Wednesday, July 28, 2010

Ventilation Design Basics

HVAC systems provide heating, ventilation, and Air Conditioning to buildings. Whether it is an office building with 300,000 square feet or a Japanese Steak House, the principals are all the same.

I have placed a diagram to the right which may help give you a better idea of the system layout. Air flows into ductwork from the building through ceiling registers and mixes with air pulled in from the outside at the air filter section. Next you have a blower which moves the air across two sets coils, one to cool, for the summer, and one to heat, for the winter. From there the air goes back into the building through ceiling diffusers.

The way you heat and cool the air is where a lot of people begin to get lost. But, this is typically because the person explaining is too scared to actually help and if they teach you, they are afraid you will not need them. What that does is create an cloak of magic that seems to engulf Ventilation system design. Whether trying to remove grease, smoke, heat, dust or airborne bacteria from an air stream the guiding principles are all similar. One of my goals here is to help remove the mystery and help educate, any feed back that can be given on these articles would be greatly appreciated.

One of the key elements you must remember when designing a well balanced air system is that you are designing for people in the real world and not in a laboratory. Engineers are great at coming up with ideas which work in theory, but then it leaves the customer scratching his head trying to understand why their restaurant is filled with smoke, the kitchen floor is greasy, and why his customers can not open the door to come in and eat. Same idea with office buildings, you can have trouble opening doors, residual moisture on windows, people constantly sick, and no one is comfortable. All because one person over looked the human element.

I do not want to overwhelm anyone so we will end this lesson here. Next we will look at how equipment conditions. Thanks for reading, and we'll see ya on the roof!

Friday, July 23, 2010

Environmental Systems Check List

To kick off our first Blog, we want to review the basics for HVAC Maintenance. When looking at your Environmental system, you should always be aware that like a car, it will require maintenance. The level of maintenance you choose to do will directly effect your investment in the system. The following is a good 20 point inspection which should be done quarterly for Roof Top or Split Systems:

1 Exposed Contacts

2 Check Motor Amps

3 Safety Devices

4 Lubricate as necessary

5 Blower Bearing Play

6 Condenser Fan Bearing Noise

7 Condenser Fan Blade Condition

8 Thermostat Operations

9 Condensate traps, lines, and pans

10 Outside Air Dampers

11 Fuse Holders

12 Capacity Controls

13 Exposed Piping within Sight of Equipment

14 Blower Wheel

15 Visual Signs of Leaks

16 Oil Color and Level

17 Equipment Panels

18 Belt Condition & Tension (replace yearly)

19 Visually Check Coils

20 Air Filters (replace quarterly as per agreement)

As we add more articles we will cover not only the general equipment design, but also what is required for larger more complicated and control schemes.

Thanks for reading, and we'll see ya on the roof!