Trane TRG-TRC014-EN manual System Comparison, What Is Variable Air Volume?, period one

period one

What Is Variable Air Volume?

notes
	System Comparison
		constant-volume,	constant-volume,	VAV
		single zone	terminal reheat
	◆ Constant fan		◆ Constant fan	◆ Fan energy
		energy	energy	savings
	◆ Refrigeration		◆ Nearly constant	◆ Refrigeration
		energy	refrigeration	energy
		savings	energy	savings
	◆ Delivers comfort		◆ Delivers comfort	◆ Delivers comfort
		to only one	to many spaces	to many spaces
		thermal zone	inefficiently	efficiently
			◆ Reheat energy
			increases at part		Figure 14
			load

Contrasting the three systems discussed in this example, the simple, constant- volume, variable-temperature system consumes constant fan energy while providing refrigeration energy savings at part load. However, it can only deliver comfort to spaces with similar loads.

The terminal reheat system can serve many spaces with dissimilar load requirements, but consumes constant fan energy and nearly constant refrigeration energy at part load. It also uses an increasing amount of reheat energy at part load.

On the other hand, the variable-air-volume system is capable of providing both fan and refrigeration energy savings at part load, making it the most energy efficient of these three systems. In addition, the VAV system can efficiently serve many spaces with dissimilar cooling and heating load requirements.

TRG-TRC014-EN 9