What Is HVAC?
This acronym stands for heating, ventilating (or ventilation), and air conditioning. This technology is used indoors and in vehicles to ensure environmental comfort combined with acceptable indoor air quality. These systems are a subdiscipline of mechanical engineering, based on the principles of heat transfer, thermodynamics, and fluid mechanics. This industry is a global endeavor, with many avenues including education and research, equipment design, manufacturing, and sales. It also includes operations and maintenance.
Almost half of the domestic consumption of electric power goes to HVAC systems. Many factors contribute to this high-scale consumption; including the efficiency of the installed systems, sizing calculations and the lifestyle of the consumers.
We can cut down the rate of power consumption by making right choices regarding the factors mentioned above. This article will discuss in detail, the factors that can contribute to the efficient functioning of the HVAC systems and save high amounts of energy costs.
Exploring ideas on the best way to replace your AC system to ensure that you find what’s right for you and your home. You should repair your system if it is within warranty, or a few years out of warranty. Finding a good licensed contractor will assist with that decision.
What is the most awful thing that could present itself to your house in the middle of summer?
Your cooling or HVAC unit stops working.
Now you are, sweating and suffering, wishing you had implemented a plan to anticipate such an event. Considering that we transition from the spring into the heat of summer, it becomes significantly important to have a plan available to ensure you are not sitting with no AC in the middle of August heat. How do you prepare?
One of the absolute most important questions you can ask yourself is: What contractor should I use? When selecting a HVAC contractor, it is vital to think about whether your contractor is certified and which certifications they currently carry.
What Type of HVAC is best?
A heat pump is a device that provides heat energy from a source of heat to a location called a “heat sink”. Heat pumps are designed to move thermal energy opposed to the direction of impulsive heat flow by absorbing heat from a cold space and releasing it to a warmer one. A heat pump uses some amount of external power to accomplish the work of transferring energy from the heat source to the heat sink.
While AC systems and refrigerators stand out as examples of heat pumps, the term “heat pump” is more general and relates to many HVAC (heating, ventilating, and air conditioning) devices used for heating or cooling. When a heat pump is used for heating, it employs the same basic refrigeration-type cycle used by an air conditioner or a refrigerator, but in the opposed direction – releasing heat into the conditioned space as opposed to the surrounding environment. Within this use, heat pumps generally draw heat from the cooler external air or from the ground. In heating mode, heat pumps are three to four times more efficient in their use of electric power than simple electrical resistance heaters. Typically installed cost for a heat pump approximatly 20 times greater than for resistance heaters.
Heat pumps are used to deliver heating because less high-grade energy is required for their operation than appears in the released heat. Much of the energy for heating comes from the external environment, and only a fraction stems from electricity (or other high-grade energy source required to run a compressor). In electrically powered heat pumps, the heat transferred may be three or four times larger than the electrical power consumed, giving the system a coefficient of performance (COP) of 3 or 4, as opposed to a COP of 1 for a conventional electrical resistance heater, by which all heat is produced from input electrical energy.
Heat pumps use a refrigerant as an intermediate fluid to absorb heat where it vaporizes, in the evaporator, and after that to release heat where the refrigerant condenses, in the condenser. The refrigerant flows through insulated pipelines between the evaporator and the condenser, allowing efficient thermal energy transfer at relatively long hauls.
Both inside the house and outside heat pump units contain moving mechanical components which produce noise. In 2013, the CEN started work with standards for protection from noise pollution a resulted of heat pump outdoor units. Although the CEN/TC 113 Business Plan outset was that “consumers increasingly require a low acoustic power of these units as the users and their neighbors now reject noisy installations”, no standards for noise barriers or other means of noise protection had been developed by January 2016.
HVAC Noise Restrictions
Noise from outdoor units in some cases exceeds noise levels tolerated by the legislation. As an example, the 2015 data sheet of the “Mr Slim” Zubadan Inverter Heat Pump informs whoever reads it, including the pump’s owner’s neighbors, that the Mr Slim outdoor unit generates 52 dB in heating mode. This is much more than is permitted by legal guidelines in some countries, for example the UK, where this or similar pumps are used. Another example is Poland, where the noise level permitted in residential areas is 40 dB after dark, which is more than the UK limit (35 dB), but still puts the Mr Slim outdoor unit 12 dB above the limit. In the United States, the allowed nighttime noise level was defined in 1974 as “an average 24-hr exposure limit of 55 A-weighted decibels (dBA) to protect the public from all adverse effects on health and welfare in suburbs (U.S. EPA 1974). This limit is a day– night 24-hr average noise level (LDN), with a 10-dBA penalty applicable for nighttime levels between 2200 and 0700 hours to account for sleep disruption and no penalty placed on daytime levels. The 10-dB penalty makes the permitted U.S. nighttime noise level equal to 45 dB, which is more than is accepted in some European countries but less than the noise produced by some heat pumps.
Therefore, it is very important to pay special focus on those heat pumps which are advertised as being extremely efficient and generating noise at a very low level, supposedly, at the same time. The simultaneity of both conditions being met together could be tested in the example of the Toshiba Residential Super Daiseikai G2KVP Inverted Hiwall Heat Pump. The product is advertised as having “extremely high efficiencies with 5.15 and a noise level of only 20 dB in ultra-low fan speed for the RAS-10G2KVP”. It is possible to download a brochure by clicking on a pdf download button at the bottom of the site. The Technical Specifications are given on the last page of the brochure and one can verify the correctness of the initial commercial information. The detail missing at the beginning is that the value of 20 dB for RAS-10G2KVP only pertains to the indoor unit in the quiet mode (42 dB in the high mode) whereas the external unit produces 61 dB in the Heating mode which is not reported in the commercial introduction. The level of 61 dB exceeds the environmental noise limits worldwide.
The location of an outdoor unit relative to the building wall is significant. The unit shown on page 7 of the Heat Pump Product Brochure published by American Standard Heating & Conditioning is placed approximately the center of the house wall, like a musician of the Symphony Orchestra playing a concerto. Shells and walls composed of hard material are used behind a sound source if passive sound amplification is desired. Such a location of the outdoor unit adds extra dB of noise reflected from the wall. The dB level is not reported in the brochure and the location of the neighbors’ house is not shown in the picture, but this sort of location should not be used alongside a place planned as a quiet place whether or not the unit is quiet. The heat pump outdoor unit is not a musician playing to an audience.
Another aspect of ASHP external heat ex-changer is their need to stop the fan from time to time for a period of several minutes in order to get rid of frost that accumulates in the outdoor unit in the heating mode. Afterward, the heat pump starts to work again. This part of the work cycle generates two changes of the noise made by the fan. The acoustic effect of such disruption on neighbors is especially powerful in quiet environments where background nighttime noise may be as low as 0 to 10dBA. This is included in legislation in France. Inning accordance with the French concept of noise nuisance, “noise emergence” is the difference between ambient noise including the disturbing noise, and ambient noise without the disturbing noise. The emergence should be below 3 dB at night (between 10.00 pm and 7.00 am), so the pump in France, once stopped during the night, theoretically should not be allowed to turn on again until morning. Furthermore, the level of ambient noise including the disturbing noise must be below 30 dB in France, a condition which definitely can not be met without an effective sound barrier by most ASHPs which were commercially available by the end of 2015.
However, ASHP outdoor units are still being installed in houses worldwide with no noise protection, as no recognized standards for heat pump outdoor noise barriers are available yet, as of January 2016.
An air handler, or air handling unit (often abbreviated to AHU), is an unit used to manage and disperse air as part of a heating, ventilating, and air-conditioning (HVAC) system. An air handler is usually a large metal box containing a blower, heating or cooling elements, filter racks or chambers, sound attenuate systems, and dampers. Air handlers usually connect to a duct-work air flow system that distributes the conditioned air through the building and returns it to the AHU. Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served without duct-work.
The air handler is normally built around a framing system with metal infill panels as required to suit the configuration of the components. In its rudimentary form the frame may be made from metal channels or sections, with single skin metal infill panels. The metalwork is normally galvanized for long-term protection. For outdoor units some form of weatherproof lid and additional sealing around joints is provided.
Larger air handlers will be assembled from a square section steel framing system with double skinned and insulated infill panels. Such constructions reduce heat loss or heat gain from the air handler, as well as providing acoustic attenuation. Larger air handlers may be several meters long and are produced in a sectional manner and therefore, for strength and rigidity, steel section base rails are provided under the unit.
Where supply and extract air is required in equal proportions for a balanced ventilation system, it is common for the supply and extract air handlers to get joined together, either in a side-by-side or a stacked configuration.
There are many things to take into consideration when selecting an honest, reliable contractor, a few of which involve:
What experience and level of training do they have?
Where does their level of proficiency and expertise currently stand?
Do they recognize the problem and your needs as a customer?
Air Conditioning Contractors of America (ACCA) and North American Technician Excellence (NATE) are two nationwide, not-for-profit HVAC accreditation s that support many of the values found in professional contractors.
Air Conditioning Contractors of America
ACCA prides itself on its history. With over 40 years of experience, the organization is actively connected with all aspects of the HVAC industry, from the streets of Washington D.C. all the way to your home. ACCA promotes rigorous, comprehensive training of their accredited technicians, and puts together technicians through onsite and online community training sessions, where contractors are able to fine-tune their skills to ensure efficiency and accuracy. Technicians are held to a high standard of proficiency to ensure they are thoroughly prepared to fix the problem in a timely manner. Search for a professional contractor in your area here.
North American Technician Excellence
NATE has been involved with the HVAC industry for the past 20 years and prides itself on preparing technicians with rigorous, real world, knowledge-based exams to ensure they are prepared to fix problems connected with HVAC systems. NATE provides technicians with online resources to further ensure that their certifications remains up-to-date and relevant to the needs of their customers. Additionally, NATE technicians are obligated to continue their education by getting re-certified every two years. Search for a NATE-certified contractor in your area here.
Determining which contractor to use is a difficult decision. Choosing a contractor who is not certified, though, could end up costing you big league. Having this in mind, it is important to take the necessary steps to ensure you are making an educated decision when choosing a contractor. Luckily, both ACCA and NATE have high standards for their technicians and value the needs of their customers by providing proficient technicians to fix the problem right the first time.
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