air condition mold
2008-08-20

History While moving heat via machinery to provide air conditioning is a relatively modern invention, the cooling of buildings is not. The ancient Romans were known to circulate aqueduct water through the walls of certain houses to cool them. As this sort of water usage was expensive, generally only the wealthy could afford such a luxury.

The 2nd century Chinese inventor Ding Huan (fl. 180) of the Han Dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered. In 747, Emperor Xuanzong (r. 712–762) of the Tang Dynasty (618–907) had the Cool Hall (Liang Tian) built in the imperial palace, which the Tang Yulin describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains. During the subsequent Song Dynasty (960–1279), written sources mentioned the air conditioning rotary fan as even more widely used.

Medieval Persia had buildings that used cisterns and wind towers to cool buildings during the hot season: cisterns (large open pools in a central courtyards, not underground tanks) collected rain water; wind towers had windows that could catch wind and internal vanes to direct the airflow down into the building, usually over the cistern and out through a downwind cooling tower. Cistern water evaporated, cooling the air in the building.

Ventilators were invented in medieval Egypt and were widely used in many houses throughout Cairo during the Middle Ages. These ventilators were later described in detail by Abd al-Latif al-Baghdadi in 1200, who reported that almost every house in Cairo has a ventilator, and that they cost anywhere from 1 to 500 dinars depending on their sizes and shapes. Most ventilators in the city were oriented towards the Qibla, as was the city in general.

In 1820, British scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate. In 1842, Florida physician John Gorrie used compressor technology to create ice, which he used to cool air for his patients in his hospital in Apalachicola, Florida. He hoped eventually to use his ice-making machine to regulate the temperature of buildings. He even envisioned centralized air conditioning that could cool entire cities. Though his prototype leaked and performed irregularly, Gorrie was granted a patent in 1851 for his ice-making machine. His hopes for its success vanished soon afterwards when his chief financial backer died; Gorrie did not get the money he needed to develop the machine. According to his biographer Vivian M. Sherlock, he blamed the "Ice King", Frederic Tudor, for his failure, suspecting that Tudor had launched a smear campaign against his invention. Dr. Gorrie died impoverished in 1855 and the idea of air conditioning faded away for 50 years.

Early commercial applications of air conditioning were manufactured to cool air for industrial processing rather than personal comfort. In 1902 the first modern electrical air conditioning was invented by Willis Haviland Carrier in Syracuse, NY. Designed to improve manufacturing process control in a printing plant, his invention controlled not only temperature but also humidity. The low heat and humidity were to help maintain consistent paper dimensions and ink alignment. Later Carrier's technology was applied to increase productivity in the workplace, and The Carrier Air Conditioning Company of America was formed to meet rising demand. Over time air conditioning came to be used to improve comfort in homes and automobiles. Residential sales expanded dramatically in the 1950s.

In 1906, Stuart W. Cramer of Charlotte, North Carolina, USA, was exploring ways to add moisture to the air in his textile mill. Cramer coined the term "air conditioning", using it in a patent claim he filed that year as an analogue to "water conditioning", then a well-known process for making textiles easier to process. He combined moisture with ventilation to "condition" and change the air in the factories, controlling the humidity so necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name of his company. This evaporation of water in air, to provide a cooling effect, is now known as evaporative cooling.

The first air conditioners and refrigerators employed toxic or flammable gases like ammonia, methyl chloride, and propane which could result in fatal accidents when they leaked. Thomas Midgley, Jr. created the first chlorofluorocarbon gas, Freon, in 1928. The refrigerant was much safer for humans but was later found to be harmful to the atmosphere's ozone layer. Freon is a trademark name of DuPont for any Chlorofluorocarbon (CFC), Hydrogenated CFC (HCFC), or Hydrofluorocarbon (HFC) refrigerant, the name of each including a number indicating molecular composition (R-11, R-12, R-22, R-134). The blend most used in direct-expansion home and building comfort cooling is an HCFC known as R-22. It is to be phased out for use in new equipment by 2010 and completely discontinued by 2020. R-12 was the most common blend used in automobiles in the US until 1994 when most changed to R-134. R-11 and R-12 are no longer manufactured in the US, the only source for purchase being the cleaned and purified gas recovered from other air conditioner systems. Several non-ozone depleting refrigerants have been developed as alternatives, including R-410A, known by the brand name Puron.

Innovation in air conditioning technologies continue, with much recent emphasis placed on energy efficiency and improving indoor air quality. As an alternative to conventional refrigerants, natural alternatives like CO2 (R-744) have been proposed.

How do they protect you

One cause of indoor air contamination is due to bacterial and fungal contamination of air filters, heat transfer coils and ductwork within airconditioning systems that are poorly designed and maintained. Air passes through dust filters prior to being cooled at the cooling coil and blown out from the air conditioner. Dust filters are usually intended to remove larger particles that would foul the cooling coil and aren't effective at removing small (respirable) airborne particles. As the larger particles are trapped by the filter, they form a layer that Improves the removal of respirable particles, but at the same time they reduce the air flow and (If they become wet) provide nutrients for fungi and mould to grow inside the air conditioner. Also, when air cools at the coil, It drops Its moisture to the coil surface and If this Is not allowed to drain away, fungi and bacteria can grow there too. Since the building air Is being circulated through this system, fungi and mould spores and bacteria and odorous VOCs are released through the use of the air conditioner and contaminate the air. Regular maintenance of air-conditioning systems should detect and prevent these problems. Air conditioning ducts should be regularly inspected to ensure there is no excessive dust buildup on surfaces (airborne dust will deposit to these surfaces over time). Fungi and mould growths can occur In ducts where condensation occurs. If these Can be seen, call an air conditioner specialist to fix the cause of the condensation and to clean or remediate the air conditioner. Ideally, this will prevent mould and fungi from continuing to grow. If you find large amounts fungi or mould growing in the air conditioner ducts, first you need to fix the cause of moisture that's supporting the growths. Fungi and moulds won't grow without moisture/condensation. If you clean them without fixing the moisture problem, they'll re-occur. Do not try and remove large quantities yourself and/or clean them in bleach. Mould can be highly toxic and if in large quantities should always be handled by a professional. Bleach doesn't kill mould, but make it invisible whilst also feeding it. For small amounts of mould,use an 80%-20% white vinegar solution. Cleaning ducts requires specialised equipment to get along the long duct lengths and most importantly to capture and contain the dust released so that it doesn't contaminate your home. Make sure you use a reputable professional cleaner and ask them questions about these things. If you do nothing your air conditioner will continue to release odorous gases and fungal spores, which can impact respiratory health, such as flu-like symptoms, asthma, respiratory tract infections, allergic reactions and toxic reactions.

Regular Servicing

Make sure you get your air conditioner serviced regularly, and try to open your doors and windows regularly to allow ‘fresh' air to be included into your air conditioners cycle. The only real way to know if your air-conditioning system is clean is regular inspection. It is fair to say that new installations would be expected to have a clear period of health of approximately five years, however our industry is no longer in a position to assume these things. Some systems may be fine for 10 years, others one year. Related matter: all of the above discussion has been for refrigerative airconditioners - they have a refrigerant liquid pumped around the equipment under pressure and this refrigerant assists in removing heat. Many domestic airconditioners are evaporative, and in these the building air is pumped through a wet medium and as water evaporates from the medium the air is cooled. Important considerations with these are: - They work best in climates where relative humidity is low (this means there's more evaporation and therefore cooling) - The water reservoir supplying the medium must be kept clean by regular replacement and cleaning of the reservoir - They Introduce large amounts of moisture into the building air and you must be careful of condensation occurring. Also some people use humidifiers [cool mist or ultrasonic humidifiers] to try and ease breathing difficulties. However, these will also introduce large amounts of moisture into building air and their reservoirs can become breeding grounds for biological contaminants, with resulting potential for causing diseases such as hypersensitivity pneumonitis and humidifier fever. Dehumidifiers are also used In some buildings - these may be refrigerative (like the airconditioners) or use a dessicant drying system. In both cases, the water removed from air must be drained away or collected for disposal. Food refrigerators will have a condensate tray from cooling and auto-defrost operation - these are usually located at the rear of your refrigerator and rely on the water to evaporate away. While small compared to an airconditioner, you should inspect these every year or two to check they're operating and clean. A general rule: Condensate trays in any air handling system must drain and not support fungi and bacteria - regular Inspection will confirm they continue to function.

Gree and Daikin will build a air condition mould factory Japanese air condition enterprise-Daikin declared that, it combined with domestic air condition enterprise-Gree Electrical Home Appliances (simplify with Gree) to built a air condition meter mould factory in Huaxin. In addition, Gree will get OEM orders from Daikin. Daikin entrust Gree with home air-condition production which are mostly face to Japanese market from Autumn 2008 the order is 500 thousand per year. Daikin indicates that, new factory plans to start operation in Autumn 2009, total investment is up to 20-40 billion yen (about £¤1.4 billion yuan to £¤2.8 billion yuan ). Investment proportion and other details both side will be decided later. Daikin and Gree will develop power-saving type air-condition together, and achieve one million productions in 2009. The combination of Daikin and Gree is aim to achieve low-cost production, and enlarges the sales of energy-efficient products abroad. The price in Japan is fierce, so Daikin is always in the state of loss in home compact machine. Though Daikin have declared the joint news, Gree refused to talk about it. Chairman Secretary of Gree Company Liu xinghao declared that,”we don’t have any news to disclose present, and it isn’t necessary to publish”, when he accepted journalist’s interview, "it is unusual for Japanese air-condition factory cooperate with Chinese enterprise in the stage of product designing and component developing." household electrical appliances expert Lu Renbo declared that,"Daikin has strong advantage in technology, and Gree has strong ability in capacity and manufacture, both two enterprises supplement each other, increase competitiveness via deep cooperation. And the trend of air-condition is environmental and energy-saving, they exploit this kind of air-condition together, and the market is not bad."