Energy-Saving Fan Systems for Efficient Space Conditioning

Circulation of air within conditioned space consumes substantial fan energy, both for air handling unit system or a fan coil unit system. This is required for these purposes,
a. Recirculation of air from space through coil.
b. Bringing in ventilation air and filtering it.
Segregating these two processes is desirable when high volumes of air flow are required to condition a space. In this case dedicated fresh air unit is used. Inlet connection to this unit is through fresh air intake louver. All air is taken from outside and is treated. Its capacity is worked out after adding ventilation air requirements of serving zones. Recirculation air component is always a major part of total volume flow. Energy consumed for this recirculation can be saved by using technologies which control wall or ceiling temperatures. Water tubes pass through suspended ceiling panels or are imbedded in the structure. Hot water and chilled water flows through this network. Area of these tubing’s is planned according to air conditioning load of the space. Temperature of these panels is maintained at a set point level. Flow of water is controlled for this purpose. Heat is transferred to the space through radiation and convection.
Performance of the system improves due to elimination of fans and motors. Maintenance of these systems is easy. Overall HVAC system energy consumption is reduced.
These panels can be integrated with interior schemes. There are no moving parts. Noise level issues are resolved with this technology. It gives aesthetic look to internal spaces.
There are no grilles and diffusers inside. Architects get free hand to use other elements in their plans.
Hot and cold pockets in space are controlled with the use of this system. Temperatures inside remain uniform throughout the space. In conventional systems, there are complaints of cold drafts reaching occupied zones. Hot zones close to supply air grilles create discomfort. With panel system surface temperature is kept at a uniform setting. This provides homogenous temperature throughout the space. Indoor environment improves with this application. Space required for central air handling unit is reduced. This space becomes available to architect for other purposes.
Rentable areas of the building increase with reduction of mechanical spaces. Buildings with this technology generate more annual revenues as compared to conventional buildings. Major equipments are all centralized in plant rooms away from building rentable spaces.
There are no issues of condensation with this technology. Drain lines and drain points are not required. This also improves indoor air quality. Moisture on cooling coils and drain pans is responsible for growth of microorganisms. These are mixed with air and are distributed throughout the space in a conventional system. With panel systems, there is no chance of air contamination from moisture. Clean air provides enhanced indoor air quality. Building value increases with better quality of inside air.
There air certain limitations in applying this technology for comfort. As no dehumidification is involved, this is not used where high latent load is involved. Separate dehumidifiers are used for high latent load applications. This system is suitable for areas with high sensible loads.
Simultaneous cooling and heating can be provided with four pipe type system. Perimeter areas of a building are connected to different set of pipes than central or core areas. Different temperature set points are obtained using this set up, according to requirements in the building.