In large commercial occupancies such as grocery stores, refrigeration is a necessary part of the business model. Coolers, refrigerators, and freezers line several isles containing produce, frozen food, meat, and dairy products. Connecting these indoor components to compressor and condenser units requires several hundred feet of refrigerant lines. These lines are typically field-installed copper pipe with many brazed joints. Pressure testing connections before beginning equipment startup is essential. The cost of refrigerant, malfunctioning equipment, environmental hazards, and the safety of occupants are good reasons to ensure leakproof refrigeration systems. Additionally, most mechanical codes and the Environmental Protection Agency (EPA) require pressure tests for new piping installations.
Thermostats have changed a whole lot in the last 20 years. Gone are the mercury bulbs and long levers. Even first-generation programmable thermostats are second class to the newest variety. Thermostats such as Google Nest, Honeywell T9, and Ecobee lead the way with the latest features for home comfort and energy savings.
Smart thermostats make it easy to get comfortable. These devices can be controlled remotely with a phone, tablet, or computer, and even utilize their own intelligence to keep a home’s temperature right where the owner wants it. How about a thermostat that you can talk to? It’s available with some of the smart thermostats. Because these thermostats are WIFI enabled, programming them to work with the different “talking” services can be easy. You can tell the thermostat you are leaving, which would reduce the system run time while you were away. You could tell the thermostat you were going on a vacation. This command indicates the home is unoccupied and will not need the same comfort conditions, thereby saving energy. Or, you could just say “Alexa, set the temperature to 77 degrees.”
Its 95 degrees on a hot, humid day. A service repairman, working on your HVAC, opens the door to your vented crawlspace. He observes ductwork dripping with water, mold on floor joist, and termite tunnels on the crawlspace walls. He services your air conditioner and recommends you call an exterminator. Why are you having all these issues in your crawlspace? Could it be that the naturally vented crawlspace doesn’t work anymore? Some people would say, it never worked. Why is this?
When we see the acronym HVAC, most only think of heating and air conditioning. But the V is for ventilation, an important role when considering the air quality in buildings. Indoor air quality is achieved through ventilating and filtering air in a space. The International Mechanical Code’s definition of ventilation is “The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, a space.” When we supply fresh air to spaces and remove stale air, we improve the breathing air quality for the occupants. When air is “conditioned”, it means several things that include removing or adding heat, cleaning the air, removing moisture, and replacing air.
What if a refrigeration system could exist without a mechanical compressor, oil, or the typical blended refrigerant? A totally new design that required much less electricity to operate? Components of the system consist of an inert gas and large pressure vessels connected by pipes. This mechanism would be based on thermoacoustic principles that had very few moving parts. Considering the environmental issues faced today, wouldn’t it be an amazing achievement?
The combining of fuel, air and an ignition source creates combustion. This combustion process is utilized in furnaces and water heaters to heat air or water. Byproducts of combustion are carbon dioxide, water, occasionally carbon monoxide and other gases.
According to industry experts there are over 100,000 HVAC contractors currently doing business in the U.S. However, statistics show that 50% of small business startups fail within the first year and 95% fail within five years. Therefore, the 100,000 plus contractors successfully doing business have figured a thing or two out. Let’s look at some standard business practices of these HVAC companies that keep them profitable and out of the failure statistics.
There is an old joke among HVAC contractors. When bidding on a replacement system for a customer, step back 100 feet from the house and hold up your hand. If three fingers will block the view of the house, install a three-ton unit. If it takes four fingers to block the view, then install a four-ton unit. That meager attempt at humor does highlight an issue that has been kicked around since the beginning of the industry. Are load calculations necessary? If so, how do you properly size a heating and air conditioning system for a house or commercial building?
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