The majority of HVAC installations dating back to the 1990s have R-22 as their main working fluid. However, recent studies have proven that R-22 or as we commonly known as “Freon” (brand type) is not as environmentally friendly as we once thought it was. Ergo the use of this refrigeration type has been banned by the Environmental Protection Agency along with other substances which contributes to ozone depletion. With phasing out of R-22, HVAC manufacturers and end-users are forced to look into other comparable refrigerants which won’t negatively impact the environment as much.
R-410A offers a few benefits when compared to the traditional R-22 fluid – one of which is greater energy efficiency which translates into lower operational costs. This hydro-fluorocarbon has been approved for use in new systems and is classified as a non-ozone-depleting HFC. One note that has to be taken into consideration is that R-410A operates on roughly a 50% higher pressure than R-22, thus can only work with high pressure limit equipment.
R-407C has been set as the new standard for the U.S residential air conditioning system as of two years ago. Consequently, the commercial refrigeration system (including air conditioning and chilling units) R-407C was found to be the most frequent refrigerant to be used as a substitute of R-22. Of the higher temperature this type of refrigerant gives similar operating characteristic to R-22. R-407C, a non-ozone-depleting substance, gives better performance in comparison to Freon due to its higher pressure and refrigeration capacity.
R-134A is currently one of the most common refrigerant fluids; especially in HVAC applications in the automotive industry. Many machines are retrofitted to match this fluid from R-22; though one should be careful not to mix and cross contaminate R-22 with R-134A which can result to danger of raising compressor head pressure as well as unfavorable reliability. R-134A is made of one single component, which comes with the advantage of utilization of a single recovery machine and adding into that, according to recent studies, R-134A is environmentally friendly which makes it an even more attractive choice.
A few decades ago, opening and closing a window was enough air temperature control. In modern days though, the standard bar of comfortable living has become higher and the occurrence of global warming, which raises the world’s temperature to the extremes, is abundant. With all this in mind, temperature control becomes a major necessities. During this post, we will be exploring factors which should be considered for a new installation of a HVAC system either to modern or conventional homes.
Regardless of the size of property, ductwork that is balanced and well designed must be installed to make sure that the air and temperature circulation is optimal –especially for locations with extreme weather conditions. Externally insulated round ducts are found to be the most efficient. Installation of balance dampers in the ductworks should also be important to regulate airflow.
End users should also be paying attention to materials of the HVAC unit. The condenser coil type directly relates to the reliability and stability of the HVAC unit, which is even more important in harsh environments. In common applications, coils which are made from one types of metal are usually more reliable and generate better efficiency.
HVAC application has several types of working fluids also known as refrigerants. The main function of refrigerant fluid is to cool, dehumidify and distribute the low temperature air in the system. For a long time, R-22 or Freon happened to be the most common refrigerant in the market. Nowadays though, the use of Freon has been banned for the reason of being environmentally harmful. Currently, there are a couple other refrigerants that are commonly implemented in such application including R-134a, R-407c and many more. Those refrigerants have their own advantages and disadvantages which end users should compare themselves to see what would fit their needs the best.
Efficiency should be the most important aspect to study before settling on a type of HVAC system. There is minimum efficiency which is settled by the government, though aside from legal limit, this would be an ultimate factor to be analyzed by users since efficiency directly correlates to operational costs (the higher the SEER, the lower utility bill you get). Thus, an up-front investment might benefit in the long run.
A compressor unit is an important component in an air conditioning system used to remove the heat laden vapor refrigerant from the evaporator. The compressor raises the temperature and pressure of the working refrigerant fluid and transforms it to a high temperature and high pressure gas. Since the compressor is one of the most vital parts of a cooling system, to be able to have an efficient working cycle, an appropriate and optimum compressor design must be installed.
Generally, there are 5 types of compressor that can be used in HVAC installations, the most common of which being reciprocating compressors used within a smaller scale conditioning system. Reciprocating compressors utilize pistons and cylinders to compress the refrigerant and an electric motor is used to provide a rotary motion.
In recent application, scroll compressors are found to be increasingly popular as an alternative to reciprocating compressors in HVAC installation. This type of compressor outstands in the reliability and efficiency sector when compared to reciprocating compressors. Scroll compressors consist of one stationary scroll and a second moving scroll which compresses the refrigerant – giving this type of compressor fewer moving parts and thus, higher reliability and efficiency. At a smaller size, scroll compressors can achieve similar flow rates and outlet pressure when compared to reciprocating compressors.
There are different kinds of rotary compressors, the most common ones being rotary screw and rotary vane. Rotary vane compressors are known to be smaller, quieter and more reliable and are commonly used in smaller residential split system applications. The application works with a rotating shaft as the blades move around the cylinder. The other rotary compressor consists of stationary blades which are attached to the housing, used for larger applications in comparison to rotary vane compressors.
Last but not least is the centrifugal compressor. Centrifugal compressors are mostly used in industrial installations due to the ability to cool large capacity of air. No piston, valve or cylinder is incorporated in the design and it relies on centrifugal force enabling it to have very few moving parts leading to higher efficiency and reliability.
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In the last post, we covered the area of HVAC dealing with air conditioning and refrigeration. For today’s blog post, we’d like to quickly go over the other major topic of HVAC industry – heating systems. In geographical areas where temperature fluctuation tends to be quite extreme, a good working heating system is a vital necessity –especially during the colder winter months. The main challenge of heating systems frequently comes from the heat distribution method. There are a couple types of heating system and it is important to take into account their functionality to decide which is the best type for your application.
The first systems we are going to focus on is central heating, which is the most common heating system in North American residential applications. This system comes with primary heating applications such as a furnace, boiler, and heat pumps. Each heat source is rather unique and uses different methods of distributing heat into the targeted environment. Furnaces use ducts to blow heated air through in order to disperse the generated energy. Implementation of such technology in the USA is controlled by the Annual Fuel Utilization Efficiency where it estimates seasonal efficiency, averaging peak and part-load situations. Boilers utilizes hot water which travels up to radiators and gets circulated around in a system – so instead of using a fan and ducts, appliances which utilizes boiler as a heat source commonly uses pump to flows the hot water to other parts of the house/building. Since circulation is the most recurring challenge in heating appliances, an optimal pump design must be installed into the system to make sure that the heat is distributed evenly to each part of site. Within central heating there is also heat pump system which works as two-way air conditioner (direct and reverse). During the hotter season, heat pumps work to moving heat from indoor (cooler) to outdoor (higher temperature), and vice versa during the colder months. Heat pumps generally use electricity to move heat from one place to another.
The second heating system utilizes direct heat. Usually direct heat is used to transfer heat /raise temperature in a small targeted area. In the most common cases, the heat output is relatively small. The most common installation nowadays which utilizes this system is gas fired space heaters or electric space heaters (for more modern implementation), whereas the more conventional one would be fireplaces. This type of heating is less effective for an overall building system.
During the past week we’ve talked about challenges, improvements and development of HVAC technology. But taking a step back, what is a HVAC system? Heating, ventilation, air conditioning systems and refrigeration (or known as HVAC&R) is a technology developed to manipulate environment temperature and air quality. The applications of such technology are based on the principles of thermodynamics, fluid mechanics and heat transfer.
Commonly HVAC systems are grouped into four main systems starting with the heating and air conditioning split system, which is the most ordinary implementation of residential applications encompassing both inside and outside installations. The application, which can be controlled with a central thermostat, consists of air conditioning system which cools the refrigerant to drop the temperature, and heating system which involves gas furnaces. Ducts used to circulate the adjusted air from both heating and conditioning, with the help of evaporator/fan coils – a terminal unit which is used to provide heating or cooling to the targeted space.
A split system is known for its simplicity, efficiency and low cost. That being said, the second type (hybrid heat split system) is actually found to benefit over the first one from an energy efficiency standpoint since the application utilizes heat pump systems. With the incorporation of heat pumps, the system is able to pump cooled or heated refrigerant to make both system able to be controlled through electric power. The heat pump is used to move energy using outside surrounding air as an air source for heating and heat sink for refrigeration/conditioning systems.
A duct free split system would benefit the most to be installed at locales where conventional ducts cannot fit or are not directly connected to central control thermostats. No ductwork would be needed in the system, thus enabling flexibility of delivering air directly to the targeted zones. Since the technology allows you to directly zone the cooled air, using ductless technology could improve efficiency, lower operation cost and reduce carbon footprints.
The last system to note is the packaged heating and air conditioning system – which is normally the system that is installed at locales where there is not enough spaces available for the components of the split system. A package unit has a heating and cooling system combined into one unit, making it easier to access for maintenance as well as to be conservative on installation space.
While the term of air conditioning in relation to automotive might instantly correlate to a system which provides passenger with a comfortable air temperature/environment, HVAC systems also are used for heating and cooling of batteries in such application as well as cooling of the vehicle fuel systems. Thermal management for automotive application isn’t easy though. Many factors have to be accounted for in order to build a dependable cooling system.
While talking about HVAC concerns and challenges which arise in automotive application, the biggest inconvenience commonly comes down to the lack of cold air produces. Mobile refrigeration/air conditioning systems come with quite a few concerns from two sides: the refrigeration side, where it removes heat and injects cold air, and from the electrical side which provides control. From the system, the most common challenges are found in moisture –which would fail the cooling system if present in the air, soiled condenser which would block air flow, and various other mechanical complications which might occurs.
While diagnosing an air conditioning issue, especially if environment temperature seems higher than it should be, there are few conditions that can be looked into including freon leak, failed blower, damaged or failed motor, damaged condenser to the most common problem usually arises from the compressor. Compressor, compressor clutch switch, fuses, wires, fan belt and seal are at the top of the list to be check for functional adequacy. Consequently, with many concerns arising from the compressor side of the system, a good and reliable compressor design must be implemented to avoid unwanted challenges during operation. Design your automotive turbomachinery with SoftInWay! Ask us about the projects that we’ve done in this field and how our turbomachinery development code will be helpful for your automotive and HVAC design, analysis and optimization activities.
Humid climates commonly come with the challenge of moisture standards. When HVAC (heating, ventilations, and air-conditioning) systems do not maintain proper moisture conditions/humidity control, it causes damages and defects to the building.
A humid climate is defined as a condition where the average monthly latent load (energy required to remove moisture from the air) of environment’s air is the same or higher than the average monthly energy needed to cool the air during the cooling season. Using air with high latent load easily brings moisture in and accumulates it in building materials.
Maintaining humidity control isn’t an easy task. The HVAC unit has to be able to support a proper pressurization system using dehumidified air to entire the building. In order to provide the right dehumidification, a HVAC system must be able to dehumidify the air that flows across the cooling oil (which means the precise sizing of cooling coil must be selected to meet the load of both outside and return air). That is not the only criteria that an HVAC system needs to fulfill though. The system must also meet the sufficient run time to remove moisture from the interior air. In a humid condition, temperature control is not enough. Moisture control comes second on the priority list ( though this has to be fulfilled without scarifying the main goal of giving comfortable temperature to users).
In geographical areas with humid weather, such as in the southeast, public housing generally uses chilled water and direct expansion for the cooling system. This requires an outdoor condenser unit to exchange heat to the outdoor air.
When asked about problems rising in the HVAC industry, people typically point to the availability of trained workers or labor force. The growth of the HVAC industry brings more open jobs into the market. According to a report by U.S Department of Labor, by 2020, this particular market should bring about 90,000 new jobs in the industry. With that being said, the spike in work doesn’t necessarily align with quantities of qualified workers. Even with strong job security and above average pay, HVAC doesn’t seem to attract too much young potential. In the past year, the HVAC industry has lost thousands of workers, not only from the lagging economy, but also due to the work force available. Currently, the average age of the entire 7.5 million HVAC workforce is around 55 years old, which is much older than the normal workforce.
With the rate of how quickly technology in the HVAC industry is currently growing, the pool of talent in the market can’t quite seem to catch up. Day by day due to increasing demand and competition, leading companies in this industry is required to come up with new design and new technology with better efficiency, easier operation, and better control is needed. Demanding increase in technology does not meet with the current available skill pool. As a result, the hiring process for skilled labor takes considerably longer. Finally, once you take into account calculation of training and orientation, the entire hiring process requires a lot of investment both in time and money.
Technology companies seems to spend most of their available budget on research and development activities. It’s important to pay attention into this particular trend since a high bleed could really impact on the cost of production. During this difficult time of short talents, it makes sense for companies to source out their research and development activities. Our R&D engineering team consists of consulting experts who have completed extensive projects on the subject. We’d be more than happy to assist you with any project needs.
According to the new market research report, the industry of heating, ventilation and air conditioning (HVAC) is predicted to rise at a solid, stable compounding annual growth rate of 5.9% up to the year 2022. With the growing trend of smart homes and changing weather conditions, cooling equipment is expected to remain the largest major share of the entire HVAC market taking around 70% of the entire market totaling to a prediction of 24.28 Billion USD – including coolers and room air conditioners.
With global warming and increased temperatures taking effect, demand for cooling systems continues to rise in geographical areas where weather is a significant factor, such as Asia Pacific. Countries such as China, Japan and India are significantly driving the growth of this market, as the automotive air conditioning sector plays an important role in these geographical areas as they are still the leaders of the automotive manufacturers by volume. Rise in middle income (and improvement of environmental standard) in developing countries also push the construction boom and replacement of older technology in air conditioning.
Though it’s a positive outlook on the market, increasing demand also leads to tougher competitions. Many new technologies have been introduced in the market, from thermally-driven chiller that provides lower cost alternative to electrical air conditioning units, better sensor control, new software for energy monitoring and improved insulation technologies. The main factors which influence air conditioning efficiency and economic feasibility are still the refrigeration cycle and compressor component itself. With improvements of compressor mechanisms for less noise and less energy consumption, a slight improvement on blade design or incorporation of more compressor stages to save energy could go along the way.
With the blast of the French nuclear power plant a few weeks ago, safety of nuclear power plant designs has fallen under more scrutiny. Although according to sources the blast took place in the turbine hall and no nuclear leak was found, this event has brought more attention to improved design and operation standards.
Following the incident earlier this month Toshiba, a Japanese multinational company, announced the resignation of its chairman following a $6.3 billion loss in their nuclear sector –also withdrawing from the nuclear business. The two back to back events have highlighted the main two problems of nuclear power: high cost and environmental/safety concerns. Said to be a green technology, nuclear power raises concerns with potential nuclear meltdown and risk of safety from toxic waste, accompanying the fact that building a new plant cost around $5,000.00 per kilowatt of capacity with around 6 years of lead time. Each dollar invested on a nuclear power plant has about 2-10 less carbon savings and is 20-40 times slower compared to other alternatives. Yes, evidently nuclear power is found to be very reliable, enabling consistent baseload energy production at any time of day and night. Though, it has been questioned whether this reliability is worth the high cost of nuclear production, in fact all nuclear plants are still operating with 100% subsidized.
Transatomic power, a company started by two MIT PhD candidates, came up with a new approach to safer and cheaper nuclear reactors. Utilizing molten salt reactors, which has not really been used commercially and so far is only existed in paper, the technology is promised to cut initial cost and increase safety. Today’s conventional nuclear reactor is cooled by water, due to the high operating temperature, failure to do so will open the risk of radiation leak as well as hydrogen explosion. The high boiling point of salt helps solve some of the problems associated with the technology. The new design also incorporates ways of producing faster neutrons, enabling the reactor to burn most waste materials, thus keep waste to minimum. The ability of this smaller unit to be made in a factory (and not onsite) as well as cost reduction on the safety side makes this attractive economically as well. That being said, this generation 4 nuclear reactor is still in design and development will take years and high capital cost.