Call 020 7582 8950 Air Conditioning Hire (London) Ltd

Portable Air Conditioning - Problem Applications

'We don't have access to a window'

We are often asked if we have a unit which does not require a window to work. This is usually because an internal room is too hot and there is no immediate access to an opening window. Typically server/comms rooms and meeting rooms are partitioned off near the core of the building. Commonly buildings have their HVAC systems designed for an open plan office layout. Partitioning of cellular offices can create hot spots through the lack of any air conditioning outlet in an office.

It is important to understand that air conditioning moves heat - usually from inside the building to outside so when there is no obvious location to which hot exhaust air can be piped, there is a problem.

Sometimes evaporative cooling is suggested as a solution but this is not appropriate as there is inadequate ventilation for it to work properly. Another solution which is often put forward is to pipe the hot air into the ceiling void above the room. Unless there is a means of getting this heat away most of the heat will simply come back down into the room.

We look at a number of possible options:-

  • Use of a monobloc unit with the exhaust piped to a building extract duct so that the building's installed system can take the hot air outside. Care needs to be taken to ensure that that building system is not compromised and the flow of air across the portable unit is not impeded.
  • Use of a monobloc unit with the exhaust piped to the ceiling void provided that the ceiling void extends across adjacent office areas and either that heat will not cause problems in those other offices or the building air conditioning system will remove the heat from adjacent areas. Extended ductwork above the ceiling may be needed to ensure that the heat is taken away from the overheating area.
  • Use of split unit with the condenser placed where the heat will not cause a problem and might vent naturally from the building.
  • Use of a monobloc unit in conjunction with a fan assisted temporary duct to allow us to discharge the hot air over a longer distance to where it can be vented from the building.
  • Use of a water cooled split unit which allows us to place the condenser up to 30 mt away from the room.

Phone us on 0207 582 8950 if you have a problem to which there is not obvious solution. We can usually devise a practical solution and we can arrange a site survey free of charge is need be.

'We have monobloc units in our server room but the temperature is still too high in hot weather'

This is a problem which we come across and to solve it we need to understand why it occurs. Monobloc units cool the air by around 12 deg Celsius as the air passes through the machine. They also exhaust a significant volume of air from the server room to outside via the exhaust duct and this air is replaced in the room by air from the surrounding area or from replacement air entering the partially open window. On a hot day with the replacement air coming into the room at 30 deg C the room temperature cannot fall below a figure somewhere in the range of 18-30 deg C. (18 deg C being the temperature of the cold air from the unit) If this figure is actually 24 deg C and the temperature behind the racks is inevitably somewhat higher, then no matter how many monobloc units are added, the IT equipment will be overheating.

The solution is to use split units and to seal the room as well as possible. Split units will re-circulate the same air through the evaporator (Indoor) units until the temperature drops to the setting required. The total cooling capacity will need to exceed the heat being given off by the IT equipment.

Talk to us on 0207 582 8950 about your IT cooling requirements - we will look for the right solution.

'We are in an older building and our 13 amp circuits will not take the extra load of air conditioning'

Most air conditioning has a coefficient of performance of about 3. This means that you get 3KW of cooling for every 1KW of power which the unit uses. So if you need 15KW of cooling to keep staff comfortable then you will have a continuous load of 5KW which is 21 amps and you will need a temporary ring main on a 32amp circuit breaker to supply the air conditioners. The extra capacity is needed to allow for peak loads on start-up of the compressors in the machines.

Call us on 0207 582 8950 if you have a problem. We can advise on the amount of cooling you need and we can liaise with your electrician to ensure that your air conditioning will work properly.