High Efficiency Computer Room-Guolian Green Technology(Wuxi) Joint Stock Co., Ltd.

High Efficiency Computer Room

The refrigeration station in the HVAC system is made of several pieces of equipment. It is an organic whole, the comprehensive performance of which is reliant on combined and coordinated cooperation. It is, in essence, a system project. Now, in China, invitation for bids is generally carried out separately for different equipment for engineering management of refrigeration stations in China. Installation of trades such as heating and ventilation and strong and weak electricity is carried out separately. There is no systematic engineering concept. As such, the equipment operation and overall performance of refrigeration are too often disappointing. Furthermore, many chilling stations are based on simple variable-frequency control of water pump, and start/stop of equipment operation. In another word, experienced operation of operators is needed. It can hardly ensure that the machine room is actually operating efficiently. The measured efficiency is low.

The “Average Annual Chiller Plant Efficiency” is used to evaluate whether a chiller plant is energy conserving:

Energy Efficiency=

W（Chiller）+ W(Chilled Water Pump)+ W（Cooling Water Pump）+ W（Cooling Tower）

Q(Total Cooling Capacity)

According to standards proposed by ASHRAE, the overall energy consumption level indexes of A/C plant room are as follows:

As shown above: Machine rooms with“average annual chiller plant efficiency”below 0.85KW/RT (i.e., the overall COP>4.14KW/K-W) are regarded as high-efficiency chiller plants (generally, for new projects, the value should be lower than 0.7kW/RT, namely, the overall COP>5KW/KW).Through energy audit, if the comprehensive energy efficiency of the chiller plant is higher than 0.85KW/RT, it should be transformed.

The high-efficiency machine room service of Johnson Controls is a kind of service that involves energy-conserving transformation of energy-audited chiller plant and guarantee of the after-transformation efficiency of the chiller plant. To obtain a high energy efficiency chiller plant, in-depth optimal design of the systematicness, intelligence and integration of equipment in the central A/C plant room, including water chilling unit, chilled water pump, cooling water pump, cooling tower, pipe valves and control system, is needed, so as to ensure the entire chiller plant sustains its maximum range of overall efficiency throughout the process. It is a complete solution, and an effective tool developed by Johnson Controls based on its more-than-100-year innovation experience in HVAC and building automatic control, through constant integration and in-depth exploration. It aims to improve the overall performance of the chiller plant and lower the operation cost. Johnson Controls will provide effective confirmation of the actual level of the overall energy efficiency of the chiller plant.。

Seven Steps to Build A High-efficiency Machine Room

Measurement, Review and Management
Operation and Maintenance
Optimal Control
Automatic Operation
System Application
Equipment Selection
System Structural Design

Characteristics of A High-efficiency Machine Room

Real-time Measurement, Instrument Report and Failure Analysis
Preventative Maintenance
Procedural Security
Control Loop With Continuous
Self-adaptation
Most Suitable System Configuration
Efficient Equipment
Full
Variable-frequency

To obtain a high-energy-efficiency chiller plant, the energy efficiency of the equipment itself should be high. High-energy-efficiency main engine, water pump and cooling tower should be used (the main engine should be variable-frequency unit; the pump motor should be high-efficiency motor). Furthermore, system control is of great importance. The high-precision sensors should be used. Instrument that meets the requirement of installation environment is used. Control strategy should ensure the entire system maintains a high-efficiency range. In addition, to achieve high chiller plant efficiency, resistance of the water system should be reduced (including local resistance and on-way resistance). The pipelines with different use characteristics requirements should be separated. Generally, use of valves should be minimized to reduce local resistance (variable-frequency should be used to accommodate the change of cooling capacity). Local resistance at the elbows should be reduced; a general method to reduce on-way resistance is to reduce length of the pipeline, and choose the shortest path from the main engine to the water pump.。
With use of the intelligent control technology, unattended automatic operation is realized for the high-energy-efficiency chiller plant. Furthermore, it is easy to operate. Maintenance in later stages is also easy, thus greatly reducing operation expense and maintenance efforts. High-energy efficiency chiller plant system is not only simple supply of equipment. Its value is reflected by the optimal selection of equipment, optimal system design, integration of HVAC equipment with the chiller plant control system, equipment installation and engineering management and overall commissioning of the entire system.