In the majority of IPPC applications, CASs are multi-compressor installations. The energy efficiency of such multi-compressor installations can be significantly improved by CAS master controls, which exchange operational data with the compressors and partly or fully control the operational modes of the individual compressors.
The efficiency of such master controls strongly depends on the capabilities of the communication link, which can range from simple floating relay contacts to networks using automation protocols. An increase in communication capabilities offers more degrees of freedom to retrieve operational data from the compressor, to control the operational mode of the individual compressors and to optimise the overall energy consumption of a CAS.
The control strategy of the master control has to take into account the characteristics of the individual compressors, in particular their control mode. Some remarks on control modes of common compressor types are given to illustrate this. The most commonly used control modes of individual compressors are:
●switching between load, idle and stop, and
●frequency control.
The main features of sophisticated compressor and master controls can be summarised a s follows:
●advanced communication features (e.g. based on automation protocols)
●comprehensive access of the C AS master control to operational data of individual compressors
●comprehensive control of all compressor operation modes by the CAS master control
●self-learning optimisation of master control strategy, including recognition of CAS properties
●determination and activation of highly energy efficient combinations of loaded, idling and stopped compressors and transitions between these states to match total free air delivery (FAD) demand
●effective control of variable frequency compressors to compensate short term fluctuations in FAD demand avoiding inefficient long term operation at constant speed, in particular at low frequencies
●minimisation of switching frequencies and idle operation of fixed speed compressors
●sophisticated prediction methods and models for total FAD demand including recognition of cyclic demand patterns (daily or weekly shift and workspace patterns, etc.)
●additional functions like remote monitoring, plant data collection, maintenance planning, teleservice and/or supply of preprocessed operational data via web servers
●control of other CAS components in addition to compressors.
在歐盟，大多數壓縮空氣系統的應用都是裝有多台壓縮機設施。這種複機型系統採用壓縮空氣系統主控系統來運轉，能源效率有明顯的增加。這主控系統可以與各壓縮機之間交換運轉資料，並完全或部分控制各個壓縮機的運轉模式。
這種主控系統的效率強烈依賴通訊系統的容量。通訊系統可以是浮控電驛，到使用自動介面的通訊網路。越來越強的通訊能力提供從壓縮機資料擷取運轉資料更大的自由度，用來控制每一壓縮機的運轉模式，並優化壓縮空氣系統整體的能源使用。
主控系統的控制策略必須將每一個壓縮機的特性及他們的控制模式納入考慮。一些常見的壓縮機得特色如下，最常用的各型壓縮機的空置模式有：
●在加載、空轉與停機間切換
●頻控
先進的壓縮機和主控系統的特徵歸納如下:
●前端的通訊特點，自動介面語言
●全方位進入壓縮空氣系統主控系統以取得每一壓縮機的運轉資料
●以壓縮空氣系統主控系統全面控制全部壓縮機的運轉模式
●自我學習優化型的主控策略，包括壓縮空氣系統特性的熟悉
●決定與激化綜合加載空轉與停轉壓縮機運轉模式的高能源效率，以及這些狀態間的移轉來符合總排氣量的需求
●有效的控制變頻壓縮機以補償排氣量的短期波動需求，避免無效率的低頻定速長期運轉
●減少定速運轉壓縮機開關頻次和空轉現象
●總排氣量需求做精確的預測和操作模型，需求循環態樣(每日、每周、班別與工作區)的熟習等
●透過網站侍服器從事其他功能，像遠端監控、工廠作業資料收集、維護保養計畫、通信服務、供給品預處理等操作資訊等
●控制壓縮機以外的壓縮空氣系統組件
None.
無
According to the SAVE study, the retrofit of sophisticated control systems is applicable to, and cost effective for, 20 % of existing CASs. For typically large CASs in IPPC installations, the use of sophisticated master controls should be regarded as state-of-the-art.
The highest energy savings can be achieved if the implementation of sophisticated master controls is planned in the phase of system design phase together with the initial compressor selection or in combination with major component (compressors) replacements. In these cases, attention should be paid to the selection of master and compressor controls with advanced, comprehensive and compatible communication capabilities.
Due to the long lifetime of a CAS, this optimum scenario is not always within reach, but retrofitting an existing CAS with sophisticated master controls and – if there is no more progressive alternative – even connecting old compressors to it via floating relay contacts, can provide significant energy savings.
根據SAVE的研究，既有壓縮空氣系統可以加裝精密的空制系統，其成本效益可省20%。歐盟典型的大型壓縮空氣系統加裝使用精密的主控系統，被視為是先端技術。
如果在壓縮空氣系統設計階段，及壓縮機選用時，或在包括壓縮機等主要組件更新時，將精密主控制系統一併設計進去，則可以達到很高的節能效益。在這情況下要特別注意選用先進的、完整的、主控系統，和可以匹配能力的通訊系統。
由於壓縮空氣系統的生命週期很長，最佳狀態並不是天天都可達到，但在使用中壓縮空氣系統以精密主控系統改裝，如沒有更好的方法，即使與使用浮式電驛的老壓縮機連接，仍會有可觀的節能效果。(譯註: floating relay,浮球開關，水位空制開關， 此處指以壓力高低控制on/off開關)。
The cost effectiveness for integrating master control systems in a newly designed CAS depends on circumstances like demand profiles, cable lengths and compressor types. The resulting average energy savings is estimated to be 12 %. In the case of retrofitting, a master control system in an existing CAS, the integration of older compressors and the availability of plans gives another uncertainty, but a payback time of less than one year is typical.
新設計的壓縮空氣系統上採用整合型主控系統的成本效益要看使用情況如需求條件電纜長度壓縮機型式等而定。所達成的成本效益估計平均約12%。改裝使用中壓縮空氣系統整合舊壓縮機和主控系統，這計畫的可行性還是有不確定性，不過其回收年限通常少於一年。
Energy Efficiency (2009) 3.7.4
