PROBLEM SOLVING

Everyday we face problem. But all the problems, we manage to solve it eventually. But before the problems been solved, we will worry about it. Why? Because we are so committed to our work. We worry it will spoil our reputation, worry about our year end appraisal, worry about the client will not be happy with us and end up with termination of project, and there are so many worries!
Every problem sure will has its solution. If we spend some time to analyze the problem and situation with open minded, then we will see the ways! Of course, who caused the problem? Don't blame people, it always our faults or careless mistakes. I learnt from mistakes. Not mistake but mistakes. Now, everything I follow black and white. No argument after this. Fair to every parties.
Talk easy and advise people lagi easy. When I face problem, also 'musam muka' for the whole day.

ACR3422 PSYCHROMETRICS 1ST ASSIGNMENT

Question 1:
Given:
7500 cfm of chilled air at 57 deg F DB and 56 deg F WB mixed with 2500 cfm of outside air at 96 deg F DB and 78 deg F WB.
Find: The properties of mixture.

Question 2:
Given:
Air at 35 deg F DB and 60% RH. Air is to be heated by passing through a coil to 95 deg F DB.
Find:
For the 95 deg F air, its percent RH, WB and DP temperature. For the process, the amount of heat added to the air/lb.of air flowing.

Question 3:
Given:
Air at 82 deg F DB and 50% RH being cooled to 53 deg F DB and 52 deg F WB.
Find:
Total heat removed.
Total moisture removed.
Sensible heat ratio for the process.

Deadline for submission: 16/8/07 at 12.00p.m

DESICCANT DEHUMIDIFICATION VS MECHANICAL REFRIGERATION

Both desiccant dehumidifiers and mechanical refrigeration systems can remove moisture from the air, so the question is - which type is best suited for a given application? There really are no simple answers to this question but there are several generally accepted guidelines which most dehumidifier manufacturers follow:
1.
Both desiccant-based and refrigeration-based dehumidification systems work most efficiently when used together. The advantages of each compensate for the limitations of the other.
2.
Refrigeration-based dehumidification systems are more economical than desiccants at high temperatures and high moisture levels. In general, mechanical refrigeration systems are seldom used for applications below 45% RH. For example, in order to maintain an outlet condition of 40% RH, it would be necessary to bring the coil temperature down to -1 deg C (30 deg F), which results in the formation of ice on the coil and a reduction in moisture removal capacity. Efforts to prevent this (defrost cycles, tandem coils, brine solutions, etc.) can be very cumbersome and expensive.
3.
Desiccant-based systems are more economical than refrigeration systems at lower temperatures and lower moisture levels. Typically, a desiccant dehumidification systems is utilized for applications below 45% RH down to less than 1% RH. Thus, in many applications, a DX or chilled water pre-cooling coil is mounted directly at the dehumidifier inlet. This design allows for removal of much or the initial heat and moisture prior to entering the dehumidifier where the moisture is reduced even further.
4.
The difference in the costs of electrical power and thermal energy (i.e. natural gas or steam) will determine the ideal mix of desiccant to refrigeration-based dehumidification in a given application. If thermal energy is inexpensive and power costs are high, a desiccant-based system will be most economical to remove the bulk of the moisture from the air. If power is inexpensive and thermal energy for reactivation is costly, a refrigeration-based system is the most efficient choice.

air conditioning system

Last Tuesday, I attended a power breakfast which organised by Trane Malaysia. The speaker was their Director. The seminar was really useful and valueable.
The new technology that being used by Trane can now produce chilled water at a lower temperature compared to the conventional chiller. The normal design chilled water supply temperature is 44 deg F, whereas the chilled water return temperature is 54 deg F. The temperature difference is 10 deg F. But now, Trane's chiller can produce a higher temperature difference at 16 deg F, which chilled water supply temperature can reduce to 42 deg F and the chilled water return temperature can be increased to 58 deg F. Since the chilled water flowrate depends on the temperature difference, therefore, the pipe size can be reduced and the installation and material costs will be lowered. Besides, a smaller pump will be installed too.
The formulae involved is:

Water flow rate, usgpm = tonnage x 24/ delta T.

If the delta T is a bigger value, then the required chilled water flow rate will be lesser. Therefore, we need a small chilled water pipe size.

ACR0213 1ST ASSIGNMENT - Fan principle & laws

An AHU with 20 HP motor is supposed to supply 26,000 cfm cold air to an open office area. During the testing and commissioning stage, it was reported that the air velocity taken at the duct (48”x 36”) is 1,800 fpm. The running current taken was 20.1 A. The motor pulley size is 6” whereas the blower pulley size is 4”. The full load current for that particular motor is 28.1A and the rpm 1455.
Please upgrade the system to achieve the design air flow.

Deadline for submission: 7/8/07 at 2.00p.m

ACR3933 - 1ST ASSIGNMENT

Kindly size up the units using CLTD.

Area (UPS room): 1st floor (27 sqm, ceiling height 3m) x N + 1 air-cooled wall mounted split unit
Room requirement: RH 45% +- 10%; 21 deg C +- 1 deg C
Design criteria:
lighting: 20W / sqm
occupancy: 90W sensible & 40W latent
Small power load: 40W/sqm
Heat load 60 kVA UPS
16 L/s /person
10 sqm/person

air movement should be maximum 0.25m/s at 1800mm

Deadline for submission: 8/8/07, 8.30a.m

Power Gel

Before this never hear about power gel. Until after joining all the runs and marathon, then only I know this product. Can you image how important this power gel to me? Because of the Utusan 10km run, we went to a few shops such as Watson and Guardian to look for this product. From Kajang to Puchong, from Puchong to Sunway Pyramid. After searching for weeks via internet, eventually we found it at Sunway Pyramid. A small packet cost us RM5.50, is that expensive? Well, it's worthy to consume it for runs. Perhaps it is not true to say this, I feel more powerful and energitic. Runs become easier and more fun. The only difficult thing is to register for all these runs. In order to register a run, we need to go to Kelana Jaya and Bandar Damansara. It took us more than 3 hours to complete the task. Sigh!

Dream...

My mom is a full time housewife and my dad likes to cook. Therefore, I am influenced by them and like to cook. Not only continental food, but western food as well. Mom likes to bake cakes and bread. So, I learned from her to make cakes and pau. And very lucky, my neighbours are pastry chef some more. He taught me to bake cheese cake and tiramisu. And 2 days ago, I learned making pizza chrust from him too. This time I can say is successful compare to last 2 times.
Outside food is added with chemical ingredients. I prefer to make myself and let my lovely children to bring to school. Previously, I have a dream to open a bakery near my house, and let my wife to run the business. At the same time, she can take care of the children. But she seems like enjoying her work as a banker.