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.
When properly installed, fuel gas is a safe energy source for cooking, heating, clothes drying, and exterior lighting. It is available to serve residential and commercial buildings in the form of natural and liquified petroleum gas. Although these two fuel gases have different characteristics and work under slightly different manifold pressures, appliances can be converted to use either type. Adequately sizing the gas delivery piping is mandatory for safe operation. The piping cannot leak and must provide enough fuel for combustion to each appliance burner.
A vent is defined as a pipe or conduit that contains a passageway for conveying combustion products and air to the atmosphere. Products of combustion contain carbon dioxide, water, and sometimes carbon monoxide. Therefore, it is important to safely vent a gas furnace.
Modern gas furnaces are available with efficiencies that range from 80% to 98% Annual Fuel Utilization Efficiency (AFUE) ratio. Furnaces that are 90 to 98% AFUE are considered very efficient and utilize a category 4 vent system. This means that the flue gases operate under a positive vent stack pressure with a low vent gas temperature, causing the gases to condense before discharging from the vent. Venting materials used for category 4 furnaces are those recognized by the furnace’s installation instructions such as stainless steel, PVC, and ABS. Furnaces one tier lower in efficiency use more traditional venting methods than the 90+% units. Even though these systems are associated with conventional chimneys and vents, special attention must be given to their installation.
The International Code Commission (ICC) mandated HVAC duct leakage testing for the first time in the 2009 International Energy Conservation Code (IECC). Since the first leakage test requirement was rolled out, extensive testing procedures and equipment have remained in the Code. Obviously, the scope of the IECC is to conserve energy. Leaking conditioned air to unconditioned spaces is wasteful and unnecessary. There are many duct sealing systems available that will fill most of the small openings around duct fittings. To seal ducts and conduct a leakage test, a HVAC contractor, engineer, or HERS rater use these specialized tools and metho
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.”
The world continues to move in the direction of sustainable energy, and HVAC systems are no exception. Three types of systems in particular — DeVap, Solar, and Geothermal — are serving on the front lines of the HVAC fight against nonrenewable energy.
Learn the basics of each type of system and how they promote a more comfortable environment inside and a more sustainable one outside.
Sometimes it takes a dramatic event to institute real change. In the case of the COVID-19 pandemic, building ventilation systems could potentially be forever changed. Here, we attempt to predict how ventilation systems might evolve in the aftermath of the coronavirus and what those changes will mean for HVAC professionals. […]
When homeowners receive quotes from HVAC contractors, they typically are given two duct replacement options, sheet metal or fiberglass duct board. There is a third option, phenolic duct, that is made of plastic foam with a foil liner on the inside and exterior. It hasn’t been on the market long enough to weigh in on its merits and shortcomings and will not be included in this comparison. Homeowners usually go for the product their HVAC contractor recommends; however, all systems have their strengths and weaknesses. Here are the advantages and disadvantages of two of these materials when installed in the typical residence.
It’s mid-January and 15 degrees outside. A fresh snow has fallen and covered all the roads and yards in your neighborhood. Thanks to your natural gas furnace, your home is a toasty 70 degrees. This is because a properly installed gas furnace has a large temperature rise that heats your home quickly and works very well on high demand days. Could it be possible that a new gas furnace will be unavailable as a home heating appliance in the coming decades? Not only is it possible, it is probable.
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