Project 8 – M K Rajan


Since Willis Haviland Carrier invented the A/C machines in 1902, human beings are under house arrest! All of us are confined within 4 walls.

TM of the day, …

In Dubai alone the A/C business is worth Dhs 690 million! People in urban areas spend 90% of their time indoors. So the quality of indoor air has a direct effect on their health and poor IAQ will lead to diseases called ‘Sick Building Syndrome.’ Long term effect of this can be stress and quarrels in the house.

The factors affecting IAQ are:

  1. Temperature & Humidity
  2. Air purity
  3. Ventilation
  4. Air distribution
  5. Noise & vibration

Let us see how we can control the IAQ in an A/C environment.

1.Temperature & Humidity

The ideal comfort room conditions are 750FDB & 50% RH. Low temperature causes muscular pain, shivering and reduces immunity to infections. Low humidity causes dehydration, itching, irritation to eye, nose, throat etc. We feel discomfort if conditions are high. Women are more sensitive to temperature and less to humidity. Even after 22 years of married life we still fight for the correct temperature setting!

2. Air purity

Air contains impurities like dust, lint, pollen, virus, bacteria etc. Different types of filters are used to clean the re-circulated air. Foam filter, synthetic filter, metallic filter etc. are commonly used filters. It is very important to keep these filters clean always, because improper filtration causes respiratory illnesses, cough, wheezing, asthma, allergies etc. A clogged filter will reduce efficiency, increase running and maintenance costs, increase your medical bills and ultimately reduce your life span.

3. Ventilation

Indoor air also contains impurities like smoke, odour etc. To dilute these impurities and to avoid stale air being circulated, fresh outside air is introduced and part of the air exhausted using fans through bathrooms and Kitchen.

4. Air distribution

Improper air distribution will cause uneven cooling and if cooled air is directed towards some part of the body, this will cause joint stiffness, muscle pain, catches etc.

5. Noise & vibration

Noise & vibration causes discomfort and constant exposure may cause deafness.

What should we do to avoid Sick Building Syndrome?

1. Set the correct temperature.
This will also increase the life of the machine, reduce running cost and you will be richer.

2. Clean the filter regularly.
Now a days there are machines with inherent O2 generation system, triple filters to remove smoke, odour etc in addition to dust and other pollutants.

3. Make sure that enough fresh air is introduced.
Open fresh air inlets and ensure exhaust fans are running.

4. Adjust the grilles and dampers.
Change the direction of the airflow by adjusting the blades of the grill and adjust airflow using dampers.

5. Select speed and check unit installation.
Adjust fan speed so that noise and vibration are reduced. Check and modify installation if necessary.

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