Air Conditioning

In our units a heat pump is used in which the device uses energy to transfer heat from a cooler to a hotter location. In a standard air conditioner an unidirectional heat pump which moves heat only form a cool interior into a hotter exterior. Air conditioning units can reverse the refrigeration cycle, from removing cool air from the exterior and moving into the interior, it will remove the heat from the cooler exterior and re-produce it in the warmer interior, therefore heating the room in a given area. Using an air conditioner is a far more efficient way of heating a space as opposed to using an electric heater which uses an element to cool the room. When the heat pump is enabled the indoor evaporator coil switches roles and becomes a condenser coil, producing the heat, and the outdoor becoming the evaporator coil, venting air colder than the ambient outdoor air.

Heat pumps work most efficiently in mild winter climates, between 4-13 degrees Centigrade, this is because heat pumps become inefficient in extreme cold temperatures as ice forms on the outdoor unit coil, blocking the air flow, to compensate for this the air conditioner must temporarily switch back into the regular cooling mode to switch the outdoor evaporator coil back into the condenser coil to de-ice the coil. An air conditioner used this was used electrical resistance therefore heating the indoor air path in this mode to compensate for the temporary air conditioning, which would drop in interior temperature without this option. The icing problem becomes worse the lower the outdoor temperature reaches.

Portable air conditioners are one complete unit, on wheels to ensure it can easily be moved around the home or office. The portable units available are vast, ranging from 6,000 to 60,000 BTU, some will even come with heaters built in. Portable A/C units are commonly found in 2 forms, split and hose. Evaporative coolers are also available in a portable form. Air Cooled portable air conditioners are compressor based, using compressed refrigerant to exchange heat, in the same way a car and typical air conditioners work. With this type of system the air is dehumidified whilst it’s being cooled. They collect the water that is condensed from the cooled air, and will produce hot air which is vented outside the cooled area( released from the outdoor air conditioning unit).

In 1990 Aimed to reduce consumer energy bills by approximately 25 billion pounds in 10 years. As of the millennium, the standards reduced the American carbon emissions from fossil fuel consumption by almost two percent. To keep the emissions down, prices have increased slightly; the Lawrence Berkeley National Laboratory research indicated the benefit energy savings are over three times the cost on a net-present value basis.

In 2000, the standards reduced the peak generating needs by approximately 21,000 megawatts (MW), which is over 70 300 MW power plants thus reducing the costs. As redundant applications are replaced by new ones the positive impact of the energy efficiency standards will continue to grow. From 1990 to 2030, it is estimated that consumers and businesses will save approximately 90 billion pounds just from the existing standards that have been adopted. Currently, the debate concerning appliance efficiency standards has revolved around the Bush Administration’s proposal to weaken the standard for air conditioners from the SEER 13 standard set by the Clinton Administration to a SEER 12.

Air Conditioning units are operated by electricity as standard. Any input of energy into the system that will be used to maintain a set temperature, will require the energy rate from the air conditioner to increase. This increase has the effect that for each energy input the air conditioner has to remove it. In order for the air conditioner to do that the air conditioner must increase its consumption by the reverse of its efficiency. As an example, presume a closed system had a 100 watt light bulb activates, and the air conditioner has an efficiency of 200%, the air conditioner’s energy consumption will increase by 50 watts to compensate for this, thus making the 100W light bulb consume a total of 150 watts of energy.

Air conditioners typically operate at efficiencies of significantly greater than 100%, see the next blog.

With air conditioning units there are little maintenance that needs to be done to the machine to ensure it is working at optimum temperature. To ensure your unit is clean and is producing filtered air you need to clean the filters (simply pull out and wash in warm water) and ensure the inside of the unit is clean. If your unit is not cleaned and maintained regularly bacteria builds up and promotes the growth of germs, in poor circumstances Legionella pneumophila, the bacteria responsible for legionnaire’s disease.

Air conditioning units have many functions built in to prevent the growth of bacteria, such as, air filtration, dehumidification, cooling, humidification etc. When air conditioning is used, it filtrates the air, providing you with a safe and clean environment. Air conditioning has also been proven to be advantageous to sufferers of allergies and asthma.

In the summer seasons, air conditioning provides a cool sanctuary for the elderly and saves lives of many. Some councils have even created cooling centers for the less fortunate who cannot afford air conditioning.

Poorly maintained units can make excessive noise and in some extremes can even contribute to loss of hearing if endured for long times. Properly operational and maintained units create little to no noise, not effecting hearing.

The Refrigeration Cycle

Refrigeration cycles are the model used in refrigerators and air conditioning units and heat pumps. The man differences between the two is, heat pumps change from cooling to heating and refrigerators will cool only. Technically in the heat pump cycle it incorporates the refrigerator cycle. To put it in another way, a heat pump chooses which side of the system rejects the heat that was accepted by the evaporator to give the user the required temperature.

A heat pump removes heat from a low-temperature source, and expels it to a high-temperature sink, with a bit of help from external mechanical works.

The opposite of the heat pump cycle is called the thermodynamic power cycle. In this cycle, heat is supplied from a high-temperature source, to the heat engine, also a part of the heat is used to produce mechanical work and the rest being rejected to a lower temperature sink. Having this here satisfies the second law of thermodynamics.