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 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.
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.
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.
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).
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.
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.
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.
Geothermal power market has been showing sustainable growth globally, with many installations in developing countries. As people turn to renewable sources while demand for energy is experiencing rapid growth, geothermal is found to be a reliable energy source and current development is calculated to increase global capacity by over 25%. Geothermal power plants can usually be divided into several types of cycles, including binary, flash, double flash and more. Flash power plants are found to be the most common forms of geothermal power plant and specifically, we are going to talk about the double flash cycle.
A flash system produces high pressure dry steam to move the turbine, generating electricity after going through a flash separator. A double flash system uses two flashes separating systems in order to generate more steam from the geothermal liquid and increase cycle output. The cycle starts with high temperature fluid extracted from a geothermal source to a high pressure separator (HPS) for flashing. The HPS produces a saturated steam that enters the high pressure turbine and the remaining brine is directed into a secondary low pressure separator (LPS). Reducing the flashing pressure increases the mixture quality in the LPS, which results in higher steam production. Low pressure saturated steam is mixed with the steam flow exhausted from the high pressure turbine and the resulting steam flow is directed to the low pressure turbine and produces more electricity. Steam that is exhausted from the low pressure turbine will then be compressed and injected back to the ground. In a flash system, separator pressure has a significant effect on the amount of power generated from the system – and the flashing pressures also influence double flash cycle significantly. In order to optimize one design, the value of parameters versus cost of operations should be taken into account.
Power generation and energy sectors happen to be very politically volatile. With our new leader in the USA taking control, we are expecting a shift in technology trends. The topic of bringing more coal fired power plants back to the equation has been brought up quite often, coming after Trump’s skeptical statement regarding global warming and climate-change. To follow that statement, Donald Trump pledged to lift restriction on US agencies funding new coal plants in other parts of the world. In addition, Australia’s minister also has been arguing regarding adding new coal power plants into the mix. As world’s largest coal exporter, it should economically make sense for Australia to forego with the plan.
There are three major categories that typically determine whether a technology would be suitable to be implemented: cost to public, reliability of supply and environmental impact. The old coal power generator is found to be less reliable as well as less environmentally friendly. Consequently, a new technology must be used to provide “cleaner” energy from coal. Southern Company has become one of the first private sectors using new technology to produce energy from coal. The technology is said to be generating electricity while at the same time capturing carbon dioxide from coal. Maybe if this technology is implemented, we will come back to coal.