higher efficiency is needed.
• The warm liquid leaving the condenser (point 3) passes through an expansion device
which lowers the refrigerant pressure before it returns to point 4 to repeat the cycle.
Now The modification:


The potential source of heat to be reclaimed comes from the refrigerant leaving the compressor [3]. In the original design of a conventional air conditioning system, the copper tube containing the superheated refrigerant from the compressor is diverted directly into the condenser coil for heat removal. In order to reclaim the potential heat source from the superheated refrigerant, modification need to be done on the rotary compressor of the air condition unit.

This circuit is replaced by plate type heat exchanger in place of condenser.










Wednesday, November 25, 2009

MiaOsk - Our maintenance KIOSK created

Dear Friends,
Our maintenance Kiosk as I described in my earlier post is just created. Now it is us, who have to participate promptly to rip gain of it.
It's a general forum to discuss our problems for solutions, new information on just achieved improvements and A lot.

Initially  data Kiosk (Manuals, training presentations discussion and other form of datawill be available to group generally.
 All data and other benefits will be strictly restricted to members only.
Group Link: http://groups.google.co.in/group/maiosk.


Please Join and improve our MaiOsk - Our own Maintenance KIOSK 
 

VT93JYF6R8TZ

Thursday, November 19, 2009

Why to analyze breakdown and which format to follow?


Once upon a time, there was a king in Mathura , named Kansa. He was the most outrageous king .every body was too ungratified to stay in his kingdom. Once a voice from heaven foretell that the eighth son of sister Devaki & Basudeva will kill him & save mathura. …………………………………

Horrified Kansa arrested them & kept them in jail .He brutally murdered their seven children but the eighth son, lord Krishna escaped from there with divine help. Later lord Krishna killed Kansa & brought peace in Mathura.
Teacher stopped and asked the students, have you any question about it?
One of them raised his hand. Teacher thought what question can arise within this traditional saga.
He asked “if kansa knew the fact then why he kept Devaki and Basudeva in one cell?”

(Please, I have no intention to heart anybodies believe but it’s a nice story to understand the need of root cause analysis I have ever heard)

Moral of the story is without digging the root cause if anybody wants to take an immediate action, then the killer cause may got escaped .
Rather than taking actions that are merely band-aids, a why-why helps you identify how to really prevent the issue from happening again.

I have seen that without looking for expected outcome almost all are following a common format blindly. Either of WHY-WHY or 5W2H.

5W2H is one of the best format to communicate the problem to management but daily breakdowns should be discussed and analyzed in WHY-WHY format and outcome should be a kaizen or final countermeasure ( Change in JH maintenance sheet or preventive maintenance sheet) to stop it

Just compare the both

1. 5W2H

a) What (Happened) ?
b) Where (Happened) ?
c) Who (Identified /Responsible)
d) Which (Part)
e) Why (It Happened OR Why it is a problem)?
f) How much (Quantify to understand the severity )
g) How to do (Action plan to stop)
h) When (Time line to execute the action plan )

It's a complete informative sheet to communicate to the management but searching for root cause is absent. So, By 5W2H the objective of breakdown analysis is not getting satisfied and Management hopefully  have interest only in actions to stop breakdowns rather than in detail of each breakdown until unless management involvement is require for some particular major breakdowns.   Out from TPM, Just see the classic example bellow, It's a mail communication what I got from 350.org (easily communicated the subject matter in 5W)























So, the solution is


1. Why-Why

a) Why
b) Why
c) Why

…Still a actionable root cause found.
It is a method of questioning that leads to the identification of the root cause(s) of a problem and So, To find root cause and take permanent corrective action, WHY-WHY is best brain storming method. Others are FTA analysis, MFMEA (Before machine design), Parato (for priority setting).




How to conduct WHY-WHY analysis?

I usually follow the format I learnt from Yamaguchi San where to ask to final action and I feel it is easy to go down logically rather than to describe B/D phenomena and ask why it happed.
a) Conduct analysis season imitate after the breakdown got over ( memory will be fresh and so it is easy and less time consuming)
b) Ask why to the final action after which machine gets started (Generally we have several actions in way to make the machine up)
c) Then WHY WHY WHY….

Expected Outcomes:

Generally causes of breakdown fall in following five categories and expected final action is-
1. Poor Basic condition – Final action on preventive Maintenance to restore and honor basic condition (JH and Or PM).
2. Poor Operating condition - Final action on Maintenance (JH and Or PM)
3. Deterioration – PM check sheet or frequency is expected to be modify
4. Week Design – Cry for a Kaizen (Brain storming) to rectify the same
5. Skill – Training to enhance skill in same area.

Why why Format and example is available in TPM club India web site and you can download it here.
You will get more other Doc.s to download in there download section.

Thursday, November 5, 2009

Energy and Cost Savings in Air Compressor


Air is free but compressed air is too costly. And by its operation, We have a lot scope to save Energy and money from their operation. Common methods are

1. Arresting air leakage
2. Air inlet system should be cool and dirt
3. Pressure setting and compressor modulation
4. Installing VSD (variable speed drive) to optimized it’s power consumption on load and no load
5. Optimizing Air line to reduce pressure drop

But before to discuss its saving aspects, let’s see how costly it is

Cost of Compressed air = {(BHP) x (0.746) x (# of operating hours) x ($/kWh) x (% time) x (% full load BHP)}/Motor Efficiency


1. Where BHP—Compressor shaft horsepower (frequently higher than the motor nameplate
Horsepower—check equipment specification)
2. Percent time—percentage of time running at this operating level i.e full load % and no load %
3. Percent full-load BHP—BHP as percentage of full-load BHP at this operating Level
4. Motor efficiency—motor efficiency at this operating level

5. And Total cost = Full load cost + No load cost

Example
A typical manufacturing facility has a 33.5 hp compressor (which requires 45.56 BHP)
That operates for 6800 hours annually (Assume compressor operated 2 shifts a day, 5 days a week) . It is fully loaded 85% of the time (motor
Efficiency = 95%) and unloaded the rest of the time (25% full-load BHP and motor efficiency = 90%). The aggregate electric rate is Rs. 7/kWh.

Cost when fully loaded =

{45.56 BHP) x (0.746) x (6800 hrs) x (Rs. 7/kWh) x(0.85) x(1.0)}/0.95

= Rs. 1447520

Cost when partially loaded =

{45.56 BHP)x(0.746) x(6800 hrs)x Rs. 7/kWh)x 0.15) x (0.25)}/0.90


= Rs. 60668

Yearly cost of Air generation
(Except Timely maintenance cost ) = Rs. 1447520 + Rs. 60668 = Rs. 1508188. + Std. Maintenance cost.

Now see bellow example for leakage cost
Example:
Stop all loads and check for load and unload pattern for 8 to ten cycles and take average for accuracy. at compressor end. Assume leakage test yields flowing results
Compressor capacity (m3/min) = 35
Cut in pressure = 6.8 KG/ cm2
Cut out pressure = 7.5 kg/cm2
Load KW drawn = 188 kw
Unload Kw drawn = 54 kw
Average load time = 1.5 min
Average unload time = 10.5 min

So, Leakage qty. = (1.5 / (1.5+10.5)) X 35 = 4.375 m3/min
Leakage per day = 6300 m3 / day
Power require for air generation = 188 kw /(35 m3/minX60) = 0.0895
Energy loss due to Leakage / day = 0.0895 X 6300 m3/day = 564 kwh
Assuming Rs. 7 /KWH in average cost of air leakage = Rs. 3948 / day , Rs 98700/ month.

SO..STOP Leakage!


2. Air Inlet System – Compressor room need to be well ventilated and need separate exhaust for hot air

3. Compressor modulation = Optimize sizing and scheduling of compressor
4. Installing VSD = A very sensible issue but before to install we need to check our requirement or else it will not give saving as desired fashion and still for many cases, motor with soft started and Pressure on/off control is cheap and efficient option. Flowing are hints
a) Due to efficiency factor of VSD, at full load, compressor with VSD drive takes more current then general compressor.
b) A compressor controlled by a variable speed drive draws power in almost direct proportion to the load, with energy consumption dropping to near zero at no-load. In contrast, conventional compressors are less efficient because at no-load they consume between 13 and 85 per cent of their full-load consumption, depending on the manufacturer and operating mode.
c) VSD system will give significant savings 0f 10 % to 30% of operating cost if and only if compressor is running with fluctuating load between 40 to 80 % and install with pressure sensor to modulate VSD outputs. Because No load loss will be almost near to zero and may run with friction of efficiency as per load demand.

Monday, October 26, 2009

Maintenance KIOSK


It’s an Idea of mine that to make a maintenance KIOSK on local basis where a group of maintenance members will be able to exchange their individual views, knowledge on Kaizens Poka-Yoke whatever they have implemented by their own in their companies. As an individual, we all have limited ideas which come from experience on different machines, examples and more or less from technical exhibitions.

But if we make a common forum , for example of three companies maintenance member, and every company generates five general or technical Kaizens which they can share to all then, in this forum, total available kaizen will be fifteen and all members will get ten additional kaizen.

Yes, there are lechers in our society and we can prevent them by 1:1 ratio. What’s the more, We can make a virtual stores of common maintenance items like belt, bearing etc. (sometimes non-availability of a small screw also cause a considerable breakdown)

Why for common items like belt and bearing?

In spite of all efforts, hope we all experienced that running out of common spares due to there low costs, easy availability and non-critical. And on that time the neighbors companies are easy source that to purchase it from market.

So, again for example, the three companies, if declared KIOSK store contribution in starting of month in the forum and update it for their own interest in some defined interval, then chance of running out of stock will come down to 15 % (Consider that the chance of running out of stock is 5%).

This KIOSK can actively operate without any extra cost and more efforts which again will increase the low cost maintainability.

Involvement increases the knowledge.

I am reachable by Joydeep.jc@gmail.com for any assistance.

Saturday, October 24, 2009

Books on Kaizen

Here are some books on kaizen methodology

1. Kaizen Costing

2. Ideas Are Free

Maintenance Help - Common Symbols

Dear Friends,
Here are some collection on Technical Symbols. Some times I find it a most time consuming job to search a symbol.Hope you find it needful

1. Hydraulic & Pneumatic Symbols

2. Pneumatic applications and reference handbook
3. Refrigerating Symbols
4. Single line Symbols
5. General G codes

Wednesday, August 5, 2009

Attitude - The main obstracle to implement TPM


It’s a Japanese culture who was almost totally destroyed in 2nd world war but came back with a bang by their sincerity , dedication to improve

On the same time we got freed from British…. May consider the situation as sub zero and still we need a lot to go. This is what I feel, due to attitude problem, we like to blame others for our failure.

We consider all failures as our own shame (others also think in same way) and like to keep a soft shade on it or blame to others for it. Just see the bellow picture


First step to implement TPM is fear free environments where anybody can confess there limits and ask for help.

Let us have a look in following situations:

  1. I have seen a industry who are too much customer oriented! They doesn’t need any rescue boat and leaving happy with their hell. They need some certificate to satisfy customers. But not in mood to bring invest for quality. All corporate targets are nice and reports show a rosy picture …. Sales gone up…profit gone up….and so cost…..Manpower are cheaper in India so profit margin are so and so. WHY we are silent on PROFITABILITY? Is there any sign of improvement or not?
  2. Have a look in the maintenance and quality departments’ presentation...

Breakdown goes up…due to no schedule PM for machines. WHY?

- Production schedule was high. So, no machine was planned for maintenance and we were busy for breakdown maintenance only. Innocent answer.

- Low cost ….low cost. Low cost…nobody take my words into account…SO, new spare collapse without a notice…This is not actual savings. WHOM TO BLAME?

  1. I am the poor scapegoat for TPM kickoff activities only because of the WORD maintenance. There is no help or awareness from other departments even management are also concentrated on number games. They sent me to so many seminar but show cold shoulder when it comes to implementation. Every steps taken by me or quality is thrown in to dustbin by production only because of they feel it reduce productivity.
  2. Quality is responsible for quality and maintenance for breakdown and they both for TPM. We at production have so many inter department problem…we are lack of manpower, whatever we have they are unskilled or semi skilled. If we start to train them then who will achieve the target with given manpower? So, produce…Quality DOG is there to prevent the rejection to go to customer…we will rework most of them on SUNDAY!
  3. Due to lack of motivational activities, from top to bottom all the working forces are working with less morality and willing to join to other companies.
  4. Cost of poor quality is high but it is child of quality. Low quality incoming material, customer rejection, Quality is answerable for that.

- Why you are not changing vendors?

- They are lowest bidder. And the cost finalize by corporate office. We have mailed them.

RESULT ?

The same has repeated after few months. Vendor too understood the game.

  1. Customer care representative are normally quality person. It is his skill to make all analysis as per customer wants. He knows 8D formats, why-why formats, 5W2H formats and managing the show

- BUT down the stream are all knows it ? NO.

- did all people know about customer rejection ? NO

- There is no defined communication method a book is there but who has the time to open it regularly?

  1. Skill to analyze at lower level is zero and they are not the team member for that. We are analyzing it by sitting in AC room so solutions are far from real root cause and so, problems are bown to repeat. But We make customer to feel good for this time…my job is done…..lets see in next time.
  2. 5S is our MANTRA. We recite it before customer visits or some top official visits or if we want to irritate our colleges and subordinate. We never derived into solutions. We spent a lot of money in that but we spent no time to moderate our attitude.
  3. TPM stand for TOTAL PAINTING OF THE MACHINE.

More or less, we all experience the same. There are so many contributing factors in that including lack of motivation and commitments in upper management level but we fell encountered when we experiencing the situations. How far it is lack of experience and knowledge, I will share my experience and knowledge.

See you next time. If you want to share your experience, your views, your suggestion pls mail me at Joydeep.jc@gmail.com