Office air conditioning hire products

Calculating How Much Cooling is Needed

To determine the amount in KW of cooling needed in an office environment we need to take a number of factors into account, inlcuding:-

• Floor area and ceiling height
• Window area and amount of direct sunshire
• Amount of natural ventilation
• Gains from electrical equipment including computers
• Number of people

As a general guide for offices the starting point would be to allow 120 watts of cooling per square metre and then make adjustments for abnormal factors including those listed above. This means that our PM38Q model at 3.8 KW of cooling output would be adquate for an average office of 32 sq mt. However, as made clear below the ability of a monobloc unit to maintain an ambient near to 22 deg C when the incoming ventilation air reaches 30 deg C is limited and a split unit is better.

Choice Of Air Conditioner Type

The choice of which type of air conditioner to use will often depend on the practicalities of the installation. If you have opening windows in the vicinity of the air conditioner then the simplest installation will be a monobloc unit with the exhaust hose to the window. Where it is possible to locate a small condenser outside with the flexible refrigerant hose passing to the indoor (evaporator) unit then this has a number of advantages. A summary of the advantages and disadvantages of each type, monobloc, split or evaporative cooler, follows.

Monobloc air conditioners

• Simple to set up with hose to window
• Exhaust hose can be withdrawn and window locked at night
• Air conditioner needs to be located near to window which opens at lease 75mm
• Outside air is drawn into the window opening to replace exhausted air
• Room ventilation rate is increased
• Humidity in the room is reduced a little
• A neater installation which does not require hoses to be moved is achieved with window/wall vent holes
• Monobloc air conditioners can be moved easily to where needed
• Wiht both evaporator and condenser fans in one unit monobloc a/c units tend to be noisier than split units
• Some designs need a condensate tray to be emptied regularly
• Performance is reduced in very humid environments and when it is very hot (over 30 deg C)outside

Split air conditioners

• Require the condenser to remain positioned outside without creating a security problem
• Window needs to be kept open only 2cm for flexible refreigernat pipe to pass through
• Condenser can temporarily hung on straps just below a window so no permanrent fixing needed
• Condenser can be placed outside a door and brought in to allow door to be locked at night
• Operates in the same way as installed air conditioning by circulating room air across the cooling coils
• No increase in ventilation rates allowing more effective cooling of the room air
• Facility to disconnect flexible refrigerant pipework allows refrigerant pipework to pass through wall or window hole for a neater installation
• Humidity in the room is reduced significantly creating improved comfort in humid weather
• Condenser needs a location where there is no objection to appearance or condensate drips
• Any noise from the condensate fan is outside allowing quieter operation in the office
• More effective than the same output monobloc unit at cooling in hot and humid weather

Evaporative coolers

Evaporative coolers are not air conditioners but are a fan which evaporated water from a tank into the air flow to create a cool flow of air which has had moisture added. Their effectiveness is very dependent on the humidity of the ambient air. The dryer the air the more evaporation takes place and the lower is the resulting air temperature from the unit.

• Does not require a window for the exhaust hose or condenser refrigerant lines but does need to be kept topped up with water
• Should only be used where the additional moisture evaporated into the air will not be a problem or is vented away
• Ideal for local cooling in large areas
• Not suitable for cooling computer equipment or server rooms
• Smaller units reasonably quiet but larger ones have powerful fans and hence are relatively noisy

Spot Cooling

Cooling of the whole area is sometimes just not practical, in areas such as in warehouses and workshops. Spot cooling or creating respite areas may be the way forward. It may also be advisable to create air movement to increase heat transfer from staff and improve their comfort. Where heavy manual tasks are are involved spot cooling can have a significant effect in improving productivity in hot weather. Industrial units with more powerful output fans are most suitable for spot cooling.

The Value of Good Advice

The best outcome will only come from a proper assessment of the cooling load, the right choice of equipment type and the appropriate model installed to be convenient for you to use. We, at Aircon Hire Ltd have many years experience of assessing the options and choosing the most effective and convenient solution. Use our experience. We provide it free of charge and can visit site to fully familiarise ourselves with the application before making a recommendation, if your require.

Healthy Working Conditions

Whilst there is no statutory maximum working temperature here in the UK, studies show that comfortable, healthy working conditions lead to more efficient working practices and a reduction in days lost due to sickness. Government advice on the importance of thermal comfort is quite specific and takes account of the 6 basic factors of air temperature, radiant temperature, air velocity, humidity, clothing and meabolic heat. Go to the HSE website further information.

Portable Air Conditioner Effect on Humidity

All air conditioners remove moisture from the air as it is passed over the cold condenser coil and this has the effect of reducing humidity. However, it is relative humidity which is important to our comfort and a relative humidity of around 50% is most comfortable for humans. Refer to psychrometry, relative humidity for further information.
The good news on the use of portable units is that whilst they will reduce higher humidities they will not normally lower relative humidities below the 50% figure for best comfort. Very little condensate is produced once 50% relative humidity is reached.