Often we are asked to demonstrate the electricity savings potential of our Eqobrush system in chiller systems. In this article we give an insight in how the potential gains from an automatic tube cleaning system can be easily assessed.
Obviously we need to know the electricity consumption on the chiller to make such an assessment.
VFD controlled chillers vary the power consumption via variable compressor performance whilst staying in an efficient range even at a lower capacity. Both VFD and. Non VFD controlled chillers will switch to neutral when desired RT’s are delivered.
It is easy to assess the accumulated kWh’s consumed over a fixed time window (by collecting consumption data throughout this window) and from there calculate the kWh power per chiller tonnage delivered.
Possible energy savings to be achieved by brush cleaning can be predicted by taking data on kWh/RT:
- Just before a cleaning session AND
- Just after a cleaning session
Calculate power consumption savings using the formula below:
((kWh/RT)2 -/- (kWh/RT)1) x 0.5 x ∑RT x $/kWh x 80% = Amount saved in $
Where:
| (kWh/RT)1 | = | kWh per RT just after cleaning session |
| (kWh/RT)2 | = | kWh per RT just before cleaning session |
| ∑RT | = | Total tonnage output between sessions |
| $/kWh | = | Price per kWh |
| 0.5 | = | Calculation factor on assumption of a linear increase in the consumption due to fouling |
| 80% | = | Safety factor to bridge from theory to practice |
In locations with little variations in Wet Bulb Temperatures and Cooling loads the chiller may be running in similar (daily) conditions between sessions. In such case the formula could be simplified by replacing the RT with Days:
((kWh/Day)2 -/- (kWh/Day)1) x 0.5 x ∑Day x $/kWh x 80% = Amount saved in $
Contact us to assess the details for your specific situation.
