Air-conditioning frequently used terms and questions answered:
Mitsubishi Electric air-conditioning – Mitsubishi is a trusted global leader in the air-conditioning market, founded in 1921 the company has risen to the forefront of the industry. They offer a full range of products to suit all cooling, heating, heat recovery and ventilation applications.
Daikin air-conditioning – Daikin UK is a leading supplier of heating and cooling solutions based in Weybridge, surrey. The company is a fully owned subsidiary of Daikin Europe NV and offer a wide range of highly efficient climate control systems to provide the right solution for any application and requirement.
Mitsubishi Electric BSP (Business Solutions Partner) – The Mitsubishi Electric Partner Programme is open to all air conditioning businesses who share the companies values and standards – large or small. Mitsubishi Electric has created 2 types of partner – Accredited Installer and Business Solutions Partner to reflect the size of the Partner's business. These partner types do not reflect any form of commercial bias on there part but are a straight-forward reflection on the business’ stage of growth.
Business Solutions Partners will typically:
a. Have a permanent and staffed office
b. Have been trading for at least 2 years
c. Have a well-equipped and fully employed staff of core engineers
d. Bring to Mitsubishi Electric annual equipment purchases in excess of £200K
e. Have had a credit account with Mitsubishi Electric, or its Wholesaler, for at least 12 months
Daikin D1 approved installer – Daikin Air-conditioning UK Ltd products and systems are marketed and sold through an extensive UK network of installers who act as Daikin direct sales representatives throughout the UK. The D1 Partner Network is a recognised group of highly skilled independent companies who have an active and on-going dialogue with Daikin UK and provide many advantages to the customers they serve. These advantages are explained below and play a vital role in understanding why you should choose a Daikin air conditioning system for your premises and a D1 Partner to install and commission it.
WHY CHOOSE A D1 PARTNER FOR YOUR NEW AIR CONDITIONING SYSTEM?
· Established partners with the full support of Daikin UK.
· Expert installers with full design and technical capability.
· Detailed quotations explained to you in straightforward terms.
· Committed to training and developing installation engineers to the highest
· Recognised by Daikin UK with ‘Approved Installer’ status.
· Many D1 Partners offer full service and maintenance.
· Professional and established businesses with diverse industry experience.
· Many D1 Partners are recognised members of industry organisations and the
· leading trade associations –providing additional sources of information and
· Expertise for the installer.
· Access to tools and knowledge from Daikin UK for the most up to date product
Why air-conditioning - With air conditioning you can create the comfort in which you feel best, with the right temperature and a comfortable humidity. Modern air conditioners produce clean, healthy fresh air, dehumidify the air and prevent mold. All of this is able with neither draught nor noise.
In short, air conditioning makes you feel better, more active and fit, resulting in many advantages, because he or she who feels better is more creative and productive. And who doesn't like to be in a shop, café, restaurant or hotel with air conditioning, certainly in the summer?
Effect on personal performance - There is a close correlation between a person's performance and the temperature of his immediate surroundings. An environment that is too hot, too cold or too damp will certainly not contribute to higher working efficiency.
The graph illustrates this correlation. Performance begins to drop at about 22°C whilst above 26°C, it falls dramatically. It is important therefore, to keep temperature under control. Please note that the term 'effective temperature' is assumed to include humidity.
It is scientifically proven that:
· Accidents tend to occur more frequently during extreme temperatures – the optimum temperature appears to be about 20°C.
· Mental performance and work rhythm drop off sharply when it is too hot.
· Obviously, the provision of a constant environment is subject to many influences.
· For a building to operate comfortably and efficiently, due attention must be paid to its services.
Effect on indoor equipment - Air conditioning is not only bringing you comfort and clean, healthy air but it also has a positive effect on your indoor equipment. Especially the function of dehumidifying is to be considered. The low humidity level ensures a prolonged lifetime of your equipment. A humidity level of 40-60 % is advised for a good conservation of indoor equipment.
Effects on your health - More and more health concerned people pay attention to indoor air quality. You may experience health effects from indoor air pollutant soon after
exposure or possibly even years later. Air conditioning is able to prevent or reduce some of the health effects. The way houses and buildings are constructed to conserve energy has reduced the natural ventilation of fresh air, which, in the worst case, results in sick building syndrome. When you stop ventilation of the house, you'll reduce the energy required to heat and cool the house. But this means also that humidity levels are maintained within the house by re-circulating the same air and pollutants day after day. Dust, smoke, bacteria, viruses, mold, fungus, mildew and gasses circulate through the house. The dust comes from the skin, hair, clothes or just comes off shoes when we walk in and out. The mildew, fungus and molds can come in along with the dust. Gasses can be caused by dyes, paints, varnishes and adhesives. And, humidity of at least 50 % greatly reduces the survival rate of the influenza virus. Solutions to lower the concentration of indoor air pollutants are ventilation, filters and humidity control. Air conditioning offers these solutions. Every air conditioning unit has a filter. The type of filter depends on the type of system. A system with integrated ventilation requires a less effective filter. The efficiency of a filter is measured in the percentage of arrest of particles.
5 year warranty – The standard warranty provided by air-conditioning manufacturers is 3 years however if you have the equipment installed and correctly maintained by an accredited / approved supplier, such as a Mitsubishi Electric BSP or Daikin D1 company this can be extended up to a 5 year period.
Planned preventative maintenance regime – To safeguard the equipment efficiency and also the installers / manufacturers warranties a client should agree a suitable planned preventative maintenance regime with a qualified company. The PPM contract will consist of a number of agreed visits per annum where the installed equipment will be maintained in line with the supplying company’s recommendations. An emergency call out facility may also be available as part of the agreed contract.
Emergency call out – In the event of a mechanical malfunction you will need to call a suitably qualified air-conditioning engineer to investigate and rectify the fault. The engineers time both travel and site will normally be charged together with an associated parking or congestion charges.
24hr / 365 day cover – Depending on the importance of the area being conditioned an emergency call out system may be required that’s available 24hrs/365days per year, additionally with a guaranteed response time.
R12 refrigerant – R12 refrigerant is a CFC (Chlorofluorocarbon). The term CFC refers to a series of compounds developed since the late 1920's, which display an unparalleled range of qualities for use as refrigerants. This refrigerant quickly replaces most of the early refrigerants in many applications and they were almost solely used as the preferred refrigerant used in early and later refrigerated compressed air dryers. After many studies, it was found that the chlorine compound in this refrigerant (which is known to damage the Ozone layer) migrates from the refrigerant when ultraviolet rays come into direct contact. For this reason, legislation has been put into place (see above table) to limit and finally remove this substance from all of the countries subscribing to the |Montreal Protocol (see below) and all European union member states.
R22 refrigerant – R22 refrigerant is part of the group of HCFC (Hydro fluorocarbon) refrigerants that were developed somewhat later than CFC refrigerants. These were basically CFC refrigerants combined with a Hydrogen atom to give different characteristics. The manufacturers of refrigerated compressed air dryers used these as almost the sole refrigerant for production. Again, after many studies, it was found that the chlorine compound in this refrigerant (which is known to damage the Ozone layer) migrates from the refrigerant when ultraviolet rays come into direct contact. For this reason, legislation has been put into place (see above table) to limit and finally remove this substance from all of the countries subscribing to the Montreal protocol (see below) and all European union member states.
R134a, R404a, R407c – These named refrigerants belong to a group designated HFC (hydro fluorocarbon). These refrigerants are known to cause no damage to the Ozone layer and therefore are widely accepted as good replacements for both CFC and HCFC type refrigerants.
How can I tell what type of refrigerant is in my air-conditioning / refrigeration system - Looking at the data plate on your unit outdoor condensing unit. This will give you the make & model of the machine and the refrigerant type.
Heat pumps = Using air conditioners to heat - Heat pumps are an integral part of air conditioning technology. Heat pumps transfer heat from one environment to another via refrigerant. In cooling mode, heat pumps transfer the heat in an enclosed area (room, industrial process) to the outside air, resulting in a cooling of the area in question. This is the role that heat pumps play in common refrigeration and air conditioning systems. Heat pumps, however, also allow this process to be reversed. They can pump heat extracted from the outside air indoors, allowing indoor environments to be heated as well as cooled using the same technology.
Heat pump efficiency - Heat pumps offer numerous advantages as a heating solution. The same systems used to cool can also be used to heat, resulting in less initial investment and simplicity in operation and maintenance. They / Heat pumps also have an important advantage in the area of efficiency. Unlike fossil-fuel based heating systems, heat pumps extract available heat from the outside air. Heat pumps offer efficiency gains on the order of 3:1 and higher, compared to electrical heating. Thus for every unit of energy consumed by the heat pump, three or more units of heat are gained.
Capacity conditions – These are the basis of the cooling and heating capacities shown within a pricing list and must be investigated as part of the overall equipments design.
Indicated annual energy consumption – This figure indicates the approximate amount of energy consumed per year by the unit, based on a standard household model. The annual consumption is calculated by multiplying the total power input by an average of 500 hours per year in COOLING MODE AT FULL LOAD. In order to calculate the cost of annual energy consumption, you merely multiply this figure by your electricity tariff.
Energy Efficiency Ratio – This is the cooling output of the unit divided by the amount of electricity the unit requires to deliver it (total power input). In other words the higher the EER, the greater the energy efficiency.
Inverter control – "Inverter" air conditioners use a variable-frequency drive to control the speed of the motor and thus the compressor. The variable-frequency drive uses a rectifier to convert the incoming AC current to DC and then uses pulse-width modulation of the DC current within an inverter to produce AC current of a desired frequency. The AC current is used to drive a brushless motor or an induction motor. As the speed of an induction motor is proportional to the frequency of the AC current, the compressors runs at different speeds. A microcontroller can then sample the current ambient air temperature and adjust the speed of the compressor appropriately. All this electronics of course does add to the complexity and cost. Conversion energy losses from AC to DC and then back to AC can be as high as 4 - 6% for each conversion step.
Air-cooled water chillers – Air cooled water chillers provide via an air-cooled refrigeration circuit(s) a constant supply of chilled water to the equipment requiring the product. Water chillers can be utilised in arrange of applications from supplying water to air handling unit cooling coils or printing press rollers in order to assist in the printing process.
Replacement technology – With the phase out of R22 from the beginning of 2010, both Mitsubishi Electric and Daikin air-conditioning have introduced equipment that can re-utilise the existing pipe work. This obviously reduces the overall installation cost together with the level of disruption caused to the customer.
Cooling duty – This is the estimated level of cooling required for the air-conditioning application, normally expressed in a kilowatt rating.
Heating duty - This is the estimated level of heating required for the air-conditioning application, normally expressed in a kilowatt rating.
Return air – This is the path for the return air to find its way back to the rear of the fan coil where it will be filtered, its temperature monitored and
Supply air – when utilising a duct mounted fan coil the conditioned air is delivered to the office space via supply air grilles. These come in a range of square or circular design and also at an additional cost paint finishes.
Return air filter – This is the method of filtering the used return air prior to it entering the fan coil for cooling or heating. The return air medium can be of a washable or replacement depending on the units manufacturer.
Humidification – What is Humidity?
1 Water vapour in the air
2 Dew point (in °C or °F) tells us:
- At what temperature condensation will occur, if the air is cooled
- A measure of how much water vapour it holds in absolute terms
1 Relative humidity (in %rh) tells us:
-Saturation of the air from 0-100%
2 Other units
- Wet Bulb, WB
- Dry-Bulb, DB
The role of temperature - Temperature is clearly the most important comfort factor, including radiant temperature (for example influence of the sun). Large differentials in temperature increase comfort ‘complaints’. Draughts increase heat dissipation from the body.
The important role of humidity - Humidity affects the rate at which the body loses heat by evaporation. In hot weather, high ambient humidity reduces comfort levels by limiting the body’s ability to reduce temperature (low differential in body to air water vapour pressure).
Legionella risks - Legionnaires disease has been overblown by the media and it is not something you can contract from domestic air conditioning. The majority of cases are caused by incorrect cooling tower maintenance. Cooling towers are primarily used in commercial air conditioning to cool water cooled condensers and industry to cool recirculated water. They provide an ideal place for Legionella bacteria to grow (temps between 28 to 40°C) and the operation of the towers causes drift which aerosols the bacteria allowing people to breathe it in. There’s probably more danger handling potting mix than from a cooling tower because by law all towers have to be maintained and treated with biocide. Evaporative coolers have been suggested but not verified as potential disease transmitters. Modern evaporative coolers also have dump valves which further lessen the risk. The disease does not affect everyone who comes into contact with the bacteria. The groups most at risk are:
People over 50 years of age (predominantly males)
People with chronic lung disease
People with impaired immune systems (i.e. body defence mechanisms)
De-humidifiers - Mitsubishi Electric's compact, energy-saving dehumidifiers remove excess moisture from the air, and are simple to operate and easy to maintain. In addition to helping prevent the build-up of condensation and mold, these systems also provide benefit by helping making it easier to dry laundry.
Linear grille – This is a straight line supply air grille normally suited to perimeter applications, it is available in a number of air slot outlets. The non live (not supplying air) can be utilised as a method of return air.
Wall mounted air-conditioning unit – An indoor unit that provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Ceiling mounted air-conditioning unit – An indoor unit that provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Under ceiling air-conditioning unit – An indoor unit that provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Floor mounted air-conditioning unit – An indoor unit that provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Ceiling void concealed mounted air-conditioning unit – An indoor unit that provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Ultra thin ceiling void concealed mounted air-conditioning unit – An indoor unit that is ideally suited to hotel applications or those where ceiling voids are tight, the unit provides the conditioned cooled or heated air, supplied in a split, twin split, triple split, multi or variable refrigerant volume or variable refrigerant flow configuration.
Computer room close control air-conditioning systems – computer rooms require a close tolerance of both temperature and humidity control and this is established by utilising a CCAC unit, which when supplied in full function status can provide heating, cooling, humidification and de-humidification.
Air-cooled condensing unit – This is the outdoor heat exchanger which converts the refrigerant from a gas into a liquid form, allowing its expansion which creates the cooling effect with in the indoor fan coils evaporator.
Water -cooled condensing unit – This is the heat exchanger which converts the refrigerant from a gas into a liquid form, allowing its expansion which creates the cooling effect with in the indoor fan coils evaporator.
How does air-conditioning work –The principle of air conditioning always comes down to the same: Absorb energy in one place and release it in another place
The process requires an indoor unit, an outdoor unit and copper piping to connect both. Through the piping the refrigerant flows from one unit to another. It is the refrigerant that absorbs the energy in one unit and releases it in the other.
1 Indoor unit
a fan blows the hot indoor air over a heat exchanging coil through which cold refrigerant flows. The cold refrigerant absorbs the heat from the air and cooled air is blown into the room.
2 Copper piping
the refrigerant circulates through the units and the piping and take the heat from the indoor unit to the outdoor unit.
3 Outdoor units
through compression, the refrigerant gas are heated and its boiling point increases. In the outdoor unit the obtained heat thought compression is released to the outdoor air by means of a fan which blows the outdoor air over a heat exchanging coil.
The liquid refrigerant flows back to the indoor unit.
5 Indoor units
back in the indoor unit, the refrigerant is decompressed and thus enabled to extract heat form the indoor air.
Egg crate grille – Commonly used as a method of return air being a square 12mm typical core offer a very high free area keeping pressure drop and noise levels generation to a minimum.
Plenum box – These are the connecting box between the supply / return air grille and the ductwork system. They can be supplied internally or externally insulated together with an acoustic lining to reduce air noise.
RAL9010 colour 20% - 80% Gloss finish – Typically the standard white finish requested on ceiling mounted grilles, with a choice of either a dull or shiny paint finish depending on the level of gloss percentage.
VRF Mitsubishi Electric air-conditioning – Mitsubishi Electric's VRF air conditioning systems offer the luxury of distributed airflow and the independent control of indoor units. Installation flexibility and a wide selection of indoor unit designs and outdoor unit capacities ensure "best match" solutions for air conditioning needs, even for the most diversified requirements. Consideration for the environment during development has led to the manufacture of powerful, compact units that consume minimal energy, have a high coefficient of performance (COP) and contribute to maximum room comfort.
VRV Daikin high efficient heat recovery solution - The primary function and benefit of VRV heat recovery is the transfer of heat energy from areas that require cooling to areas with a need for heating, resulting in efficiency levels of up to 10:1
Split system – A split a/c system is simply a one to one combination of one indoor fan coil (evaporater) and one outdoor air condensing unit.
Twin split system – A twin split a/c system is simply a combination of two indoor fan coils (evaporaters) and one outdoor air condensing unit.
Triple split system – A triple split a/c system is simply a combination of three indoor fan coils (evaporaters) and one outdoor air condensing unit.
Multi split system – A multi split a/c system is simply a combination of up to four indoor fan coils (evaporaters) all served by one outdoor air condensing unit.
Air curtains – Air curtains are installed above opening doorways and provide a warm air barrier between in indoor and outdoor conditions. They can be provided ion a range of capacities and can be connected to refrigeration, low temperature hot water and electrical supplies.
Mini VRF system – A mini VRF unit allows a number of fan coils, in either wall, ceiling, concealed or under ceiling design to be connected to one larger capacity out door condensing unit.
Mini VRV system – A mini VRV unit allows a number of fan coils, in either wall, ceiling, concealed or under ceiling design to be connected to one larger capacity out door condensing unit.
Refrigeration – Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work. Refrigeration has many applications, including, but not limited to: household refrigerators, industrial freezers, cryogenics, air conditioning, and heat pumps.
BS box – A BS box is a branch selector box which is provided by Daikin and allows various fan coil units connected to the same air-conditioning system to independently generate heating and cooling at the same time.
BC box – A BC box is a branch connection box which is provided by Mitsibishi Electric and allows various fan coil units connected to the same air-conditioning system to independently generate heating and cooling at the same time.
Four (4) pipe fan coil units – A traditional method of air-conditioning a building where both chilled water and low pressure temperature heating is available. The fan coil has two separate coils and control valves which allow the flow of either into the air stream depending on the units temperature setting.
Mitsubishi Electric Lossnay unit - The unique Lossnay heat-exchange technologies developed by Mitsubishi Electric help refresh a room's air while leaving temperature and humidity largely unchanged. The Lossnay core is comprised of a diaphragm constructed of specially processed paper configured into a cross-flow, plate-fin structure. The advanced heat-transfer and moisture permeability properties of the paper help maximize the recovery of heat as air is circulated through the element. The result is substantial energy savings and a more comfortable indoor environment. Lossnay ventilators can be used alone or in combination with other air conditioning/ventilation systems.