TecKnow of the day
General Thumb Rules in HVAC.
Normal chilled water supplytemperatures in the range of 45 – 55 degrees Farenheit. This is the correct range of chilled water supply temperatures for comfort cooling. Normal hot water supply temperature is in the range of 100 – 150 degrees Farenheit.
One cfm per square foot of floor area is the average air quantity required for a room or entire building.
Rules of thumb are abbreviated short cuts, time savers, and approximations. Each is a quick estimation of what most systems should do most of the time, but remember that none of these numbers are infallible.
The rules are not cast in concrete. They do not always apply to every system, nor do they work in every circumstance. It is expected that the technician using them is a professional who can use reason and exercise caution in their application.
Rules of thumb usually assume certain normal design and operating criteria, which are not always present.
The rules are not to be used for system design purposes. Rather, they are the result of carefully studying good system designs. Technicians and engineers, however, can benefit from using them as tools for estimating and solving operational problems.