Air Handling Plant with Heating and Cooling

In large areas it is often appropriate to use air handling units which can be roof mounted or located in purpose made plant rooms. The air can be distributed via a ducted system and ceiling diffusers discharging the air into occupied areas.

Fan Coil Unit Systems with Chiller Plant

In circumstances where large buildings are split into smaller individually occupied areas, it can be more appropriate to use multiples of ceiling void fan coil units. These units would incorporate heating and cooling coils fed from main boiler and chilled water plant and would discharge air through ducted systems. Each fan coil unit can be independently temperature controlled to give more accurate control to each zone throughout the building.

Split Systems

When smaller areas require air conditioning it is often appropriate to install split systems which comprise of an indoor unit providing cool air to occupied areas and an outside unit discharging the heat to atmosphere. The indoor units can be ceiling or wall mounted, and are connected to the outdoor units by refrigerant lines and control cables. Most of these types of system can be operated by a hand held remote control or an automatic control system where appropriate.

Cooling by Ventilation

Where an area has high internal heat gains, a limited amount of cooling can be achieved by using supply and extract ventilation. This type of system can be successful in night clubs where the supply air is required at night when the outside air is relatively cool. However when a factory has heat emitted from equipment it is often effective to extract air from as close to the heat emitting equipment as practical to minimise the effect on the internal air temperature. An equal volume of outside air would be introduced to replace the air being extracted which can help to minimise the increase in the internal temperature. A good volume of general supply and extract ventilation can often help to prevent the internal air temperature rising too much. However as the outside air temperature rises during the summer the effect of cooling by ventilation during the day is considerably reduced and other methods such as evaporative cooling should be considered to be used in conjunction with the supply air.

The effect of cooling by ventilation can be increased by using the system to provide night purging. This can reduce the residual heat within the building during the night. However this requires a good control system to avoid over chilling of the building and activation of the heating.

Evaporative Cooling (View Evaporative Cooling Brochure)

Evaporative cooling is the natural process of water evaporating as warm air is blown across its surface. This process occurs naturally when a warm wind blows across the surface of the sea. This causes some of the water to evaporate and the latent heat of evaporation lowers the temperature of the air. This is why a cool breeze can be felt at the coast on a warm day. The evaporative cooling units reproduce this process when outside air is delivered into a building via this type of equipment and supplies cool, fresh air.

In large areas such as factories it is often prohibitive to cool by the conventional electric compression method, from both the installation and running cost aspects. Evaporative cooling is the perfect solution for these areas as it is less costly to install and the running cost of this type of system can be less than 20% of a conventional air conditioning system designed to cool the same area. It is not only good commercial practice but environmentally friendly by reducing energy consumption and therefore reducing carbon emissions to atmosphere.

Enright Engineering Services Ltd can provide advice for particular applications.