We can supply all types of air conditioning units from leading brands such as Panasonic, Stulz, Hitachi, Mitsubishi etc. We install, service and maintain a large range of units. See details:
We can handle the installation of:
Split Air Conditioning Units: This is the most familiar form of installed air conditioning. They are called ‘split systems’ because they comprise of an indoor unit (mounted to a wall or ceiling), which re-circulates the air in the room, either cooling or heating to your requirements. The indoor unit is linked to an outdoor unit (condenser), by a pair of small diameter copper pipes contained in an insulating jacket. The heat removed from the room is dissipated to the atmosphere by the outdoor condenser. When heat is required, the system will run in reverse, taking heat from the outdoor condenser and transferring it to the indoor unit.
Multi Split Air Conditioning: This operates in much the same way as the ‘split’ system. The ‘Multi-split’ system enables a number of indoor units to be individually controlled from a single outdoor condenser.
- Up to four units can be operated in cooling only or heat only form.
- ‘Multi-split’ systems offer an ideal way to treat a number of areas whilst minimising the space required for outdoor units.
VRF Systems: Variable Refrigerant Flow systems are the most modern and sophisticated development of the ‘split’ systems.
- Up to 16 indoor units can be connected to a single large outdoor condenser.
- The outdoor condenser is constructed to respond proportionately to the number of indoor units operating, each being controlled for heating or cooling.
- Offering the ultimate in flexibility, individual indoor unit temperature can be changed independently, allowing personal choice as indoor and outdoor conditions change.
- VRF systems offer a year round solution to indoor climate control with unrivalled flexibility and energy efficiency.
Close Control Units: are precision air conditioning units to address the specific requirements of sensitive electronic installations and the need to ensure that they operate efficiently and reliably around the clock.
We would recommend STULZ Precision Air Conditioning Units should you require close control air conditioning.
The following is a STULZ article which discusses the difference between Precision and Comforting Air Conditioning.
Precision Air Conditioning or Comfort Air Conditioning?
Is it really a good idea to use a comfort air conditioner to maintain conditions in a small computer room?
The Simple Problem
Here is small equipment room containing telecommunications racks, file servers or a midrange computer and it needs cooling. The hardware manufacturer controlled conditions of 22.00C + 2.00C and a relative humidity of 50% + 5%. Is it really necessary? And how can it be achieved cost effectively?
The Obvious Solution
The cheapest solution is clear to business maintenance – just fit a small comfort fan coiling cooling unit tapped in the existing chilled water system. Alternatively, if the chiller is offline outside office hours, or shut down for the winter, just install a small comfort air conditioning unit or a split system. That’s all there is to it! Isn’t it?
The Hidden Costs
The obvious (i.e. the cheapest) solution is simply based on capital cost. No-one has considered running costs. At this point, take another look and uncover the hidden costs of comfort air conditioning.
Cooling Equipment Vs Cooling People
If we look at the differences between cooling people and cooling electronic equipment, we find a mismatch in requirements. Firstly, people add moisture to a room and electronics are dry. Latent cooling is the ability to remove humidity from the air, whereas sensible cooling is the ability to remove heat. You, therefore have to consider the actual sensible cooling capacity of any proposed air conditioning system.
Standard room air split system, residential central air handling plant and office building air conditioning systems are usually designed with a sensible cooling ratio of around 0.60 to 0.70. In essence this means that 60 to 70% of the work done by a comfort system will lower the air temperature and 30% to 40% of the work will remove moisture from the air. This is a typical ratio for a building full of people with a moderate degree of traffic.
Cooling Capacity: Total and Sensible In contract, the precision air conditioning units manufactured by STULZ have a much higher sensible cooling ration in the region of 0.9 to 1.0. This means that over 90% of the work done by a STULZ unit will be devoted to cooling the air with less than 10% used in the removal of moisture.
How does this affect the cost equation of Comfort Vs Precision cooling?
- The cooling capacity stated for a comfort unit is usually its total cooling capacity (i.e. sensible + latent). This means that you need more comfort capacity to do the same job as a STULZ precision air conditioning system. A general rule is that it takes 9.0 kw of comfort capacity to do the same job as a 6.0 kw precision cooling unit (i.e. 9.0 kw x 0.7 = 6.3 kw).
- If the comfort system is removing moisture, it will drag the relative humidity level down well below what is considered to be acceptable. With no personnel adding moisture to the room, the only long term answer is to install a wall mounted humidifier at additional cost.
The precision air conditioning units manufactured by STULZ take very little, if any, moisture from the air unless the automatic control system determines that this a necessity and energizes the dehumidification saver circuit. For the small amount of re-humidification that may be required, your STULZ precision unit has an integral humidifier that will add just enough moisture to maintain the computer manufacturer’s recommended level.
Equipment Load Density
The average room will, comfortably, accommodate a lot more electronic equipment than people. Consequently, computer or switch rooms require much more cooling capacity per square metre of floor space than the typical office. For general guidance, the “rules of thumb” are 5.0kw of comfort cooling for every 35-40 sq metres of office space compared to 5.0kw of precision air conditioning for every 7-15 sq metres of equipment space.
Precision Temperature Control
If the equipment room temperature gets too high or low, date integrity and reliability can be severely affected, leading to costly downtime. Some computer manufactures state in their warranty conditions that their equipment must be maintained in stable conditions of 22.00C + 1.00C. The rate of change is also very important where large slabs of heat load can be energized and de-energized several times a day. STULZ precision air conditioning systems have been specifically designed to maintain close tolerance conditions with ease. Typical office comfort systems simply cannot provide this level of control and the very best that can be expected is + 3.00C.
Air Distribution and Filtration
With the high heat load density identified in the typical equipment room comes another big difference in air conditioning needs. To achieve the high sensible cooling ratio, remove the high density heat load and carefully maintain the temperature and humididy levels, requires a very large volume of air. If we compare the average comfort system, which will move air through its cooling coil at the rate of about 230/270 I/s per 5.0kw of capacity, to the average precision system, which will move air at the rate of about 350 to 400 I/s, we find that the precision system is moving nearly twice the amount of air. The much large air volume also contributes to good air distribution in the space and a better level of filtration.
Dust is the enemy of any electronic equipment. Dust will build up on printed circuit boards and charged electronic components causing overheating, short service life and premature failure. Dust in the head of tape and disk readers will cause physical damage to storage media.
Comfort systems usually incorporate this disposable or washable filters of undetermined efficiency. They are put there of protect the unit from damage. The filters fitted to a STULZ precision air conditioning system are rated at Eurovent 4/5-EU 4 grade and have been selected to remove dust from the re-circulated airflow to protect the customers’ vital electronic equipment. Higher efficiency filters can be installed for specific applications.
A major consideration that is often overlooked is that most computer systems and telecommunications switch facilities operate continuously. This means 24 hours a day, 7 days a week for 52 weeks a year and any shutdown needs to be planned well in advance.
The air conditioning system is, therefore, in operation continuously. The circulating fan runs 8,760 hours a year with all the other components turned on and off as directed by the microprocessor environmental monitoring and control systems.
Precision Humidify Control
Humidify or lack of it can be a major problem to electronic equipment. High humidity levels cause paper handling problems and the possibility of condensation in the electronics. Low humidity levels give rise to static electricity where the discharge from a finger touch can destroy components and alter data. In addition, magnetic media can suffer oxide shedding increasing the possibility of lost or altered data.
The target area is 45% to 55% which is well within the grasp of a STULZ precision unit, designed with the control accuracy to meet and maintain a set point of 50% + 5%.
Comfort air conditioning has two main modes of operation: cooling and perhaps heating. Part of the nature of comfort cooling is to dehumidify, but this takes place continuously and there is no method of re-humidifying the air. Basically, a comfort system rarely offers any control whatsoever over humidity levels.
Comparison of Costs
Providing an apples with apples comparison of capital costs is impossible. Unfortunately, a precision system Vs a comfort system is an apples with oranges situation and the comparison is unfair.
A STULZ precision air conditioning system is an entirely different animal to the typical comfort split system and offers one huge economic advantage – lower operating costs. Some operating costs are not easily quantifiable, such as the cost of downtime when all the system users are starting at blank screens, or when the telecommunications network is unavailable for an hour or so. However, the basis system operating costs can be put into context. Firstly we make some assumptions:
- Every 1.0kw of total cooling needs 3.5kw of power input
- Compressor and fan motors are 90% efficient
- The humidification period is 3,650 hours (November to March)
- The STULZ precision system has a 0.9 sensible heat ratio
- The comfort split system has a 0.6 sensible heat ratio
Service and maintenance is a vitally important requirement for all air conditioning systems and it can save you money and extend the life of your air conditioning units. If you maintain and service your system you will get the very best results so that the air conditioning operates at 100% efficiency, 365 days a year.
As standard most manufacturers offer a 3-year warranty, provided that a maintenance contract is taken out for that period. Therefore we recommend to all our customers that their units are maintained every 6 months (depending on their usage), and that a maintenance contract should be taken out after installation.
Included in each preventative maintenance visit:
- Filter cleaning
- Removal of indoor fan for cleaning and drain tray if necessary
- Spraying of indoor coils with coil cleaner
- Spraying of outdoor condensers with condenser cleaner
- Refrigerant leak testing
- Full operational and safety checks, i.e. pressures, volts, amps, temperature etc.
- Nitrogen and cleaning products
Should you like a quote for a preventative maintenance contract please contact us (01) 462 4338 or by email to firstname.lastname@example.org.
Whilst our preventative maintenance is designed to reduce any breakdowns, should one occur you can be assured that it will be repaired promptly; as our air conditioning service is available 24 hours a day, 365 days a year provided you have taken out a preventative maintenance contract with us.
Our Engineers are well trained and very competent, repairs are carried out fast and efficiently, with the air conditioning back up and running as soon as possible.
Air conditioners and refrigerators work the same way. Instead of cooling just the small, insulated space inside of a refrigerator, an air conditioner cools a room, a whole house, or an entire business.
Air conditioners use chemicals that easily convert from a gas to a liquid and back again. This chemical is used to transfer heat from the air inside of a home to the outside air.
The machine has three main parts. They are a compressor, a condenser and an evaporator. The compressor and condenser are usually located on the outside air portion of the air conditioner. The evaporator is located on the inside the room, sometimes as part of a furnace. That’s the part that heats your room/building.
The working fluid arrives at the compressor as a cool, low-pressure gas. The compressor squeezes the fluid. This packs the molecule of the fluid closer together. The closer the molecules are together, the high its energy and its temperature.
The working fluid leaves the compressor as a hot, high pressure gas and flows into the condenser. If you looked at the air conditioner part outside a house, look for the part that has metal fins all around. The fins act just like a radiator in a car and helps the heat go away, or dissipate, more quickly.
When the working fluid leaves the condenser, its temperature is much cooler and it has changed from a gas to a liquid under high pressure. The liquid goes into the evaporator through a very tiny, narrow hole. On the other side, the liquid’s pressure drops. When it does it begins to evaporate into a gas.
As the liquid changes to gas and evaporates, it extracts heat from the air around it. The heat in the air is needed to separate the molecules of the fluid from a liquid to a gas.
The evaporator also has metal fins to help in exchange the thermal energy with the surrounding air.
By the time the working fluid leaves the evaporator, it is a cool, low pressure gas. It then returns to the compressor to begin its trip all over again.
Connected to the evaporator is a fan that circulates the air inside the house to blow across the evaporator fins. Hot air is lighter than cold air, so the hot air in the room rises to the top of a room.
There is a vent there where air is sucked into the air conditioner and goes down ducts. The hot air is used to cool the gas in the evaporator. As the heat is removed from the air, the air is cooled. It is then blown into the house through other ducts usually at the floor level.
This continues over and over and over until the room reaches the temperature you want the room cooled to. The thermostat senses that the temperature has reached the right setting and turns off the air conditioner. As the room warms up, the thermostat turns the air conditioner back on until the room reaches the temperature.
Imagine that you took an air conditioner and flipped it around so that the hot coils were on the inside and the cold coils were on the outside. Then you would have a heater. It turns out that this heater works extremely well. Rather than burning a fuel, what it is doing is “moving heat.”
A heat pump is an air conditioner that contains a valve that lets it switch between “air conditioner” and “heater.” When the valve is switched one way, the heat pump acts like an air conditioner, and when it is switched the other way it reverses the flow of the liquid inside the heat pump and acts like a heater.
Heat pumps can be extremely efficient in their use of energy. But one problem with most heat pumps is that the coils in the outside air collect ice. The heat pump has to melt this ice periodically, so it switches itself back to air conditioner mode to heat up the coils. To avoid pumping cold air into the house in air conditioner mode, the heat pump also lights up burners or electric strip heaters to heat the cold air that the air conditioner is pumping out. Once the ice is melted, the heat pump switches back to heating mode and turns off the burners.