The optimum control system maximizes the centrifugal chiller performance, controls the entire heat source equipments, and achieves significantly higher energy efficiency.
The optimum control system consists of 1 through 7 in the following diagram. The control software for the heat source equipments is packaged, reducing the workload involved in designing the system and its installation.
Primary pump system
Primary and secondary pump system
Actual case
Sony Group Corporation Sendai Technology Center
Equipment with better energy-saving performance has been installed for the Great East Japan Earthquake (11-Mar-2011) Renovation project.
Before VSD Centrifugal Chiller(Previous Model NART-50I 3units)
High efficiency heat source control system in 2004
After VSD Centrifugal Chiller(Existing Model ETI-50 2units)
Optimum Heat Source Control System
VSD : Variable Speed Drive
Renewal contents
Replaced latest model VSD chillers
Changed chilled water system from primary pump system to primary and secondary pump system
Changed the control system of cooling tower from fix speed control to variable speed control
Applied optimum heat source control system
Heat Source Control
Control of the number of VSD chillers*
Variable flow rate control of primary and secondary chilled water pump*
Variable flow rate control of cooling water pump
Variable speed control of cooling tower fan
Control to operate in optimum load range of the chiller
1Reference: “Energy Saving Performance and Effective Operation Strategies of Cooling Plant System Using an Inverter Chiller for Building Air-Conditioning : Part1, Part2, 47th Academic Papers Award by The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan (SHASE), 2009
2Reference: “Development of performance evaluation method for optimal controlled heat source system : Part 2”, by Tai (Kyushu University) and other 8 members, , Air-Conditioning and Sanitary Engineers of Japan (SHASE), 2013
3CO2 emissions was calculated using CO2 emission factor 0.546kg-CO2/kWh (FY2011 actual record by Tohoku Electric Power Co., Inc.)
4Calculated based on high voltage electricity price JPY 11.65/kWh (summer period, June-2013) by Tohoku Electric Power Co., Inc.
5Power Consumption (Before) is calculated based on 2012 data divided by 2004 System COP 5.9 (FY2012 Actual Power Consumption x FY2012 Actual COP / 2004 Actual COP)
