What is HVAC?
Tuesday, November 10th, 2009 | Uncategorized
Did you know that the Romans used something called “hypocaust” to heat their homes? It was a central heating system which had a furnace in the basements and flues to distribute heat. It had a system for radiating heat for rooms and even steam for the baths of the rich.
There are a lot of terms that people hear that are associated with the Heating, Ventilation and Air Conditioning (HVAC) industry but do we really know what they mean?
Cooler weather is just around the corner and everyone wants to keep their homes and offices warm. The small portable heaters are starting to show up under the desks in many cubicles. These little heaters are typically around 5200 BTUs. What is a BTU? A British Thermal Unit (BTU) is the amount of heat energy needed to raise the temperature of one pound of water by one degree F. Think of it this way. Take one gallon (8 pounds) of water and put it on your stove. If the water is 60 degrees F. and you want to bring it to a boil (212 degrees F.) then you will need about 1,200 BTUs to do this.
We talk about our air conditioning units in tons. Maybe your house is a 3 ton unit. Does that mean that it weights 6,000 pounds? Nope. A “ton” goes back to when people used a fan blowing across ice to cool their buildings. One ton of cooling is based on the amount of heat needed to melt a ton (2,000 lbs) of ice in a 24 hour period. In 1881, when President James Garfield was dying, naval engineers constructed a box-like structure containing cloths saturated with melted ice water, where a fan blew hot air overhead. This contraption was able to lower a room by 20 degrees Fahrenheit but consumed half a million pounds of ice in two months’ time.
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